I installed a set of these today and needless to say fitment was kinda a hastle. I have about 90 miles on them and noticed a few things. At certain RPM's the cats seem to introduce a vibration into the car around 3500 4000. I also noticed that under WOT the car seems to ok but under normal to slow driving there is a raspy sound given off. This sound seems to come and go. And finally when I sit idle and get on and off the gas a little im getting a light rattle.

Now all that being said I did install the shims and seemed to have plenty of room between the x brace and the exhaust. Im curious how many people that own these have these same issues, and is there something you did to fix any or all of these issues. I know there are alot of threads that have various stuff in them but I wanted to start a new one

Any feedback would be great....

 

no rattles here.
it get a little raspy at high rpms, but its bareable.
it did seem to lower my exhaust piping a little, but lowered enough to slightly scrape my y-pipe on a huge driveway hump.

 

How long have you had the RT Cats? Is that the stock Y-Pipe you scraped? Do you have aftermarket exhaust?

 

I just had mine installed today also. I paired the cats with the Nismo exhaust and stock headers. I drove approx. 45 miles with nothing noticeably vibrating. I even toasted a teenager in a GTI who got intimidated by the new growl. I've seen a bunch of threads with complaints of that same vibration. I'm sure something will pop up though, always seems to when the mods start.

 

Yah the vibration seems to be in 4th gear around 4k rpm's.
Im going to try and lower the brace a bit more ....

 

I had the problem. But not now. I had to double shim. There is about a 1 inch gap between exhaust and brace. Be careful going over speed bumps.

 

i had the cats for close to 2 months. i still have the oem ypipe and exhaust.

 

Going to try to double up the the spacers. I noticed while driving today the cats add alot of volume to the Nismo exhaust when you get on it even just a little. They are quiet when cruising. Still undecided if the increase in volume is ok or not. Still hoping the vibration goes away.....

 

Had my R/T Cats installed today. Put 100 miles on them and no rattles. Just loud as hell ! especially once you pass 2500 RPM's.

 

Where did you get the extra shim. I'm getting the vibration during warm ups. It goes away when the engine and exhaust heats up.

 

yea, I totally agree. on the first z, i had the borla td exhaust w/ stock cats, and it didn't increase the volume, just the exhaust tone. but after putting both the rt cats and the borla exhaust on my new z, i was blown away by the volume change. with the rt cats, it makes the exhaust considerably louder. i never really understood why people called the borla's sound like a muscle car, but with the rt cats i would have to say this is true. to my ears its a good sound, but just loud as all h@ll!!

 

I'm installing the RT cats tomorrow, and I'll get it on a dyno by weeks end - if the weather holds...

I know you'll never see them unless you're up on a lift, but damn they're sure pretty... very impressed with the finish and craftsmanship.

 

Doubled up on the spacers solved the rattle problem. Vibration seems to be gone. After driving alot today only thing I dont like is how much louder the exhast is. Power is great cars pulls harder now thru all gears but I might go back to stock to get the original tone of my Nismo back...

 

Do you have any pics of your install?

 

...

 

No sorry =(

 

You can use washers to shim as well.

 

Give it about 200 or 300 miles. And then see how it sounds.