discussion - why is rev limit stock 6000?

[navyblue2000]

Ok, I did a little research.

Ignition system is fine.
It seems our fuel system goes 100% duty cycle around 5800 RPM's.. This is due to injector pulse widths. Our injectors are just too small to be able to handle the higher RPM's. This doesn't mean we can't rev high, it just means that we may run a little lean. 24lb injectors should due the trick though.

Regarding revving. I read that a few GTP's were revving close to 7K RPM's occasionaly on stock valvetrains WITH COMP cams. I would be concerned with valve float past 6500 RPM's but these guys seem to be ok.

It is probably a good idea though to upgrade the springs to rev higher with a faster ramping cam. The stock pushrods should be ok as long as the gemoetry is correct. The rockers should be no problem.

As far as the bottom end, well from what I hear, high RPM's isn't very engine friendly.

If you rev higher, you risk breaking sooner.

What do you guys think?

*experimental*

[3.4 slow to go]

<blockquote>quote:</font><hr> If you rev higher, you risk breaking sooner. <hr></blockquote>

that's why ricers are always breaking down, cars w/no torque gotta rev high to move [img]tongue.gif[/img]
(crotch rockets excluded ;) )


it's also the "theory" behind big block motors (nascar excluded): make ungodly amounts of power & keep redline around 5500-6000 rpm.

[nocutt]

If you have a completely stock motor then I wouldn't REV past the stock limiter...too many issues, on the other hand, guys with a better head package and cam can do it, although as stated 6500-6700 is safe enough...especially if you have aftertmarket rocker arms (you are good to go) the stock bottom end is good for ABOUT another 700-1000 RPMs (but how many people want to test the unknown limit?).This is also assuming you can flow more fuel (to be on the safe side)...on two occasions I removed the VSS thinking it will eliminate the speed-limiter...oh duh...lol!! That thing went past 6K so quick (no shifting mind you!!) it was really scary...
Although there is nothing conclusive here but you get the drift...the car had enough air (turbo) and fuel (aftermarket computer) at this high RPM...I was safe (at least for that day)...

[ October 04, 2002: Message edited by: nocutt ]</p>

[Amped96]

<blockquote>quote:</font><hr>Originally posted by 3.4 slow to go:

(crotch rockets excluded ;) )


it's also the "theory" behind big block motors (nascar excluded): make ungodly amounts of power & keep redline around 5500-6000 rpm.<hr></blockquote>

Huh? Crotch rockets rev very high and so do a lot of drag cars.

[MustangEater8251]

notice alot of drag racers break [img]smile.gif[/img]


I would not consider reving that high on stock internals, I thought you said somethine about upgrading to something else.

3 things kill a motor.

No oil
heat
High revs


Some our connected and kill your motor in conjunction.

[3.4 slow to go]

they're excluded because they're designed to rev high. I've seen Crotch rockets w/redlines around 12 stock. Drag racers & nascar are built using aftermarket forged internals to withstand the high revs & abuse they will undergo. valve float can be an issue, but that can be overcome thru the use of higher pressure springs & full roller valvetrain assembly to help counteract the additional friction from greater valve spring pressure.
Rev limiter: Maybe it's just a built in safety feature to keep those (including myself [img]graemlins/dunce.gif[/img] ) from blowing up their engines.