L98Terror

So during qualifying on Sat morning I went from 3rd to 2nd in the middle of a corner I got the clutch back in pretty quick but the engine saw 8250 RPMs per my memory tack

Everything seemed to be OK so I ran the first race and all seemed fine than at the start of my second race my throttle stuck wide open and it bounced of the 7500 RPM Rev Limiter (Yeah I know that should be lower) for a second or two.


I'm thinking that's bad, BTW the car ran great for the rest of the race minus me not being able to go to full throttle beck of a sticking peddle

tiojames

You don't mention if you have after market valve springs or not. If you don't have them you are leading a charmed life with the limiter set to 7500. Since you feel the car runs OK it would seem that no damage was done. Only you can tell if the car doesn't perform as usual.

Old Rotor Head

I hit the rev limiter once to often and broke 4 springs. You'll know when it happens. That's 4 broke and 3 cracked, weakened. I'd take a look under the valve covers when you get a chance just to be sure.

L98Terror

Stock LS6 springs, I figure at least it needs new springs

John Shiels

not good

overBlown

I'd change those springs for sure. The throttle going wide open by itself is weird though. It's a fly by wire system so somethings going on there that you need to have traced. Why is your rev limiter set so high? That's crazy!

ctsv510

~Josh

7k+ rpm on a stock bottom end is asking for it.. Revving that high even with Comp 918 springs is insane.

Poor car.

Deception

I've done something similar when I went from 3rd to 2nd. Like everyone else has said pull the valve covers and check the springs and pushrods.

John Shiels

replace springs and push rods and may be timing chain.

XtremeVette

Ok first off...how was your car able to run with a sticking throttle? The normal "safeguard" is "reduced engine power". This is normal for all C5's. Soon as the throttle blade sticks it will trip this sensor and throw you into "reduced engine power mode". Also what have you done to the car that allows you to go 1500 over redline?

To answer your "titled" question....YES, 8250 is bad. Shoot anything over 6000 is considered bad as the stock LS1's redline is 6. Some raise it to 6500 for the moments of peaking....but still from the stuff your describing, I wouldn't give that LS1 of yours too long treating it like that. Be prepared.

The other thing Ken, what kind of car are we talking about here. Your profile says you have a 91 L98? Hope thats not the car we are actually talking about lol. That's even worst! The L98 peaks at about 4400 RPM. So doubling that!

Might want to update your profile if it's a C5.

0Randy@DRM

Independent1

Have to agree with others that it was not good.

Looks like you may have gotten lucky.

Would think that with only stock springs you would have encountered serious valve float with anything over about 6800 rpm.

L98Terror

It was in my race car, LPE WC spec LS6 bottom end w/stock heads also the car has a manual TB all those electronic safe gaurds are long gone. So far looks like no damage but we haven't dug deep yet

Normally I shift around 6800, but depending on the track 7k has been seen

I also have a 91 coupe, that has seen high 6s my times again far from stock

RideZX6R

check your spings and pushrods.
Anything else gone wrong you'd have known it already as the car wouldn't have "ran fine" for the rest of the day.
get it on a dyno and check to make sure power is there, get it re-tuned and have them lower your fuel cut to be a little safer.

John Shiels

mechanical over rev from what I understand he said is how it happen. No electronics to stop that to my knowledge. I have a LS6 H&C and keep in runnig no more than 6800 but usually shift at 6600. I do run in in the upper rpm range compared to most in and out of corners.

8200's I would think it is compromised somewhere mechanically which could lead to a real expensive boom if not checked very carefully.

From memory I though the LS-1 was redlined at 6600? yes no

John Shiels

bet it didn't do the timing chain any good even though it may be running OK now.

Y2Kvert4me

Stock, the LS1 rev limiter is set at 6200, LS6 is 6500.

The stock valve springs and pushrods are by far the weakest links, followed by rod bolts.

If (as stated) these are stock LS6 heads, that's a pretty light and stable valvetrain out of the box, and likely can handle that RPM in bursts, but not advisable for continued operation. The usual consequence of an unloaded over-rev like this would be valve float, valves hitting pistons, and pushrods would be coming out shaped like boomerangs. The valve seals may also unseat or endure some damage in the event of a serious valve float case. The timing chain will deal with it, unless a harsh valve impact jerked it beyond it's yield. (the shape of the pushrods would tell that story though).

If the engine is still running good and quietly, it's likely none of that occurred, and probably no need to worry.

Oh, and FWIW, even though the engine under load can probably take it, setting rev limit at 7500 with stock valvesprings and pushrods is really gambling.
A simple beehive spring and pushrod upgrade would make it much more stable at that limit.

twinturbogto

if you have not had any problems i would not worrie about it on my ls6 with a fast 90 and american racing 1 7/8 headers i shift at 7200 from light to light for the last 3 years sometimes missing a shift but i do not know what RPM it flashes to i have the reve limiter set to 7500. i did the tick MC upgrade and never miss a shift anymore well worth doing!

RideZX6R

true. I was thinking you'd hear it but then I read all he had modified on the motor, you probably wouldn't hear it over that.
So it might not be a bad idea to check if youre gonna tear it down anyways.