superloaf

I'd like to know what your stock turbo sounds like. Do you hear any kind of air sounds or whooshing? Can you hear when the wastegate opens?. Anything? I don't remember ever hearing any kind of turbo noise but now hear lots of air sounds. I've fixed a couple of leaks which were causing noise but even now I still hear what seems to be the wastegate when it opens. It's strictly an air movement sound and not any kind of exhaust leak so I'm pretty sure there are no leaks.
So what sounds does the wastegate make? Do they make sound when something goes wrong?
Car is basically stock k26/6 turbo and wastegate with weltmeister chips, Lindsey boost enhancer and boost set at about 14. Also, boost seems to have fallen to 12 but I'm not positive on this.
Anyways, I really hate the air sound and like I said, never remember anything like this.

944crazy

The waste gate shouldn't be heard, unless you have a 'screamer pipe' that vents directly to the atmosphere instead of plumbing back into the exhaust after the cat like on the stock set up. Even with a screamer pipe, it won't be a whooshing sound, just normal exhaust sound but very loud as it isn't going through any mufflers.

If you have a loud air movement sound when boosting, then it is most likely you still have a boost leak somewhere. There are many places that these can happen, pretty much any hose/rubber connection that is under boost can be suspected. The first thing you can do is just go over all your hose clamps and make sure they are tight, and check all your vacuum lines. Then go and check for brittle hoses. When I had a leak, it took a while to find because one of the rubber intercooler pipe joiners had a small crack underneath it that was opening up under boost and making a wooshing sound...so if the leak isn't obvious, try taking off your intercooler pipes and checking all the rubber joiners for cracks. If you find one that's cracked, you can get silicon joiners off ebay for a good price.

ilikemy944

If you are hearing air when you let off the gas or shift/etc - this is the diverter valve.
And you can definitely hear this in a stock-ish setup. More boost (chips/boost enhancer) means more air to release.

lart951

I hear a lot of noises similar to those from a jet turbine

superloaf

It's not the diverter valve as it's only under boost and stops immediately when lifting. Also, it sounds like the wastegate, seems to be coming from that area as best as can be told from the driver's seat while blasting down the road. And it sounds like the old group B rally turbo cars with a strange staccato fftt fftt fftt fftt fftt as the boost comes on and rises. There is also an air rushing sound included in all of this.It's hard to describe so I hope this makes some sense. What worries me is that max boost seems lower than it should which would sound like an intake leak but I would think even my old worn out K26 would be able to maintain 14 psi even with a leak. Oh, and both intercooler to hard pipe hoses are new, they both failed in the past 2 years or so. I looked for leaks and tightened all the intake hoses and nothing stood out as a problem. Anyway, I suppose I'll figure it out eventually but I'm driving from Nashville to LA in a few days so was trying to figure it out before then.

What problems does the wastegate tend to have as it ages? What fails? What are the signs and results of failure or impending failure?

Dougs951S

like others have said, if you are hearing airflow noise you didnt hear before AND you have lower boost pressure = obvious boost leak. Build a boost tester with some pvc pipe parts and a schrader valve and find it.

superloaf

New development:

I noticed while driving tonight that although the air sound goes away when I lift, the boost gauge shoots up from max boost of around 12 to just past 15, maybe 17psi tops. I don't remember the gauge doing that and I assume the diverter valve is responsible for letting the boost spike. Am I correct? Also, can this spike damage anything? It's strictly when lifting and goes back down as soon as the throttle is opened again after the shift. And it spikes insanely quickly; I didn't know the gauge could move that fast!

Anyways, would love to hear thoughts tonight as I'm leaving for LA tomorrow...

Thanks

schip43

I think it's safe to say if your not set run at more than 15 psi then you have a boost spike?? So something is off somewhere start looking for a vacume leak.

Mine is set for 18 psi and windows up not that loud windows down it sounds like the hounds of hell just got cut loose!

superloaf

So found a vacuum leak, a broken off vacuum line to the HVAC reservoir, and plugged that up and now the car is much better. Of course not perfect but the midrange power is much better when boost is lower than max.. At max boost it still ends at 12 psi and then the car feels flat; it used to keep pulling. Also, the noise is still present but sounds more normal if that makes any sense. There is still a strong wastegate squeaking/chattering and also the air whooshing sound. But now it sounds more contained and not so much like an air leak as before. And now the wastegate chatters, or it could be the diverter valve, when lifting to shift and the boost also spikes but not as much or as quickly as before, maybe up to about 15.

Maybe a leak somewhere else or maybe the diverter valve is failing.....