What is the K-Pro ECU?
The K-Pro ECU is a specially modified 2002 to 2004 Honda ECU with an USB interface to a notebook PC running Windows XP. It is currently available for the standard shift Acura RSX base model and Type-S, the US Civic Si and the Euro Civic Type R. K-Pro ECU Manager software allows the setting of cam angle, ignition advance, fuel, and a variety of other aspects. The purpose of the K-Pro ECU is to fine-tune the Honda ECU for best possible engine performance under various operating conditions and with various engine configurations. Note that as of Summer 2004, 2005 model year ECUs are not supported.
Who should use it?
Anyone who wants to a) take full advantage of modifications, from simple bolt-ons to extensive engine work, by tuning the engine specifically for those modifications, b) monitor the engine via datalogging, and c) learn how numerous variables inside the engine relate to one another and how they are influenced by making changes to fuel delivery, ignition timing, cam angle settings and other variables.The K-Pro is far more than just another performance modification. It is a tool to monitor and change the operation of the ECU which, in turn, monitors and orchestrates the operation of standard “conventional” modifications such as less restrictive air intakes, headers, intake manifolds, cams, exhaust systems, and even super and turbochargers.
Unlike those “passive” modifications, the K-Pro is an “active” modification. Its operation must be learned and understood. If used properly, the K-Pro is key to unlocking the true potential of a Honda engine. If not, it may become an incomprehensible source of frustration. It may even harm the engine if inappropriate changes are made and uploaded into the ECU. A prospective K-Pro user should therefore expect a learning curve. Those unfamiliar or unwilling to learn K-Pro operation and the principles behind it can still use the K-Pro to good advantage, but they should expect paying a tuner to tune the car properly. Tuning may be necessary not only to get the best possible performance, but also because the base K-Pro calibration may cause the engine to knock. That’s because unlike the Hondata reflashes which are safe one-size-fits-all maps, the K-Pro calibrations are much more aggressive because, after all, K-Pro users can always modify the calibrations to make them fit their engines.
Those willing to spend the time learning the K-Pro will find it an incredibly powerful tool for unlocking the true potential of their engines. Those do not feel up to it and do not want to foot the expense of having a professional tune their K-Pro can always resort to Hondata’s static ECU reflashes.
Your car’s ECU will have to be sent to Hondata’s facility in Torrance, California because the ECU needs to be modified by Hondata. The modification requires actual soldering and other work on the Honda ECU. The upgrade needs to be ordered via a Hondata dealer as Hondata does not sell to the public directly. If you order from a local dealer, they may take the ECU out of your car and send it to Hondata, then reinstall it for you. You cannot use the car while the ECU is at Hondata unless the dealer lets you borrow a K-Pro ECU.
Even though the Acura RSX uses an immobilizer system that is keyed to the ECU, you do not need to send the immobilizer (a ring-shaped plastic contraption that wraps around the ignition key lock) and a car key (the car key has a transponder in it that communicates with the immobilizer) to Hondata as you do when you have your ECU reflashed by Hondata.
You can also order the K-Pro upgrade from a dealer that is not local. If you do it that way, the dealer will send you a box with a Fedex shipping label, the required paperwork for you to sign, and ECU removal instructions.
What you receive
I ordered my ECU upgrade via ClubRSX.com. They sent me a box via UPS. I sent my ECU via Fedex to Hondata on Monday, March 29, 2004 and received the modified ECU back via Fedex from Hondata on Thursday morning, April 1. The package included:
The modified ECU with a big Hondata sticker on it
K-Pro Manager software and USB drivers on a CD
My immobilizer and car key (I erroneously had sent those as well)
A six-foot USB cable
2 silver Hondata stickers
A ECU board jumper for nitrous applications
The modifications included installation of a 1.75 x 4.5 inch Hondata-branded daughterboard. This required soldering a couple of connectors onto the motherboard. I analyzed the daughterboard because I was curious as to what it does. The two main chips on it are:
A Microchip PIC16F877A, which is a $5 20MHz 8-bit CMOS FLASH-based microcontroller (RISC CPU) that uses Microchip’s PIC architecture and has 35 single-word instructions. It is designed for automotive applications and can handle temperatures between -40 and 85 degrees Celsius. It has 14,336 bytes of program memory and is primarily used for analog to digital conversions.
A FTDI FT245BM chip, which is a USB FIFO device. FTDI specializes in converting legacy peripherals to USB. ECUs normally communicate to external OBD readers and other diagnostic tools via serial connection, so the FTDI chip probably enabled Hondata’s USB interface for much faster communication.
In addition, Hondata made a small cutout in the rear wall of the ECU housing to accommodate a standard USB connector. As is usually the case with USB peripherals, the USB driver must be installed before the ECU is plugged in for the first time. After that, the ECU can be connected to the computer even if it is not in the car. The PC will then recognize it and install the proper driver. When it first came back, I simply connected the K-Pro ECU to my notebook and installed the USB driver. Then I put it back into its mounting bracket in the passenger footwell of the car and reconnected the various cables. Initial calibration and calibration libraries
The Hondata K-Pro comes with a number of calibrations for various engine configurations. The term “calibration” refers to a complete set of cam angle, ignition, and fuel tables, as well as additional settings that can be made with the K-Pro. Those calibrations are starting points for tuning. Some, especially those for near stock engines, work quite well as is. Only road and dyno testing can tell how well a calibration performs in a given car. Calibrations are actually standard ASCII text files and can be viewed in any word processor or text editor. It is not recommended to change calibrations via text editor. However, you can use, for example, Microsoft Word to view calibrations or compare different calibrations with Word’s compare feature. This is a lot easier than eyeballing it.
When I received my modified ECU back there was no information about what kind of calibration Hondata had loaded onto the ECU, if any. And since the version of the K-Pro ECU Manager software available at the time when my ECU came back could only upload calibrations to the ECU but not download one that was already in the ECU, I had no way of knowing what was in the ECU. This was not a very good situation as a customer’s car might have modifications that may not get along with whatever maps are loaded by Hondata. An email sent to Hondata tech support inquiring as to what calibration was loaded onto my ECU when it was modified yielded a “we do not know what calibration was loaded.” Given that my system was serial number 67, it was hard to believe that Hondata did not know. This situation was addressed in the K-Pro ECU Manager version 1.0.9 which allowed downloading of calibrations from the ECU into the notebook computer.
Further, while the Hondata K-Pro system ships with a set of pre-configured calibrations, it is important to realize that none of them is the actual Honda factory calibration, the one the car had when it was first purchased. Hondata announced on the ClubRSX.com bulletin board that a factory calibration would be included, and this happened with revision 1.0.8 of the ECU Manager software. Hondata stated that this calibration, called “k20a2-stock,” was close to, but not identical, to the factory calibration. I wondered why Hondata does not include an actual factory calibration. The answer is that the K-Pro tables are different from the factory tables and it is not possible to create an exact factory calibration with the K-Pro. As is, the “stock” calibration does not return the same CVN (Calibration Verification Number) as the stock ECU. The Calibration Verification Number is a checksum value that changes if modifications are made to the ECU. At this point it is not used for anything, but in the future authorities may use the CVN to determine whether an ECU has been modified or tampered with. So keep in mind: If you upgrade your ECU to K-Pro status, you can’t load a true factory calibration nor can you return the ECU to factory status.
For the same reason, Hondata also cannot include the standard “Hondata 4″ calibration that the company used to reflash customers’ ECUs before the programmable K-Pro system became available. While existing K-Pro customers receive a more than fair discount when they “upgrade” to a K-Pro system (reflash = US$599, K-Pro = US$999, K-Pro for reflash customers = US$500), they therefore lose the Hondata 4 reflash they already paid for. A lot of customers stated it would be educational to be able to compare “Hondata 4″ with the calibrations included in the K-Pro libraries. For example, a customer may wish to start from the factory settings and tune from there. Or the supplied calibrations result in knocking and the customers wishes to temporarily revert to the factory or the older Hondata 4 settings. Having those two calibrations would enable customers to analyze those maps, determine the differences and changes, and then modify the K-pro calibration(s) to work on a particular engine. The lack of having either the exact factory or the Hondata 4 calibrations available is one of the few drawbacks of the K-Pro, but it can’t be helped as the K-Pro works differently from the factory ECU.
Another are that can confuse those new to the K-Pro is Hondata’s calibration naming convention. The K-Pro initially came with two “stock” calibrations, one for all stock engines and one for all stock engines with a Cold Air Intake. However, those two calibrations are not “stock,” but dyno-tuned sets of maps that, in essence, replace Hondata 4. The version 1.0.8 “factory” calibration that approximates the stock Honda settings was confusingly named “k20a2-stock,” replacing the tuned “k20a2-stock” of earlier versions. Starting with software version 1.0.9, a “k20a2-stock-tuned” calibration was added.
It’s important to realize that most, but not all, calibrations are the result of extensive development and tuning by Hondata. This applies especially to the stock/tuned calibrations. Other calibrations, especially those for highly modified engines are to be seen as rough starting points for tuners. That makes sense as a highly modified engine requires a careful professional tune for best engine health and performance more so than a stock or near-stock engine.
