Lacking power at high revs

[wslogue]

I''m the proud new owner of a V8S - hurray! I''ve been getting used to the car over the past few days and, though I could be wrong, the engine seems to weaken (slightly) at high revs (ie above 4500). Aside from this, it seems fine. Low down torque is great, really strong. Could this be a simple timing problem that would be sorted out by half a degree forward or back ?

[wslogue]

Ignore that above comment, I think I've divined the problem here. Believe it or not, I think I just wasn't pressing the throttle all the way to the floor. It's got quite a long travel and, when it feels as though it's fully open, there is in fact another 50% to go. What a plonker!

[Heath]

You maybe sitting too far back. Do not position yourself as if driving a normal car, you should sit closer to the steering wheel so that your arms are bent. You gain more control this way and will naturally be closer to the pedals! Good luck and be careful with those high revs, a friend of mine has one who gets wheelspin in fourth at 70mph.

[wslogue]

Perhaps I really am slightly lacking power at high revs. After correcting the above mentioned problem, ahem, it still seems to weaken above 4500 rpm. It's as if peak power comes at 4000 rpm. I suppose there could be many causes. Incorrect timing, clogged air filter, clogged fuel filter, low fuel pressure etc. However, it could be in my imagination. I'll have to get another V8S owner to drive it and give me their opinion.

[GreenV8S]

quote:Perhaps I really am slightly lacking power at high revs. After correcting the above mentioned problem, ahem, it still seems to weaken above 4500 rpm. It's as if peak power comes at 4000 rpm. I suppose there could be many causes. Incorrect timing, clogged air filter, clogged fuel filter, low fuel pressure etc. However, it could be in my imagination. I'll have to get another V8S owner to drive it and give me their opinion.

Peak torque will be around 4000 rpm, peak power is around 5,500 (not that you would want to rev your V8 that far routinely). These are torquey engines that have relatively little top end. If you want to do a proper comparision, get yourself a Race Tech accelerometer (details on this site) and compare in-gear acceleration curve against a similar car. Cheers, Peter Humphries (and a green V8S)

[wslogue]

Thanks Peter. I'm convinced that there really is some power loss up there and it's not just my imagination. It doesn't seem consistent either and, as I rev above 4000 rpm, it seems like the power wavers up and down slightly. The acceleromoter you mentioned would certainly spot this as the power graph would get a bit irregular instead of the normal power curve shape that one would expect. However, I'm thinking about getting it dynoed. I've read the reports elsewhere on this page about various TVRs getting dynoed. The most impressive bit was that the engineers present obviously knew their stuff and managed to make any necessary adjustments where power was below par. Anyone know of somewhere that really knows their Rover V8s ? The dyno itself may not be necessary, just an engineer who can recognize and correct any problems that he may find.

[GreenV8S]

quote: Anyone know of somewhere that really knows their Rover V8s ? The dyno itself may not be necessary, just an engineer who can recognize and correct any problems that he may find.

Tower View have done excellent work on the V8S including engine problem diagnostics as well as tuning upgrades. They are at the bottom of the M1, phone [phone]. Cheers, Peter Humphries (and a green V8S)