Turbo Boost query

[PulsarLee]

hey guys n girls

have a general query about turbo chargers / boost guages. if my turbo sounds like its spooling and shows 1 bar on both guages i have . and holds boost, could my turbo still be knackered??
i have the occasional puff of blue when changing up:?.

when people say the turbos gone, (as i think mine has) would it still reach boost levels?

cheers

Lee

 

[whytie]

Proberly on it's way out the seals might knackered.

 

[PobodY]

...or it could be that you've put the wrong grade of oil in and it's leaking past the journal bearing.

 

[PulsarLee]

if i disconnect the tmic and find any oil what so ever, does this probably mean that a seal has gone? Should there be no trace of oil in the ic?

Cheers,


Lee

 

[gtir_pimp]

there shouldnt be any oil in there. or take the induction pipe off the turbo and check for oil in the pipe and check the turbo for play.

 

[PobodY]

Do you have a catch can, or does your crank case vent into the inlet piping? - If it vents into the inlet piping there's a possibility it's oils that has not been caught by the separator; that's quite common and can look like a failing turbo.

If it seems to be boosting fine, check you don't have too much oil and maybe check your compression... or not if you don't want to know that you might have a leaky piston ring.

Do you often boot it, or is it just every now and then you open it up and get a bit of a puff?

 

[dotalot]

Is it a bad puff??? A slight puff of smoke on gear changes while driving on boost is normal.

 

[PulsarLee]

thanks guys,

aint a massive puff of blue smo0ke but can be seen through the rear view window :sad:.

can anyone tell me, is a comp test difficult and what should the readings be on a good condition engine?(tmic)

thanks fellas

 

[PobodY]

If you've got a compression gauge, it's pretty easy to test; take the spark plug(s) out and put it in the hole. Turn the engine over a couple of times and see what it says.

I think it should be about 140 (PSI?) per cylinder, but if they're all the same it's ok (unless they are all stupidly low I guess). If one is significantly different from the others, you have a suspect.

That's the basic version, because that's all I know. There are other tests you can do, but someone else will have to explain them.

 

[watoga]

I think it should be about 140 (PSI?) per cylinder

Yep, my four cylinders all measured between 140-144 PSI when I checked mine.

Dave

 

[boost]

as long as all cylinders are within atleast 10% of each other

 

[pulsarboby]

i would say more like 5% if a cylinders reading 150psi then you use 'within 10%' that means the one next to it could be 135psi which is way too low in comparison and there would obviously be a prob on that cylinder

a really good engine with standard thickness h/g and 8:5.1 comp ratio should really be getting 150+ per cylinder, anything less than 140 then the engines getting pretty worn

 

[gtir_pimp]

dont forget to do the compression test on a hot/warm engine. the instructions will come with the tester. also use the search button on here and you will find all you need to know about compression testing.
the turbo will boost normally when its on its way out untill it gets really bad

 

[PulsarLee]

Thanks fellas, useful info again
think ill invest in a comp tester.. any particular makes / types you recommend?

Thanks,

Lee

 

[ollydj]

i pressure tested mine the other day and had 150psi across all four cylinders, thats with 600 mile on a fresh rebuild. i also get a puff of blue smoke ocasionally on gear changes, i put that down to what was said above about the oil grade due to running in on cheep oil.