Zeb Christensen

This is the stock turbo on a 93 it seem to make some noise when you let off the throttle hard, I would refer to it as a turbo bark. What really gets me though is sometimes it does it repeatedly under throttle and when it is doing this it will not go over 15 psi boost. Usually if you back off it a second then get back on it is just fine.
I took the air filter off and it seems to have a little shaft play. Is it just says that it is time for a new turbo?

edwinsmith

A little side to side shaft play is pretty normal. The turbo works with an oil pressure bearing. I can't speak about the barking though. Do you have a pyro?

mknittle

A quick whistle is normal when you let off quick. go here.
Holset Turbo Model Information watch for the highlighted links in the pdf.

Zeb Christensen

Yes I do have a pyro. The noise is not really a whistle it's more like a chatter.

Alec

If it is the STOCK turbo compressor, then it does not have Map Width Enhancement. At lower engine speeds (which means a lower mass of air is flowing through the system) and high boost conditions the h1c without MWE will "surge". Normally this only happens with turned up fuel and or a smaller than stock exhaust housing. If you have a manifold pressure gauge, you should be able to see the gauge flutter if the turbo is surging.

It could be something else, but as mentioned above, some side to side play is normal, especially after you "push out" the oil in the bearings wiggling on the shaft, if that makes any sense.

Zeb Christensen

I do have the pump turned up and 50 horse injectors. Your are talking the exhaust manifold pressure, right?

Alec

Intake manifold pressure. Normally if the turbo is surging, you will see the intake manifold pressure pulse around a maximum pressure for a given engine speed. That is, the gauge needle will go up to say, 15psi and then start vibrating around the 15 mark when the turbo starts to surge. Maybe you have something else going on.

Zeb Christensen

So from what you are say it sounds like it is surging. Is this bad for it, will it hurt anything? And to get rid of it would be looking at different turbo?

1972RedNeck

If it is the stock turbo, I have a hard time believing that it will ever surge. The exhaust housing is too big and the compressor too small to surge.

cougar

Check the boots. If one collapses when you let off, it will act like a restriction until it pops back out.