Uploading calibrations and maps
Since most people will upload and perhaps modify calibrations and maps before they have a full understanding of the K-Pro software, I’ll mentions some do’s and don’t’s. First, there is a difference between the uploading of a new calibration and the uploading of a few changes to an already loaded calibration. The initial upload of a calibration takes about 30 seconds and the engine must be off for that. If you make changes to a calibration while the notebook is connected to the ECU, uploading those changes only takes a couple of seconds and can be done while the car is running. Changes to fuel tables take longer to upload than changes to ignition tables. That’s because fuel tables are 16-bit (as they must accommodate large values) while the ignition tables are only 8-bit. In general, it’s best to upload changes with the engine not running. You may have heard of aftermarket ECUs that allow real-time changing of variables. “Real time” means you can put a car on a dyno, watch the torque numbers the motor generates at certain rpms, and then change ignition advance on the fly until you get the advance that gives you the most power. You can’t do that with the K-Pro because the K-Pro uploads changes in batches.
The K-Pro ECU Manager software
The Hondata K-Pro ECU Manager software, also called KManager, runs under Microsoft Windows. Hondata officially supports only Windows XP although the software also works with earlier versions of Windows. There is no Macintosh or other version even though the software does work under Microsoft’s Virtual PC on a Macintosh. The ECU Manager borrows heavily from Hondata’s earlier s100 and s200 Series software. Those who are familiar with those applications will be right at home with the ECU Manager. However, the ECU Manager is also different. For example, it combines datalogging and ROM editing into one single application. On the other hand, the ECU Manager is missing some of the Hondata s100/200 Series’ features. Hondata has been adding some of those features in new revisions.
The notebook computer does not need to be connected to the ECU to run the K-Pro ECU Manager software. You can analyze datalogs and make changes to calibrations without being connected. However, the notebook needs to be connected to the ECU in order to a) communicate with the ECU, b) upload or download calibrations, or c) log data.
The main views and windows of the K-Pro software
The K-Pro software is built around two main functions: a) viewing and modifying the tables that contain the cam angle, fueling and ignition advance values the ECU uses, and b) datalogging so that you can capture, view and analyze what the engine does when it is running under various conditions. The following sections describe the main functions of the K-Pro software
The K-Pro ECU Manager software has various windows to show information. The central one is Tables. Tables (Windows>Tables) consists of two side-by-side displays. On the left is a data table where the rows are engine rpm levels and the columns are manifold vacuum and pressure levels. On the right is either a two or three dimensional graphical depiction of the data table. Through the Tables window you can view and modify a total of no less than 26 tables. They are:
2 cam angle tables (low-speed cam and high-speed cam)
12 fuel tables (6 each for cam angles between 0 and 50 degrees for low-speed and high-speed cam)
12 ignition advance tables (6 each for cam angles between 0 and 50 degrees for low-speed and high-speed cam)
In all tables, rows represent different rpm and columns represent different manifold vacuum. Each cell therefore represents the cam angle, the fuel value, or the ignition advance value at a specific engine rpm/manifold vacuum intersection. Each table has 20 rpm rows and 10 vacuum columns, plus an additional six “pressure” or “boost” columns used by turbo or supercharged engines. (The last three columns require the addition of a 3bar MAP censor.)
What is the significance of the different vacuum/pressure columns? This is very important for understanding the tables and how they relate to tuning:
Columns one and two represent deceleration
Columns three and four represent idling
Columns three to seven are the cruising range
Columns eight to ten are the full throttle “power” columns
Columns 11 to 16 are boost columns
Rows always have the same unit, rpm, and everyone is familiar with that. Columns however, representing vacuum and pressure, can be shown in several different units:
psi (pounds per square inch),
kPa (kilopascal), or
The relationship between those units is as follows:
1 psi = 0.069 bar = 6.89 kPA = 0.068 Atm
And conversions are as follows:
1 psi = 0.06895 bar
1 bar = 14.50326 psi
1 psi = 6.8948 KPa
The K-Pro has a Settings control panel where the units can be set either to mbar, kPa or Inch in columns 1-9 (the “vacuum columns”) and to no less than five different units in the “pressure columns” 10-13: mbar, kPa, bar, kg/sqcm, or psi. I generally use kPa because the datalog and sensors windows, unlike the Tables window, by default display vacuum and pressure in kPa.)
So what does it all mean? In naturally aspirated engines, full throttle means the throttle plate is completely open and manifold pressure is the same as outside atmospheric pressure. 1 atm is 101.3 kPA, and that is roughly the value in column 10. Boost columns 11-13 generally display boost in psi because that is usually what turbo or supercharged boost is measured in. Problem is that, again, the sensors and datalog windows, by default, display the MAP value not in psi, but in total kPA. What does that mean in kPA?
Column 11 = 4 psi = 101.3 + 27.56 = 128.9 kPa
Column 12 = 8 psi = 101.3 + 55.12 = 156.4 kPa
Column 13 = 12 psi = 101.3 + 82.68 = 184.0 kPa
While using kPa for vacuum and psi for boost makes some sense, early K-Pro users with boosted engines had to get used to using kPa or mbar because that is how the K-Pro datalogs displayed the data. Even under boost, there weren’t any data points that showed, for example, 4 psi of boost. Instead the sensor display showed 19 psi, which equals atmosphere plus 4 pounds of boost. This was changed in rev. 1.0.11. A new unit now displays boost the commonly accepted way.
When viewing a datalog and having a calibration loaded, the table will show the current sensor value by highlighting a 2×2 cell matrix. Why a 2×2 matrix? Because the ECU calculates the actual ignition and fuel values based on the four closest cells (which are really points rather than cells) and even interpolates across cam angle tables. Therefore, it actually calculates the value based on an interpolation of four points each in two different tables. The 2×2 highlighted cell matrix is therefore not an optimal graphical representation.
The Sensors window can be opened via Windows>Sensors. It displays all sensors tracked by the ECU Manager. If a datalog is open or the system is actively logging data, the Sensors window will also display the actual values of all sensors. As of version 1.1.8, a total of 42 sensors are displayed.
Display (Windows>Display) is a window that displays up to ten of the major sensors in large size digital format. This is useful if you wish to view sensor values while driving.
Graph is used to graphically depict sensor values over time. Graph “templates” can show up to four different graphs, with each graph tracking up to four different sensors. K Manager comes with a default graph template. You can add as many new templates as you want. Creating a library of different graph templates is key to analyzing and understanding datalogs.
Parameters (Windows>Parameters) contains a number of control panels with various settings. The Parameters control panels are: Fuel Trim, Rev Limits, VTEC, Knock Sensor, Compensation, Nitrous, Closed Loop, Protection, Lean Protection, Idle, Sequential Shift Cut, Misc., and Notes. Parameters controls some of the major settings. It is important to familiarize oneself with all of the Parameters panels.
Fuel Trim lets you set the injector size. The stock Type-S engine uses 310cc injectors, and those are adequate for most naturally aspirated engines. If you use, for example, 440cc injectors, you set injector size to that value. You will not see a change in the fuel tables when you change injector size. The software computes the new injector duration automatically in a linear relationship. You can also change overall and cranking fuel trim, or trim for individual cylinders. Cylinder #3 usually runs a bit hotter, and so adding an extra 3% fuel to #3 may help it run cooler.
Knock Sensor lets you a) disable or enable the engine’s knock sensor, and b) set it so that the Check Engine light flashes whenever knock is detected. Disabling the knock sensor theoretically keeps the engine from retarding ignition when knock is detected. However, upon finding Honda’s own knock sensor system lacking, Hondata decided to disable knock sensor-triggered ignition retarding and instead entrust tuners with tuning the maps so that knocking does not occur. Leaving the knock sensor enabled lets you see knock sensor output in a datalog, and allows the ECU to determine when knock occurs. During a dyno run, Hondata’s Doug MacMillan left the knock sensor enabled; since it does not retard ignition is not necessary to disable it.
Having the Check Engine light flash when knock is detected is definitely a good idea. It is somewhat hard to see in daylight, especially since most knock just produces a brief flicker. Still, I’d leave this turned on as you generally can’t hear high speed knock.
With regard to the disabled knock sensor-triggered ignition retarding, Hondata’s Doug MacMillan stated that when they analyzed the K20′s stock ECU, they found not only the standard ignition maps, but also special knock maps that told the ECU by how many degrees to retard ignition. MacMillan said it was as if Honda had tuned the engine for racing gas, and then added a “negative ignition map” to retard ignition so the car would run on commercially available gas. Hondata did many tests to see if the knock sensor signals had an impact on ignition retarding. They found none. The ECU would simply look up the values in the “negative ignition map” and subtract those from the main map. Hondata admits that they did find unexpectedly large variances in power output among RSX engines, and that those variations largely disappeared when the knock sensor was disabled. Hondata concluded that there “still may be some sensitivity there (in the stock ECU, not the K-Pro,” but decided to delete the “negative ignition maps” and use the space for the boost columns instead. In essence, they concluded that the stock ECU primarily looked at the “negative ignition maps” and didn’t really use knock sensor input in a meaningful way, so they decided to take the risk and not use the sensor at all. This decision enabled them to make significant power gains with their reflashes and the K-Pro, but it means there is no knock sensors triggered ignition retarding to act as a “safety net.”
