Hi Guys. I guess this is a question for those with built engines, what are you revving them out to? A well balanced engine, with good rods and pistons? I know there is no point revving harder if your not making power, but am curious as to what other folk are doing? Cheers. Col
No need to rev a VG more than 7500rpm I made my max power by 5800rpm on last dyno run . A GOOD SET UP REVS QUICKER TO MAX RPM NOT NECESSARILY HIGHER .
More for my own education then anything else, the main limiting factor on maximum rpm is the valve train right? How much does changing the camshaft or valve springs affect it either up or down?
It's lots of things, the biggest really though is the design of the plenum, heads, porting etc., there is so much engineering in these engines that shifts the power band as low as possible it's very rare to see one modified to the point that going past 7-7.5krpm makes you go any faster. The bulk architecture of the block and the valve train etc. is very similar to the RB so if you did all the stuff like valve springs, ditch vtc, high quality light rods and pistons, maybe a little less stroke, you could probably get them up to the 8.5-9krpm range same as a really good rb build (maybe even without the oil pump issues). The single turbo heads (from the Y32) are supposed to have much better peak flow so you might find some of those that have actually been built for high revs.
Most of its been covered, however I'd also like to point out the cross flow crank design in regards to oiling particularly at higher rpm. I rev out to 7500 but that's because I chase a top speed with my events, otherwise I'm shoting closer to 7000 until 4th.
Thanks for the reply's guys. Ill see what its doing at 7k and maybe push it to7.5k if its still going strong. Thanks again. Col
Why do you want to push it to 7.5? Look at the torque curve. That's where you want to be. If anything you'll actually change gears early to maximise torque and acceleration, especially in 3rd but also in 4th.
Just as a loud exhaust does not indicate High Performance, high revs also are no indication of ultimate driveability. Keeping your vehicle at, or about the peak torque/Revs band will produce the best outcome(in MOST circumstances). Anything else is a waste of time/money(and will ultimately leave you looking like a Wanker).
