CVR_Rally

I've put my factory CAT back into my S after tossing out the broken Magnaflow. I use the factory S muffler.
To sum up, the Magnaflow was a little short so there was always plenty of clearance of the factory resonator to the crossbar.
With the factory CAT back in it once I get going and it heats up I am guessing the resonator is rubbing right up against the bar.
I also was getting the muffler bracket pushing up against the sheet metal so I removed some and made that work. You can see some marks on the bar where it has been hitting.

So I find it interesting how fast the geometry of the exhaust (length) can expand that fast once you get going causing this rub.

Short of ordering a new cat-back exhaust seems like removing the resonator is the only other option.

V2Rocket

Something isn't right. With the factory front section and factory muffler section there's usually a 1/2" or so between the exhaust and any of the underbody parts and it doesn't rub.

CVR_Rally

When I had the old engine it didn't do this. The new one does and really is noticeable at 3k rpm. I removed the sealing ring and used gasket material to add some space but that just made it quiet for a little longer till it heated up again.

3rd option is to replace the broken CAT from the Magnaflow and put that back on. I'm going to go look under the car again tonight.

V2Rocket

Any chance you have new engine mounts?

CVR_Rally

I have new ones I have not installed yet. Do you think this is a sign of bad ones? I get no other symptoms like jumps in the gear lever.

V2Rocket

New mounts are 1/4" or more taller than old ones which can raise the exhaust into the body if the exhaust was positioned with the old mounts.
I just had to fix my exhaust for that same reason.

CVR_Rally

Okay that’s not my issue then. I just can’t seem to pinpoint it. Here are a couple of pics.

Since this is only an issue with the factory CAT I may end up replaced the broken Magnaflow cat with another and go back to that setup.

On the right is the gap between the resonator and the crossbar

Pic of the wear mark were it was rubbing

A better pic of the wear

V2Rocket

the muffler end has slotted holes to give some vertical/angle adjustment; maybe your muffler is "all the way up" and could slide down?

if not that, i don't know what it could be. weird.

CVR_Rally

It was hanging in the lowest position, I'm trying alternate...ran it at idle to see if I could witness the scraping I was pointing out but it looks like it has plenty of clearance.

I can grab and shake the exhaust from the tip and it acts like there is plenty of clearance. I'm starting to wonder if the internals of the CAT have come loose so when the metal expands inside the CAT housing it gives it enough room to vibrate and cause a cross between a drone and a vibration and that's why the other one didn't have this issue.