Rev limit musings
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Joined: Oct 2010
Posts: 2,447
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From: Australia
Rev limit musings
Currently, my RA rev limit is:
ON: 7156
OFF: 6977
This is left over from GST Base Map 2.0 - I retained that particular setting when moving to Bryan's more recent base maps. Boost tapers quickly to 14.5psi at 7000rpm on our dinky stock RA t/c, and torque is falling fast from about 6200rpm. So there doesn't really seem a lot of point to wringing its neck up top.
Having said that, I dislike the rev-limit knock I see on the rare occasions I do hit the limiter... when the red mist descends on-track.
So... is there any reason not to spread out the "limiter on / limiter off" gap some, so the engine isn't bounced so fast between fuel-cut and fuel-restored? eg.
ON: 7396 (GST 2.5 limit)
OFF: 6977
Or would such a change mean more drivetrain stress when the respective limits are reached? I'm mostly thinking about whether the "staccato" rev limit effect of the stock 150-rpm difference is actually more gentle than a distinct on/off cycle with a gap of (say) 300rpm.
If anyone has direct experience coming from playing with rev limit fuel-cut hysteresis, I'd be keen to hear your thoughts.
Rich
PS. I know... don't hit the rev limiter. Rev limiter bad. But the real world keeps crashing in.
ON: 7156
OFF: 6977
This is left over from GST Base Map 2.0 - I retained that particular setting when moving to Bryan's more recent base maps. Boost tapers quickly to 14.5psi at 7000rpm on our dinky stock RA t/c, and torque is falling fast from about 6200rpm. So there doesn't really seem a lot of point to wringing its neck up top.
Having said that, I dislike the rev-limit knock I see on the rare occasions I do hit the limiter... when the red mist descends on-track.
So... is there any reason not to spread out the "limiter on / limiter off" gap some, so the engine isn't bounced so fast between fuel-cut and fuel-restored? eg.
ON: 7396 (GST 2.5 limit)
OFF: 6977
Or would such a change mean more drivetrain stress when the respective limits are reached? I'm mostly thinking about whether the "staccato" rev limit effect of the stock 150-rpm difference is actually more gentle than a distinct on/off cycle with a gap of (say) 300rpm.
If anyone has direct experience coming from playing with rev limit fuel-cut hysteresis, I'd be keen to hear your thoughts.
Rich
PS. I know... don't hit the rev limiter. Rev limiter bad. But the real world keeps crashing in.
