So I may be obtaining a Hahn 3' Catless down pipe for my LNF. I don't plan on doing a custom tune for a while. I realize that this may throw a code, but could running catless without specifically tuning for it cause any damage to the engine? I'm on a Trifecta tune currently if that matters.

Also, since the state of Missouri requires a catalytic converter, the guy I'm buying the DP from says that doing a second muffler as a "test pipe" will allow it to pass inspection. Does anybody know exactly how this works? Thanks!

 

I think it's useless to get a DP without tuning

 

I will eventually get tuned for it.

 

Should still help it spool a bit faster than stock, but you really won't see any real benefits, just make sure you have an inspection done if it's going to run out before you plan on getting the tune.

 

I ran catless downpipe with no tune for a few thousand miles. Cel came on but no other problems. Cold starts and boost is quite a bit louder, but other than that sounds almost the same as stock to me.

 

I had catless downpipe on for about 3 months before I got tuned. I had ordered TurboXS downpipe since it came with an angled 02 defouler, so I didn't get any p0420 codes.