To adapt a Bosch Drive-By-Wire (DBW) throttle body to the FD RX7’s upper intake manifold, we are using a Turblown RX-7 To Bosch DBW Adapter.
Now that we committed our plans to convert to a DBW setup, we were able to ditch the long and archaic throttle cable.
Going to DBW also allows us to ditch the factory Idle Air Controller (IAC) since the ECU will control the idle with the main throttle body blade.
We decided to go with an 82mm Bosch DBW throttle body which gives us 5,281mm^2 of area compared to the 5,518mm^2 area of the stock FD 3-blade throttle body.
This package is significantly smaller, simpler, and lighter than the heavily mechanical factory throttle body. I really like how clean the conversion makes the engine bay, and ditching the coolant lines that run through the throttle body greatly improves serviceability of the engine.
9 comments
This is a no-stone-left-unturned kind of build and I am glad you are documenting it! I hope you make a video at the end covering everything you have done over the years.
Thank you. We will do a video recap at some point.
I had no idea the stock TB was so complex. It’s actually pretty cool, and I’m sure it was a great setup for a stock or closer to stock engine, but I can only imagine the new e-throttle will give far better drivability and support making more power on the new engine.
but a 5% reduction in size… I’m surprised they didn’t find an option that was just barely larger, instead.
If you consider the throttle shafts into the equation, the effective area is actually the same. I would imagine that a single butterfly impedes flow less than several smaller ones.
LS3 throttle body is 90mm but the motor is huge and probably wouldn’t fit very well here.
What bothers me most is that the throttle pedal spacer in installed the wrong way up. That’s going to cause some serious issues.
Lol. You’re right. It’s upside down. Well, should be an easy fix.
Ha, you’re right. Good catch. What serious issues will it cause?
It will cause no issues whatsoever. It just doesn’t line up with the opening in the carpet and that’s too much for my OCD.
GrantC – There’s a hypothesis that a much smaller 74mm TB will perform better at power levels up to ~500whp… That might need testing.