ChicagoX

CPT let their fabrication wizards go on my exhaust, and this is what they came up with.

I was jealous of AMG Rider's exhaust sound - mellow at idle, but hell-raising at full-throttle. I wasn't able to duplicate it, but the results were acceptable.

The closest thing I've heard to it was coming from a big-block Chevelle sporting a Gear Drive timing set (quiet version.) It's a muscular sound at full-tilt, to say the least. I can't wait for headers.

The final setup was a stainless 75mm straight-pipe to the stock mufflers. Primary cats replaced with SS 200-cell, SS flex section to prevent header stress, V-band clamps, and provisions for DMH low-profile cutouts.

Here's some pics after 2000 miles on the car:













Here's a shot of the LET Heat Exchanger, after a few miles:

bobgodd

Sound clips??

ChicagoX

Working on some fly-by and in-car clips for you.

mht_v10

is that one of Chris Jannasch creation ?



suhweettt...been wanting to get the exhaust done ...but I just have no time to send the car out.

sound clip would be nice Sir ...

ChicagoX

It's actually a CPT creation, thanks. (www.gocpt.com)

Clips coming.

E55 PWR

NO X-PIPE ?!?!?! You need to redesign that ASAP!

ChicagoX

Original design had an x-pipe.

This sounds much sicker.

Fr33kn63

I like it...I have gone totally dual as well..."F" the X pipe

splinter

Nice. Have you run it uncorked?

Zora Arkus-Duntov specifically excluded an h/x-pipe so that his machine’s would sound that much more menacing.

Hurry up and install those LET manifolds.

Dr. C36

if you don't have crossover you are leaving HP on the table. a crossover is necessary for both performance & sound reasons, it helps improve scavenging and top end flow as well as cancels out the pulses for much higher quality sound. If you want more power put an X-pipe in there.

jangy

Sound aside, can anyone show HOW the X or even H pipe helps? I want to get schooled on theory here. Thx.

bobgodd

Each cylinder has it's own exhaust port, so you don't have one constant linear flow of air through the pipes, you have 8 individual pulses flowing through the pipes. The engine fires side to side; so you have one pulse, then a gap, then another pulse flowing through the pipe. When using straight pipes the pulses just continue on their path and exit the muffler. When having a crossover such as an x-pipe, the pulses come together and push each other through, increasing their velocity. Instead of having; left bank > gap > left bank > gap, through a pipe, you now have: left bank > right bank > left bank > right bank, and the opposing bank pulses are pushing each other through the exhaust making it more efficient in scavenging exhaust from the engine.

Que no?

blackbenzz

Nice setup! I'm sure it sounds like a BEAST with the plates removed.

That heat exchanger looks awfully familiar! Hmmm

jangy

I get that part, just kind of confused on how it literally helps bring more heat out. Thanks for the write up, though. I think I will try one out and see what the butt dyno says...

bobgodd

I guess you can say that instead of letting each new exhaust pulse push out all the exhaust that's already in the pipe, you're using the exhaust pulses to pull each other out. Something about the way they (pulses) meet at the x-pipe causes them to not just "fill out" the gaps, but the pulses actually push each other out and through the pipes faster, with in turn creates a sort of "pulling" for pulses that haven't yet reached the x-pipe, which in turn helps them exit the exhaust port at the cylinder heads faster.

Think of it this way; if you had a mesh screen over each exhaust port on the cylinder head, between the head and the headers, you would be choking your system and thus see lower power numbers and lower performance. So by taking that restriction out, you allow your spent exhaust to leave the engine as fast as possible. That's what the x will do, it will allow the spent exhaust to leave the engine as fast as possible.

That's the way I've always understood it. I'll admit though that I don't know jack isht about Merc engines and their exhaust engineering, so I don't really know how the engine reacts to a more free flowing exhaust. I think that respect to our engines (55k) the x-pipe isn't really making the exhaust more free flowing, rather it is making it more efficient. Now if you had straight pipes from the headers to the tips, that wouldn't be the business lol.

ChicagoX

It's ungodly. I have the electric cutouts that bolt up there, but need to have the turndowns extended slightly so as not to further char the undercarriage.

While theory says that an x-pipe would assist with scavenging, I have yet to see an exhaust make power. This install is purely a method by which to scare animals and small children. The headers are coming, and those will be expected to bump up the HP a bit.

blackbenzz

Yea, I took the muffler and resonator off once and it was loud as SHYTE!

phatmitzu

Cutout plates?

ChicagoX

Did the charring give it away?

I have some DMH low-profile electric cutouts going in their place. AL@CPT installed the switch where the ciggy lighter goes in the ashtray area. The turndowns needed extending a bit; I'll post pics/sound clips once they are back on the car.

IIIMBPIII

I took my mufflers and resonator off and it sounds F-ing amazing! Granted I dont have mods like most of you guys but I work with what I got!

phatmitzu

Excellent!