My 91 TT seems to be billowing a load of whitish smoke from the exhausts, i am aware that this could be the head gasket or turbo seals. Does anyone know if there are any ways to pinpoint what is causing this as i don't want to drive the car incase it causes more damage. Appreciate any input. Cheers

is its head problems a compression test should tell you (i think)

White smoke is 99% of the time going to be water getting into the exhaust system either through the tubbys or directly into the combustion chambers through the headgasket. have a quick smell and you'll be able to tell if it smells wet.

 

First thing to do is check our oil cap for signs of water having entered into the oil, it looks like a mayonase consistancey and colour gunge.

Have a smell of your coolant, you get quite an acridy smell if combustion/exhaust has got into the coolant, it will also look quite brown

 

 

As Dipone said a compression test should find you the problem pretty quick, though if you have the time and equipment a leakdown is better. If the headgasket is the culprit then I suggest when you have it changed go for some metal ones as these will last till dooms day ;)

 

If its not the headgasket then it will be the turbo's unfortunately which is going to be an engine out job to fix. However you may be able to get away with cutting off the water supply to the turbo's by way of blocking/removing the lines which pass the water to the turbo body.

The water that is passed through the turbo pretty much doesn't do anything anyway so won't be missed and it will sort the water problem fast and cheap.

 

Hope that helps ;)

If its not the headgasket then it will be the turbo's unfortunately which is going to be an engine out job to fix. However you may be able to get away with cutting off the water supply to the turbo's by way of blocking/removing the lines which pass the water to the turbo body.

The water that is passed through the turbo pretty much doesn't do anything anyway so won't be missed and it will sort the water problem fast and cheap.

 

Hope that helps ;)

 

Unfortunatly, white smoke related to a Turbo failure is usually oil getting past the seals, rather than water.

 

Also, stock turbos require water cooling and without it will fail very early.

Unburnt oil ie after the combustion stage can well be white though by far more common cause of white smoke is water.

Though blue smoke, oil through the seals, is also a well known pointer for turbo failure

 

Turbo's can be run fine without the kettling effect of the water channels, think on this one we'll have to agree to disagree ;)

think you need to say whether it's smoke or steam - if it lingers it's smoke and points to the turbo seals, if it's steam it's water coming through.

 

Do a search and there's loads of info/ causes...

Unburnt oil ie after the combustion stage can well be white though by far more common cause of white smoke is water.

Though blue smoke, oil through the seals, is also a well known pointer for turbo failure

 

Turbo's can be run fine without the kettling effect of the water channels, think on this one we'll have to agree to disagree ;)

 

With the Stock TB22 turbos the weak point is oil seals, and every set of turbos I have sent off for reconditioning, (with White smoke being the main sympton) has been down to Failed turbo oil seals.

 

I know that Water bypassing is popular with the 200sx, but I have seen early turbo failure several times on the 300zx from water starvation.

As said before blue smoke is also very much a common sign of turbo seal failure. I also mentioned that he should be able to smell the difference.

I have sent of my fair share of tubbies for recon too buddy ;) and Im sure non of the many you sent off have had normal symptoms of blue smoe on decelleration, squealing on boost, rattling sound/vibration, or inability to make boost which for all other cars are common faults....

 

All turbo's have the down point of seals.

 

Bypassing water channels is quite common in most tuning circles and while I respect your knowledge given the amount of posts you have made we will have to disagree on this point as I have removed/blocked many waterlines and not had any adverse effects, not to mention most large chargers while not cpnatining vastly larger oil channels do not have the addition of water cooling simply as it is not efficient

Not going to get involved in this but surely if the turbo has a good water feed it will run cooler and therefore bearings etc will last longer?

That is the logic of it yes but unfortunately the operating temps of a turbo are so high that the very small amount of water that is passed through, often only a half turn of the turbo, provides neglagable cooling effects if any at all really.

 

Also the thing you want for a turbo is 'heat' if heat dispersal was a necessity then why use heat wrap?? thermal efficiencey.

S13Girly - what is your occupation?

I'll believe you!

:D you really wouldn't lol!!

Awwww..... go on, you can tell us!

 

Or are you Timmy Turbo pretending? Eh? eh? eh? :tongue:

Also the thing you want for a turbo is 'heat'

 

Why ??? please enlighten me :)

Also the thing you want for a turbo is 'heat' if heat dispersal was a necessity then why use heat wrap?? thermal efficiencey.

 

I thought that was to protect other things from the heat the turbos are giving out?

 

I cant see why heat is a good thing. Thats why theres intercoolers to cool the air down that the turbos have heated up.

 

Also, all the turbos you have worked on, are they from 300zx's?

Right here goes the short version :tongue:

 

Turbos work by means of expanding HOT gases being forced through them at high pressure causing the spool.

Right main word there is HOT

Your manifold especially if stainless will transfer some of that HEAT ENERGY to air much in the same way a radiator does, ie as air passes it heat is lost thus COOLING thus energy lost.

