So since I purchased my r53 one month ago I noticed a little rattling at around 2.5k rpm in first and second gear. I am quite sure its the resonator or a cat? I can't target it exactly. Anyone have the same problem? Could it be the cat? It really makes me sound like a beat up rice box when it rattles. Any input would be greatly appreciated! I am running the OEM r53 exhaust.

Thanks all!

 

me too, but I've a JCW exhaust at 149k miles.

I am assuming it is the resonator, but replacing the whole darned system for the obvious reason that a CAT with that mileage is not likely to be a big performance gain.

What mileage does your system have on it?

 

Mine rattles at almost exactly 3 grand. Stock exhaust header/cat with Magnaflow cat-back.

 

With the run running, and someone working the accel pedal for you, listen for the rattle. Since you have the stock exhaust (assuming not a JCW car), your cat is in the front near the engine while the resonator is in the rear (looks like a muffler). You might even be able to tap on the resonator to get it to rattle. If you have a JCW exhaust the resonator is in the middle of the exhaust with two small mufflers in the rear.

 

I have 66k on the car as it sits the exhaust is completely stock and its just an s non-jcw. It seems to be coming from the rear which is why I am assuming its the resonator. By the way is this something I can fix by cutting out the resonator and knocking the baffle out? Would this be too much work?

Thanks for the useful replies everyone!

 

Some people just remove the resonator and replace it with exhaust pipe. A muffler shop should only charge around $75 to cut out the resonator and bend plus weld in a replacement pipe. However, the exhaust will be louder.
This is called the "one-ball" mod if you want to search on NAM.

 

I fixed it with a one ball mod. Definitely nicer sounding and cost 40 bucks.