A admin

Inside Hybrid Racing R&D: K-series Throttle Body

Sep 27, 2017

At Hybrid Racing, we strive to constantly push the limits of the quality and performance of our products. This blog is the first in a series meant to show the consideration and effort that goes into developing some of our most unique and complex parts. In this entry, we’ll be examining what went into the design and testing of our 70mm and 74mm, cable-actuated, k-series throttle bodies.

When practical, we use the latest software to design our products. The video below shows an exploded view of a computerized model of the 70mm RSX throttle body. Models like this are particularly useful when making sure all of the many parts will fit together as planned, but design is only half the battle. After the design is complete, we must validate the product’s performance through various methods of testing. Preliminary analysis can often be performed on a computer. This could be to measure the flow of fluids through a part, the stress developed during use, or the fatigue incurred during long-term use. In the case of our throttle bodies, all of these types of analysis were performed.

Once we are satisfied with what we’ve learned from computer-based analysis, we have a batch of prototypes manufactured. This allows us to have parts for testing, but it also allows us to fine-tune the manufacturing process in preparation for future production runs. Testing on vehicles is a necessary and obvious means of proving what a product is capable of, but often we need to see how a product will perform after years of use and abuse. Obviously, it’s impractical for the development of a single product to take several years. To achieve years of abuse in only a few weeks, we often employ custom built test rigs that cycle the part repeatedly for days, weeks, or months on end. In the case of this throttle body, we built a rig that used pneumatic cylinders to actuate the throttle and cruise control cables. Each cable was pulled to wide-open-throttle (with approximately 100 pounds of force) over 1.5 million times. A TPS constantly monitored the throttle position, sending data in real-time to the controller. The controller was designed to pause the rig should the TPS indicate there was an issue preventing the throttle body from opening or closing properly. This allowed us to look for issues like sticking, fatigue, and failure. The video below shows the rig in action.

Once we are satisfied that a product will perform as we expect it to, we move on to vehicle-based testing.  This testing will often include a combination of vehicles we keep at our shop, along with drag racing and road racing vehicles we sponsor. When applicable, we perform dynomometer testing at our facility to validate and quantify the performance gains from the part. One of the primary test motors was a k20a2 motor with an RBC manifold, 11:7.1 compression, Brian Crower stage 2 cam shafts, with a 3” cold air intake, a 4-2-1 SSR header, and full 3” exhaust. We tuned the motor for maximum power with both an OEM RSX throttle body and our 70mm throttle body. Below is a graph comparing the two best “pulls” made with each throttle body. With this setup, we were able to achieve 5- 10 hp and 5-10 ft-lbs of torque across the majority of the RPM range. When we are testing, we always strive to put equal effort into tuning both before and after a part is installed. This insures the results you see on our graphs will be faithful to the results you can expect when you purchase any Hybrid Racing product.

Once we are satisfied with the results we’ve gathered using test rigs and vehicle-based testing, we move into production. Each time we receive a production run of a part, we inspect the parts to ensure the critical dimensions and tolerances are within the required range. For many parts, custom tools must be designed to speed up the assembly process or to perform specialized tasks unique to the product.  For example: our throttle bodies are the only aftermarket throttle bodies for Hondas that feature staked butterfly bolts. Staking is a process in which either a bolt or the adjacent metal is deformed to make it impossible to remove the bolt. This is done to ensure that even if one of the butterfly bolts loosens, it cannot fall out. We do this as a preventative measure to protect the motors our throttle bodies are installed on. To stake the bolts, we created a custom tool. This tool is a modified end nipper designed to crush the ends of the bolts, making them too wide to be removed from the center shaft.  Shown below are images of the pliers and how they are used to stake bolts on our throttle bodies.

For some of our more complex parts, we perform tests on each unit after it is assembled. Once assembled, each of our throttle bodies is physically inspected to ensure that all parts are functioning as they should. Once we are satisfied with the assembly, each throttle body is mounted on a specialized testing rig that creates a pressure differential across the butterfly, just like the butterfly sees when the car is idling or when boost surges when the butterfly closes. The purpose of the test rig is to measure the flow rate of air that can leak past the butterfly when it is closed. The nature of a modern throttle body design makes attaining a perfect seal nearly impossible. For that reason, a small amount of leakage is acceptable. If any throttle body shows an unacceptable leakage rate, it is resealed and retested. Shown below is a throttle body being tested on this rig.

A lot of time and consideration goes into each one of our products. We do everything we can to ensure we are giving our customers the best products possible. We constantly keep this goal in mind through each stage of product development, and we work hard to improve our standards and quality with each passing day. Keep an eye out for similar tech articles in the near future!

Let us know what you think in the comments below!


Link to share

Use this link to share this article