Hondata S300 for B/D/H/F Series

Hondata S300 V3 - OBD1 ECU Tuning System for B/D/H/F Series Honda

If you're running a B, D, H, or F series Honda with an OBD1 ECU and you're tired of not being able to tune your build? The Hondata S300 Version 3 turns your stock OBD1 ECU into a fully tunable engine management system. You're getting complete control over fuel maps, ignition timing, boost control, safety limits, and way more without swapping your factory computer. You supply the manual transmission OBD1 ECU, the S300 module drops in, and you're tuning. We run these on our own cars because they work and they're reliable. Hondata designs, manufactures, and assembles the S300 in the USA.

Here's What Makes the S300 Worth It

Chipped ECUs are cheap but they're locked to whatever the tuner burned on the chip. Your setup changes and you're mailing your ECU off again waiting for a reship. The S300 gives you full tuning control through your laptop. You're making fuel and timing changes in real-time while the engine's running. Changes upload in under 2 seconds for a full calibration, way faster for small tweaks. You change something in the SManager software and it's live in the ECU immediately. That's the difference between guessing and actually tuning your car.

Real-Time Tuning and Fast Datalogging

The S300's real-time tuning means you're uploading changes with the engine running without cutting power or resetting anything. You're on the dyno making pulls, you adjust your fuel map between runs, and the new calibration's loaded before the dyno operator's ready for the next pull. The datalogging's built into SManager and it's 2-4 times faster than older Hondata units. You're logging over USB or Bluetooth, graphing sensor data, and saving runs so you can review what happened. The S300's got onboard flash memory too. You can log without a laptop connected and download the data later. It'll store about 120 minutes total across multiple logs. Start and stop logging with an external switch or set triggers (like start logging at 5000 RPM, stop when you drop below 3000). That's how you figure out what your engine's actually doing instead of guessing.

Ethanol Content Sensor Support

The S300 supports ethanol content sensors so your tune can adjust to real ethanol percentage instead of you guessing what's in your tank. You're running E85 and the station's blend is anywhere from E70 to E85 depending on the season. The S300 reads your ethanol sensor and compensates. Your fueling and timing stay dialed in even when the fuel changes. If you're running flex fuel, this feature's essential.

Bluetooth and Dashboard Output

The S300 V3's got Bluetooth built in. You're tuning and datalogging wirelessly from your laptop or phone. No USB cable running across your car. The S300 also outputs data over CAN bus and serial for external dashboards like AiM MXL and Racepak IQ3. If you're running a standalone dash, the S300 feeds it engine data directly.

What You Get

• Hondata S300 Version 3 module (for USDM rectangular OBD1 ECUs)
• SManager tuning and datalogging software
• Real-time tuning (changes upload in ~2 seconds)
• Bluetooth support (laptop and mobile datalogging)
• Onboard flash memory (~120 minutes total log storage)
• Ethanol content sensor support (flex fuel tuning)
• CAN bus and serial output (external dashboard support)
• 2-4x faster datalogging vs. older Hondata units
• Designed, manufactured, and assembled in USA by Hondata

Compatible Engines

• B Series (B16A, B16A2, B16A3, B17A1, B18A1, B18B1, B18C1, B18C5, B20B, B20Z)
• D Series (D15B, D16A6, D16Y5, D16Y7, D16Y8, D16Z6)
• H Series (H22A, H22A1, H23A1)
• F Series (F20B, F22A, F22B, F23A)

Requires

• Manual transmission OBD1 Honda ECU (USDM rectangular case)
• Windows laptop with USB or Bluetooth

Note: The S300's designed for USDM rectangular OBD1 ECUs, the ones found in 1992-1995 Civics, 1994-2001 Integras, and similar chassis. It won't work with JDM square ECUs or OBD2 ECUs. If you're not sure which ECU you've got, check before you order. The S300's for off-road and racing use only. It's not legal for street use in the USA. All S300 sales are final once you've received the unit. We don't accept returns on tuning devices because of licensing and potential use. Confirm your ECU fitment and make sure this is what you need before you order. If you're not sure, contact us before you buy. The S300 gives you full engine management control, but you need to know how to tune or you need a tuner who does. Don't buy this expecting to plug it in and make power without understanding fuel maps, ignition timing, and how engines work. This is a professional tuning tool.