Smoke - Accelerating Extremely Hard

[waynef]

Ok my car has just hit 72000 miles and I noted the other day that sometimes when I absolutely floor my S4 a puff of whitish smoke appears from the exhaust. Now when I try to replicate it normally in 1st gear 2nd gear hard acceleration it does not happen again.

What is this likely to be....I mean are we talking engine rebuild? Or is it common for a turbo charged engine to sometimes ommit smoke under extreme acceleration.

The car is regularly serviced and has been compression tested with good results.

Just want to know if any one else has had this?

The car drives fine still starts first time does not eat oil and has a huge punch when the turbo kicks in. She is chipped to 330bhp but surely this should not have any effect. She also has a straight through exhaust with no Cat and is ported. Just some extra info to help.

Very Worried!!!!

Waynef

[Tentenths]

Could be turbo wear.

Edited July 6, 2007 by Tentenths

[mangel]

couldbe bearing wear in the turbo. Which chip have you got as I believe the car isn't under full boost in first and second on the standard chip and some of the aftermarket ones!!?

Hasten to add I'm no expert so maybe one of the more knowledgeable ones can add to this!!

[t70]

White smoke? possible head gasket issue... but since your compression is good, that's not likely. Check your PCV valve... it's possible that crank-case pressure is building and causing a seal issue within the turbo charger under full boost.

[Riddlemr2]

If it is the turbo it would likely emit a puff after idling for a while (like while sitting at a light). This happens when oil builds up in the turbo and burns in the turbine side of the turbocharger. Accelerating very hard would blow all the smoke and oil out of the turbo which may cause you to see it then, then have it go away. You can pull the intake off the turbo and check to see if the impeller shaft is loose. If there is any play or wobble in the impeller, the turbo might need a rebuild. Do NOT put too much force on the impeller when you try to wiggle it. If it is loose, it will be easily apparent...you may even see the impeller blades scraping the housing.

Rebuilding a T3 should be very simple and relatively inexpensive from any turbo rebuild shop.

All that being said, it is normal for a highly-boosted turbo car to blow some smoke at full throttle, but the smoke should be brown, not white.

[andydclements]

If it is the turbo it would likely emit a puff after idling for a while (like while sitting at a light). This happens when oil builds up in the turbo and burns in the turbine side of the turbocharger. Accelerating very hard would blow all the smoke and oil out of the turbo which may cause you to see it then, then have it go away. You can pull the intake off the turbo and check to see if the impeller shaft is loose. If there is any play or wobble in the impeller, the turbo might need a rebuild. Do NOT put too much force on the impeller when you try to wiggle it. If it is loose, it will be easily apparent...you may even see the impeller blades scraping the housing.

Rebuilding a T3 should be very simple and relatively inexpensive from any turbo rebuild shop.

All that being said, it is normal for a highly-boosted turbo car to blow some smoke at full throttle, but the smoke should be brown, not white.

I agree , normally Blue somke = oil being burned

White Smoke = water being brough into the combustion.

I don't know, but could it be water from the turbo, either getting into the induction or exhaust side?

I suggest that rather than head gasket as good compression has been mentioned.

Andy

[Advantage]

I'd offer that the symptoms shown are the first signs of turbo wear. 72k miles at 330 bhp? That little glowing red snail is doing some puffing and is probably wanting a well earned rest!

[Paul93Lotus]

You should get a friend to drive the car and you be following behind (or vice versa) to get a good look at what is coming out the pipe. At least you will know how serious it is.

Sounds like a turbo issue. Can you hear a faint siren type noise(if blades were rubbing...bearing wear) from the turbo yet?

[waynef]

Hey Guys

I think its what Dave has said as it happens if idling for a bit then taking off. Does not do it again once out on a good run. Friend of mine followed and said it only did it once again 1st to 2nd gear change very hard acceleration.

No Blue smoke and only a puff. My Turbo was brand new a year ago and is using fully Ceramic bearings. Although it is a hybrid T3 running slightly oversized impellor I know for a fact that it is fine.

She is running a PUK No 5 chip and appears to run fine.

I guess then there is nothing to really worry about. Oh one lastr hing I did have engine top end rebuild one and a half years ago.

Thanks Chaps

Waynef