galognu

2008 GTS 123K miles. Have had it for 2 months and loving it. Had bad exhaust leaks on both flex pipes off the primary cats. Local shop was able to cut above and reweld 2.5in SS pipe as well as get rid of secondary cats. What a huge difference to have actual exhaust growl out the correct end. Its awesome.

However. Since then, which makes me think it may have something to do with the job, I get this metal rattling noise at around 3-4K primarily under heavy load. If on flat ground I can run it full out through all gears and no noise. If I'm going uphill or dowshift, but under load, the rattling noise is clearly audible, almost palpable. Most noticeable at higher speeds. Seems from the front. Driving me batty. I took it back for a tiny leak and got a good look at center support shaft bearing. No broken rubber though you can grab the shaft and move it with what would seem relatively not that much pressure. I have a slightly loose heat shield near the drivers side up by where the primary cat is. But I was there for the whole job, it was not touched. My next step is to get a gopro under and see what I can see.

Hoping some expert here has heard it before and can say with certainty...this is what it is.

I'm trying to attach a video. Having some trouble. If not I'll do it through you tube.

Thank you

can hear noise at 3-4K

Once again, noise under load. When I push accelerator.

Going uphill...Dropped phone..nothing happened.

Magdaddy

Did that local shop fabricate the secondary cat bypass pipes also? I would suspect it might be a simple case of that exhaust work being off center so to speak with the exhaust hangers. Possibly your upper torque arm bushings are worn, allowing the motor to move slightly more under load also...would exaggerate any exhaust hanger issues also.

Get the GTS up in the air, and inspect the exhaust from the repairs back.

Agree that removing the secondary cat’s(resonated bypass pipes for me), really makes these motors sing.

good luck

Petza914

Couldn't see the videos, but it a ounds like they eliminated the flex pipes? Those are there so that the motor can move slightly relative to the exhaust from the effect of torque. Open the hood and after the car is warmed up have some blip the engine pretty strongly and you'll see the motor twist for a second - that's torque. The shop has now tied the exhaust firmly to the motor so when the engine torqued, it moving the exhaust pipes too and now in that situation sounds like one of them is coming in contact with a heat shield and rattling.

galognu

Yes. Shop did everthing. I was right there taking pics and helping out. I 100% agree it must have something to do with the exhaust job...... though after having had the car up then, and a second time for the leak as well as me getting under it...I just dont see anything close. When I got the car I took off all engine cladding cleaned, ceramic coated oil/filter change....and inspected the torque arm. Rubber is intact. All of this specultion is very good. I'm hoping the gopro will give me the answer.