I use a Hybrid Boost control setup on my WRX and love it, mainly for the almost idiot proof tuning. I'll explain.

Course the WRX has serious partial throttle full boost issues because the turbo is so small, so just slapping on an MBC in most cases nets some unwanted results. But if you connect a 3 port like a Perrin/GM solenoid and an MBC in parallel, you can set max boost with the MBC and use the ECU to control partial throttle situations. On the Subaru ECU, I just set the 100% TPS column to 100% WGDC (Always Closed in this case), so when you put the hammer down, the solenoid shuts completely and the MBC takes over.

Looking at Mrfreds boost control stuffs and other things on here, I wonder if it is feasible to do the same using the Evo ECU with an MBC. Not that PTFB is a real problem with the Evo but I can certainly hit max boost at 50% throttle.

And the question I hope gets answered. Are the different ECU ID's for the same model year car simply upgrades or completely different code? What keeps you from switching from say VIII -0008 to VIII -0015? Shouldn't any USDM VIII ECU tables work on any USDM VIII ECU?

/brox

 

I have never really understood needing TPS in your WGDC selection.

cant you control boost with your TPS anyways?

anyways if you really really wanted we could do a special patch that had TPS as the "other" axis for your WGDC map...

 

I can answer part of your question, the particular ecu numbers you mention 0008 and 0015 for the 2003 year evo8 are in fact for the same car. The 0015 was a factory update to the 0008. No particular problem changing that id.

 

Some turbos spool too easily at part throttle making it difficult to control power delivery. Its like having a throttle pedal that's only an on/off switch.

 

I just control mild closed loop/off-closed loop boost with the diverter valve. Ported the bottom of the valve with a 3-port controlled by the IC spray harness via TPS table. It's a stock valve originally so when the diaghram isn't collapsed (WOT), it drives just like stock. But when energized at WOT it doesn't leak.

The configuration enabled me to use a Tephramod for boost taper under knock. Been keeping engine happy for 15 months. So instead of 28psi with detonation, it's 19 psi, which is plenty with methanol spray.

FYI, if driving a solenoid (normally transitor ground energized by ecu) with the IC spray harness you might want to put about 20 OHMs of resistance on the solenoid ground side. It tends to put a voltage on the car's ground.