 

The more heat energy contained in a gas the futher the expansion, in the case of the inside of a manifold it reads - more heat energy means more expansion of gases = more pressure = better spool.

 

Heat wrap is also used to keep surrounding area's from the heat created by the manifold again especially in the cases of stainless mani's which glow red hot when used well ;)

 

 

Intercoolers are a completely seperate section of the turbo route puppy. You have one side of the turbo that deals with the expanding gases released from the chambers (exhaust) this passes through the turbine at around 1.5bar plus any boost pressure. This pressure causes the turbine to spin, the air compression side that you are questioning about is the other side of the bearings to this. Although the compression side impeller does sit on a common shaft to the exhaust side the amount of heat transfered between their bodies isn't huge but its aluminium shell aids the cooling well thus temps in the exhaust side is 500+deg or something like that and the air leaving the compression side is only about 100deg if high.

 

Intercoolers are further on from this side (aka the hot side) the cooler is used to lower the charge temp to about 40 deg if good before it enters the plenum and subsequent chambers as high temps will not equal a good volumetric efficiency. This side ie post intercooler is known as the 'cold side'

 

 

I've tried to make it as simple as poss so everyone understands :) hope it helps

 

 

I have worked on alot of turbo cars from simple TD's to supra's GTO's etc etc oh and I have my own zed too, anyone wanna see a pic ??

:bow: good explanation :D

 

Yes please, have you got any pics of the zed?

Thanks ;)

 

This my baby, not a huge amount of mods at the moment, just a:

 

* Blitz induction kit

* Kakimoto Racing exhaust

* Custom decat

* Lowered

* Alloys

* Colour coded rear wing (not sure of origin)

* and just a few gauges

 

This is her

 

 

 

 

 

 

 

 

Mod plans are quite normal really full engine rebuild, possibly forged pistons, lightweight flywheel, stage 4 paddle clutch,740cc injectors, 1.4mhg, knife edge crank, Twin GT28RS's, nitrous 50hp antilag system, custom FMIC withhard pipes, adjustable exhaust silencer, Twin BOV's, either a couple of piggy backs or a replcement management system from Apexi.

 

Only looking for about 500horses as to not 'overly' stress the engine but still be silly quick ;)

When did that car last get waxed??? ;)

Cheeky :P

 

Only just washed it then it started raining, so took the pics really really fast lol!!

 

Biggest mod at the mo is manual conversion tbh

LOL

 

Heat isn't necessarily what is driving the turbo ;) The idea is to keep the heat in the exhaust gasses before they get to the turbo - as they cool they contract and you will lose pressure/velocity...

 

Removing the water cooling will NOT stop the white smoke - the water gallery is completely seperate from the centre housing - if there was a crack in it then it would contaminate the oil flowing through it, NOT pass into the exhaust... The white smoke is caused because the oil is getting into the hot exhaust. It isn't being burnt in the combustion chambers, its just being heated so gives off white smoke ;) Blue means there is oil in the combustion chambers getting burnt...

 

The water cooling on the turbo doesn't really do that much - its the oil flowing through the CHRA that does the major cooling job.

 

:)

Thanx for the replies there folks checked a few things out, and there is no white gunk under the oil cap and the coolant is not brown. the 'smoke' does not seem that wet and has a slight chemical smell of it, though it seems more like steam. You can tell i know very little about these things so excuse my ignorance lol. As for the turbos they are not stock as there is documentation from when new ones where fitted. can't help thinking the car is ****oed now, should have expected problems as when i viewed the car i thought it had prob been 'clocked' because the mileage counter was slightly wonky and the documentation did not add up. but i bought it anyway cause it looked so cool. lol.

LOL

Heat isn't necessarily what is driving the turbo ;) The idea is to keep the heat in the exhaust gasses before they get to the turbo - as they cool they contract and you will lose pressure/velocity...

 

Really I did not know that........:rolleyes: if your re-read what I wrote you'll see that was pointed out, but thanks for re-writing it for me ;)

 

 

The water cooling on the turbo doesn't really do that much - its the oil flowing through the CHRA that does the major cooling job.

 

:)

 

Thanks again for reitterating my point ;)

Turbos work by means of expanding HOT gases being forced through them at high pressure causing the spool.

Right main word there is HOT

 

Really think that the main words there are high pressure to be honest, then followed by expanding. the turbo turns because of the flow of gases, heat helps by expanding the gas therefore increasing the volume, more volume of gas means the turbo turns faster. I see what you are trying to say but dont agree that heat is the most important thing for a turbo. fling the turbo in a foundry oven plenty heat there, bet the turbine dont turn, but you will end up with a lump of molten metal.

Is the smoke on start up or all the time?.

Is the smoke on start up or all the time?.

Seems to be all the time although i havent driven it much since incase it makes it worse. startin to cut out aswell. i dunno i think its time to burn it out, then it will really smoke lol.