i was wondering how high we can rev the 4g63 in the evo...

my question comes cause i am running the 6 speed MR transmission and bouncing off 4th gear rev limiter about 3-4 times before crossing the 1/4 mile line. trapping 114.

stock rev limit is around 7400? i was wondering how high we can rev without dueing damage. maybe raise it to 7600? 7800? or when do i need to upgrade the valve train? thx!

trying to break into 11's with TBE cams and tuned(evo8). i believe if i raise the 5k launch control to 6k or around there, and raise the rev limit to 7600-7800, then i wont bounce off it until after the finish line, maybe improving my 12.2@114, to a 11.9@115-116 with a better launch and not being held back by 4th gear rev limit.

 

If you get a flash or tune, they can raise it to around 7800 which should be fine on the stock internals. why don't you just shift to 5th? Some members shift earlier than 7400 because there might be a little loss of power right at that level...

 

friends don't let friends type "RPM's" (RPM is plural)

 

Use taller tires


unless rotation is constant and minutes is variable, ha ha hha

 

instead of criticisizing, how about actually posting something like I did to help this guy out, I am sick and tired of read all these posts with maybe 10% usefull information.

 

I too am curious as to why you don't shift to 5th... It can't be as bad as our 5 speed's 4-5 shift. Even so, just as dan said, your power actually takes a dip after 7600 or so. Just try shifting at 7400 and go to 5th.

 

That would be MPR not RPM.

I've tagged 8k a few times because my flash lets me go up there and the engine is still living.

As most manufacturers do, the stock limit is probably a conservative limit and is why you see tuners pushing it to 7800+. I still fear oil starvation when in a high speed corner at high engine speeds, so 7400 is it for me. On my next flash I'm having it dropped back down to the stock limit just for safety.

 

I gained 2mph in the 1/8 and lost almost 200 rpm (7800 down to 7650 rpm) going from stock 235's to 245 45's. You may not think that's "useful information" young man, but to me and possibly others, it is very significant.

 

taller tires will most definitely lower your engine rpm at the same speed.

 

First of all, on the stock rev limiter, which is 7600rpm, you can't go over 111mph, so I don't know how you're hitting 114mph unless you already have a rev-limit-raising flash. Dynoflash raises the limiter in his flashes to 7800, so if you have one, then that's where it is.

If you are already trapping 114mph, then you already can hit 11s if you learn to launch better and shift faster. Before my flash, I managed to hit 12.01, but was hitting the rev limiter and only trapping 110-111mph. After my flash and a rev limit raise to 7800rpm, I have never once hit the limiter at the drag strip, but my h ighest trap is 113.7mph (usually low 113s). I still am stuck at 12.000, but if I were actually able to hit 114+, then I'd be in the 11s. It sounds like you just need to learn to cut some 1.6 60's, but you could probably raise your limiter to 8000rpm and be fine. People go that high on the stock engine/head internals.

Btw, raising your launch control to 6k rpm or whatever will have no effect on your end-of-track rpms - not sure what you were thinking there...

 

thanks everyone who gave useful information =)

 

sorry if this doesn't make sense, but what would be a feesable(sp) limit w/ cam gears and 272's or would it change anything?

I don't mean to hijack the post. I was just curious and it applies to the topic.

 

If 6K will get a car out the dig faster then it would have a slight effect on trap rpm, but then again I'm not a physicist.

One thing I do know, tire spin gave me significant trap rpm change.

About safe rpm with stock eng, I want to know that too.

 

Three obvious things that need to be considered with the EVO pursuant to a safe rev limit are valvetrain, piston speed, and optimum shift points. When you look at all three, a practical rev limit of around 7800rpm seems like a good compromise.

The stock valvetrain doesn't appear to be intended to keep things in check at extraordinarily high rpm, and aftermarket cams with higher lift and/or more aggressive ramp rates will make matters worse, not better.

The 4G63 is a long stroke engine, which means that piston speed hits 25 m/s around 8500rpm. That's usually recognized as a practical limit for a robust street engine. The EVO's cast pistons aren't exactly the best choice for swimming in those waters (especially with a turbocharged engine), and so I'd consider a safe limit to be somewhat lower.

And perhaps most significant, with pretty much anything smaller than a GT30R variant, optimum shift points tend to occur around or before 7800rpm. Where this is the case, there is no reason to rev it beyond that figure. If you're making enough power to where that point limits 4th gear at the track, that is an aggravation that requires compromise in one way or another to resolve.

 

It won't change the fact that he's hitting his rev limiter at 114mph. It doesn't matter what rpm you launch at. What you are referring to is a better (or worse) 60' changing how soon you get to the traps. It's not going to give him anymore rpm or mph, because the limiter won't change.