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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N54 Turbo Engine / Drivetrain / Exhaust Modifications - 335i > Jerk/surge versus starting rpm of acceleration



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      07-31-2009, 08:12 PM   #1
Slidewayz
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Jerk/surge versus starting rpm of acceleration

OK, so maybe this is subjective, but...

It seems like the time rate of change of acceleration (jerk/surge) is greater when acceleration starts at a higher rpm.

This isn't just spool time for the turbo...enthalpy of the exhaust gas...blah blah blah.

What I have noticed is that if I start accelerating at, say, 1500 rpm, the rate of acceleration is lower at 5000 rpm than it is if I start accelerating at 3000 rpm.

Is this an ECU thing? Not clear how it can be measured or if I'm just hallucinating, but I did a bunch of runs and it sure seems like you catch the car napping...
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      07-31-2009, 08:29 PM   #2
JayKay335i
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Take a peek at the torque curve.
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      07-31-2009, 10:31 PM   #3
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what I'm getting at is how power delivery varies AT THE SAME RPM depending upon the initial WOT rpm.
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