Help! Over-Rev
Thread Starter
Instructor
Joined: Jan 2002
Posts: 147
Likes: 0
From: The shore of Lake Ontario NY
Help! Over-Rev
Last fall I let a friend drive my vette. Yeah, I know. He mis-shifted from 2-3 and went 2-1 @ redline instead :eek: ! Any ideas how many rpms she may have seen? Anyway, afterwards the car seemed fine. I put about 1000 miles on it last fall before she was put away for the winter and everything seemed fine as well. As the snow melts and the salt washes away, I'm getting closer to having her back on the road and I'm starting to worry about it again. Should I or would I have seen a problem already? Please help ease my mind (or give me nightmares if that's the case). Thanks!
Le Mans Master
Joined: Feb 2002
Posts: 7,858
Likes: 2
Re: Help! Over-Rev (vetteman32)
The control module should shut off fuel to the injectors at anything past 5800rpm. The module has a programmable "rev limiter" setting-- the stock setting is 5800rpm. I believe the stock LT1 in Corvettes is good up to 6600rpm (but I may be wrong). Hypertech Power Programmer III sets the limiter to 6200rpm as part of it's power tuning operation, for '95 Corvette LT1.
My guess is you're okay-- the rev limiter should have protected it from over revving to the point of damage if your engine control module is using the stock GM programming.
My guess is you're okay-- the rev limiter should have protected it from over revving to the point of damage if your engine control module is using the stock GM programming.
Burning Brakes
Joined: Aug 2000
Posts: 984
Likes: 1
From: Cincinnati OH
Re: Help! Over-Rev (bmh95)
In the scenario described, no rev limiter in the world would have done a darn thing. If he really was at redline in 2nd gear and downshifted to 1st, the motor was mechanically forced to an rpm which is redline*1stGearRatio/2ndGearRatio (of course the rpm probably dropped so it may not be nearly that high). I don't know the ratios off the top of my head. The rev limiter just prevents the engine from "revving itself" past a certain rpm, but in this case there was an external mechanical input causing it to blow past redline.
Le Mans Master
Joined: Feb 2002
Posts: 7,858
Likes: 2
Re: Help! Over-Rev (Vince Ivanc)
In the scenario described, no rev limiter in the world would have done a darn thing.
Melting Slicks
Joined: Aug 2001
Posts: 2,516
Likes: 0
From: Lockport NY
Re: Help! Over-Rev (Vince Ivanc)
In the scenario described, no rev limiter in the world would have done a darn thing... but in this case there was an external mechanical input causing it to blow past redline.
Try a compression test. If the valves touched the pistons and bent, they won't seat/seal correctly. It should be noticeable...
(This assumes the compression was consistent before you loaned it out)
Don't let this person near your car again... :nono:
Melting Slicks
Joined: Jun 2000
Posts: 3,215
Likes: 6
From: Tampa Florida
Re: Help! Over-Rev (vetteman32)
If the engine runs fine for 1000 miles then I wouldn't think any damage was done...your valve springs may little lower on pressure now but again if it runs like it did before-no worries.
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