Ported VF34 Wastegate on my WRX, now I have a constant hissing sound..??
 

I have a VF34 that was experiencing horrible boost creep. It would hold at 1.2-1.3 bar (17.5-19 psi) up until 5000 rpm but then the boost would take off to 1.5-1.6 bar ( 22-23.5 psi)and then i would let off the throttle.
I pulled the turbo and ported the wastegate today in hopes of fixing this problem. I read a lot of things and had a DSM guru come over to help me get started on things. I opened up the wastegate a good amount but left what I felt was a safe amount of material to seal with the flapper. I also tapered the inlet of the wastegate passage.
I put the car back together, and now I have a constant hiss. It doesnt sound like any exhaust leak i've ever heard, and is audible all the time -- at idle, low boost and high boost. You can hear it coming from the turbo area and it is even clearer if you stick your head under the passenger door area or near the front passenger wheel well.
The car doesnt seem to have any extra lag, but it peaks at about 1 bar, hitting 1.1 max (14.5 and 16 psi, respectively). This combined with the hissing sound I am hearing makes me scared that the wastegate is no longer sealing properly. This doesnt make sense since like I said above I took extra care to make sure there was ample material to form a good seal still.
Anyways I'm going to pull the car apart again sometime this week when I can and hopefully find a line somewhere that wasnt tightened, and it wont be the wastegate. I couldnt find any info about it here or on nasioc so I figured I'd make a post and see what I could find.
Here are pics of my finished wastegate porting, so you can see how much material I left. I dont have a pic of when I started, but stock it was lopsided... one thin and one thick side. The stock thickness I retained was the width that is directly across from the hinge of the wastegate... about 7-8 oclock in the first pic. I basically made the entire thing the width of that thinnest stock point, so I dont see how there would be any possibility of a leak there...

(two versions of the same thing because shadows/glare make it kind of hard to see)
http://www.bryantroll.com/other/wastegate1.jpg

http://www.bryantroll.com/other/wastegate2.jpg


hopefully i'm not in as much trouble as I think I am. Hopefully someone can tell me what a constant hissing sound would indicate. It stays totally constant at idle, low boost, and full boost.

Thanks in advance to any gurus who can help with this...
Bryan

sounds like a leak to me

You won't hear a hiss coming from your wastegate. In fact, no one will hear a hiss from a wastegate. Ask G1GSX above, lol.

A leak at the wastegate, WITH an external dump sounds like an exhaust leak. A leak at the wastegate in a system that routes exhaust back into the main exhaust is not detectable at all, by ear!

The only way you can find if your wastegate is not sealing properly anymore is if the car lags more. (period) (no other way)

The hiss might be coming from your intake pipe or IC pipes. Even BOV, maybe.

Btw, you did remember to take the sock out of your turbo after you ported the compressor outlet, right, lol.

Sounds to me like you've fixed the boost creep problems. Now turn up the boost controller and run 20 psi already, lol. Unless your saying your can't do that.

Btw, a leak at the line going to your wastegate actuator would cause your turbo to boost like crazy... I should know.

i forgot to tell you this. take the bov off first them troubleshoot. you were right in the end. shouldnt have put it on when trying to problem solve.

So you put on another BOV after the port work....

TAKE YOUR BOV OF BRYAN.....its not for you. and give me your stock turbo

lol

cough*BOV*cough

yea thinking back last night u could hear that hiss from both sides of the car. wouldnt be surprised if it IS the bov. after u jinxed yourself saying your putting this on while trying to solve a problem haha.

*off topic* found those penut butter reeses haha. im not telling where they are.

Dude can i pitch in with you and buy them all out and then we can eat them infront of him...
Back on topic

Are you sure a snake didn't crawl up into one of your hoses or something? That might account for a hissing sound... :rolleyes:

But I do agree, though we had fun playing with the BOV I say take it off, see if anything changes, and you can always put it back on.

a 2 hour break from work let me check over some things...
without pulling the turbo i cant see the bottom 1/4 of the turbo inlet hose, but the rest of it is on just fine and butted right up as far as it can go, so i assume its just fine. unless there's a hole/crack in it somewhere which is possible since the thing is rubber garbage.
i checked every bolt in the area except for the one uppipe bolt which is tucked underneath the downpipe, everything is tight.
also checked every hose that i touched yesterday and everything is fine.
i put my stock bov back on.
i checked my wideband bung and my rear 02 sensor. everything was tight.

now for my guesses right now...
the one thing i did find, is that a gasket that i never touched, the turboxs downpipe to catpipe flange, has a small leak on the upper side that i can feel. i've never heard a hissing exhaust leak before, but i guess its possible.
another guess is that i got coolant on my uppipe/turbo gasket during the install... i wiped it as clean as i could and reused it. again, never heard a hissing exhaust leak before but its a possibility that this may be the issue.
another thought... i took the exhaust side off of the turbo to port it, i put it back together using the vband and tightened it well, but who knows, maybe it didnt seal?
lastly, the lower oil return line... that little wire clamp is there and i think its fine, but its actually sitting slightly below where it used to. i can tell because i can see the indentation from where it was before. i wasnt able to get it any higher and its within a half inch of where it was before.

the sound can be heard by sticking your ear over the turbo, but it does seem to be clearest from the wheel well or if you put your head under the car right behind the wheel. could be the point of origin or it could be the sound resonating through the exhaust.

so there's my update if anyone can gather any more info from this.
thanks...
bryan

p.s. i'm already a pro at putting on and taking off this hyperflow tmic. just hate removing my strut bar everytime i do it...

Yeah, I understand that completely. I think I might have misplaced my strut bar a while back, lol.

or replacing it.

sell the vf to ivan