Closed Loop contains settings related to closed and open loop operation. Closed loop means that the ECU uses sensor input to keep air-fuel ratios at predetermined levels. Open loop means the ECU will disregard sensor input and go by the fuel maps. The panel suggests disabling closed loop when tuning. This really only applies to part throttle tuning. At full throttle, the engine will be in open loop anyway. Disabling the P1167 (oxygen sensor heater) and P0134 (oxygen sensor response) error codes is only needed if you use a race header without catalytic converter and oxygen sensor. (The ECU will be able to go into open and closed loop even if there is no secondary oxygen sensor). Set maximum MAP for closed loop to 80 kPa for most NA applications. This means that the engine will always go into open loop when manifold vacuum goes above 80. Disabling fuel over-run cutoff keeps injectors from running an extra half second after getting off the gas. This makes shifting smoother in vehicles with large injectors.
Rev Limits sets the overall rev limit (fuel cutoff) and also lets you set a “launch limiter.” The fuel cutoff in the stock Type-S is, I think, 8200 rpm. It can safely be set to 8600 rpm, but I wouldn’t advise going higher with the stock valve springs. The launch limiter (also called “launch control”) sets fuel cutoff at an arbitrary rpm as long as the car goes less than 3 mph. If you set it to 4000 rpm, you can then floor the gas pedal at a red light or race and the engine will bounce off that limit. It is not a perfect solution and pretty slow. Depending at what rpm the launch limit is set, the engine will bounce at about 0.3 second intervals and with amplitude of about 200 to 300 rpm.
Compensation handles air temperature compensation. Air density varies by temperature. The Honda ECU compensates to some extent, but in Hondata’s opinion not enough. That’s why the ECU lets you modify the air temperature compensation tables yourself. If your datalogs show that your air-fuel ratio varies too much with different temperatures, you can change the table settings. Please note that there was a bug in early versions that supported temperature compensation. This was fixed in rev. 1.0.15, and from rev. 1.0.18 on, the software specifically checks for temperature compensation table errors.
As of rev 1-1-8 (Feb 2005) Hondata replaced the extremely conservative stock Honda settings in the calibrations with more realistic compensation percentages computed with my compensation calculator. From rev 1-1-8 on, calibrations assume they’ve been tuned at 86 degrees Fahrenheit and compensate for higher and lower intake temperatures.
VTEC allows you to manage VTEC engagement. You can set either a VTEC point or a VTEC window. To set a VTEC point (engine always switches from low-speed cam to high-speed cam and back at the same rpm) set lower and upper boundary to the same value. To set a VTEC window (engine switches at lower boundary rpm at a certain manifold vacuum and at the upper boundary at another manifold vacuum), determine what rpm you want the engine to go into VTEC at full throttle and at what rpm at light throttle. In-between these two rpm and manifold vacuum points, the engine will cross over along a straight line. VTEC should not be set lower than 2000 rpm for a number of reasons. One is that the VTEC mechanism uses oil pressure and may not leave enough for the rest of the engine. It should also not be set higher than about 6500, or else the high speed rocker arm can float and cause damage. The VTEC oil pressure switch must be on is US engine, but off in JDM engines. The Secondary Intake Runners only applies to the US base model.
Idle is self-explanatory. It is normally set to 750, but my car tended to stall with the air conditioning set to high, so I raised it to 850. Those using wild cams or very large injectors may also set idle somewhat higher
Misc includes a number of ECU options. The Immobilizer can be enabled or disabled. If it is disabled, a yellow warning light will be flashing on the left side of the instrument pod. Unless you swap engines with a vehicle that does not have one, Multiplexor should always be enabled. It communicates with other parts of the car. Unchecking the OBDII box disables a number of OBDII functions. If you use a race header without secondary oxygen sensor, unchecking OBDII will keep the check engine error from happening. However, it will also prevent OBDII tests. Copy Protection allows locking a calibration. If the “Copy protect ECU Calibration” is checked, an uploaded calibration cannot be downloaded from the ECU.
Nitrous allows a great degree of control over nitrous and alcohol applications (dry nitrous systems). Input and output control determine which ECU pins are used to arm the nitrous system (input) and to control the nitrous solenoid (output; the EVAP vent signal). The Conditions window lets you set minimum and maximum engine speed and load, throttle and vehicle speed for nitrous to activate. Fuel & Ignition determine how much extra fuel will be added and how much the ignition will be retarded. Why making fuel and ignition changes here and not in the table maps? Because we only want them applied while nitrous is on. When tuning with nitrous or alcohol, start by adding a lot of fuel for nitrous, then remove until it’s right. As a rule of thumb, if you have a 200 hp engine and add a 100 shot to make it a 300 hp engine, you add 50% fuel, i.e. look up the fuel value in column 10 and take 50% of that. For smaller shots, adjust accordingly. Ignition should be retarded by 2-3 degrees for 30-50 shots and 4-5 degrees for 75-100 shots. With alcohol, you actually subtract fuel and advance timing because alcohol is already a fuel and very knock-resistant.
For those interested in using the K-Pro to control nitrous in their K-Series engines, Hondata has a witing diagram on its website. However, Hondata’s diagram could be clearer and the ECU pins shown are not for the K-Series, so I will try to clarify things:
In general, a nitrous activation system works as follows: you turn on a switch that “arms” the nitrous system. However, you don’t want to spray nitrous via hand-operatd switch, so there is usually some sort of an additional trigger, like a microswitch under the throttle. Once that’s triggered, a relay snaps on and routes full 12V power to the solenoids that then open nitrous.
With the Hondata K-Pro, the ECU replaces the micro trigger. You still have an arming switch on the dashboard. Turn that on and power goes to pin E16 in the ECU. The ECU is now also “armed” and will check if the conditions you set in the nitrous control panel are met. If yes, it sets output pin E21 high. E21 connects to the relay, which then snaps on and routes full 12V power to the solenoid that then opens nitrous.
So look at the diagram on Hondata’s website, but use input pin E16 instead of the B8/B5 shown, and output pin E21 instead of A15/A20 shown. Also, the dashboard switch needs a 12 Volt source and not just ground as shown in the Hondata diagram.
Note that Hondata recommends using the two “nitrous” pins that come with the K-Pro instead of tapping wires. You can crimp wires to those two pins and then push them into the E16 and E21 positions on the wire connectors.
Notes lets you record notes about the current calibration.
Protection was added in rev 1.0.18. One part of it limits boost when the engine is too cold or too hot. The other provides overheating protection. You can set the overheating threshold to a reasonable value (usually around 220). If the temperature rises above that, the ECU will automatically turn on the MIL light and generate a P0217 overheating code. Optionally, you can also set it so that the car will go into a 4000 rpm limp mode or cyclically apply a rev limiter or both. You can also specify that fuel be added to help cool the engine.
Seq Shift Cut
(introduced rev 1.1.5, Jan 2005) is not likely going to be used by any casual drivers. Hondata added it for sequential transmissions-pure racing stuff. The dialog boxes can be used to set things so that the engine cuts for a certain period of time while the sequential transmission shifts into the next gear.
Lean Protection (introduced rev 1.1.8 Feb 2005) The new “Lean Protection” parameter dialog boxes allow you to set two protection criteria. From what I can tell, you can use those for any engine running conditions, though the two examples shown suggest you use “Lean Protection 1″ for NA applications and “Lean Protection 2″ for boost. Not sure why they chose “inches” as the engine load indicator in the help file, but it translates into 90 kPA, which is usually what we set in NA cars as the closed loop/open loop threshold. What it boils down to is this:
If you are concerned about running lean with your NA engine, then try out “Lean Protection #1.” If you use it and do a WOT run, you’ll quickly find out if you run lean (of course, you can see that in a datalog as well). For those who want to have this extra assurance but don’t want to be cut-off all the time, Hondata lets you set the “Trigger Time,” i.e. how long the engine must be in the lean condition before the engine cuts out.
If you are concerned about running lean with your turbo or supercharged engine, you can use either one or both lean protection boxes. If you use two, then the engine will cut if your AF exceeds the max AF and engine load you set in the first box until you reach the engine load set in box 2 when the AF you set in box 2 kicks in.
If you feel confident that you’re okay as long as you’re not in boost, you may only want to use one of the protection boxes and protect while under boost. Or you could even use both boxes for box and use box one for low boost with a longer trigger and one for high boost with a shorter trigger.
Most may not need to use lean protection at all, or set it very conservatively. Those who want to use it will need to play with the settings so that they make sense for you car. After all, it’s no fun if you have a little redlight encounter with some punk and just when you pull away your engine cuts. “Umm, yeah, my car runs real good but then my lambda went over 14.2 there in third else I would have won,” won’t “cut it.”
