Bought a used perrin intercooler y-pipe and installed it the other day. I didn't do any highway driving until today. On the freeway, I had to pass a car, so I rev-matched into 3rd and laid on it. With the windows up, radio off, I noticed the spool of the turbo is now much louder than it ever was. I love it, but I don't understand how that could be. I wouldn't think that the silicone hoses would let any more noise out than the stock plastic one. I didn't notice any decrease in power, so I'm not sure if this is normal or if I have a leak.

My 2004 wrx is all stock except for a catback and the y-pipe. Anyone else notice a difference in noise when they installed just the intercooler hose?

I searched for this and found a couple posts, but they all refer to a wind/whistling noise more common with a leak, than just an inscrease in spool noise.

 

I did my IC hoses with the uppipe, and there was def more noise. It makes sense, because the stock y pipe is designed to restrict air flow.

As long as there is no noticable power loss dont worry about it.

 

you're fine, if there was a leak in your intake tract, your car would run like a huge, steamy pile of dog crap. The turbo spooling noise is a normal thing for our cars, but changing anything in the intake or exhaust will make this sound more noticeable. You've heard my car when I am pulling out of BDG havent you? My turbo is LOUD compared to most other peoples cars i've heard.

Things that will make the spool sound louder are:
changing any intake hoses like the y-pipe or turbo inlet hose,
removing the intake silencer (the name says it all),
changing the air filter to something more free-flowing (like a K&N or AirHog)

Also, removing catalytic converters (especially going catless) will dramatically increase this sound.

-Ted

 

Spool Away!