Hey guys, my car is at ~1500 miles now and I'm starting to hear a scratchy sound from my turbo during boost (3000+ rpm) more and more. In the beginning, I would hear it when the car was cold, but now it's become more prevalent. This is my first turbo car and first Evo, so I'm not sure how normal this is. Most of the time I get a nice smooth whirl from the turbo. Is this a problem with the waste gate? Thanks in advance

 

I've put about the same number of miles on my Evo, and can say that I have never had a car full of so many curious noises. From feedback I've gotten from the members and some other Evo owners in my area, we need to learn to get used to it. Consider the mechanical complexity of a turbo AWD car, add a trick computer system and gumball tires and you have a symphony of odd noises.

To answer your question directly, the noise from the turbo is not consistent. Gear and temperature seem to have something to do with it. I have the AEM intake, so I can hear the turbo slightly more than stock, so the differences stick out quite a bit. I'm looking into getting a boost gauge so that I can stop relying on my ears and memory to guess at how well the turbo is responding.

Bring it around other Evo owners in your area or post up a vid if you are concerned that something is wrong.

 

a whistle that's on thing. A whooshing sound that's another. but scratch? I would like the above person said post up a vid if you can or I mean with 1500 miles take it to mitsu. You shouldn't have to worrie about anything odd with 1500 miles on a car. If you have mods though don't take it to the dealer with mods. I can't think of any scratchy sound in the evo that's normal but I have a X

 

Ok here we go, try this.

1, remove the heat shield covering the turbo, there are 4 bolts, 2 on top and 2 down, 3 that are easy to see and one that is a bit hidden, but you will be able to feel the head of the bolt.
2, now have a look at the 4 nuts that hold the turbo in place on the exhaust manifold, my bet is that some of them are loose. This causes air to escape and will also create vibrations between the turbo and the manifold making a "whirring" sound or as you call it a scratching sound. This will also happen if you make boost with the engine cold as all the parts(manifold, turbo) have not expanded properly and therefore no sealing properly.
3, If they are loose then get hold of 4 lock/spring washers and place them under the nuts, one at a time as you don't want the turbo to come off!!

This will solve the noise problem, but if nothing is loose there and you still have a cat on the car there is also the possibility that it has broken a piece off and sucked it back into the turbo and damaged the turbine, have had both things happen to me!

 

Do a boost leak test. Or just check your intercooler and throttle body clamps

 

Thanks for the replies guys. I'll go ahead and take this to Mitsu in a few days. Car is completely stock. Hope they find the problem!

 

You'll be fine.

Just one of "those noises" that all cars have (I hope!)

 

These are the times when its good to have your car all stock so you can take it to the stealership and they won't hagger you about 'mods'.

 

^+1
i have the same noise, is in the 3000-4000 rpm i can't hear it all the time but i will check this weekend all the clamps and silicone hoses that i have and see if any is gone

let me know please what does they find at the dealership