Quote:
Originally Posted by Dmacc
My guess would be there is a possible vacuum leak. Maybe a line leading to one of your wastegates. What spring are you running in your bov?
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Quote:
Originally Posted by Freon
The throttle opening back up makes sense after the injectors stop spraying fuel in a 0% accelerator situation. It will reduce lag the next time you press the accelerator down as it allows the turbo to keep spinning with less resistance.
Not sure I'd consider it a problem. The stock diverter valves were certainly designed with this in mind, so if your HKS setup has symptoms perhaps it's not the best DV/BOV solution.
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You are right...the ECU is obviously trying to control BOV operation via intake manifold vacuum using throttle body angle...I just don't know for what reason...I thinks its stupid and I want to get rid of it....sadly i think this is deeply coded in the throttle body map tables...
My theories:
-The car will hold 5 PSI every time I let off at HI LOAD/HI RPM...its always 5 PSI, Sometimes it reminds me of a NO LIFT SHIFT setup....Initially it'll blow off anything over 5psi, when it hits 5psi, the throttle body opens for what seems like a preset time frame(in milli second I guess) causing the BOV to seal for fractions of a second, and then blow off everything....Maybe BMW internationally coded this so that when you engage the next gear (6mt) the system is already in positive pressure, instead of having to start from vacum, yielding faster boost buildup.
-Some type of PCV gass recirculation technique by BMW...which doesn't really make sense given the symptoms.
The HKS bov is replicating exactly what the stock BOV's did down to the milli second...I am 100% sure it is not the HKS bov or it's current calibration...BTW I am using the stock 11psi springs, I get no fluttering, and the valve does not open during idle...the calibration is perfect.
Ive read a lot of members on here have this "hi load/hi RPM double blow off" using all types off diff BOV...its the ECU trying to control boost pressure during overrun..
To me it's a huge issue, almost a make it or break it type issue
Has anyone tried fixing this thru a cobb tune? iirc, cobb gives you access to absolutely all ECU reference tables
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