Cat Bypass & M&K = OMG
 

Well, I finally got around to removing my cat & replacing it with a bypass pipe. Bolted it up to my M & K 1 in / 1 out, pulled it off the stands and fired 'er up. Nice rumble & very deep sound.Not much different than with the cat & the M &K.
Then I took it out for a spin.Holy *****!!!!! Good lord what a difference in sound and volume,especially the wail above 4000 RPM.Man, women & children ran and dogs began barking when I passed. I am shocked at how much the volume & the sound has changedwith the cat deletion! As I rolled thru the hood later in 2nd gear with the windows down, I could hear the noise bouncing off the fronts of the neighbor's houses. I should be really popular next spring when I leave early for work and shake all the windows.
Unfortunately, it is now down for the winter but I can't wait to have some fun next spring. I cannot imagine the sound with a set of SSI's & a 2 in/ 2 out.

just got the same thing, and it sounds glorious. Backing onto my lift in the garage shakes the whole building :)

Cool! That's sort of the setup I've been looking at getting.

Anyone tried the Fabspeed Euro Pre-muffler with the STOCK 1 in 1 out 3.0 muffler?

I am getting a bypass and a Dansk sport muffler installed tomorrow. Its basically a stock muffler 1in, 1out. I will let you know how it sounds later this week. I'm thinking I should get some more horse power @ the rear tires. maybe 20? someone have any feedback on the power?

20bhp seems a bit high.
i'd say 10-15bhp if you're lucky.

Truthfully, my seat of the pants dyno didn't really note much of a difference. I'm thinking maybe 5 hp.

Next thing he'll be telling us is how he likes to go downtown, drive through all of the parking garages counting how many car alarms he sets off.;)

To get all the benefits of the sport muffler\cat bypass installation...they have to be matched to a performance chip...!!!

I wish I could chip!!!

I really didn't notice any significant HP change going from cat to no cat to bypass with M&K.

+1 on the high rpm wailishness, though.

Anyone have a definite answer on the Cat Bypass / HP issue other than "seat of the pants" dyno numbers?

I've got the old headers and two in two out mk and my niebhors love me!

I'm sure my neighbors hate me. I went SSI and 2-in-1-out M&K. Absolutely amazing, it hurts my left ear ;-)

lfot,

I've got the set-up you're asking about: Fab Euro Pre-muffler and the stock exhaust. There is a slightly deeper exhaust note but that's about it. If there was a HP gain I didn't notice it. I do like the fact that that side of the engine is little cooler with the Cat gone.

Thanks Kurt.
You just helped me NOT spend more money I can't afford right now.
Engine music is great, but I think that project has been moved down the line of things to do. With no real performance gain, my money is better spent elsewhere (suspension, 9's, tires?).

I recently went with SSI's and a 1-out M&K. The car DEFINITELY pulls stronger and doesn't start to wheeze at higher rpms. However, the exhaust note is considerably louder than I thought it was going to be. Ben (M&K) told me that the increased sound wasn't so much the M&K muffler, but the SSI's. He said that there's only a difference of a decibel or two when comparing one of his 2-in-1-out sport mufflers to a stock 2-in-1-out stock Porsche muffler. I didn't go the cat-bypass route because the car will no longer be subject to emissions testing. There's was quite a bit of free-breathing hiding in my car, all stuck within the heat exchanger crossover pipe and the constricting cat, all being dumped into a single inlet muffler.

Steve

it is wonderful

You make it sound like having a car with a loud exhaust on the street is a good thing. I respectfully disagree.
Your neighbors and the people you share the streets with probably do too.

I have the Dansk sport muffler WITH the cat. Frankly, I'm disappointed with the sound. Not much different from stock. One of these days I'll get an M&K...

Scott

I'm with Sammy on this one. I put Fabspeed cat bypass pipes on my 3.6. It sounded like a V8. I was embarassed to drive down my street & couldn't wait to yank those things. Don't you want to hear your fan whine?