westtra

Hi,

Have just fitted a prodrive cat to an 02 sti type uk. There are still the sounds of turbo spining up etc but there is a new sound that I am not too sure about.

It happens when the car is coming on boost just prior to the boost spike. Its a secon ish long chirp/screech(not good at explaining things. Happens in 3rd to 6th not sure about 1st or 2nd.

The differences between the cat to turbo connection is an extra 1" pipe on the prodrive cat compaired to standard cat and I am wondering what this pipe is and what its for. Could this be causing the chirp?

What i think it may be is possibly the waste gate making a sound when closing(the waste gate actually moving or exhaust gases pasing through the restriction prior to it closing/opening) it doent isnt a flutter sound as if the waste gate is hunting just a quick chirp every time the car comes on boost.

The other possibility is maby DV leaking when I get the boost spike but i cant see why as I wouldnt have though the boost spike would of been that much higher with the new cat.

The car is completely standard bar the new cat. there are no cels etc showing on dash and car still pulls very very well. I know i'm probably worrying about nothing but thought it better to check in case I do any permanent damage.

any suggestions are appreciated.

cheers

Mark

funkyspider

If you are refering to the piece of metal on the mouth of the prodrive cat then the answer may be here

https://www.scoobynet.com/general-te...e-wrx-sti.html

Are you sure the chirp isnt just spool-up or is it louder than you would expect for that. Have you checked all the pipes and clips that you could have knocked.

westtra

the chirp is seperate sound that I hear during the turbo spooling up. Still get the whistle/whine which is a bit louder than prior to the cat being fitted.

Have a couple pics of new and old cats.

old

new


the link above explains what the small entry to the cats for. Would it be down to this that I am now hearing the waste gate close/open now? which is causing the chirp.

Have checked every pipe i can access easyily. Was a subaru garage that fitted it so would have expected it to be fitted correctly.

westtra

anybody????????