komp55

Took delivery today of my center resonator replacement pipe options. I had two configurations prepared, the first a straight through bypass, and the other a X-pipe configuration. Hope to install this weekend, time permitting.

deaded

Just curious, what exactly does this do? Does it increase horsepower or does it make it sound better? Sorry for being dumb.

dtxmob

SOUND FTMFW!

bobgodd

Where'd you get the pipes from?

chiromikey

well...unfortunately just deleting the resonator and adding an x-pipe will do very little, if anything, for sound (or hp).

jangy

HOLY COW!!!! I was just about to get the same thing done.

What does the X pipe do? I've always seen them as a source of turbulence so I have not liked them. Plus, I happen to like the slight side to side sound. I'm just curious what the X or H pipes do (sound and power). I know the power is negligeable.

chiromikey

an h-pipe will help equalize gas pulses and tends to yield a bit more (or better depending on opinion) sound. a properly constructed x-pipe will force gasses to increase velocity as they merge therefor increasing scavenging effects. contrary to the idea you mention, this acceleration can actually decreases turbulence as faster moving gas will tend to flow instead of tumble through the tubes.

jangy

WOW, I didn't think that way. So, it kind of helps break up the slower eddys? So to speak? Crap, now I have to try it. i was hoping I had laminar flow in the straight pipes

Blacksport350

Who fabricated those? They are nicely done.

rflow306

I agree, very little power gains from any exhaust mods after the header's imho.

komp55

Agree on the power comment. I already installed Evosport headers on my car, and these pieces will be will be for enhanced sound when they're hooked up to the Supersprint mufflers they're to go on to the car with. It's going to be a LOT easier R&R'ing the rear half of the exhaust system than it was doing the header install.

Vadim @ FD

Kompressed55:

Very nicely made!

Twin pipes will make the car sound more like a muscle car.

The X-pipe will make it sound similar to Ferrari flat crank sound, with more rumble.

I have not seen any power gains with either setup.

jangy

How about on removing the secondary cats, too? I know normally that would reduce backpressure and not help, but if the car is tuned then wouldn't an exhaust tune have potential, too?

narf

im considering having the same thing done: x-pipe + resonator and secondary cats delete.

From what i gather, there is very little change from just losing the resonator, the secondary cats have to go as well.

No performance gain is to be expected.

Apparently VRP can hook you up with an X-pipe, though I've got no clue as to how much they charge...

jangy

kompressed pictures looked like some pretty high quality work. I think I am going to try taking the secondary cats out, too and seeing if it makes a difference....I gotta add headers and see what they do first.

narf

From what I've gathered, removing the secondary cats will not yield much more than a little more noise (and possibly a little more emissions, but we didn't buy 5.5 liter supercharged V8s for the environment, did we?).

For exhaust tuning, the yields can be found in headers (long tubes more than short tubes, at the expense of having to move your primary cats down and having to extend and relocate your 02 sensors, possibly leading to CELs and definitely leading to not passing annual testing at least in Sweden, and from what I understand, California).

Removing the primary cats also yields some power and torque, also leading to CELs, testing and emissions problems, and angry neighbors (due to noise). Im not sure but I think you might get American Muscle Car (tm) noise as well (not something I'm after).

I could imagine that removing the resonator and secondary cats might lead to a small increase on a heavily tuned car (read: yours, not mine), but I'm not sure if its prudent to expect anything at all.... Someone with more experience and knowledge is bound to chime in a smack me down for not knowing what I'm talking about.

komp55

Spent some time installing the resonator replacement piece I had fabricated, along with the rear half of a Supersprint Exhaust (inlets, pipes, mufflers). The removal of the factory exhaust is somewhat of a PITA due to its use of rubber hangers which require removal of the mounting arms of the exhaust from them. It's possible to do on the mid hangers, but in the rear it was much easier to just remove the hanger mounting brackets with the rubber mounts attached and then separately remove the rubber hangers. Using just two jack stands, removing the factory exhaust is a one person job.

For the initial configuration, I selected the straight through pipes piece since I figured it would likely be the most agressive sounding. The install went very smoothly, and I give kudos to my fabricator for the perfect fit of the resonator replacement piece and to Supersprint. I can confirm the Supersprint pieces fit perfectly the first time and were very straight forward to install, with no welding required due to the clamping system they utilized in the design for the E55.

Here's a shot of the custom center straight through pipes as installed:



I was very pleased with the sound resulting from straight pipes with just the Supersprint mufflers. At idle, the note is very deep, and during engine acceleration, the sound is deep, contained and powerful. I will post sound clips after I get a chance to record some. There is some cabin resonance between 1,800 rpm and 2,000 rpm, but so far, it's not obnoxious enough to be concerned about. I may swap in the X-pipe piece just to see if it curtails the resonance at the indicated rpms. Other than that, perfect fit and the sound I was looking for. Not sure how much the already installed Evosport headers contribute to the overall exhaust note, but the car definitely sounds more aggressive now.

gonzjed

very nice, who made the x pipe?

Dr. C36

X-pipe is always better for both sound & performance, much better scavenging effects at high rpms. straight pipes are just for noise, no real power gains. swap out with X, you will like it more.

bobgodd

jangy

Looks MINT!! Let us know when you try the X pipe. Is it possible for the rest of us to get the x pipe, too?

komp55

Several guys have asked where I had these pieces fabricated. I had them made at Specialty Products Design, Inc. Definitely not cheap, but top quality workmanship and fabrication.

http://www.spdexhaust.com/