4K Rev Limit in Drive
Thread Starter
Drifting
Joined: Apr 2000
Posts: 1,442
Likes: 209
From: Lake Mary Florida
4K Rev Limit in Drive
I understand the factory tune has a 4000 RPM rev limit for certain conditions e.g trans in park or neutral, extreme cold outside temperature, etc. Has anyone experienced this 4K limit "randomly" override the 6500 RPM rev limit set by a custom tune during during "normal" conditions?
On the first time run Saturday the 4K Rev limit hit again at launch after a "normal" burnout that went well above 4K. The week prior I had three good runs with no problem. A Google search showed a number of references to this problem but all were from an HP Tuners blog site that was all highly technical tuning stuff that I could not understand. My tuner noted this problem before, reset the rev limit to 6500, and made number of good dyno pulls. Obviously something is happening that is causing this to reoccur. Any ideas about a fix that I could discuss with my tuner will be appreciated.
On the first time run Saturday the 4K Rev limit hit again at launch after a "normal" burnout that went well above 4K. The week prior I had three good runs with no problem. A Google search showed a number of references to this problem but all were from an HP Tuners blog site that was all highly technical tuning stuff that I could not understand. My tuner noted this problem before, reset the rev limit to 6500, and made number of good dyno pulls. Obviously something is happening that is causing this to reoccur. Any ideas about a fix that I could discuss with my tuner will be appreciated.
Last edited by BIGMAC; Nov 9, 2020 at 06:24 AM. Reason: typo
Race Director
Joined: Dec 2013
Posts: 12,502
Likes: 3,631
3K is the neutral rev limit on a auto trans car in either park or natural (cmd gear control limits), and it not the same as the redline limit.
But cmd gear control limits can be changed from 3K to 4k when the car is in park or neutrals to allow it to rev that high, and may be what is going on, and the car not seeing itself in gear with an A6 trans.
As for M6 trans cars, then don't use the cmd gear control limits, and it's turned off when the trans is set as manual.
Well kind of, but will kick in if you are launch control on later cars, and have the car in launch mode until you come off the lower clutch pedal sensor.
If you can post a copy of the tune, should be able to find that value(s) that is screwed up in the first place that is causing the problem.
But cmd gear control limits can be changed from 3K to 4k when the car is in park or neutrals to allow it to rev that high, and may be what is going on, and the car not seeing itself in gear with an A6 trans.
As for M6 trans cars, then don't use the cmd gear control limits, and it's turned off when the trans is set as manual.
Well kind of, but will kick in if you are launch control on later cars, and have the car in launch mode until you come off the lower clutch pedal sensor.
If you can post a copy of the tune, should be able to find that value(s) that is screwed up in the first place that is causing the problem.
