Engineering a Race Motronic EFI system.
The Bosch "Race Motronic" system is the state of the art means for controlling the race engine on your VW Golf Kit Car or LeMans winning Audi R8. Unfortunately we didn't have the $20,000 in the ITS budget to purchase one. Besides a fully stand alone system isn't quite within the rules for this SCCA road racing class.
So instead we decided to reprogram our own. This section will describe the trials and tribulations involved in developing our own SCCA legal racing EFI system.
The Bosch Motronic M2.9
It's only a coincidence that the Bosch ECU in our VR6 Corrado shares the same numeric designation as Bosch Motorsport's top of the line Race Motronic ECU....or is it ? (yes of course it is) So as we continue, please understand that we have not placed a full race, stand alone, EFI system into the ITS Corrado. We are developing a reprogrammed "racing version" of the original Bosch Motronic M2.9 ECU found in all VR6 Corrados delivered to the USA.
Why are we reprogramming the M2.9 when GIAC, Neuspeed, Techtonics etc. all offer chips that we could just plug in and "voila!" more power? Well... not to take anything away from these companies who do a great job of producing performance parts for the street... our experience was that for racing they just didn't cut the mustard.
We had one of the above chips in our car for a few test days at the local track, BeaveRun Motorsports Complex.
It seemed to be making decent power in the mid range but the engine was not pulling any harder in the upper RPMs and the top track speed was no better than stock. We were not able to gather any specific engine data during the test because our data acquisition system wasn't enjoying the bumpy ride so much and kept shutting down on us. So, off to the dyno we went.
Well our fears were realized when the dyno told the truth. After a few pulls it became apparent that our engine was making no more power than a bone stock VR6. Why? In a word "knock". The engine made great torque and midrange HP. However after long wide open throttle (WOT) pulls and after the engine was at racing temperatures we saw massive ignition retardation due to knock. Even on the pulls where knock was not a factor, the engine was flat on the top end and the AFR showed why.
to be continued...
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