What should the Lean Protection settings be for a supercharged car? That’ll take a bit of experimenting. Here’s what to do to determine the values:
Use the new lambda overlay display feature of rev 1-1-8 to see what lambda you actually have in your datalog test runs. In order to do that, simply do a good, long datalog that includes the usual 2500-8500 WOT runs. Save the datalog, then load your calibration and that datalog into K-Manager. Set Table to “Fuel” and click on the new lamda symbol (the second from the left of the new symbols in 1-1-8). You can now see what AF (presumably the highest in each cell) you recorded in the datalog run. I analyzed one of my runs, and was always in the low to mid 12s under full boost. However, had I found several instances of being over 14 in boost column 11, I could now use the new “Lean Protection” with the following settings: Max lambda 14 when Engine Load is over 3 psi. Trigger 100 ms. So next time I am boosting and my AF goes over 14, the engine cuts out. Quite obviously, if that were the case, I’d tune my calibration instead, but it’s still good to have a fail-safe.
Without a doubt, the K-Pro system’s datalogging ability is one of its main attractions. Unlike standard OBD-II scanners, the K-Pro’s hardware modifications allow much quicker and much more extensive logging of all the values tracked by the ECU via sensors or computations. While OBD-II scanners generally bog down when you try to get them to track more than a few items, the K-Pro has no such limitations. The system keeps track of no less than 42 sensors, and it automatically tracks all of them during a datalogging session. This means that you can view just about anything that’s going on in the engine.
Using Graphs to analyze datalogs
Combined with another incredibly useful feature of the K-Pro, the above mentioned ability to create an unlimited number of custom graph templates, datalogging provides a detailed look into the functioning of the engine. Each graph template can keep track of up to four graph windows each showing a maximum of four data items. You can even create new graph templates and apply them to already recorded datalogs. So if you want to see at what rpm VTEC kicks in and how it relates to ignition timing, you can create a custom graph for that. Or you may want to see how often the air conditioning switch or the electrical steering assist comes on and what kind of load it places on the electrical system. Or you want to track your air-fuel ratio and see how it relates to rpm, duty cycle, and injector operation. Or if your engine is supercharged, you may want to see when you are boosting and what boost levels you reach. All are just a simple custom template away.
Setting minimum and maximum values for sensors
In addition, you can set the minimum and maximum values for each sensor, and you can set minimum and maximum warning values. If you set a minimum and a maximum warning value, the numbers will display red outside the warning window, and green inside. This is useful in the Display where color coded values quickly show which numbers are within the normal range and which are not.
Datalogging: frames and frame rate
The K-Pro logs data in “frames.” Each frame is a snapshot with a complete set of data values. I initially thought the frame rate was fixed at so and so many frames per second, but then I found that it varied. I had datalogs with as many as 20 frames per second and others with as few as two or three frames per second. When you want to analyze a problem, the more frames the better. Often, crucial things happen within a second or two. Obviously it’s better to have 20 data frames per second than just three or five to analyze, say, a knocking or lean problem. Turns out that the frame rate depends on your computer and how busy it is. When I recorded high frame rates I did not have live graph windows or data displays open. For best data analysis close all display windows and have no other programs running in the background.
I did some testing with a 1.3GHz Toshiba Portege 3500 notebook computer, with just the K-Pro Manager software running. I started with just datalogging, and then incrementally opened more K-Pro windows. Here are the results:
Datalogging without ANY other windows open: 19 frames/second
Add Sensor window: 14 frames/second
Add Graphs window: 9 frames per second
Add Tables window: 7 frames per second
Display 4 graphs instead of just one in Graphs window: 5 frames per second
Interestingly, a much faster notebook with a 2.4 GHz Pentium 4 processor only recorded ten frames per seconds. This is most likely because the power management reduced the notebook’s CPU speed when it was not plugged in. The standard Windows power management control panel does not let you set CPU speed. Some notebooks have special third party power management systems (my Toshiba does) so that you can set CPU speed even under battery power.
I tried yet another notebook, a 1.5GHz Toshiba Portege M205. Once again I created a special power setting and named it “datalogging.” Everything was set for full CPU speed and full power. Yet, when I datalogged the frame rate was a disappointing 10 frames per second.
Version 1.0.14 of the ECU Manager software brought drastic improvements in the data capture speed. My Toshiba Portege 3500 now captured 57 frames per second with all other windows closed, and a still very respectable 19 frames per second with all windows open. I tested three other notebooks, including a relatively slow Tablet PC with a Transmeta processor, and all captured data at an identical 50 frames per second (with all other windows closed).
Bottom-line: If you want to gather the best possible data for later analysis, only run datalogging. If you want to see what’s going on while you drive, open as many windows as you want, but realize that the frame rate will be three or four times lower. For the highest possible frame rate, try to get your computer to run as fast as possible by creating a special power setting that will run the CPU at full speed.
K Series Tuning Process – Issues
By and large, the stock answer/recommendation to questions regarding K-Series tuning is “have it dyno-tuned.” Problem is that properly dyno-tuning a K-Series engine can be rather involved and expensive, so it pays to learn as much as possible about the tuning process. Some (but not all) tuning can be done by anyone with a good understanding of the K-Pro and some of the basic fueling and ignition timing principles.
The biggest difference between a K-Series motor and prior Honda motors is the addition of VTC, ECU-controlled variable timing control that constantly changes the cam angle from 0 to 50 degrees (or rather -25 to +25 degrees in earlier Honda motor speak). Getting a handle on this is key to squeezing the most from a K-Series motor. If you look at the cam angle maps in the K-Pro software you see that each cell in the table representing an rpm/pressure value has an angle setting.
In factory maps, the cam angle settings represent what Honda felt was best for the car as a compromise between emissions, fuel economy, and performance. In tuned maps, the cam angle settings are what Hondata, or your tuner, felt was best for optimal power and performance.
Tuning calibrations with the K-Pro can be done the short way or the long way. The short way consists of using one of the calibrations that comes with the K-Pro and “tweak” the settings via road and dyno testing. This can be done within just a few hours, with perhaps two of them on the dyno. The long way consists of creating a brand-new calibration from scratch. This can take a day or two. The following sections explain the two approaches.
Tuning from scratch
Concept and goal: Tuning from scratch means you create a brand-new calibration for your particular engine and its modifications. The idea here is to explore the variable cam timing of the K-Series to the max by first creating and tuning fuel and ignition maps for all cam angles between 0 and 50 degrees in increments of ten degrees, and then creating composite cam angle maps for both the low-speed and the high-speed cam. For each rpm range, those composite maps will put the cam at the angle that has shown to produce the most power on the dyno.
How it’s done: You need to create a total of twelve test maps, six each for the low-speed cam and six each for the high-speed cam. You then dynotune each for optimal fuel and ignition advance, create a composite cam angle map, then dynotune that composite map.
Dynotuning fixed angle cam maps
You need to create a total of twelve test maps, six each for the low-speed cam and six each for the high-speed cam. In each of those sets of six, the first has ALL angles set to zero, the second ALL angles to 10, and so on to the final map that has all angles set to 50. You then go on the dyno and do runs for all twelve maps. In order to do separate runs for the low-speed cam and the high-speed cam, you need to set the VTEC point to 6500-7000 first (for the low speed runs) and then to perhaps 3000 for the high speed runs. That way, the engine will stay on one cam for the entire rpm range that matters. For each procedure, set both the high speed and the low speed cams at the same fixed angle.
Start with the first fixed cam angle map and optimize it first for proper air-fuel ratio and then for ideal ignition advance. That requires considerable time and expertise, especially since the K-Pro doesn’t have that handy target lambda feature of the s200 series (yet?). However, it is not too difficult to arrive at a proper air-fuel ratio by adding and removing fuel across rpm ranges. For ignition timing, you can create a map from scratch if you are a true expert, or use the ignition maps from a similar calibration if you’re still learning. Determine best power by advancing ignition by two degrees at a time until engine power no longer increases or the engine starts knocking. It is generally advised, in the interest of engine longevity, to stay about two degrees shy of maximum power.
After quite a few dyno runs you end up with an engine that is optimally tuned for each angle at each speed AT A STEADY ANGLE, and you have twelve dyno maps.
You may wonder why you should spend a lot of time tuning the 0 degree cam angle map since it doesn’t make much power and is rarely used in regular driving. In fact, the 0 degree cam is important because that is where the engine is at when it is first started. The cam stays locked at zero degrees for ten seconds, and it’s important that it is set properly. In addition, in limp mode the engine reverts to, and stays at, zero degrees, so there again we need a well-tuned zero degree cam angle map.
Creating a composite map
Now you superimpose those maps and you’ll find that certain angles produce the most power at certain points in the rpm curve. By and large, you’ll find that in the mid range, the larger the angle, the higher the output. However, down low and up high, things overlap and less advance may produce more power. Still, it’s easy to look at the curves and see at which angle the engine makes most power at any given rpm point. You then create two tables, one for low speed and one for high speed with the optimal angle at each rev point. So now you have two optimized angle maps. But will they work in real life?
Back on the dyno for fine tuning. Take ignition back a couple of degrees for the entire table and see what happens. Advance it by a couple of degrees and see what happens. This is where a combination of knowledge and gut feeling come in handy.
