Brangeta

This question isn't related to the LS engines specifically, but this section of the board will do nicely for this discussion. Discuss engines in general.

Here's the scenario:

I revved the engine in a Pontiac G8 GT up to 4000 RPM (where the rev limiter is) several times in neutral.

I posted a video on youtube and two guys have the idea that this does damage to the engine.

I think this is crazy talk. That 4000 RPM would never hurt a warm engine on a nice warm day that has the proper amount of oil in it.

What do you think? Who's full of crap? Me, or the other two guys? Discuss!

c5_ls1_6spd

iTrader: (-1)

There is no load on the engine, it's just free revving so I don't see why it would hurt it.

ls2pontiac

iTrader: (1)

you could throw a rod if you hold it there for too long. If you mistakenly put the lever in drive while the motor is revving you will blow out the transmission as well

Project GatTagO

iTrader: (7)

Do you seriously believe that to be true? Give me a break.

Guys that use 2 steps to launch at the track routinely hold the RPM at higher levels than 4000. You don't see rods flying anywhere.

Andrew

GO BABY GO

iTrader: (15)

I think it has something to do with the oil pressure not keeping up with the sudden change in high rpms that damages the engine. I believe i read that somewhere but you cant believe everything you read. Just a thought i guess?

Doomsday

iTrader: (8)

Im no expert, but I feel it does. My first few sportbikes I owned were driven hard and kept at the upper RPM. I never rev my car or bikes. To me the load tends to keep it "stable". Where as other dumbass that bounced it of the rev limiter, had the some noisy valvetrain going on, this is bikes of course.

Zosickness

Shouldn't hurt it. Depends on the piston speed and what rpm the engine was designed to run at.

dshag

iTrader: (1)

as long as your past the break in then it shouldnt hurt...but i doubt you are since those just came out

unSStoppable

iTrader: (1)

i def think you can float a lifter by over revving it

Brangeta

I forgot to mention a few details that might make a difference to a few of you guys' answers.

1. The car's redline is (best I can tell) between 7000 and 8000 RPM. Strangely the gauge doesn't actually have a "red zone" on it like all other cars I've been in, so without researching it, I don't know the exact redline.


It seems like most of you guys agree with me that just a bit of revving doesn't really matter.

2. The car has a rev limiter at 4K that just plain STOPS the car from revving any higher. Neither my LT1 nor LS1 have this (if the LS1 has it, I've never seen it happen), so I didn't even know what it was when I first saw and heard the car stop at that RPM.

I don't know if bouncing off a 4K rev limiter is bad or not. Probably not the best thing for whatever "limits" it, but I can't see it hurting the engine as a whole...

3. I forgot to post a link to the video. http://youtube.com/watch?v=x_R6sVhNvbc As you can tell, the RPM only jumps past 4K one time, but from my perspective (whether I'm an idiot, or not): big deal! I've revved up my factory stock LT1 in park/neutral a few times to 4K with no known problems and no catastrophes, and my LT1 definitely doesn't have a redline that high nor such high quality internals.

Let the discussion continue...

WickEdSix98

iTrader: (4)

A free revving engine will tear up quicker than one with a load on it but 4000RPM isn't enough to worry about.

bad2dbone

iTrader: (37)

To Much Of It Everytime Def. Will

P Mack

iTrader: (6)

Revving a cold engine is bad. And reving an engine puts a lot more stress on the timing chain because it has to accelerate the camshaft at a much higher rate than normal.

Beaflag VonRathburg

iTrader: (176)

Why is there a 4k rev limiter? That's odd...

needadvice

revving an engine anywhere near redline is completely useless and a waste of engine wear and gas.

4,000 rpm rev limiter, what the hell is that all about?

drz

iTrader: (3)

Many auto-equipped cars these days have secondary "neutral" position limiters to protect the drivetrain from careless owners who might intentionally or accidentally engage the transmission in "drive" while free-revving the engine - aka as a "neutral drop". While it still wouldn't be good for the transmission to experience this at 4k rpm, it won't explode like it certainly would at 6k.

4000rpm under no-load isn't going to hurt a thing, not when these engines are dyno-tested by GM to withstand 200+ hours of full load, 4000-6500rpm as part of their development program.

Does nobody remember the old days of the 3 and 4 speed gearboxes that had no overdrive? Some were factory equipped with 4:10 rears! 4000rpm was the highway cruising speed for those cars, but that didn't keep them from being driven great distances anyways!

needadvice

Oh, I didn't know there were "nuetral" rev limiters. Yeah, 4,000 rpm is nothing, its revving to redline in nuetral that can't be too good for something in an engine.

UTE 500

I read about this somewhere on an Australian forum i think. the idea is to stop 'hoons' (young idiots) from messing arround revving their cars in an anti social way. you better be careful, i read that if you keep doing it the PCM assumes you have stolen the car and are trying to blow it up, and it will shut the engine down, requiring a dealer re-boot.
Then it locks you in the car and sets off all the air bags. (only kidding about the las bit)

MeentSS02

iTrader: (11)

I think the biggest danger is over-shooting the rev-limiter before it has a chance to kick in with no load on it. I have my rev-limiter set to 6300 RPMs, and in 2nd and 3rd gear (with a load) I can still get at least 50 RPMs over this limiter before it actually has a chance to do anything (verified with my scanning software). I'm sure it could go more than 50 RPMs over without a load on it, and that might cause some damage if you don't have the parts to support such an over-rev.

brad8266

iTrader: (23)

You can bang it off the limiter in neutral and it wont do **** valvetrain wise.

The problem is that supposedly with no load on the engine you can get ring flutter when revving hard in neutral.