E30 325iX twincharged build

[muuris]

I made a larger breather hose fitting for the valve cover, ICV hose fitting for boost pipe, a small spacer for alternator pulley to fine-tune belt alignment:





The cut Eaton inlet pipe was fitted with a 3" curve:





Eaton outlet pipe was quite time-consuming, here it is almost finished. At this point I was going to use a Volvo 960 thottle body along with a VNT servo:




Exhaust manifold in place:





I welded intercooler brackets to the body and started to make boost pipes, but then I decided not to use Volvo tb, but a DBW from M54 instead. First some prototyping on a breadboard:




This would be controlled with Speeduino VVT output with slightly customized firmware to incorporate TPS value. The PCB and code took some time, I tried to make it in OEM-style so in startup it tests that the return spring is ok, uses both potentiometers, has a failsafe/limp mode control etc, and the control tries to avoid hitting mechanical stops. After all the adjustments it takes ~160ms for tb to go from 100 % to 0 %.

The DBW-tb was physically larger than the Volvo tb, so I had to filler weld the flange in boost pipe.
The enclosure was my first 3D-print, will do it's job:





Boost pipes almost done, all 3" except for the very first section after turbo:







Then some wiring changes to support alternator relocation, added PWM-fan, emp measurement etc:




A short video of the dbw testing in car:

[Panici]

This would be controlled with Speeduino VVT output with slightly customized firmware to incorporate TPS value. After all the adjustments it takes ~160ms for tb to go from 100 % to 0 %.

Are you happy with the throttle body performance as it stands?
I personally am not a fan of any DBW vehicles that I have driven. That said, I have never played with a custom setup. I imagine you can get it dialed in to exactly how you want it.

Certainly opens up options to play with traction control, throttle kick for rotational idle, and ALS.

[e30davie]

I haven't come across this thread before, what a project!

[muuris]

Are you happy with the throttle body performance as it stands?
I personally am not a fan of any DBW vehicles that I have driven. That said, I have never played with a custom setup. I imagine you can get it dialed in to exactly how you want it.

Certainly opens up options to play with traction control, throttle kick for rotational idle, and ALS.

I wasn't too clear on my previous post about the that this dbw isn't the main (intake) throttle body, the standard M52 throttle body in still in the manifold. This dbw is only used as supercharger bypass, hence the performance of the flap affects the time it takes to reach most of the boost. I think it's quick enough for instant response feel, but surely I wouldn't mind if I could have gotten it faster.

[muuris]

I haven't come across this thread before, what a project!

Thanks!

[Panici]

This dbw is only used as supercharger bypass, hence the performance of the flap affects the time it takes to reach most of the boost. I think it's quick enough for instant response feel, but surely I wouldn't mind if I could have gotten it faster.

Ah gotcha, thank you for the clarification.