Burning smell when in reverse gear - plus faint smoke coming from engine bay

[matth76 1]

Hi

Firstly my car runs really smoothly when driving along - (although it has lost 15bhp mysteriously on the dyno but the power graph, although with 15bhp less, was still incredibly smooth - which added to the mystery). I have also noticed on the odd occastion when in reverse gear that I notice a burning smell - its not strong but definitely noticable and soon disappears within a few seconds. I also noticed the burning smell when I accelerated hard the other day (when the car was fully warmed up).

The oil temp was at normal operating temp and so was the coolant. In the sunlight I could also see faint smoke coming from the front internal fan air vents and around the bonnet - but soon disappeared within a few seconds.

What could cause this? My clutch is relatively new - only fitted early this year so that should be ok - could it simply be gearbox oil? and could it cause a drop in power on a dyno? Like I said it still runs incredibly smooth (both when driving and on the power graph).

Thanks for any help on this.

Matt

[jaysVR6 2]

I reckon all this could be linked. Double check with who installed your clutch fella.

[matth76 1]

I reckon all this could be linked. Double check with who installed your clutch fella.

Could a prematurely worn or faulty clutch cause this strange burning smell and also cause a drop in 15-17bhp? My car still runs very smoothly and the power curve is very smooth too.

[mk3anni 0]

How could it be linked???

A new clutch wont cause a power drop unless its slipping, and if its slipping i'm sure vince would have noticed it.

I dont understand your logic.

[dellert 0]

If its slipping so bad it smells, you would be on a truck within minutes! Burning clutch is distinctive, smells like Fish! IMO!

I think you need to trace the source of that smokey smell, what is burning? Metal, oil, plastic?

[VR6Pete 1,455]

Was it on the same RR you had it dyno'ed on?

you cant really compare RR graphs if they are from 2 seperate dyno's.... dont forget ambiant temps, etc.. will all have an effect on the results.

I had my car ages ago on the rollers, read 174BHP, went stealth and it was pushing out a consistent 201BHP!

I woulnt read into RR BHP figures too much, it's just pub talk... i've said it once, and i'll say it again, its how it drives on the road that counts, if it's smooth, and pulling well, dont worry about it, but obvously you need to isolate the burning smell and smoke, as dellert says, clutches, plastic, metal each have a unique smell.... shouldnt be too hard to find!

[purple highline monster 0]

i kept getting "smoke" from my engine bay...turned out to be a tiny pin hole in a hose (the one on the rear of head with smaller hose to throttle housing and bulk head) it was perished and spraying coolant onto the manifold every now and then, mind it did smell of coolant! bit un nerving when smokes comes out the gaps in the edges of your bonnet when you been for a blat though!!

[matth76 1]

Yes the rolling road sessions were on the same dyno at Stealth - and only a few months between them. I asked Vince about changes in ambient conditions and he said they correct for that and also said it wouldn't cause a huge drop of 17bhp. Everything electronically was checked and nothing was wrong. However it was a sat morning so didn't have time to check for much else. Although the car does still drive smoothly it doesn't have the 'pull' or 'poke' it did when I had the 207bhp. My gf thinks it is still fast but doesn't pull her head back to the passenger seat quite like it did lol.

I'm getting the car looked over by The Phirm (as they're local) this weekend so will hopefully isolate what this burning smell seems to be - odd that it only seems to happen occasionally in reverse, not any other gear - although it did happen once as already said when I accelerated very hard a couple weeks back. The burning smell could be a hose leak - leaking coolant onto something hot in the engine bay like you say... the smoke seems to disappear pretty quickly. It doesn't seem like a toxic plasticy burning smell - could be a coolant burning smell not sure. Not sure if this is linked to the power drop or not.

Thanks for your help guys. Any more info or help welcome

Cheers

[mk3anni 0]

Weigh it in mate.

[Eat this 2]

is your 6 branch wrapped??

when mine wasnt it melted the lastic pipe that goes to the throttle body a little bit every now and then a bit of oil would drip onto the 6 branch causing smoke and a bit smelly

[purple highline monster 0]

Weigh it in mate.

[matth76 1]

Weigh it in mate.

What do you mean bud?

No my 6 branch isn't wrapped, so could potentially do what you say Eat This. However strange that it normally happens in just reverse. Still not sure if the burning smell is related to the power loss.

[jaysVR6 2]

He's being carcastic as usual!! He means scrap it!

[VR6Lee 1]

Weigh it in mate.

:-d we do love him

[matth76 1]

lol at Steve... not just yet mate...spent too much on it to get rid off just yet.

Ok had car checked over, no oil leaks, no problem with clutch at all, no oil being burnt in exhaust fumes and car drives very smoothly. However there is the occasional "oil burning smell" as though a very small amount is hitting something hot like the manifold. Any idea where a potential leak could be? Whereever it is it is only very very small as the smell only very occasionally happens.

Thanks for any help.

[mk3anni 0]

Stop worrying Matt, just enjoy the car!!!

[spanky 0]

I get this sometimes. I have a very small leak around the crankcase breather, which ever now and then drips a single drop of oil onto the manifold, and makes one hell of a stink for about 5 mins then it is fine (until wiped or it does it again). Run your finger under the pipe that joins the breather onto the air intake, and see if there is any rogue oil there!

[matth76 1]

Cool, thanks for that Spanky... wasn't too worried about it Steve just curious as to what the burning smell might have been.

Phirm did a great job Sat. Thoroughly cleaned my throttle body out and calibrated many other sensors, including lamda. Car now pulls and feels far stronger. Car has at least another 5 bhp just for doing that. Tim said it felt much stronger too. I also used Stealth's injector cleaner a while ago straight after the rr session and it made a bit of a difference after a full tank of using that. Very happy with me car now! Must have at least 195-200bhp now Not quite 207bhp but what the hell - drives and pulls like a dream now.