Bramage

Anyone know what the stock E55 exhaust diamter is? Thanks!

(W211 / 2004)

shardul

iTrader: (1)

fluctuates from 2.5 to 2.75

Bramage

Thanks Man!! Any idea the portion just before the muflers? I have some new down pipes, and will build out stainless back to mufflers, but want to be able to bolt up old exhaust. I think it is 2.5" in that last section, but I cant squeeze under my car to measure

shardul

iTrader: (1)

the section before the muffler is 2.75

Turbo 6

The section right before the muffler will slip right into a 3" pipe causing a slightly loose slip fit.

blackbenzz

What are the guys that are running 3" piping doing to fit stock mufflers on?

shardul

iTrader: (1)

3" slips right over the stock muffler piping so no reducer needed.

GT-ER

The piping is 100% 2.5" ( at every point I've checked anyways ). The only thing is that it's of a pretty thick gauge so it'll measure slightly more and in the drivers side after the primary cat it is flattened which makes it 2.75" ( although it's oval ). I put 2.5" piping to remove the cats and resonator and the inside diameter was the same all around. The outside diameter however was slightly smaller due to the gauge of the pipes.

Honestly though, 2.5" dual exhaust is pretty freaking large. I really don't see the piping on the oem exhaust to be a restriction at any power level under 700whp or so. The mufflers I wouldn't know though.

komp55

This is simply wrong. From the resonator rearward, some early '03s had 60mm OD tubing, while everything '04 and later has 70mm (2.75") OD tubing. Forward of the resonator, it varies slightly to machine forming necesary to allow the front catalyst sections to fit under the chassis.

GT-ER

I'm sorry, you're right....I just remembered I had to expand the pipe to make it fit into the rear. So yes, 2.5" before resonator, 2.75" after resonator.

Anyways, has anyone checked to see if how restrictive ( if at all ) the stock mufflers are? Are their any dyno's on exhaust systems for this car?

stevebez

After my recent exhaust work - I reckon its pretty much 2.75 front to back... if u exclude the one flattened section.

GT-ER

Nope, just checked mine after what komp55 said and he nailed it. 2.5" pre resonator and 2.75" post resonator. You can even see where it steps up to 2.75 immediately before the resonator.

stevebez

Interesting ... wonder how the chnage in size along the way affect things overall... one would expect slightly high pressure at the contrained points I would guess...

GT-ER

It goes from smaller to larger so it's not a big deal and the smaller portion keeps velocity up in the hotter portion of the exhaust while the larger rear simply keeps the pressure down. Either way, our stock exhaust is pretty huge.

chawkins2001

Dane- Run 3" all the way back from my mid I sold you. Your top end will be insane and these cars make so much tq, that if you loose any down low, it will probably be a good thing, less spin, and make up for it plus more up top. Your note will be way deeper too.

blackbenzz

But that would be a restriction I would think. I haven't seen the intenals of the AMG mufflers but maybe the inlet can be widened to 3"

I would also like to know if the stock mufflers are restrictive. Maybe I will dyno before/after although that isn't the best comparison. Too bad tracks are closed around here

komp55

The factory mufflers are engineering masterpieces. Lots of sound control with virtually no restriction. For restriction, you'd be talking about the 400 cell primary catalysts. It's been said before, but on these cars, mufflers are about sound, not performance.

blackbenzz

Thanks. I'm not worried about stock cats, they are gone. I'm worried about going from 3" piping down to 2.75" which definitely sounds like a restriction. Guess there is only 1 way to find out

shardul

iTrader: (1)

you cannot widen the stock mullfer inlet becasue there are a lot of welds around it and the will crack.
this is how the gas flows in the stock muffler. enters then goes into a S shaped pipe, the it goes through a Y to the dual tips.

blackbenzz

I meant cut the pipe clean off and weld a 3" pipe on but the way you describe it that's not possible. Thanks for the info!

TTMotorsports

Just doooo it Ahmad!

Cut the piping off at the muffler, open that hole a little and mate 3" right to the muffler!

DONE!!!

PS It is going to sound NASTY!!!!

chawkins2001

Yip, easy enough as I looked at the mufflers before I sent them to ahmad, and any exhaust shop could do that.

blackbenzz

Thanks for the info! Yea thats what I wanted to do. Cool, once I get my ECU/TCU back I will get to workin on it!
Thanks again for the mufflers! Can't wait to get rid of that nasty drone!