dleung22

I have ordered mid length headers to pair up with Akrapovic evolution system. Can you guys chime in on if I should run catless or should I have my shop put in some HJS 200 cell racing cats?

I will be getting MHP v3 tune also, they said they will trick CEL to be off so it wont matter if I have cats or not, tune wise.

Will racing cats make a big sound difference? Will I be using much much more gas running catless?

Appreciate feedback everyone!

_AMG_

catless will net you more gains then 200 cell cats.
200 cell cats should tone down the sound a bit.
No, you wont waste more gas. Catless headers will improve exhaust flow and is alot less constrictive then the OEM logs.

BTW how are you going to mate the Akrapovic evolution exhaust to the headers?

bhamg

Catless will be freakishly loud. Won't that be a problem where you live?

dleung22

with stock exhaust yes, but i have seen someone's car locally with akrapovic evolution X supersprint LTH, but he has 200 cell cats. Wasn't too loud at all, but i think our engine really opens up when we step on it so maybe that's why i didn't find it that loud as I only heard it start up and rev below 4k rpm.

i think the akrapovic system really tones down the overall sound alot though, and the system has such solid bass in real life, it's really a sound that makes the stock exhaust sound really dispersed and dare i say, soft.

other than sound, i just want to know what pros vs cons there are of running with/without cats. Since i am going to try running catless first, if it is indeed intolerable I will send it back to the shop and get some HJS 200 cell cats on the headers!

Merc63

Headers with no cats is obnoxiously loud.

BAD430BENZ

i think everyone knows that with stock exhaust , but the OP stated he has the Akropovic so it will be toned down a lot . i have MHP headers and catless mids so i decided to go with the Carlsson 3" axle-back . even under WOT , the car is still quieter than oem exhaust at start-up

dodger63

https://www.youtube.com/watch?v=AjZE...e_gdata_player

Mine isnt loud anymore

MBNiko

It's so quiet, what ever did you do Dodger!?

Staff@RPM

You can't even tell that it's running anymore.

Baby Gorilla

Personal preference, but no cats is too loud for me.

dleung22

thanks for the feedback guys.

will give everyone an update once i get the headers and akrapovic installed..and than another one after i get the MHP tune

very excited! i hope i dont run into any trouble fitting everything!!

_AMG_

Are you running MHP cams?

dodger63

Who what?

C63newdude

Catless are very loud. I recommend catted long tube headers

_AMG_

Your video title states MHP C63 headers race exhaust cams.
Just wondering if your running cams.

dodger63

Yes

Don Nguyen

My main gripe about running a catless exhaust system on any car is the smell. Can't stand it.