Interesting Noise on Full-Boost
 

I posted this in the Turbo forum, but the traffic in that forum just isn't as heavy as it is here...

I have noticed, specifically when it's cooler out, that when I go full-trottle and the turbo builds full boost, I hear a momentary, slight whining sound, which seems to correspond to the turbo building boost. Any ideas what this might be? It doesn't seem to be a problem, because the car is running great, but is it anything I should be concerned about?

there also seems to be either a something loose in the exhaust (or a loose heat shield), because I hear a rattling from the general mid-exhaust area (somewhere near the cat) at about 1200rpm

If it helps, my car seems to make the "interesting sound" with more weight in the car. For example, after I dropped off my bro tonight (230lbs), I noticed that the sound didn't seem to be occurring as often.

The noise sounds like how a chair squeaks when you pull it out on a hardwood floor sometimes

Check to see if there is a wooden chair wedged under your car.

Oh hohoho what a comedian ;)

heat shield probably.. just rips off with a pry bar. i did it to mine, rattling sound gone.

boost sound, no idea.

Hmmm...Your "whining sound" could be a pile of things but I would suspect a vacuum leak...especially if the vacuum lines are original. For that matter you should seriously think about replacing all the rubber lines including fuel, vacumm and cooling.


The rattling is possibly a loose heatshield on the exhaust manifold. The welds break loose over time and can make that annoying sound.

CJ,

The whining sound may be normal. The turbo should make a whining/spooling sound on accel and decel, this is normal. The added weight of your bro' would simply increase the boost in lower gears.


The sound you are hearing is probably a good thing, I would be more concerned if you couldn't hear the turbo spool.

No, i hear the whistling/hissing of the turbo spooling up, this is an additional sound that only occurs when i put the pedal to the floor