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Thread: E38 and E67 rev limits

  1. #1
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    Default E38 and E67 rev limits

    Hello, I have a problem that has been annoying me for years. On E38 and E67 ECUs the rev limits are a bit strange.

    One, B5209 and B5210 don't appear to do a damn thing on any of the systems I have tried them on. Description says "This parameter defines the maximum allowed RPM, this Rev Limiter will override all other RPM limiters and will always use Fuel cut for limiting regardless of the settings in B5205, B5206 & B5207." but the reality is I can set B5209 to 6000RPM and the engine will happily rev to 7000 if the other rev limit tables allow it. This is not EFILive specific, the same parameters in HPTuners didn't do a damn thing either on a 12605669 OS E38 ECU I tuned last year for a customer who already had a HPT license for their ECU.

    Two, there is no way to configure the hysteresis with the fuel cut limit which appears to be as much as 500-700RPM. If I hit the limiter at 6300RPM the engine won't start pulling again until the revs are down to 5600-5700RPM. I can fix this with HPTuners by editing a table they call "RPM limit vs torque delta vs gear" but it seems stupid to pay 100 bucks for a license just to fix the rev limiter when EFILive is a superior solution for almost everything else.
    It's really bad to lose so much wheel speed if hitting the rev limiter in the highest gear on an off road racer.

  2. #2
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    I should mention none of these cars have a VSS. Would that change the behaveour of these functions?

  3. #3
    Lifetime Member Tre-Cool's Avatar
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    more than likely a rev limiter tied in with a vehicle speed limit and with the vss most likely defaulting to 255kph

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