How high has the bar been raised?
 

Ok I am NOT worried about my oiling system, so how fast can i spin her before i get valve float? I think i saw sharp by coop was at 8500 till he blew but that was with boost and not enough fuel. I know 8100 has been done for a while till the pump blows, and i think zelminator had mentioned 8300 before. Oil pressure and consistant supply won't be an issue, nor will exploding pumps so whats up? I am also going to call JWT and see what they say, wether i should be worried about bearings, piston speeds, or valvetrain first.

the intake valve spring are much stiffer than the exhaust valve spring .
I dont remember the number but they are in the book.

Im sure they are good up to 9000 but the exhaust one, I wouldnt go higher than 8300-8400.

I tried ordering those intake valve spring but Nissan didnt want that.

If you need a side by side VHR Vs HR .. look at this.. I should have put the spring rate too..
but only the VHR intake valve spring are stiffer .. everything else has the same the spec.
http://www.the370z.com/members/megan...pring-size.jpg

is there a good amount of usable power in that higher range?

i have mine set for 8K redline since i got tuned last march. not sure if that helps your research or not lol

I'm curious... have you considered dual valve spring setup? Ferrea only has them for the VR38, though.

i wouldn't want to be a test dummy for this

I woukd agree aswell being at 8k but of course having a good Fuel and Oil pressure but isn't that risky business even raing the rev limiter to 8k??....*In for Updates*

my rev limiter is at 8k but it's not like i sit there and hold it at 8k lol i may kiss that here and there when drag racing. but i DD mine so i typically i'm not hitting the rev limiter driving to work.....unless i'm late :bowrofl: :driving:

LMFAO yea I understand xD I didn't explain myself correctly and yes I would agree as mines a DD aswell and well what were your gains at the drag strip + what were your jumbers on the dyno with your rev limiter at 8k?

I just saw your signature and your numbers *Facepalm*

numbers listed in the sig. i got the dyno sheet saved somewhere i'll have to find it. i really dont think they even cracked 7600 when dynoing it if i remember right. i could be wrong though.

edit: checked my sheet they took it to 7800. then the data stopped. kinda seems to drop off power wise past about 7400 though. maybe he was backing off then as well.

I have yet to really see anyone pick up any power by going to 8k. I really dont see what the big fuss is about with raising the rev limiter. :ugh2:

i really dont see a reason power wise but the stock rev limiter on the non-nismo Z i wanted lifted for racing reasons. there was a few times where i would be close to 7400 (stock limiter setting) and i would feel the ECU cutting in. i didnt like it so it got moved to let me drive like i wanted to without interference.

It might be if you can raise it, maintain power, and when you shift to the next gear you end up in a better part of the rev range. Allowing you to maximize power better, but at the risk of revving higher.

If it is just to give you a little more space between your optimal shift point, and banging off the limiter I guess that somewhat makes sense. However, I dont think taking it above that on a regular basis is a good idea at all, especially when you factor in that your not making any more power.

shhhh dont give away my secrets lol :bowrofl:

yea i agree but as i said before i dont run it up that high ever really. i may go above 7700 here and there if i shift late for some reason but never holding it as to cause damage.

That's a Great point! I hate when it bounces causing my next gear to be on the low rpms -.- ...will take note on that though to mantain power.

There's an early "soft" rev cut on OEM tune (fuel based, goes overly rich), I believe, to make the hard rev limit (ignition cut) put less strain on the motor.

You'll see little "divots" in the dyno graph as you approach rev limit on a factory tuned motor, just before the OEM ignition cut.

I'm intrigued by where this all goes, but I am guessing either a seriously ported and polished head and/r different IM will be needed to really capitalize on the higher rev limit.

On a related note, will the VVEL maps (if untuned) be able to extrapolate beyond, say, 7800?

Would love to see someone with stiffer valve springs and a massaged head/IM combo (and, I guess a VVEL tune plus different exahaust cam) push it into the 8+ K range. If torque didn't drop off, that would be a seriously powerful, screaming to redline VQHR.

This is all pretty uncharted territory, at least as far as I know, so looking forward to more details as this comes together :tup:

The soft cut you mentioned is what I touched on earlier. I didn't like being somewhat close to 7400 and it cutting some power. Once I raised mine when I got tuned I love that there's no interference from the ecu now.

Let me rephrase this, how high have guys run their motors without running into valve problems? As for making power above 8000rpm I'm looking at something already to fix that that so for the sake of the question how fast have guys spun the vvel heads?

I don't feel there's power to be made that high to be honest.