dwightlooi

What do you guys think about a True Dual Exhaust modification for the C55?

I actually, don't want additional noise -- growl or otherwise. However, it appears that the stock 2:1:2 setup may be unnecessarily restrictive. Why not just run two separate pipes to the two mufflers? I'll even throw in a resonator in the middle for good measure to reduce noise levels and also to create a semi H-Pipe effect. (See illustrations below)




Another way to attenuate the sound -- and especially the drone -- is to add a close ended pipe to each of the exhaust pipes at ~ 90 degrees and with an office in between that is 1/2 or 1/3 the diameter. The pipe is closed off with a screwed on section which can be turned in and out. In essence, we'll have created an adjustable Helmholtz resonator.

hooleyboy

I have a true duel exhaust on my C55 and i love it. Most of the benefits of doing a TDE is getting rid of the junk you dont need. IMO thats were the power is. With the removal or secondary cats and resonator will add power but it will also bring noise. I dont think there would be any added power/performance benefits with the setup you have shown. There is just a lot of places that are still restrictive in the system. Until those areas are addresses... I cant see and real benefit to doing a TDE while having restrictive stock pieces in place. From what I know.. You want to have place for exhaust scavenging as close to the motor as you can. The secondary cats location is the ideal spot for a Xpipe or Hpipe or what not. IMO I just cant see this system making much more, if any power over stock.

WaveyKat

hey hooleyboy or any other C55 Owners can you fit a Full Size Spare in the spare tire tub?

hooleyboy

No, The spare tire is broken down and comes with a pump. Knock on wood.... I dont even drive around with a spare. Not that I think it makes me faster I just keep forgetting to put it back in.

hooleyboy

Rethinking this exhaust setup..... It would be nice to have this setup with a set of cutouts installed You will pick up power and a sound that will get people looking for a hotrod. BTW your photoshop skills are top notch, It dupted me the first time around, even thinking it wasnt a C55.

dwightlooi

It's a low res picture... so it's not hard to do an OK job on in 10 mins.

Anyway... Do you know if the car will pass smog without the secondary (under car) cats?

hooleyboy

You will have no problem passing. the stock cats primary cats I was told are 400 cell. I chopped mine up and they look think 500 or 600 cell cats. that more then enough to meet emissions. I just put in 300cell 4 inch primary cats with no secondary cats or res with no check engine light. YOur system would work maybe give it a slightly deeper tone but to gain any power you would need to remove the restriction points. If i were you I would go to an exhaust shop and have then chop out your secondary cats and resonator. The sound is amazing and removing the secondary cats will add about 10whp and 15 or so wheel torque give or take a few. I know this because i've done it.

RedBull

I wouldn't recommend cutouts. Electric cutouts tend to have problems staying sealed correctly after a while, which will make your car sound like a hotrod all of the time. If you use manual cutouts, it becomes a pain to open and close them after a while......not to mention problems with seized bolts.

dwightlooi

When you say "secondary cats" you mean the two under the car just ahead of the resonators right? And, by "primary cats" you mean the small ones on the exhaust headers? I just want to be sure we are on the same page here.

How loud is the car without the undercar cats? I mean I am not a fan of loud exhausts. And when you say you have done it, did you remove the undercar cats or both these and the resonator?

greasybenz

Looks like a bent rim?!

dwightlooi

Looks like it... but it's not my car, so it's not my problem!

I used a set of undercar pictures downloaded online. My C55 is a Brilliant Silver 05, not this one.

hooleyboy

Yes, your secondary cats are just before the resonator and your primary cats are by the headers were your O2 sensors are.

here is a video of my cars exhaust note with no resonator and no secondary cats
http://www.youtube.com/watch?v=o2a9yc-lzf4

Here is a video of my custom exhaust with not resonator and no secondary cats.
http://www.youtube.com/watch?v=1da_AKDISho

ProjectC55

Most folks get rid of the primary cats and keep the secondary's which is opposite of what you have . More power is found doing it that way. Ask the guy with the 12.5 sec 112mph W208 CLK55(BlkonBlkCLK).

You need to free up as much as you can near the exh manifolds. That's where the major restrictions lie.

c55asleep?

Project your right, that's the setup I had and was the best result I got after trying different ways. Headers, x-pipe, and then some magnaflow 200cell cats. Primarys were gone and replaced with the kleemann downpipes included in the package of the headers.

hooleyboy

If you do it that way you will have to rewire the O2 sensors. I got random Technology hi-flow cats. Some time down the road i would like to move them though.

c55asleep?

Hooley no rewiring needed just weld a bung and put the o2s. You just need to send your ecu to get your cel corrected.

ProjectC55

+1 +1 +1

mb_c55amg_guy

sounds awesome...hmmmm...me likey, me wanty oney!!!!!!!!

l3iGD

On my SLK32, I am planning on removing primary cats and resonator. Is this also the best route on this car?

lkfoster

The wife's Audi TT has a vacuum actuated damper on one of the two muffler outlets. Seems to work well so far. I seem to recall that the RS4 has a similar arrangement.

alboogiee

It is a bent rim! and it is my car...well it wasnt when that picture was taken. But the rim doesnt affect the car at all.

F1Bobby

hooley both clips sound great. Damn! Looks like my C55 will need that done also!

RLx02

I'm also looking into modifying my c55's exhaust as well.

So I'd like to remove at least one set of cats and perhaps keep the resonator (the resonators don't affect performance right?). However, if I get rid of the primary, I'll have to weld a bung and place the o2 sensor where the cats were before correct? Now, if I do this, will I get a CEL? Also, if i get rid of the primary but keep the secondary can I pass emissions on the secondary alone?

Basically I'm just trying to keep it from throwing buncha codes and be able to pass emissions while making some gains.

Thanks.

superstar

I have removed both primary and secondary cats and installed the Kleemann headers with downpipes. Now, the car stinks real bad! I cannot stand behind the car while the motor is running! It will make me stink like a muffler! Hey hollleyboy , from where did you buy your Random Technology hi-flow cats? Does your car stink?

hooleyboy

I got my cats from random technology's website, and no the car does not smell bad at all.

http://www.randomtechnology.com/

the cat on the home page is not the cats i have. If you call them thay can get you waht you need and they can get it to you fast.