skool u

Seeing if anyone can help me diagnose my turbo woes. This problem has progressively gotten worse and now it's to the point that once the car is warmed up, there is no boost. The setup is a t4 on an s2k with a log style manifold. The turbo itself slightly buts up against the side wall and has rubbed and this is evident on both the wall and the compressor housing. The car has been turboed for about 5 months now and problem has made itself evident just recently.

What happens is that once the car is warmed up and I get on the throttle, a very loud "whirring" noise (almost sounds like a high pitch vibration) is emmited and is varied on how much throttle is given. No boost is produced when this sound is made and it just gets louder when the throttle is depressed. I haven't noticed any smoke but maybe I'm not looking hard enough.

I've narrowed it down the turbo and wastegate; however, upon taken off the wastegate and inspecting it, the shaft is still in tact and the valve moves up and down freely and the diaphram is still in tact with no holes or tears.

The turbo was removed and superficially inspected and othing seems to be loose; however, it was not as thorough as a check as the wastegate. I did not take it apart. The wheel spins very freely and while on the car, the wheel is moving with the exhaust.

i was told that possibly the seals or something is causing this problem once warmed up, but I'm not too sure which seals it could be. There's no white smoke that I can see; however, it's just that. When the car is warmed up nice and hot, that sound comes and it won't build boost. But when the car has been sitting and I start to drive it, it'll boost fine...until warm!

I was chatting to some other lads and they said the same thing, that they would hear a loud whirring noise when accelerating and it ended up being the turbine seals. The only thing is that I couldn't see any smoke coming out...or maybe I just wasn't really looking.

The shaft play seems to be okay and it doesn't hit the side walls when wiggled, but like I said, the turbo's out and I'll be taking it in because when I turned it over and the compressor outlet was facing down, it puked up some oil! I Think this was because before I was using a -4 line and it was smoking at idle. I then added a restrictor and then the smoke went away.

If you have any insight or can help in shedding some light on the matter that would be fantastic!!

Cheers!
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AndyFloyd

Have you checked for IC couplers being loose? Leaks from the turbo manifold maybe? I dunno man that sounds odd, T4 is a large frame turbo. Maybe it would be better overall for a smaller turbo unless you want big power in which case youre good. haha

jari8378

manifold cracked?

Revenge

Sounds like manifold coming lose when it gets warm, maybe its warped or cracked. As it expandes due to heat it shape changes and lets the boost out and makes the noise.

skool u

Took the turbo off, took it apart and put it back together and went for a drive. Still the same result. First 5 minutes of driving, no probs, but once warmed up, the noise is back and no boost!

I'm ruling out the wastegate because I disconnected the vaccum line and plugged the other end and the sound was still there and I couldn't get any boost. The wastegate spring is working too and the pluger was definitely shut!

The turbo seems to be the last thing because the manifold is sealing and not leaking as far as I can tell. No exhaust marks anywhere. As well, I checked the charge piping and everything is connected. The turbo does seem a bit stuffed because at idle when revved, I can hear a bit of that sound coming from that area and when I removed the intake pipe, a bit of oil was sputtering out of the compressor.

But still, the blades are moving quite quickly, and if this is the case, how can I not be making boost? There is no real smoke coming out the tail pipe as well so here it goes:

The downpipe is securely connected to the turbo. The turbo is securely connected to the manifold and the manifold is secured to the head. No leaks as far as I can tell, so why in the heck does it still not make boost? how can a faulty turbo work for 5 minutes and then not work and then work again for another 5 minutes when cooled?

Is there anything else I may be missing that might cause this problem?

godmachine

Friends evo had all the same issues when one of his intercooler pipes had been overtightened. It will look all fine but it had a slighty bend and made a really bad wooshing noise and dropped boost. Guessing maybe the couplers was heating and expanding not allowing the seal on the pipe since they expand at different rates hope it helps


^ run on sent I know im at work and typing fast