Setting the VTEC point or window
Next you need to decide where to set the VTEC. That should be at the intersection of the low speed and the high speed composite curves. For NA engines we’ll want a VTEC “window,” so that we go into hi-speed as soon as it is feasible when we floor the accelerator, but somewhat later when we casually increase revs. Most of our daily driving is with the economical low-speed curves, so no need to switch to the high-speed curves when it is not necessary. With the K-Pro, you can set that VTEC window with a lower and an upper boundary that get activated depending on manifold pressure. The curve in-between is linear. So you may set it at 4,600 at full throttle but at 5,800 at very light throttle.
Adjusting cam angle for smooth crossover
One problem here is that the cam angle at any given rev point can vary quite a bit between the low-speed curve and the high-speed curve. So if you switch from 20 degrees to 45 degrees at VTEC, there’s going to be hesitation because the cam takes about a tenth of a second to turn ten degrees. The art of the deal, perfected by Hondata, is to do the maps so that the angles approach each other at the VTEC crossover. That is most important at the low VTEC point, but it’d be a good idea to fine-tune the angles along the line between the lower and upper VTEC boundaries. Note that getting the angles close can greatly reduce the noise at the VTEC cross-over.
Now you’re all done. Simple, huh? Not. And that’s why K-Pro users will probably either pick one of the calibrations that come with the system (and I hope Hondata will rapidly increase its library for different configurations, even if the maps would come at extra cost), or you bite the bullet (and cost) and have a shop do the above. And that can’t just be any shop. It must be one that understands VTC-based tuning and the K-Pro software. However, between a b it of studying and the handy target lambda feature Hondata added in rev. 1-1-8, I think a lot of K-Pro users will be savvy enough to do a little tweaking themselves.
And even if someone isn’t, the mind-boggling datalogging abilities of the K-Pro will not only result in hours of entertainment for RSX enthusiasts (and even more so once the software has better zoom-in/zoom-out features), but also allow you to learn a very great deal about what’s going on inside your motor.
Tuning from existing calibrations
Concept and goal: If the above process appears too daunting and time-consuming, you can always start with one of the many library calibrations that come with the K-Pro. Most, but not all, are the result of extensive development and tuning by Hondata. However, Hondata developed them on a particular car with particular modifications. Yours may be different and by adjusting the air-fuel ratio, tweaking ignition advance, and perhaps trying out different cam angles, you can customize and finetune an existing calibration for your car. This can be done in an hour or two on a dyno.
How it’s done: If you decided to do an abbreviated tuning session based on an existing map you will not do all the fixed angle runs to create your own composite curve. Instead, you’ll use the existing cam angle maps of a calibration and then tune fuel, ignition timing and make perhaps a few changes to the cam angle maps.
Tuning Fuel Maps
The fuel maps are tuned first because having the proper air-fuel ratios is very important for best power and also for engine health and durability. To start the process, do a dyno run and see what the air-fuel ratios are through the rpm band. Then adjust fuel to get to the proper target AF ratios.
Columns 1-6 are part throttle and there we want 14.7 AF (which the ECU corrects to anyway when it is in closed loop). In column seven we want an AF ratio of around 13.8-14. Columns 8 to 10 are full throttle and we want the AF ratio to be around 13. For super or turbocharged vehicles, the boost columns 11-16 should be 11.5 to 12.
When tuning, always select and change rectangular areas in the tables. That way all fuel lines remain parallel. Smooth fuel curves run a lot better than bumpy ones. Once the curves are all done and the next dyno run shows the air-fuel ratios we want, first increase and then decrease fuel for the entire table by 5% and do additional dyno runs to see if we get more power.
Tuning Ignition Advance Maps
The goal of ignition tuning is to have ideal ignition timing advance with minimal knock count. Getting the optimal ignition advance is key to getting the most performance. For that, you highlight columns 7-10 for all rpm, then add two degrees of ignition advance and see if performance increases, and whether or not the engine is knocking. If power increases without knocking, add another two degrees. Once best power is found, reduce ignition advance by two degrees for optimal reliability. To be right at the point of maximum power puts substantial extra stress on components. Do this for each cam angle, both low-speed cam and high-speed cam.
Knocking is caused by too much ignition advance and bad fuel. It is also worst when going uphill when the engine gets hottest. The answer to knocking is to retard ignition or get better fuel. The Hondata training example showed a datalog of a supercharged engine with significant knocking in some areas. To eliminate that knocking, select a rectangle of data points at that area, then reduce ignition by 2% or so. Test to see if the knocking is gone.
Tuning Cam Angle Maps
While not creating entirely new cam angle maps, it is a good idea to see how the engine reacts to lowering and increasing cam angles across the entire cam angle tables, both low-speed and high-speed. First increase all cam angles by five degrees from the default values by selecting all values and then use either the Ctl-I function to incrementally increase or the Ctl-J function to enter a value. Do a dyno run and record the results. Then decrease all cam angles by five degrees from the default and do the same.
What is the most important for power gains?
Tuning is a very time-consuming business. It therefore makes sense to know what parts are most important when it comes to generating extra power. According to Hondata, optimizing ignition advance is most important. Next is picking the proper cam angles for each part of the table, then setting the proper VTEC point or window, and finally setting the correcting air-fuel ratio. So:
1. Ignition advance
2. Cam angle
3. VTEC point/window
4. Proper fueling
Where should I set my rev limit?
Set it to about 500 rpm past your power peak. That way, when you shift near the fuel cutoff, you drop back to a point where you already have lots of power, but also still have a couple of thousand rpm ahead until you reach peak power in the next gear. How high can you set the fuel cut-off? That depends on the strength of the rods and the pistons, and springs that are not up to the job can result in valve float and damage to the pistons.
Day of Tuning
This is a description of a day I spent at Hondata, learning how to tune with the K-Pro.
Hondata partner Doug MacMillan had invited me down to the Hondata offices in Torrance for a hands-on tuning session. I arrived at the Hondata office at Beech Ave in Torrance at 9:15AM on May 19 and got to say hi to the crew–two technies, tech support specialist Matt, Doug’s partner Derek Stevens, and a young woman in sales. The two floor facility has office space in the front and an industrial bay in the rear, large enough for two or three cars and some gear, but, due to the location, not a place where you could run your own dyno.
After Doug had finished with his email and business stuff, we drove to the place where Hondata does its dyno tuning, that being Church Automotive, run by Shawn Church. I drove in my 2004 Type-S, Doug in a highly modified project Honda Civic Si with a Rev Hard turbo. Church’s facility is in a typical “gasoline alley” in a commercial/industrial section of Torrance. Everyone seems to know everyone else.
WDSonny and his girlfriend were already waiting for us at Church’s. Sonny had driven his supercharged RSX up from San Diego for some dynotuning and to, also, learn more about the K-Pro. Sonny’s car is the ultimate in understatement, just an innocuous looking white RSX without any visible modification or decals. Sonny removed the Type-S badge so that the car looks like an ordinary base RSX. He also uses the stock wheels. However, that car packs a punch: Race version of the Jackson Racing supercharger, race header, custom designed 3-inch Thermal exhaust and plenty more.
We started with Sonny’s car. Church uses a DynaPack dyno that hooks directly to the hubs. So the car was jacked up, the wheels came off, the hubs connected to the DynaPack. Doug stuck an exhaust gas analyzer probe into the exhaust. This connects to the DynaPack’s wideband oxygen sensor. As far as other preparations go, Doug does not turn off the RSX knock sensor via the K-Pro software (“Don’t bother”) or disable closed loop because for full throttle dyno runs the engine will be in open loop anyway. He went to the DynaPack’s terminal (it seems to use two PCs) and called up the map he did of Sonny’s car right after the race version went in, for comparison’s sake. He also showed us curves of a car with a K24-Series bottom end and a Type-S head. That engine, without any further modifications, had 50 pounds more torque across the rev range than Sonny’s initial supercharger installation, and topped out at over 300 hp. Since the K24 block has a much longer stroke, the redline is significantly lower. This modification was described in the June 2004 issue of Sport Compact Car.
So Sonny’s supercharged car is all hooked up and ready to go. Doug uses fourth gear for the runs. The mighty engine starts pulling and I see why we’re wearing ear protectors. VTEC kicks in at just over 3000 rpm, the engine gets louder and louder and screams like a crazed banshee as rpms approach the 8600 redline. Now we look at the DynaPack’s readout: 287 horsepower! But not really. Further examination shows that the DynaPack had a spike at the very top of the rpm band. Sonny’s first run yielded more like 260. That annoying glitch in the DynaPak-a big power spike that shows at the top end-bedeviled all of Sonny’s runs, making it difficult to tune the very high end. Doug believes it may be a software issue. Apparently it happens with K-Series engines. I saw it on another DynaPack.
Doug examines the various DynaPack screens. He sees something, smiles, then goes “Now, you wanna see some more power?” That’s because he concluded that the belt of Sonny’s supercharger was slipping. He goes to work, tightening the belt by making adjustments in a few places. “My guess is that this’ll get you ten or more horsepower.” Doug explains that fixing the slippage might be worth two more pounds of boost, with one pound generating about ten horsepower at the top. The next dyno pull shows a definite gain. Horsepower is up to about 272. Chart analysis shows that boost went up by over a pound, but still leveled off at around 7500. The belt seems tight so we’re not sure why, though perhaps it is still slipping a bit.
