ptindall

I don't plan on doing this anytime soon, it's just something I've been thinking about because 2/3 tracks I run on, I wind up just ridding the rev limiter for a second because a have to brake in a second so upshifting then immidiately downshifting doesn't seem worth while. What would it take to safely raise the rev limiter on my stock 2001 LS6 to say 7000rpms? Underdrive pulley, stiffer valve springs, and a tune? Anything else? The engine feels like it's pulling strong at redline, I'd assume it would keep that up for another 500rpms. Any negative side effects?

VetteDrmr

7000 rpm is pretty aggressive. Not only do you have to worry about valve train, but also the rod bolts. You could probably bump it 200 rpm, but the more you go away from the factory limiter the more borrowed the time is left in your engine.

Risk vs. reward. I don't make any money at autocross, so I left my rev limit alone when I got it tuned last week.

You could try running the higher gear (esp with the MN12 tranny), and see how that works. It might feel slower, but end up quicker (don't lose time shifting and can concentrate fully on the course. Or, when that doesn't work, just breathe the throttle when you get towards the limit (or let it hammer on the limiter, although I don't like doing that).

HTH, and have a good one,
Mike

Bill Dearborn

Just breathe off the throttle a little. In HPDEs you are not competing with anybody so why take the increased risk of having a multi-thousand dollar headache instead of a nice track day. Remember your car will not be worth one more penny when you leave the track than when you came. However, it could be worth a lot less.

Bill

Jaymz

I have a stock ls6 that the rev limiter is set to 7250. I usually spin it to 7000-7100 all of the time. Just keep fresh vavle springs in it and you will be ok.

spazegun2213

7K is fine on some of these motors. You might want to upgrade the springs and the pushrods, but thats all I'd do. I'm going to raise mine as soon as i get the headers on the car.

GettReal

I have mine set to 6800 but almost always shift around 6500'ish or will actually short shift around 6200 if I feel I need to run in that next gear for a bit, as others have said, at the end of the day the real prize is a car that aint broke. 7000 Might be on the agressive side on a stock set up

ptindall

FWIW, I do come off the throttle a tad, not just leave it floored banging off the limiter. As for the rest of your comment, couldn't you say the exact same thing about any mod to go faster? Why don't we all just leave our cars bone stock and run on runflats? We could keep warrantees and with soo much less grip, there would be less stress on all the parts and the car would last longer. Don't get me wrong, I have nothing against voicing your opinion or whether I should make the change. I'm trying to decide that myself. The point of this thread was to gauge that risk + cost vs reward by learning what needs to be done to the engine to make the higher redline safe. That's what I really want to learn.

ptindall

Doing the math, 500 more RPMs would give me another 7.7mph in third gear. I'm sure that would cover my needs. Plus it would sound more wicked. And that's priceless! Anybody else have expirience or knowledge on spinning the LS6 to 7000?

waddisme

I think if you do a search you will find in a thread where the stock motor is good for 7000 rpms. When I had my sc, I thought about bumping it up because power at 6500 was still climbing but decided not to. Now that I have an internally forged 402, I will probably bump mine up. Doesn't mean I have to use it all the time, but if I want to occasionally.

the blur

At a certain point......
(my turning point was about 5 years)
I came to realize what the others have said..
breaking parts just isn't fun anymore.
rotors, wheel bearings just to name a few.

back off to 8-9 tenths, and I'm having MORE fun.
because I'm not fixing the car any more !!
my wallet is heavier.

and I know at 8 tenths, I'm not going off track unless something real uncontrollable happens.

unless your moving up to W2W NASA or SCCA, then forget wringing every second out of the car. it just isn't worth it anymore.

but the answer is yes, the T1 guys all raise their rev limiters. I wouldn't do it on a street car, as they all replace their motors every few years.

AU N EGL

I agree with Jaymz here.

Springs need to checked often. One does not need stiffer springs, just the right springs to spin 72-7500 rpms

So each winter you might need to check you springs, valves and valve seats

davidfarmer

I was told by some of the Katech engineers that did endurance testing with GM the following:

97-00' engines: 6500max rpm
01-up engines: 6900 max rpm

This change is due to the rod bolt change in 01. The orginal bolt had very sloppy tolerances, and gave no side-support.

I certainly have run engines higher, but they said this is the highest they could test for extended red line use.

LehmanZ06

7000 rpm. For the last 3 years. Dead Nuts reliable. Sometimes on the limter for a max 2-3 seconds-----Mostly about .5 sec-----

1200 miles since change. Car is dedicated autox---ASP car

VetteDrmr

I think that's what we're trying to give you suggestions on. Some mods (intake, headers, underdrive pulleys, etc.) are very low risk mods, while spinning an engine higher increases cyclic and tension loads on the reciprocating parts. Basic physics.

I also think you'll note that everyone that's had success with 7000 rpm limits are using dedicated track cars. Mine is the fun car for my wife and me, autocross and DEs are a small part of the car's life.

I guess it all comes down to YMMV.

Good luck, and have a good one,
Mike

0Randy@DRM

I have thrown away a ton of 7000 rpm engines. Rod bolts, rod bolts, rod bolts. We have messed with drivers in the past and set limters at 6000 and even 5500 rpm and the lap times came down. Short shift that baby and let it pull in the next gear. Try and see if your lap times come down. If not, spin it to the moon.

Randy
FWI LS engines at 8000 rpm sound very nice, but require huge cost to keep out on the track.