I am just curious what all comes into play in the Rev Limiter....
I have seen some Cavy's with 6250, some at 6500....
And i know with mods you can go higher.

I am just curious as to what all comes into play in determing what your engine can safely handle.... why are some LD9's 6500 and others 6250?

What all should be addressed to handle say 7000rpm...
Not looking for anything crazy here, not trying to hit 10k... i just hit my 6250 rev limit real easy, and wondering if i am ready to nudge it up a hair.

I would just like to get a lil extra time before shifts. From what i have read, i should already have MOST of the things needed for high RPM's... please check my profile for the list.

I still have a stock bottom end, but that is about all thats left stock. from head gasket up, it is all performance parts.

I know above 7000rpm the oil pump wont cut it... but as i said, i dont need to go over 7k. pushing it TO 7k would be plenty for me. Maybe if i did a forged bottom end, then 7k+ may be an option... but for now just wondering if i am asking for trouble bumping to 7k

According to you profile, you still need to do the valve train, i.e., cam(s) and springs. The camshaft(s) is(are) the biggest determining factor as to what rpm your motor will make it's best power. Without the appropriate cam(s), there is no need to try to turn more rpms, you won't be making as much power beyond your peek HP rpm. The springs are needed to keep the valve train stable at the higher rpms, you don't want valve float (valves bouncing off the valve seats, because the springs aren't strong enough).

A bigger TB would help also. The stock TB is 52mm. You can get a 2.3L Quad 4 TB, which is 56mm or go with one of the aftermarket TBs at substantially more money and some with questionable quality.

oh crap... i guess i need to update my profile then....

i currently have a 62mm TB... "secret" cams... and...

Head: Mild sports porting and polishing with valve work to optimize mid and upper range power without losing low end torque. Comes with our special stainless steel 6mm performance valves and H.D. valve springs. Comes completely assembled with new seals, retainers, and keepers.

Wanted to go bigger on the cams, but i didnt know where to find decent ones... (but i still want streetablility... cars spends 98% of its life on the freeway)

ok, there... updated profile... i think it is current now....

ok, so again... what more do i need to safely peak at 7000?

or how far could i go with what i have now?

you need HP tuners software to raise the rev limiter. unless someone else has a different way



Im a Xbox 360 fanboy...and damn proud of it!!

i have HP Tuners, I know HOW to increase it... i just want to make sure i can do it safely...

Yeah, that looks better. I don't think the "(not so) secret cams" will peak out at 7K, but you should come close to using that as the rev limit. In other words you peak power will hit a few hundred rpms before 7K. This is a good thing, because you want a little rev room over you peak power point.

so what kinda cams do you suggest? and where does one get them?

I was rather disapointed by the nearly-stock-ness of the "secret cams" the one cam was ALMOST identicle to my stock one.... and the other was just ever so slightly bigger.

So i would no be opposed to better cams if i could find them and they didnt cost me my first born.

I need to update my profile but here is what I have right now

.430/222 cams
HO springs
stock 97 head
Diamond Racing 9.5:1 pistons
Eagle rods
2.3 oil pump swap


current rev limit is 7500 RPM

I thought that a stock LD9 could handle 7k?

I have my rev limit set to 7k, but I try not to push it that far. Stock cams start to fall off around 6k NA, but I am not sure under boost






Jason
99 Z24 Supercharged
157hp/171tq - NA
LD9 for Life

used to shift mine at 6800 or so.

Stock ....um.. everything. (besides my "bolt-ons"


Chris


'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

I thought the limiting factor on the stock bottom end was the rpm of the balance shafts and oil pump, the max rpm of the balance shafts is near 5800 or 6000 engine rpm. Someone correct me if I'm wrong but trying to spin above 5800 -6000 rpm on stock bottom end causes spun bearings because oil pump can't supply enought oil at higher revs.

maybe, but 136K.......

I also did have 15W50 M-1 in it to help the "short comings" of the small 2.4 pump.

Chris


'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

I have been running up to 7000rpms for some time now on an all stock internals and with my current setup. Short burst of 7000 is fine. I know from personal experience. I ran my car to 7000rpm shift multiple times on a daily basis. If anyone were to have a problem from this I would be the first. I am sure of this based on the way I beat on my car. I will be posting videos showing 7grand shifts in every gear soon. And when I dyno I am going to run it all the way to 7grand for hard core evidence of what power it makes at x rpm



FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!

What about balence shafts?
are these a limiter of engine RPM? or a sore point for those craving higher rpms?
I understand they can be removed, or replaced with non-weighted shafts...

Is this worth doing? how bad are the vibrations that are gained in doing such? how much power and reliablity is gained by removing them?

I just imagine those suckers spinning at 14,000 rpm gotta be a weak link in a high reving engine...

So what is gain and lost by removing them? and do performance engine mounts amplify or help to negate the vibrations caused by lack of a B.shaft

The balance shafts do not play a role in how high you can rev. Removing them will help the engine rev faster as there is less rotational mass. The trade off is obviously more vibration. I was worried it would be bad but to I can barely even tell a difference over stock with them gone. I have poly engine and trans mounts and the vibration is not by any means bad. It should make the vibrations more noticeable by not dampening them as much as rubber but I can barely even tell a difference.

Removing the balance shafts for me was merely a side effect of the 2.3 oil pump swap. I do not know where you could buy a BS delete kit for the 2.4. I am sure it was made at one time but since the 2.4 ld9 is now becoming extinct they would be hard to find. A BS delete kit for the eco is easily found. Theflyinskwirl did this to his eco to free up some power. How much it gains on either engine I doubt is known since the average jbody owner is a cheap ass and does not dyno stuff as well as the fact that usually when you tear into an engine like that it is not the only thing changed.

BS removal has been going on for as long as they have been putting them in 4cyl. The turbo doge crowd has been doing it since the late 80's.






FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!