Rev Limit? Whats Ideal

[MrG 3]

OK, my car is running 45's, has a big valve head & decent cam but a std rebuilt bottom end done especially for the track. So what would be the best rev limit to set my omex to?

 

At Marham last year I ran it without one but I think I stuck to the std limit (6500 sound about right) so would something around 6500 to 6850 be ok or is that being too safe or too high?

 

Many thanks

 

Andrew

[welshpug 1,662]

depends where it makes power and what has been uprated to cope with any extra revs if needed.

[MrG 3]

thanks WP, we did the oil pump and it has a baffled sump but apart from that it is more or less std down below. Cam is sort of unknown at present but it appears to come on cam around 3.8/4k and just doesn't seem to tail off at all. The head has the valves and inlets opened up but the spec I'll have to check again as I can't find the spec sheet I agreed to.

 

I'll have to have a chat with the guys that built it for me, but as they've been tied up with their own overseas race stuff this month (they prepare and compete in Alfas in the UAE this time of year) I've been unable to. Out of curiosity what is the std rev limit on a 1.9 205?

[mattbenselin 0]

I have been told by few people that a safe limit to go to with the standard valve springs and bottom end etc is 7000rpm. I think the standard limit is about 6500rpm as the standard 1.9 8v makes it max power at 6000rpm but the rev counter is not that accurate and cannot be used to take accurate readings from.

I set my rev limiter to 7000rpm to be safe but didn't hit it very often as there was little gain to be had going that high on standard stuff. Your cam however must be over 300 degrees so will make the engines peak power a lot higher than standard. Get it on a roller and see where it makes its power and torque and go from there.

[MrG 3]

Thanks Matt, appreciate the info.

 

It's due to go on the rollers again end of March.

[welshpug 1,662]

6200 with peak at 6, though the same/similar engine in a ZX on MP3.1 would rev to 6600, power at 6k again.

 

missed matt's post, exactly what I was going to suggest, get a power curve and speak to your engine builders

Edited February 14, 2009 by welshpug

[Miles 331 1 Cars]

7k is about it on a std 8v engine/head the bottom end will take a good 8k but the head won;t unless it's got different springs fitted

[James_R 3]

As said about 7k

[pug_ham 244 3 Cars]

Mine set at 7k on MP3.1 & been ok for a couple of years doing track days including missed gears.

 

I don't hit it very often though, prefer to change just before it cuts in.

 

Mines got a balanced crank + L & B flywheel (done seperately).

 

Graham.

[dimmapalmer 0]

im running a 285 cam, gas flowed head, bike carbs - and set the limit to 7k using an omex limiter. and the engine sounds fine, although ive had it round to just under 8 and it didnt make any strange noises, just kept pulling (mmm recon engine)

 

by the way you say its pulling from around 3.5/4k , the piper 285 i have pulls strongly around the 3.5k... so your smight be close? 300* cams usually pull from around 4+

Edited February 23, 2009 by dimmapalmer