Hello,

I'm looking into changing the cat to a high flow on my justa R55 to accompany my Magnaflow exhaust and DDMWorks CAI. Already have the resonator gone, and have noticed that some extra sound is hiding in the wings.

Would like to open it up just a wee bit more. My goal isn't a faster car, I would just like a little more sound, but do not want to run without a cat. Any good resources for high-flow cats? I've seen a Magnaflow universal one for $65ish.

 

Installing a header will open up the sound a bit more:
https://www.turnermotorsport.com/e/p...rmance-header/

Should help a little bit with performance, too.

If you still have the stock header with cat, you can remove the second cat and not have any emissions issues.

 

If you put a header in front of a stock cat you are not going to gain much power and some times the gaskets blow.If the second cat does not have an o2 sensor behind it take it to a muffler shop and have them weld a piece of pipe in.Unless you live in a state like California that has smog checks.Cat Convertors are just a mop up for when the engine does not burn the fuel completely.