For some reason the RT Cats are slightly longer than the stock cats. This makes the front end of the cat back exhaust lower than it was with the stock cats. The shims are to compensate for this because the exhaust is now closer to the center plate and the shims are needed for clearance.

If you have a dual aftermarket exhaust such as the Borla, The RT Cats will make your passenger side pipe come very close (and sometimes actually touch) the rear sway bar. Some adjustment may be needed here to avoid vibration. (especially when at WOT from a standstill........the car will dip down in the back end a bit....making the pipe vibrate on the sway bar)

If you have a Borla and put on RT's, you may have to look at the H pipe again. The extra flow sometimes makes the H pipe leak. It may have to be welded if the leak continues.

 

So what is the final outcome? Do the RT cats cause the same raspiness between 3K- 4K RPMs with the Borla TD that the test pipes did?

 

In a word. NO!

Regards

 

I am getting this same problem.

I have checked the seals and it all looks good. I also have the shims installed as Jason/Performance suggested.

Is there anything else I can try? If there where a couple things to look for try I would appriciate it,

Thanks

Brad