02WS6Bird

iTrader: (2)

Just installed some QTP Longtube headers w/ AIR fittings, Catted Y pipe and GMMG. I have noticed under acceleration a faint whistling or rustling can be heard coming from underneath the car by the catalytic converters location. I dont hear this soudn under cruising conditions, nor do i hear it on revs, only in motion-acceleration. At times it can be loud-it only bothers me since i can not figure out what it is.

I can tell the car is running a little richer after the install, so i thought mayb its the cats burning up the excess fuel, but then i thought i wouldnt hear that.


What do you think it might be- the nuts, bolts, clamps, bands etc. are all tightly fastened as well.

02WS6Bird

iTrader: (2)

anybody?

SgtB

iTrader: (3)

Probably if we heard it in person it would be better to diagnose.

02WS6Bird

iTrader: (2)

Its more like a rattling did a search, some people came up with heat shields, and loose clamp from Y-pipe to I-pipe I don't know how that would sound.

Would adjusting my Y-pipe be the best thing to do?

02WS6Bird

iTrader: (2)

nobody else?

LawmanSS

iTrader: (19)

As you mentioned, I remember some folks reporting problems with the GMMG causing a heat shield rattle...take another look at the rear section and check all of your clearances...also check the heat shield bolts and ensure they're tightened.

02WS6Bird

iTrader: (2)

Sweet thanks for the info

Anybody Else? Keep the suggestions coming

02WS6Bird

iTrader: (2)

Which heat shields do i have to tinker with, and what should i do to them? Pics anyone?

LawmanSS

iTrader: (19)

The ones above the mufflers (under fuel tank) and/or the one that follows the intermediate pipe over the axle, pass. side.

SgtB

iTrader: (3)

Check the ones by your y pipe.....the clearence from the heatshields to the y...

02WS6Bird

iTrader: (2)

Heat shields- no rattle, Y pipe, everythings fastened tights, when i tap the y pipe or hit it by hand i hear a rattle/jingle afterwards, but its nothing big-Car does have a bit of a sewing machine sound down there though when sitting at idle- not like its a big deal-i chevcked everything is fine-i think its from the headers mostly, i hit the y pipe bend in front of the Drivers side a tad bit to knock it in further and i tucked it up about another inch or so- We'll see what happens- maybe i'll just have to live with it- besides when im flying aroudn adn the radios on you cant really hear it especially over the exhaust itself

Thanks anyways guys

ynkssws6

iTrader: (1)

i had a rattling with my gmmg, turned out to be the where the y goes into the I pipe....looked tight but i could move it.

02WS6Bird

iTrader: (2)

How can i tighten the Y-pipe to I-pipe connection-i cant seem to turn it at all! breaker bar wouldnt even work

LawmanSS

iTrader: (19)

If that connection is using a band clamp, be careful not to overtighten, as the bands will break (I've done it). Does the I-pipe have slots cut into it at the joint with the y-pipe? The slots are necessary to allow the pipe to squeeze closed when using band clamps. FWIW, when I installed my GMMG the first time, I had to cut my own slot in one of the tips to allow it to tighten under the band clamp, so it's possible they forgot the slots. Another option would be to use a traditional style u-bolt muffler clamp that slightly crimps the pipe...this will allow a tighter seal, but will make it much more difficult to disassemble that joint later...

fasteddyss

iTrader: (1)

Your exhaust may be touching the body somewhere. Check the clearance between the exhaust and the body everywhere.

Good Luck