Boost leak
 

Hey guys, I have a leak some where , wether its exhaust or intake im not sure.

Im looking for so ideas/ methods on how to check for a leak.

Without unbolting anything yet everything looks good. No leak at the header gasket or cracks in the header. Turbo flange looks fine no soot.. Usually i would see a crack or something.

Intake looks good. All connections seem fine nothing jumping out at me so far. The leak on a scale of 1 to 10 is a 5 just to be clear.

All (3) silicones are all good no obvious leaks.

Anyone ever test there system in the car?

I was thinking of making a block off plate for the rear of the turbo and disconnecting all the rockers. Then put compressed air to it . What do you think? The only thing i was thinking that might leak would be the oil ring seal in the turbo..

Then for the intake i would block off the inlet at the turbo and do the same test.

Anyone have any ideas ?

Thanks...

Why do you think it’s leaking?



GTO George

It spools too late and its not there when i peddle it..

Had a friend that used some kind of smoke leak check machine he bought on Amazon.....but you still need to create block off plates etc to use it.

Smoke might give you a visual, but can probably do the same with compressed air and listen for leaks.

So it’s not a numbers thing, it’s more of a seat of the pants thing...... maybe it’s ignition, time doing something stupid? Just to throw some stuff out there.


GTO George

Thats a good idea.

Wish i had one .

Prob do compressed air..

Thanks

Its not igntion.

Its a time thing. It takes much more time to build pressure. Also when on and off the throttle. When its right it comes back in instant. Now it takes at least 2 seconds for it to come back..

Have someone you can trust brake boost it and stand off to the side and listen... under, hood open, ect.

Try a plumbers coloured smoke pellet for the smoke, maybe a reversible vacuum cleaner to suck the smoke in and blow it into the turbo downpipe etc.

If you have your waste gate to atmosphere, put a rag in the pipe. bring it up before gate pressure and see if it blows the rag out. gate could be open a little.

Im not sure id be able to hear any leak with how loud it is under my hood. Believe it or not for a 4 cyl its very noisy.. But i can give it a shot.

The smoke pellet sounds like it might work . How do they work ? Do you lite them off with a flame ? Where would you place it? Unbolt a pipe , throw it in then bolt it back up?

Ive tried the rag in the past. It seems to vibrate out more then blow out.. I tested the gate with turning it upside down and filling it with water an it held the water . To me its good , but i could be wrong...

Look for something simple first.
Like a crack in the pipe feeding the turbo.
Turbo Exhaust systems take a really bad beating over time
due to the high temps, expansion of the pipes, the number of
boost cycles that they see.

Rarely does a engine with a Turbocharger see 3 or 4, (usually less than 10) boost cycles in a day,
(like a Roots Style Supercharged Race Car. They might see 15 -50 boost cycles in ONE DAY, every day,
on the street for the whole summer.

Pipes wear out, even the best stainless stuff.

Just my thoughts on the subject.

Tom V.

So i made a block off plate for the front of the turbo and put 25 psi too it. I already found a good sized leak at the IAC block off plate. Enough so my compressor counldnt keep up with it. It is a small compressor though. Once the silicone drys ill continue on with the test. I cant help to wonder if this was always leaking or it was the new problem that brought me to this thread.. Hopefully i can get this on the intake side . I forgot to say i also found a crack in the up pipe to the turbo yesterday i fixed that but still have things going on i guess..

Did some more testing. Got some porosity in the intake and the turbo leaks at the back of the compressors O-ring seal. Fixed a leak at the wastegate hose from the compressor housing. The throttle body shaft leaks bad. Unbelievable..

So i fixed all the intake leaks . Put a seal in the throttle shaft . Fix 5 leaks in all. Put 20 psi of air in the intake track through the turbo and all is quite ( no leaks) . Take it for a ride and nothing changed. Lol..

I think i give up.

Been feeling like picking up the hammer in the corner and fixing it that way haha...

Have you got a blow off valve/dump valve in the intake piping? Maybe that is opening when boost gets to it , weak spring/out of adjustment etc. Or maybe the same thing but with the wastegate- cracking open too early.

I do have a BOV . I was thinking about taking it off and looking at it but not sure how to tell if its malfunctioning.It does seal when i test it an spray it with water.

I did a cranking cyl psi test yesterday and had 190 psi in all cylinders. Normally it has 170. I guess the new head is making more pressure. That explains why it feels faster per pound of boost i guess. I guess the smaller runners made this happen. Ill have to see if that changed the vacuum. Maybe when on and off the throttle the bov is out of sync like you said..
Thanks Paul..

To state the obvious without knowing your setup, sounds like a waste gate malfunction to me.

So i made a backing plate to pressurize the exhaust system. It leaked bad. Didnt even get 1 psi on the gage. Turns out the V band under the turbo was leaking half way around the entire band. It was warped with a .080" low spot. So i belt sanded it down to around .006" and permatexed it back together. Then i found the otherside was leaking but not as bad. Then the one coming off the header was leaking real bad . Turns out the crossover pipe needed to be redune. So i fixed the pipe and put it back on an it leaked still. But not nearly as bad. Now it was holding 20 psi. So as it is now i permatexed the 2 on the pipe . Im letting it dry over night and will test it tomorrow.. I cant believe all the leaks i had . Hopefully this will be the last of them...

I checked it today . It was good . It had a tiny leak at the band. so i permatexed it and it dont leakk anymore..