Thread: turbo gurus, need your help
01-28-2015, 12:36 AM #1
turbo gurus, need your help
This one has me stumped.
I had a bit of a exhaust leak due to cracked stainless, which was repaired.
Put the whole exhaust back on the turbo, all looked well, new gaskets, bolts etc.
While trying to run it and give it a bit of a clean up, I ran a bit of upper engine cleaner through the intake and got a back fire through the intake (Rookie mistake yes!).
Anyway, I noticed the clamp popped off the throttle body so I re-did it up and took it for a squirt.
It felt very strong but as I came on max boost and into the 'fun zone' in the 8000's, it felt as though a pipe came off or a massive leak of boost occurred. You could hear the turbo spooling like mad but no boost... If you chop the throttle you'd get a lot of flutter... (Internal gate)
It would not go into positive boost after this... Basically it would find its place in the mapping where it would be just on positive pressure and would not exceed (around 5500 rpm).
Soooo I pressure tested the intake manifold (With 5 psi) which came up fine with no leaks, checked all clamps and hoses and all came up fine....
I put pressure on the dump valve (waste gate) and it sprung back to closed instantly, there is no boost controller so its running just off spring pressure (less shit to go wrong right!)
After all this, what would be my next best point of call? I feel as though no culprit was found....
Intercooler is clean of water on both ends and with 1psi test there is no notable leaks.
It gets stuck at positive pressure point and won't exceed...
01-28-2015, 07:25 AM #2
Pressurize the intake manifold to 10 or 12psi They can split on the seam with a backfire.
What PSI is the waste gate set for
Do u have a BOV that is getting stuck?
01-28-2015, 07:39 AM #3
I'd say a crack and the most likely culprit is plastic since it expands at pressure and returns to normal form once pressure is released.
01-28-2015, 10:57 PM #4
01-28-2015, 11:47 PM #5
Cool ill try more psi on the intake and report back....
01-31-2015, 10:28 AM #6
If you have the fittings pressurize the intake to the turbo with everything in place.
Engine off of course. Start at 5 psi the 10 then 15. See what happens.
You might leak a little air into the motor (past the rings) if any intake valves are open. But that's fine.
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