Quote:
Originally Posted by maxnix
It's about the torque increase down low, not the upper rpm calculated number.
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What about us that want torque up top?
The reality is they got as much boost as they could under all stock hardware, and the turbo can push more boost at lower RPMs without putting out too much hot air (getting further out of inner efficiency island), so you end up having lots of torque down low (2000-4500RPM) and the turbo starts to put out a bunch of heat up top (4500-7000RPM) as it spins faster and faster to attempt to hold that same boost pressure to red-line.
Normally the octane of pump gas alone on stock hardware can't overcome that inefficiency (extra heat) of these tiny turbos up top, so they knock the boost down a few psi by redline to reduce chances of knock. (pre-ignition)
So, the torque drop happens from not only the turbos getting further out of their efficient range, but also from the tune/ECU dropping boost in the upper RPMs to prevent detonation.
If only BMW gave us a GTX3582R from the factory..........
