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Boost problemo

1285 Views 20 Replies 9 Participants Last post by  kaosv1
Hi there,

I've got a car here at the mo, can't figure out what the problem is. Its producing around 0.4 bar boost, very occationally the car makes 1 bar when the 2nd turbo comes on line, sometimes it just stays at 0.4ish and I can't feel the 2nd turbo kicking in at all. Its making a big wooshing noise when you go on and off the throttle, sounds like an IC hose is off but they all seem to be OK, I've removed them all and checked them for splits all is fine. No hoses off round the turbo area.

Anyone got any ideas?
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1bar=14.7 psi. if your on stock twins it goes on 1bar+ only if you WOT. regular cruising is around .5bar=7psi. your car doesnt do 14psi+ all day long. that wooshing sound might be your stock bov.

first of all what mods do you have on your car? is it stock?
recently there have been some folks who have had problems with intercoolers not being welded properly, and leaks developing out of that. might want to check just to be sure and pressure test it.
Car is BPU, I changed the BOV for another and still exactly the same!


TRD94JZA80TT said:
1bar=14.7 psi. if your on stock twins it goes on 1bar+ only if you WOT. regular cruising is around .5bar=7psi. your car doesnt do 14psi+ all day long. that wooshing sound might be your stock bov.

first of all what mods do you have on your car? is it stock?
Its got the std I/C fitted at the mo, haven't done a pressure test on it as yet, all looks ok though. Whats the best way to go about pressure testing it?


kale said:
recently there have been some folks who have had problems with intercoolers not being welded properly, and leaks developing out of that. might want to check just to be sure and pressure test it.
Paul,

It sounds like the sequential operations if messed up. Check for boost leaks (I wrote an article in the FAQ section) but what you're describing sounds like a sequential issue.

You can do the pressure test and then try wiring TTC. Those 2 will solve your problem, and if you want to get the sequ. working again, then you'll have to troubleshoot the actual culprit. Obviously check the vacuum lines around the vsv's and turbos.
It sounds like its more than that to me, the wooshing noise its making is VERY loud, doesn't sound like its just a split hose or vacuum hose off, I haven't come across this exact problem before, its the kind of noise thats made when an intercooler pipe is off but they all seem ok. When the engine is revved at a stand still up to around 4500rpm for instance you can hear the noise then when you come off the throttle, when I do this its sounds like a very loud BOV sound, all the sound seems to be coming from the air filter itself, hmmmm.

Nice bumper by the way....

RSA Supra said:
Paul,

It sounds like the sequential operations if messed up. Check for boost leaks (I wrote an article in the FAQ section) but what you're describing sounds like a sequential issue.

You can do the pressure test and then try wiring TTC. Those 2 will solve your problem, and if you want to get the sequ. working again, then you'll have to troubleshoot the actual culprit. Obviously check the vacuum lines around the vsv's and turbos.
um this is pretty much the problem i had a long time ago without the woosh sound. It was my vaccum lines in the sequential setup, they were connected wrong or one popped off. i made 1 bar occasionally, and usually stayed around .5 bar like you on the 1st turbo. check near the 2nd vsv, that was my problem.

-Brett
Blown #2 turbo maybe?
if sometimes the 2nd T comes in, and sometimes not, it could be a wastegate problem, or hoses related to it
Paul,

Thanks, I wasn't implying that a vacuum line was makine the noise, but that the lines controlling the sequential operation are messed up. I suspect the VSV's, reed valve , or pressure tank are messed up.
Right I've got the car back here now for a couple of days, hopefully I'll find the problem with it. Just seems strange, I've had loads of cars in with boost problems but not one like this before with the noise, going to have a good root around tomorrow on it.
Thanks for all your help so far.

Cheers
Right, went for a bit of a drive in the car and now there is no boost at all, looks like it was the turbo's after all. See if I can persuade my customer to go for a single!

Cheers
Couldn't be the wastegate is stuck open could it?
My first guess would be a hose popped off of the EGCV actuator. Or, someone mixed the hoses up. The situation you're describing is very similar.

However, if it's blowing smoke, #2 turbo is probably dead.
same prob here... so did u confirm if ur turbo is really dead or not
Not yet, the customer has taken the car back while he decides what to do, probably going to go for hybrids I think.
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