Doug mentions that the DynaPack shows air-fuel ratio about a point leaner than other dynos. He now examines the air-fuel ratios of Sonny’s car and starts adjusting. “It’s important to pay attention to column 10,” he says, as that is the switch between NA and boost. Normally aspirated cars don’t go into column 10 often unless at sea level. Doug does not expect to see much change in power from the air-fuel ratio tweaking, but it’s always good to get the fuel right! In fact, the next run shows that nothing happened at all. Problem turns out to be that changes were only made in the 50 degree cam angle map whereas the car runs around 45 in that area, so changes need to be made in the 40 degree table also. Another run and the AF is still not changing by as much as it should. Power output is the same. Doug now makes fuel changes to the low-speed cam and does another run. This makes a big difference and the air-fuel ratio is now down to where Doug wanted it. Why now and not before? Because sometimes fueling at low rpm has an effect that carries over throughout the rev range.
Now we move on to ignition tuning. Doug advances ignition by two degrees in both the low and high speed maps and does a run. The dyno shows a bit of extra power, especially in certain spots, but also more knocking. Apparently ignition timing is close to optimal. So we remove the ignition timing advance and move on to cam angle tuning. Doug removes ten degrees cam timing across the entire table, both low and high speed. This produces a weird result. Power is up, the knock count is up, and boost is up substantially in the 4000-6500 rpm range. More boost! Good. Not necessarily so, says Doug. You should always tune for maximum power at lowest possible boost. For example, if you make the same power with 8 pounds of boost at one cam angle as you do with seven pounds at another, it makes no sense to go with the settings that create the higher boost as it only heats up the intake charge. Additional tweaking with the cam angles brought boost levels back down while leaving power up.
Doug then experimented with various VTEC points. These can make for a smoother power band. They can also eliminate power dips. Before the final run Doug tightened the belt one more time and, low and behold, the top-end boost went up and another six horsepower surfaced, bringing the total up to almost 288. Sonny’s girlfriend, attractive and an exceedingly good sport who sat through the entire session, goes, “As if he needed that!” The air-fuel ratio also went up in the high rpm range, meaning that Sonny’s 440cci injectors were maxed out. Doug suggests 650s. Shawn Church stops by and we discuss the belt slippage issues some more. It’s suggested to give the Goodyear Gator back belt a try.
The bottomline here is that I can see it takes an enormous amount of time and many runs to actually get everything right. We spent two hours just changing a few things and doing six to eight runs. We did not get into fixed-angle map tuning or creating new cam angle composite maps. Yet, just by varying some of the fuel and ignition parameters, and fixing a hardware problem, the belt slippage, Sonny’s car went from a baseline run of around 260 hp all the way up to 286.
So belt slippage can be a big issue for supercharged engines. It can be seen by watching the MAP sensor voltage.
Now it’s my car’s turn. Compared to Sonny’s, mine is mild. I have a Comptech Icebox intake, a Comptech short header, the Hondata intake manifold gasket, and a Fujitsubo PowerGetter catback exhaust. And, of course, the K-Pro. Doug starts prepping the car for the dyno. The first thing he mentions is that the inner pipe at the end of my PowerGetter looks awfully small in diameter. We devise an instant measuring device and check the pipe which is visible about eight inches from the tip of the exhaust. The diameter is about two inches, if that. That could make a big difference in power, Doug says, as much as 10-15 hp. Will it? I feel deflated. I bought the PowerGetter because it’s made by a serious Japanese company that does nothing but exhausts for race and competition cars. I certainly didn’t get it to lose power.
So we start doing dyno runs to get a baseline for my car. We need to increase the rev limiter setting to 8700 so that the car doesn’t run into the fuel cut-off before the DynaPack completes its run. The first proper run yields 196.7 horses and almost 150 pounds of torque. Wow. That’s better than I expected.
Then we set out to analyze and tune the car, with Doug explaining every step along the way. We used my Toshiba Portege Tablet PC notebook to make the changes to the calibrations. We adjusted fueling, first adding a few percent, then removing and running dynos. Doug would examine a screen, for example the air-fuel ratio display on the DynaPack, and point out areas that needed improvements after those runs. We then determined what those changes should be. For example, let’s add 4% fuel at 5500 rpm to bring down a spike in the curve. And let’s remove fuel at the top end where the AF ratio went very rich. I then made the changes to the calibration, saved it under a descriptive name, and uploaded it into the ECU. Then we did the next run and checked the results. We found a bit of power that way, with most gains coming from smoothed-out dips and peaks, plus a bit on top. The best run was almost 199 hp.
After the air-fuel ratio looked optimal, we started working on the ignition. We did numerous runs with fuel changes and ignition changes, just to see what happens when ignition was advanced or taken back by a couple of degrees in both low and high speed cam tables. We first added and then subtracted two degrees across both low and high cam. We check the results and found that two extra degrees advancement added power, but also got some knocks. We worked on eliminating those knocks by reducing ignition advance in those areas until much of the knocking was gone.
Then we switched to the cam angles. We first added five degrees both across the board on both the low and the high cam tables, then subtracted five degrees. Found that five degrees less than my calibration added quite a bit of power and torque. Power was up to 201 and torque 151. Doug now explained the importance of repeatability. If you have a good run, try to repeat it. We did and, sure enough, the power gains were not the same. Perhaps the engine had been cooler during that run. So we went back to the original cam calibration, but lowered the cam angles by 5 degrees in columns 8-10. That resulted in good power, but some extra knock. We concluded that my original settings had been pretty good. Overall, I think I ended up with something like a max of 202 hp and 151 pounds of torque.
Judging by the results and comparing them to other cars, Doug felt the Fujitsubo PowerGetter may be power-neutral. There is no way of telling other by doing by a side-by-side comparison.
Since the K-Series engine is very temperature-sensitive, Doug then wanted to demonstrate the impact of a cold air intake. We connected an AEM CAI without a filter and did a run, without any additional tuning for the CAI whatsoever. The result was compelling. There were massive increases everywhere and almost all of the the dips and peaks were gone. The car peaked at 210 horsepower and 154 pounds of torque, all without any optimizing. (I ordered an AEM CAI from Chris today)
One thing I learned was that temperatures make a big difference. A cooler engine makes more power, a hotter one less. It is almost impossible to keep the temperature the same. Fueling can also be tricky. Fuel changes made at the lower end can impact the AF all the way from the changes up, at least during full-blast acceleration runs.
Honda Civic Si with Rev Hard Turbo
Doug then went on to do some testing on a Honda Civic with the Rev Hard turbo. The problem here was that RC Engineering had introduced improved 440 cc injectors with a lower 12 Ohm rating. They opened and closed much more quickly, with the pulse going from off to on almost instantly instead of on a slight curve. Theoretically, this makes for more precise fueling and also for more fuel for a given injection pulse length. Doug installed a set in the car and found the Civic’s K20A3 engine running extremely lean at low rpm, up to 20:1, with short term fuel trim in the 40% range. That was unexpected since the actual opening on the new injectors is longer, more fuel should go in and the car should run leaner. Instead, the opposite happened. At higher revs the difference was much less. This creates a real problem because the existing maps would not work with the new 440 injectors. So Doug decided to start with a stock calibration, paste in the turbo columns, and then adjust fuel and ignition to an acceptable point from where customers could take it.
This proved successful. Since K-Pro Civic support was still being finalized, Doug’s version did not allow the engine to run past 4,000 rpm. Matt brought in a newer rev of the software which worked up to redline. Doug did a number of runs, making fueling changes. The Civic’ turbo engine was incredibly loud even at 4000 rpm and it was hard to imagine how it could go all the way up to 7500 or so, but it did. The engine developed massive torque, something like 265 pounds at 4,000 rpm. Horsepower were in the 260 range. The torque actually overpowered the clutch during one run, right in the middle of the run. The dyno runs showed that the 440 injectors maxed out-100% duty cycle.
Doug then exchanged the 440 injectors with 550s that also used the new 12 Ohm design. A change in the K-Pro Parameters window from 440 to 550 yielded a reasonably close air-fuel ratio. I learned that simply changing the injector size is not enough. Additional fuel tuning IS necessary. A few more runs showed good torque and power, and the 550cc injectors could handle the flow.
Then I drove back to Sacramento, a seven hours drive. I felt I had a much better understanding of my car and how it reacts to changes. And now I want that supercharger more than ever.
Unlike the Hondata reflashes which are conservative enough to run on a variety of engines without knocking, the calibrations in the K-Pro library are more aggressive and may cause the engine to knock when first loaded. Knocking means that fuel is igniting on its own. The air-fuel mixture may ignite without a spark, or additional ignition centers may form after a spark. Depending on the kind of knocking, knocking may reduce performance or it may put a lot of extra stress on the engine. If the air-fuel mixture ignites on its own while the piston is on its way up, the explosion hits it full force.
Why Knocking Happens
Knocking can have several reasons: A) low quality fuel that ignites on its own at low temperatures. B) Too much ignition advance. C) The air-fuel mixture is too lean and gets so hot that it ignites on its own.
