bigturboz28

Just got back from the dyno..

The good news - made 553 hp @ 5500rpm @ 10.5 psi.
The bad news - We heard a noise.

The shop thinks it is the turbine compressor wheel hitting the housing, it makes like a tick-tick-tick noise then goes away. We did a couple pulls, then heard the noise, then it went away, so we did a couple more pulls, and it came back, so we stopped. Since I drove home I can not hear it. The turbo is a brand new precision Garrett GT42 (with only about 10 - 15 dyno pulls on it).

1. What could have caused this if it is in fact the case?
2. Other than taking my compressor housing off, how can I check if that is the problem?
3. What else should I check for?

Did not get a chance to do a pull in 5th (as we were going to do that after everything was dialed in), but I phoned the dynojet guys and they said that it should work fine.
Did not get a chance to modify meth amount, used 400cc/min, seemed to be the right amount.

frcefed98

iTrader: (16)

Be the easiest and best way just to pull the compressor housing off, which is pretty easy to do on the GT42. That way you can check the compressor blades and housing itself real close.

Probably wasn't hitting. My Tial BOV makes a pretty low key shh-shh-shh after getting out of boost.

J

Zombie

iTrader: (2)

When the blades hit the housing it's more of a SCREEEEEEEEECH noise. Other wise knows as the death whine.

bigturboz28

I'll check for sure, the other thing is that it made the noise even at 10inch vac., but when you get of the throttle, it goes away???

It definately was not a screeetch sound.

Any ideas what could cause it if it is the turbo?
Any ideas what else it could be?

Tiago

iTrader: (27)

maybe a spun bearing?

ls1mongrel

iTrader: (32)

Nice power !

SSilverSSurfer

iTrader: (8)

i dont think he wants to hear that...lol

NOSjohn

iTrader: (9)

The turbine side and compressor side are seperate parts. If one side is hitting then more than likely, the other side is hitting. It would NOT be a random tick-tick-tick...it would last all the time and you would be able to hear it.

If the compressor side were touching the housing, you should be able to take off your air inlet and see if the wheel is touching the sides. It is probably something else as frcefed described and others describe.

67Firebird455

iTrader: (27)

That is unbelievable power man... Hopefully you find that noise, I know I would be going nuts, I can't stand that sort of thing!

WS-Sick

I'm thinking it could be something gone bad in the internals. I'm assuming you aren't running forged internals yet?

ESR

iTrader: (7)

Ive heard that noise before.......... Sounds like the exhaust wheel or the impeller blade is rubbing the housing......take it off now and have the clearing and shaft play checked before you mess up more things........

ESR

iTrader: (7)

It can be random ............trust me been there done that..........but it will speed up slighly with RPM.........It does become more consistant as time goes though...........not proud of it just had my share of misfortune..

markp03

iTrader: (4)

what % duty cycle were yor injectors seeing? i am going to be running a setup like yors...just need to buy fuel system and wg nad bov

Big Geek

iTrader: (2)

As stated inspect both the exhaust side and the compressor side and look for any chips, nicks or scratches in the blades. Check the shaft for side to side play and that the nuts are not back out of otherwise causing an issue. It is hard to say what it is without hearing it first hand and I realize that this may seem like allot of work but it is MUCH better to take the time and do it rather than have the turbo come apart on you and end up in the motor. Trust me that is NOT funny at all!!! Mine was a defect but Harry Hruska made it right without issue.

Jim C.

bigturboz28

Thanks for all the input, I will take er apart this weekend and keep you upto date.

I'm running 60lb injectors, and twin walbro 255hp intank pumps, I don't know the exact number but there was lots of injector left. Also don't believe the myth that it is to hard to tune with 60lb, it is bullsh*t. Do not waste your money going to 38lb then 42lb then 60lb, just go 60lb. If your goals are higher then the 60lb'ers will get you, I can not speak to that, maybe someone else can chime in about tuning low hp (~500rwhp) with 72lb or 96lb injectors.

-EDIT-

One more thing to add, as time went on in the dyno runs the engine bay got hot (no sh*t), but the lines I used to connect the BOV were that clear vinyl stuff. I noticed that they were collapsed due to vacumm and them getting softer due to heat, any ideas if this could have contributed?

bigturboz28

something??? ran through the exhaust side turbine, the base of the blades (where there is a big gap to the housing, or at least there is now??) have little chips out of them. The intake side was untouched. The only scary part is that if the blades that are far away from the housing have been damaged, what was causing the noise? Could whatever went through there "kicked" the shaft and damaged a bushing? or is the turbine out of balance now and causing a problem? Any ideas on what a new exhaust turbine costs?
Any comments?

ABeasst

iTrader: (5)

most likely part of #7. sux

LSs1Power

iTrader: (5)

So something flew into the turbine housing? That will only mean one thing... I would really do a compression test.

bigturboz28

I don't think piston, I'm thinking more along the lines of a piece of weld, I did a last minute "tack" to ensure it was not leaking, but I think I might have melted a chunk in the exhaust pipe that broke off (and I learn it AGAIN - do it right the first time). The other reason I don't think piston is that the car still runs very strong.

Would the car run strong if a chunk of piston was missing? wait, I know, I know - Maybe, it depends, right?

LSs1Power

iTrader: (5)

It happend to my cosuin before in his EVO. The piston had a crack in the middle, but it was still intact. When we took his turbo out we saw the same thing on his blade, but were surprised the engine was running fine (No smoke, Sound, pressure in the oil, etc...). We did a compression test and one of the pistons were really down. We took the heads off and we saw the pistons had a clean straight line crack in the middle, but the sides were intact so it was in one piece.

Im not trying to scare u or anything.... Its just a thought. I hope its a small problem and u get it fixed.