Good news everyone: I decided recently to change directions away from the custom throttle body w/ integrated ECU covered in previous updates. At the time, smaller throttle bodies seemed nearly impossible to source so a custom solution felt necessary. Fortunately, that’s no longer the case. Throttle bodies small enough for powersports engines are becoming more readily available, making life a lot easier for us. Going this route also means that the ECU will not be integrated, instead it will be potted in its own sealed enclosure like you’d normally expect. So, heads up on that.
With that being said, let’s take a look at the throttle body. The throttle body shown here is 28mm. A 34mm version is also available, identical in features and approximate size.
Throttle body Includes:
- TMAP Sensor (Manifold Absolute Pressure + Temperature)
- TPS Sensor (Throttle angle)
- IAC Stepper Motor (Idle Air Control Motor)
I think most are probably familiar with TMAP and TPS sensors. So I won’t say much about those.
IAC Stepper Motor
Coming from the carburetor world, you may not know about the IAC feature though. “IAC” is short for “Idle Air Control”. It’s a method of controlling idle speed via the ECU, rather than dealing with the old wallowed-out idle speed screw you’re used to cursing at every time the ambient temperature rises or falls outside.
If you’re a powersports rider, I’m sure you’ve adjusted your idle screw just right while the engine was cold after a startup, only to see the engine start idling high in a few minutes after the engine warmed up. On some engines this is particularly an issue. Eventually you just learn to live with it. However, having IAC control means that the ECU will make those idle adjustments for you and keep idle at your desired setting specified in Airtune. Warm or cold, it’ll help keep your riding with less fiddling.
The nanoEFI ECU doesn’t have native support for idle steppers yet, I plan to make it available as an external module in communication with the ECU over I2C/TWI.
28mm Throttle Body (with GY6 Intake Manifold attached)
*Note for GY6 owners: The intake will be machined to add the injector seat.
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