"low boost pressure"

[slader99]

87 supra 7MGTEHi all. First time on the site, seems to be a weath of information.

Anyway point of the matter:

I bought my first supra about 2 months ago and its been running awsome. Lately however I notice my boost gauge is no longer getting to 400 mmHG. My exauhst sound at max boost now (barly 240 mmHG from 400+) is also less distinct.

After looking into the matter a bit on the internet I found some simple things to check. I removed my air filter and it looked used, but nothing restrictive yet. I did notice when makind space for airfilter removal I removed the hose leading from the intercooler to intake manifold had a little bit of substance inside. A little bit of oilish material was on part of the inner of the pipe. All my hoses look nice and fresh, my clamps are all tight.

The car still runs awsome, everything is great other than not hitting those higher pressures (and extra guts) I was seeing earlier. The turbo seems to spool up just as fast as it did before, it just cuts levels out at a much lower level. The change was fairly sudden in that it happened in a matter of days, and my oil pressure may have dropped slightly with it. My oil pressure is still above safe limits which I am told are as low as 6 psi for these supras?

Is this a sign my turbo is going?. Could this be my wastegate sticking and how do i prove it is/isnt? I dont seem to be burning oil, exausht is clean looking and no difference on dipstick. 210,000 km on car, top rebuild 10,000km ago.

Any input would be greatly appricated guys.

cheers,

Colin Slade

[bgrieger]

I would recommend going over those clamps again. Turbos, when they head south suddenly, tend to blow seals leving a large cloud of very blue oil smoke behind you, or make all sorts of funny noises. Those odd squealy sounds are aluminum being machined as the bearings come apart and the impeller impacts the housing.

If all is truly well with the piping, check the cats. A clogged cat will also give similar symptoms.

[slader99]

Ok, my oil is definatly dissapearing. Ive had to put 3/4 of a liter in in the last 2 weeks, and it didnt burn or leak a drop untill I had this insuffienct boost problem.

For the longest time i got a rotational sweaking sound that I was assuming was my front right wheel bearing. The noise would come and go, now making me think that maybe it was my turbo failing. I took off the hose leading to my intake manifold again, and there is definatly some oil in there.

Im gonna rip off the accordian hose after the car cools down, and feel for play. How much is a new turbo gonna cost, and if I want to consider higher boost pressures down the road is it worthwhile buying some sort of aftermarket turbo?

Last question is would u guys still be driving this car with a failing turbo? Im at school right now and im not rellay gonna be able to get anyone to look at it for another couple weeks.

thanks,

Colin Slade

[repinS]

Originally Posted by slader99

Im gonna rip off the accordian hose after the car cools down, and feel for play. How much is a new turbo gonna cost, and if I want to consider higher boost pressures down the road is it worthwhile buying some sort of aftermarket turbo?

One possibility is upgrading a stock turbo, the specifics of which I'm to too familar with.

[slader99]

So i took off the acordian hose, and there was alot of oil sitting at the opening of the turbo charger. Im afriad to take my bottom intercooler hose off, im sure theres gonna be that 1/2 litre of oil im missing. No play forward and backward, but side to side there must be over 30 tho. Does this indicate my turbo is shot? and are these things reparable or am i looking new or aftermarket?

cheers

Colin Slade

[bgrieger]

Certainly they can be rebuilt. .030...yep, that's not looking all that good. There are no reliable rebuilders in our area that deal to the public, so we typically send them to the US, though I'm one of the lucky ones that still has mine intact and am not sure who most of our local guys have been happy with. Expect near $1k CAD to have it rebuilt to spec (may as well upgrade while you're there).

Toyota wants 2500 new if that makes you feel any better. You mihgt give a used one a shot for a few hundred, but you are chancing on a used turbo.

[albertmdh]

well, he's obviously got a REALLY used one now, ive heard squeaking front right too, but im not burning oil, sounds more like plastic squeak anyways. I sure am unhelpful.