Quote:
Originally Posted by SeanWRT
David,
When we first tried tuning m2 last winter, we did see a few flash tuned m2 misfire from 5k rpm. Frustrated, we had to go back to piggyback solutions and deal with heat and timing instead.
We then come to the conclusion it's all in the tune - if you crank up boost hard like that, you have to run very rich to stay safe, so fuel pump fails of course. You will want to find a sweet spot of boost/AFR and make a good timing table, then you'd see, which i believe you already did, that it's the octane that can not handle the heat and boost and give up first
When you have meth to assist fueling and cooling, ethanol can be used a little bit, so boost gets much higher, to redline. That's when fueling become the real problem.
Yes, fueling will be eventually a limitation but when properly tuned, fueling would be way after octane, heat and even the de facto strong EWG turbo.
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You're right, to get more power at the higher RPMs heat and octane are the limitation. Ideally we'd like to ramp the boost down low more than we do now, but the fuel system simply can't handle it. As stated in our other thread, we spent a lot of time finding that sweet spot that would allow us to make consistent, reliable power with the stock turbo and fuel system. We know the stock turbo is good for 500+lb/ft but it does suffer at higher boost levels at higher RPMs. We're currently installing a Pure Stg2 with Fuel-It PI on an M235iR racecar, in stock trim it made similar power to our M2 so I'll post the dyno comparisons once it's completed and tuned.