[BiGGeE1787]

Hi, How's it going everyone! I'm in love with my beast and I'm happy how helpful everyone is on the forum. I have spent the day doing research here as I am going to do my Inspection II, but thats not what my question is.

I am wondering if anyone is running mufflers and x-pipe ( I have Supersprint mufflers and X-pipe), with D/A race software, no cats and stock headers? I'll probably hold off on headers to see my gains, see if I want to go with the differential first.

Hope to hear some responses and Happy Holidays :santasmile2:

 

[E55AMG2]

You wont see much (if any) gains from removing the cats unless they're bad.

 

[BiGGeE1787]

My friend is running headers, no cats, and mufflers with D/A race software on his E46 M3 and has seen incredible gains. I am wondering if any M5s are running catless with their race software.

 

[vantaam5]

Most of the gains come from the headers,removing the cats does not really add gains....

What are the gains we are talking about on the M3,BTW?

 

[BiGGeE1787]

My friend has K&N Cold Air Intake, Evosport Headers, No Cats, Borla mufflers, D/A race software. He's dynoed on a Dyno Dynamics at 336hp. Most M3s run his set up with cats are only making around 315hp. That's why I wanna know if anyone is running this set up with the E39

 

[E55AMG2]

It could very well be the dyno...either way, I'm not sure why you keep asking the same question over and over again. As was already mentioned; on the E39 de-catting makes very little (if any) difference in power output. That's assuming the cats arent clogged up or melted. Anyone who's running this setup is doing so because either a) their cats have failed and their state doesnt do tailpipe emissions b) They removed their cats when they installed headers because there is no state emissions testing or c) they like the sound and smell of going catless.

 

[BiGGeE1787]

Alright. Fair enough.