Engines therefore have knock sensors that “listen” to knocking. Those sensors are basically just microphones. In some ECUs, programming will filter out general engine noise and only register what the program considers a legitimate knock. The ECU may then issue countermeasures, such as retarding timing or reading from a different ignition map.
K. Level, K. Threshold, K.Count, and K.Retard
At this point no one, including Hondata, seems to be quite sure how the stock K20-Series’ ECU handles knocking. In older Honda engines the ECU retarded ignition by 12 degrees or so, and then slowly dialed it back in when it detected no more knocking. Hondata says that Honda’s implementation of knock control in the 2002/2004 K-Series ECU is not very good and results in excessive ignition retardation whether the car knocks or not. Apparently, regardless of the presence or absence of knocking, the stock ECU will retard ignition by preset amounts stored in what could be called a “negative ignition map,” a map that contains correction values to be subtracted from the main ignition map values. The knock sensor did not seem to have any additional influence on ignition retarding. Hondata therefore chose to substitute Honda’s “negative ignition map” that subtracted a fixed amount of ignition advance with its own mix of programming and reliance on well-tuned data tables. (And the space used by the negative ignition maps is used by the boost columns 11-16 in the K-Pro). Hondata did indicate the engine did seem to react to the knock sensor in some way, and this could explain the large power differences seen in K-Series engines; with the sensor disabled, the differences all but disappeared.
K. Level reports on noise from the knock sensor, expressed in volts. The number displayed is not the actual voltage of the knock sensor, but a relative voltage from 0 – 5 volts. As will be explained later, K.Level values are scaled differently under different engine operating conditions.
K. Threshold is the voltage at which the ECU considers the engine to be knocking. I noticed that, in general, MAP levels above 40 keep K.Threshold at a steady value of about 0.7 volts. MAP levels above 40 raise K.Threshold to a steady 5 volts. Most of the time, K.Threshold toggles between 0.7 to 5 volts whenever MAP passes 40 kPa. However, when the MAP level hovers around 40, K.Threshold may also hover or increase/decrease only slowly. And sometimes K.Threshold rises or falls in response to other, not yet identified variables. For example, an increase in Duty Cycle sometimes causes an increase in K.Threshold. Likewise, there are times when K.Threshold closely follows ignition timing. I also noticed that at low rpm and full throttle, K.Threshold tends to stay at a higher plateau, though not necessarily at a full 5 volts.
I noticed that even when MAP is under 40 and K.Threshold at its maximum level of 5 volts, K.Threshold starts to come down as soon as CLV (Calculated Load Value) gets over 30%.
When MAP goes above 40 and K.Threshold should go low to its 0.7 volt low level, K.Threshold will stop falling as soon as CLV gets above 40%, at which CLV point K.Threshold slowly rises. As soon as CLV falls below 40% with MAP still below 40 kPa, K.Threshold will jump up to its high level of 5 volts.
So there is definitely a relationship between K.Threshold, MAP, and CLV. If MAP goes over 40, K.Threshold goes to its low level of 0.7 volts. If MAP goes below 40, K.Threshold goes to its high level of 5 volts. However, it also always checks CLV. If K.Threshold is high and CLV gets over 30%, K.Threshold will start to come down. And if MAP goes over 40 and K.Threshold should come down but CLV is above 40%, K.Threshold will stop and start rising instead.
It seems that during those periods where K.Threshold is not where it should be according to MAP (i.e. where it is influenced by CLV) that the K.Threshold required for a K.Count increase is different from the observed K.Threshold.
Also, if RPM is below 2500 and K.Threshold is not coming down though MAP is above 40 because CLV is also above 40, as soon as RPM goes above 2500 K.Threshold will drop to its low level of 0.7 volts and slowly rise from there if CLV is still above 40. This only happens with starting rpm below 2500.
Interestingly, when the above happens, then the K.Level also seems to be reduced by a factor of about 8 immediately, even if MAP and CLV remain the same. What this means is that below 2,500 rpm, the K.Level scaling is different.
Bottom-line is that K.Threshold follows maps that are not visible in K-Pro Manager, and are influenced by a number of parameters.
K. Count counts knock incidences. The number increases every time a knock occurs. It is reset to zero when the ignition is turned off. Theoretically, K.Count should increase by one whenever the K.Level exceeds K.Threshold. Analysis of datalogs does not always bear that out. However, there are areas that suggest that even when K.Threshold at MAP over 40 kPa plateaus at a lower voltage level and K.Level never reaches that plateau, each time K.Level exceeds where K.Threshold SHOULD be (all low at 0.7), the K.Count increases by one.
Hondata says that in order for K.Count to increase, K.Level must exceed K.Threshold. Sometimes that exact moment is not captured in a datalog because the logging frame rate is much lower than engine rpm.
I noticed that a switch from closed loop to open loop at 80 kPa under full load often results in a knock.
Unresolved: At high revs and load it is difficult to tell the difference between knock and general noise. Perhaps this is why engine load above 40% starts increasing K.Threshold. Literature says that above a certain rpm, which could be 4,000 or more or less depending on the engine, general engine noise becomes almost impossible to distinguish from knocking, even if listened to with a special microphone attachment.
K. Retard will always show zero as the K-Pro is not using the earlier referenced Honda “negative ignition map” which reduced timing regardless of knocking.
How to eliminate a knock:
First, you should/must read up on the K-Pro in order to learn about its capabilities and also what to look out for. When you upgraded your stock ECU to K-Pro, you exchanged Honda’s “one-size-fits-all” approach optimized for emissions, longevity, and fuel efficiency under a broad range of circumstances for a programmable computer meant to give you best performance.
Anyway, here are some basics: with very few exceptions, K-Pro calibrations are all much more aggressive than the factory calibration. They are geared towards maximum performance, with the idea that you can always tune the car back. Where the stock ECU gives you the safety net of automatically retarding ignition under certain circumstances, the K-Pro relies on its own ignition maps and expects you to know enough about its programming to retard ignition yourself if you encounter knock. That is the price of performance.
Ignition Advance Issues
Why ignition advance? Because the ignited fuel mixture must hit the piston just as it starts on its way down. Since the piston moves so fast, if we were to ignite the mixture when the piston is on top, it would already be well on its way down by the time the flame front reaches it, and we would lose a good part of the effectiveness of the explosion.
Ignition Advance Analogy
Here’s an analogy to illustrate the movement of the piston and the effect of the flame front: Imagine a playground swing with a child sitting on the swing and a parent pushing the child. You can immediately conclude a few things. First, the child sitting on the swing moves fastest in the middle of the swing, then gets slower and slower at each end as the swing comes to a stop, then reverses. If you are the parent pushing the slide to make the swing go faster (or maintain its speed), you must hit the child and apply your pushing at the exact right time. Start pushing while the swing is still on its way up results in the swing pushing into your arms and slowing down. Pushing too late and the energy of your push is wasted as you can apply little to the swing that already accelerates away from you. So you need a good rhythm that is in sync with the speed of the swing. Apply all your force right after the swing reverses allows you to apply most of your force. Same exact thing with a piston.
General Ignition Advance Rules
An ignition advance map determines at what point the spark plug ignites the air/fuel mixture at different rpm and engine load points. How does one arrive at the values in an ignition advance map? Hondata’s maps already have ignition advance tables, but if one wants to start with base maps for dyno tuning with fixed cam angles, one needs to know how to build such base maps. There are some general rules that apply to most engines:
As rpm increases, ignition advance increases as well, because the piston moves up quicker. Since they move quicker, the ignition must occur farther ahead of the piston reaching the top.
However, as engine load increases, ignition timing retards. That’s because at light load with lean mixtures, the speed of combustion is slower and more ignition advance is required. At higher load with richer mixtures, less ignition advance is needed because the combustion is faster. (Note: So a supercharged engine that runs richer AF ratio under full load needs less advance).
Ignition Advance for best power
Getting ignition advance just right is key to getting the best possible performance out of an engine. In general, more advance means more power. However, there is a point at which further ignition advance will not result in additional power. This is called the MBT (Minimum Best Timing). Going beyond that point will lead to knocking and increases hydrocarbon and NOx emissions. There is also a factor called “attack rate” which refers to how quickly the ECU can change ignition timing. If a table is set for too large a jump in too small a time, the timing cannot happen in the time allowed and a knock may occur. I am not sure if this is an issue for the Honda ECU or not.
Ignition advance has the potential to damage the engine. If the spark is fired too soon, the entire force of the flame front can hit the piston while it is still on its way up. That may lead to broken rods, worn bearings, blown head gaskets and worse. Sacrificing the last few horsepower by not going to the very edge with ignition advance is good insurance against engine damage.
In the RSX Type-S engine, Hondata says that being about two to three degrees shy of where knocking begins is best for maximum power.
Boosted cars need less ignition advance (in the boost columns) because the highly compressed air/fuel mix burns faster.
Does Ignition Advance impact the air-fuel ratio?
Not directly. However, if an engine’s ignition is retarded several degrees from optimal, the engine will run rich because there is not enough time to burn the mixture completely. In such a case, advancing the ignition will lean out the fuel mixture and result in a higher air-fuel ratio.
