I have a S4, JDM swap. when i get on it hard around 6K the Turbo sounds a little different, it gets louder, it is like a whistle. twin scroll is in still on but there is no vacuum line hooked up. I also have a 3" downpipe no cat and stock turbo II catback. The wastegate is ported. I am boosting around 9.5psi or just shy of 10 psi.

 

Would a video help???

 

^ Yeah I think a video would help.

 

ive never heard one with the internal wastegate ported but i assume the turbo would be louder when its at peak boost. is that not whats happening? but a video would be helpful to hear exactly what you mean

 

I have no idea if i am overly worried or what. I will post a vid soon

 

Ok here is the video. it is really hard to get the noise on the cam. I had to hold the cam over the passager seat. I was trying to do this myself. it is at the very end of the vid. and right before the shift buzzer goes off, about halfway thru the vid.

http://s6.photobucket.com/albums/y23...t=MVI_0125.mp4

 

weird it almost sounds like metal vibrating but that might be the video

 

it sounds like a whistle. I forgot to add that I have a makeshift cold air intake. the whole car vibrates because of the MMR semi soild mounts motor to diff. and the diff is making noise

 

Remove your turbo inlet duct and check the shaft play of your turbocharger.

 

I was scared someone was going to say that. How much is too much and how do you check it.

 

Let the motor cool, remove the TID. With your fingers, grab the nut holding the compressor wheel on. There will be side to side play, that is a given, just make sure that it isn't too excessive; a few millimeters play is ok, super loose is bad, if it touches the housing it's junk. Now, pull on the wheel. If there is play in and out (endplay) it is junk.

 

Our S5 had a little whistle after we did the swap. Then one day it got worst.

http://www.youtube.com/watch?v=6JvLKtlABfY

We sent it to Brian at BNR Supercars and he rebuilt and did a stage 1 on it.

 

I will check it. I wanted to do a stage 2 but his prices went up. It is about 750 now

 

we checked the play and it was in limits. little up and down, no in and out.

 

I firgued this was cause by air going thru the ported waste gate. would only make noise after the boost gauge read full boost(8psi) as the RPM climbed.

 

could be a boost leak. i had a leak that only happened under full throttle, sounded just like a tea kettle

 

A properly ported wastegate should not make that noise.



It does sound like a sort of "metalic" whistle, though. You've checked for leaks?

 

How would one check for leaks. I did do the porting myself and I am not sure if the "proper" way

 

build yourself a boost leak tester http://www.supramania.com/forums/sho...st-Leak-Tester

 

I'd say that is your best bet.^ (I am going to bookmark that.)


When you ported the wastegate... Was there a particular website or set of instructions you went by? Did you weld on a larger flapper door??

 

I did follow instructions on here. I welded a larger washer on the flapper door.

 

thats the same thing that happened to me when my turbo blow do to extremely bad shaft play, granted i was running 17psi on a stock s4 turbo :P

 

Alright. I am not accusing you of porting your wastegate poorly... I was just curious.

Definitely use that link to check for boost leaks. That is the first thing I would do.

 

only problem is I don't have a air compressor. or a garage. I live in the barracks

 

Would it be possible to find another FC owner in your area?... I am sure someone would be willing to let you stop by to use their compressor. It's always cool to meet other FC owners.