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Originally Posted by fidozoom
What I meant is verifying the 300 lb-ft of torque @1400 - would this stay the same whether there is turbo lag or not? Also the claimed horsepower of 300@ (whatever is official) rpm - would those change if there is turbo lag?
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The torque seems to be there, but it comes with a delay, it just builds up slower. The low-RPM power clipping is no static, but a dynamic problem. Thus, you probably would not notice it on a dyno, unless RPMs are being risen very fast.
From what
Shiv has posted here:
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Another change is that wastegate duty during cruise/low load conditions has been lowered to 15-20% instead of 40-50% as with earlier ECU software versions. This makes the turbos feel a bit less responsive as well as makes the exhaust sound a bit louder/burblier.
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I would say that this effect
should be limited to low RPMs. Maximum power is made at ~6500 RPM and in that region, there seems to be no power impediment.
However, I felt that my car was somewhat slower at high RPM. Whether this came from high temperatures these days here in Germany or the "throttle closure" that Shiv mentioned when implausible values occur, I cannot say.
Shiv also stated:
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I wouldn't be surprised if 29.2 does induce this throttle closure behavior to some degree in a totally stock car. I suspect this is what people are feeling when they say that the new software udpate makes the car feel less responsive. Basically it is is now using throttle closure as a very active way to controlling boost (instead of mainly relying on the wastegate solenoids).
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My foreman told me that BMW has problems only on some cars, not all. So, it might be that the new 29.2 protection features are too conservative for some cars (e.g. variations in TMAP sensor sensitivity). This may also be the reason why some people do not have these problems.