Ignition Advance for forced induction engines
As a rule of thumb, ignition advance for super and turbocharged engines should be about 1.25 degrees per psi less than that of the same NA engine.
The fuel tables determine how much fuel the computer will use for a given manifold pressure and rpm. From what I can tell, fuel values increase by a factor of about five between columns two and ten. Fuel values on the rpm axis seem to follow more or less the torque curve. Since the RSX has two torque curves, one for the low speed cam and one for the high speed cam, many of the fuel curves have two peaks and an intersection where the VTEC point is.
If you change the injector size, the values in the fuel table will not change. That’s because the ECU will multiply each map value for the specified injector after it has read the table value.
What is the unit used in fuel tables? One would assume some volume unit such as cubic-centimeters. However, that is not the case. The numbers is the fuel tables are, according to Hondata, a “volumetric efficiency estimation of the engine.” There is no direct relation or readily available conversion to, for example, injector opening duration because of a variety of trims and modifiers.
Also interesting is that injector duration is not linear. If an injector is open for 4 milliseconds it will flow less than half the fuel of an 8 millisecond opening.
The AF (Air/fuel) ratio describes how many parts air the mixture contains per part of fuel. There is a “chemically correct,” or stoichiometric ratio which is 14.7. At that ratio, complete combustion occurs as there is just enough oxygen to burn all of the fuel. Almost complete, I should say, as in the real world nothing is ever perfect.
An AF ratio under 14.7 is considered “rich” because it contains a lot of fuel. AF above 14.7 is considered “lean” because it contains too little fuel. A richer mixture actually burns cooler and keeps exhaust gasses cooler. However, fuel economy suffers. Lean mixtures burn slower and heat things up more (pistons, etc.). The difference in exhaust gas temperatures between lean and rich AF can be hundreds of degrees.
In general, naturally aspirated engines develop the most power with an AF ratio under full throttle of between 12.5 to 13.5. Hondata generally recommends 13-13.5 for best power.
For turbo and supercharged engines, the full throttle AF ratio should be between 11.5 and 12.
Best economy is achieved under part load with an AF ratio around 15.4.
Hondata advice in a case where the air/fuel ratio was 15.5 under full load and wide open throttle at high revs: “Add 10-15% fuel where the AF is 15.5. Aim to get the AF to about 13.2 or so. 10% fuel change = about 10% AF change. Change the AF in the heat and then compare it to a cold night run.” My own tests showed that a 15 degree Fahrenheit change in intake air temperature can raise or lower the AF ratio under full throttle between 0.35 and 0.6 points.
Some sources say that even a small variation in a lean mixture has a big impact on power output. A variation in a rich mixture has a much smaller impact on the power output.
The K-Pro makes correcting air-fuel ratios is fairly simple. Here is a brief version of how it is done:
Do a Full Throttle datalog 2500-8500 rpm, preferably 3rd gear.
Open K-Manager and open the Tables window with your calibration, the Sensors window, and the Graph window. Make sure you have Options set so that the tables follow both VTEC and cam angle.
Load your datalog into K-Manager, zoom into the area of the run, and analyze with a Graph Template that shows at least RPM, AF and VTS so that you know when you go into VTEC.
Now you look at the graph and you may see that between 5800 and 8000 your A-F flatlines at 11.46, which means you’re running richer than you should. Under WOT, you want your Air-Fuel ratio to be between 11.5 and 12.
With the “Table” pulldown set to “Cam Angle,” look what cam angle your engine is at during those rpms (place the cursor on where the lean condition starst, then drag the vertical dotted line through the lean spots). Aha… the cam is between 10 and 20 degrees. Which means we have to make fuel changes too the 10 and the 20 degree High Speed fuel tables!
Now it’s time to make the fuel changes. Switch the “Table” pulldown to “Fuel,” set “Cam Angle Edit” to “Single,” and set the “Cam Angle” pulldown to 10 degrees.
Now we’re going to make a wild guess and assume you need 5% less fuel. With your mouse, select a rectangle comprised of columns 1-16 and RPM rows 5750-11000.
Hit Ctl-J to b ing up the “Adjust Selected Values” pop-up and enter -5 (minus 5) into the “Percentage Adjustment” box. Hit OK. That will remove 5% fuel from the entire rectangle you selected.
Do the same for Cam Angle = 20.
Save the calibration with a descriptive name and upload it into your car. Do a datalog to see what the AF is now.
Open and Closed Loop Operation
ECU-controlled engines can operate in a variety of modes. Most are variations of “open loop” and “closed loop.” The difference between open and closed loop is this: In closed loop mode the ECU uses the feedback from the oxygen sensor (and possibly other sensors) to automatically adjust the air-fuel ratio to a pre-programmed value. In open loop, the ECU ignores feedback and simply uses the parameters in the ignition and fuel tables. There are actually two open loop modes. “Open – cold” means the engine is still cold and fuel isn’t vaporized very well. Additional fuel is needed and the engine runs rich. “Open – driving conditions” means the ECU is in open loop because certain rpm, throttle position and vacuum conditions are met.
The Parameters window of K-Pro ECU Manager allows the setting of a maximum pressure under which the engine will be running in closed loop. If that threshold is 80 kPa, then the engine will switch into open loop as soon as the MAP value exceeds 80 kPa.
Watch the Fuel Trim
“Fuel trim” refers to the ECU’s adding or removing fuel to get to what it considers the optimal air-fuel ratio. There is short term and long term fuel trim. The ECU uses Short term fuel trim to get air-fuel ratios to what it thinks they should be in closed loop. The ECU “learns” by watching how much short term fuel trim is used and then uses that data to make more permanent adjustments via long term fuel trim. The idea here is that if an engine is almost always running lean in closed loop and needs more fuel to achieve the proper AF ratio, the ECU might as well permanently add a bit more fuel. That is long term fuel trim. The ECU remembers that value even when the engine is not running and the ignition is turned off. Resetting the ECU resets the long term fuel trim.
The ECU only uses short term fuel trim in closed loop condition. As soon as the engine goes into open loop, the ECU simply reads the values from the fuel tables. This means that the air-fuel ratio can get way off if those parts of the fuel tables haven’t been given proper attention. I noticed, for example, that my air-fuel ratio went very high on freeway inclines. Since engine load was high, the ECU went into open loop even though throttle position was only at 30% or so. Read on for an actual example.
Importance of Part Throttle Tuning
Even though a vehicle is under full throttle only a minuscule percentage of its operation and in part-throttle most of the time, many performance enthusiasts solely concentrate on peak horsepower and the full-throttle power curve. Even most K-Pro users probably spend most of their time tuning columns 9 and 10 (or the boost columns if their engine is turbo- or supercharged). Fact, though, is that the engine will spend most of its life in the low cam tables, right smack in middle, in cruising range. Making sure the engine runs optimally in that range makes for good drivability, good fuel economy, and low emissions.
Strange Part Throttle issues in earlier versions
Honda programmed many rules and conditions into the K20 engine ECU. They sort of act like a “big brother,” making sure that you don’t hurt the car. For example, the ECU may all of a sudden decide to run a richer air-fuel mixture even though the car is in open loop and should only use the calibration tables and disregard any input from the ECU. As we get more experience with the K-Pro, people are discovering more such rules and exceptions. Hondata has been addressing those that need fixing.
Here is an example of one such anomaly that I discovered early on in the K-Pro’s life: In a datalog I found that when cruising uphill on a freeway my car went into open loop even at only 25% throttle because the MAP pressure was over 80 kPA. My air-fuel ratio went into the mid and high 15s, which is too lean. I thought it might make sense to add a condition to the K-Pro that keeps the motor from going into open loop unless throttle is above a certain point and approached Derek at Hondata with this. Derek initially pointed out it was a tuning issue, and that I simply had too little fuel in that cruising range. He suggested I check short term fuel trim right before the car went from closed to open loop. I did and noticed that short term fuel trim right before going into open loop was around 3-5%. So the car had been getting 3-5% too little fuel, and the ECU compensated for that via short term fuel trim. In open loop it couldn’t do that and my AF ratio went very lean. I added about 3% fuel in the 3000-3500 rpm area to make sure the car got enough fuel.
Now this is important! Why? Because if you don’t get fueling right in those closed loop areas, the computer will constantly trim fuel and that affects long term fuel trim. Which means that the ECU will add or subtract fuel even in those areas that you carefully tuned! So make sure those part throttle areas are done right!!
This document started as just a set of personal notes and then grew bigger and bigger. In the process I tried to rewrite parts so that they would be of maximum use to anyone reading the notes, and not just to me. I realize that the information density of the document varies. In some areas I go into very great detail whereas other important areas are just touched on or not addressed at all. Some of the items I want to include:
A description of the really important changes in each rev of K-Manage
Which revs to use and which to avoid
An explanation of the Lambda overlay feature and how it can help.
Some concerns I have about the K-Pro and what I hope Hondata will fix/add soon
More general advice on how to tune for FI, wild cams, etc., and why
Whatever else readers of this document would like to see.
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