Mysterious loss in power

[matth76 1]

Hi

Just had a rolling road session with Stealth. My car is now making 190bhp instead of its original 207bhp. Nothing at all has been altered on the engine since the last rr session. The only thing to have happened since my last rolling road session is that my car overheated back in May/June when the thermostat went. However my car's oil temp at the time only hit 118 and since then no water has been lost (meaning my head gasket is fine) and the car still drives very smoothly. I wasn't aware anything was actually wrong until I had the rolling road session yesterday.

Vince at Stealth is puzzled as to what could cause it. The power curve it now has at 190bhp is very smooth, exactly like my previous rr session power curve but now with 15bhp less.

Because the power curve is smooth he says all cylinders should be ok... if one wasn't ok the power curve would be irregular and choppy. He thinks it could be partially blocked injectors causing the power drop. Or the alternative is that there could have been some very very slight friction damage when my car overheated... although the oil temp only hit 118 so it seems unlikely, even more unlikely because Vince said the car drives very smoothly.

When my car was on the rr yesterday there was a high activity of knock sensor activity (keeping pinking in check) which was puzzling. However the knock sensors did their job and there wasn't any pinking at all. No oil was being burnt either at all. Vince tried chaning the custom remap (stealth's own rechip) on my ecu a couple of times to adjust the settings but my power refused to budge from 190bhp. Very strange. Anyway I am currently trying out some of Stealth's recommended injector cleaner to see if that makes me get my power back although I'm not hopeful about this. I suspect there must be some thing else not quite right. Stealth were extremely helpful, they had my car for 4 hours in total (gave it a full service followed by rr session) and for 2 hours were checking out what the power loss problem was basically for free...great guys.

My current mods are Stealth's rechip, full s/s exhaust and high flow cat, s/s 6 branch (with a very very slight blow - but was assured this would not cause any power loss), BMC induction kit and 268 cams.

Any ideas as to what could cause my power loss? Anyone else had this happen to them?

Thanks for any help or comments.

[mk3anni 0]

No idea, but you might want to change your sig!!!

[matth76 1]

lol...yeah I'd better change that now. Could the slightly blowing stainless six branch exhaust manifold cause problems with my fuelling making it run lean and therefore lead to pinking, and ignition retard?