Quote:
Originally Posted by xlover
Right, we don't actually know where the line is for bmw engineers to change a designation, they might have huge leeway in tune and intake design but no leeway in valvetrain design....
I will add, in my opinion this adds support to the theory that the x3m was intentionally detuned off idle to give it driving characteristics more "SUV like" I suppose we won't know till later this fall when driving impressions are released.
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I’m willing to bet most of the lag is due to ECU undertuning combined with emissions filters.
Once the ECU is cracked and people are bolting on parts, I presume much of the lag will be gone.
Still, hardware wise, BMW engines can be wildly different within even the same designation and they even have changed valvetrain dimensions, compression rates, intake design, turbo design and even aluminum quality. Within the x4/58 engines I’ve seen some T designations having stronger crankshafts and more robust pistons still being the same designation ie both B58xxxx.