newbie needs help

[Justinth81]

HI there this is my first post, nice site you have here. This is my first DSM, and I have a couple questions. First of all its a 90 talon TSI awd, and I have 3 inch exhaust all the way back until u get to the muffer, I was curious whos got good prices on the 3" muffler thats made for a 90 talon?? I dont wanna nothing too guady and I only want single exit pipe, no more than 3.5" Secondly, the car idles well, has good vacuum according to my guage, but whenever I rev up the engine sitting still there is a noise being made on decel...sounds like a metal clanking on metal sound. It sounds like it could be coming from the turbo but i'm unsure. Is there any tests i can do to see if it is the turbo? Any input would be appreciated.

 

[strykersgsx]

Is it like a whump combined with a fluttering sound?

If so the only thing that I can think of is that your BOV isn't venting and the pressure is trying to backspin the turbo. However I must admit that I have never heard this sound. But that is how it was described to me.

 

[DJ_2Soxx]

"metal clanking on metal"??? not sure, but could it be loose heat shield?? possible if coming from "turbo area" . check to make sure everything is tight, again not sure, i would check for loose items.

 

[spoolup]

check your shaft play. TURN THE CAR OFF. remove intake pipe, mas, air filter, usually they can all come off as one big piece. After the pipe is off, reach into the inlet of the compressor (where the pipe was just connected to), your car is off right? Then gently move it up and down, the check left and right movement, then check in and out (passanger side of the car to the driver side of the car). I have seen pictures of stock T25s with the turbine wheel snapped right off the shaft and personally had the pleasure of having a EGT probe seperate and drop thru the turbine wheel causing what you see here.

https://home.comcast.net/~utspoolup/Blown_BT28.JPG

When the above happened, it sounded like a cop was pulling me over everytime the I applied gas trying to limp that thing home. my neighbor heard me pull up and said they could hear this metal on metal sound in there house when I pulled up. But I know of older trubos getting a bunch of play and rubbing the housing a bit causing another less faint metal on metal sound.

As suggested earlier it could just be the heat shields clinking around due to loose/ broke/ or missing bolts. maybe a exhaust leak, which I have heard sound like a metal grinding a bit when cold and first started.
can you pop the hood and use the throttle body to rev it a bit (easy since you cant see the tach from under the hood) and tell a little closer where the noise is coming from?

 

[Justinth81]

actually stryker it does sound like a whomp and like a metal fluttering sound, its definately hard to diagnose noises when your not actually working on the car.. being new to dsm's how would i know if the BOV isnt venting?? The guy i bought the car from says it has a 16g turbo on it, it has 3 inch exhaust all the way back, and he says the noise goes away when the car is warmed up... So i should look around the BOV for my problem? Ill take a look to see how hes got it hooked up

sorry If i sound like a newbie but atleast i'm not a know it all hehe, thanks for the help guys