pete95zhn

...I guessed so...

Well, I have this de-cat scrap exhaust and I was slightly bored today, so I got my angle grinder and ooops...:

MechanicalEng

nice... next time you get bored would you mind doing the same with the transmission? I want to see how it looks inside too...

Land Jet

Thanks for posting this. Not much in there but it does quiet the sound, a little too much.

GaFFLe

Thanx for posting these. So when one does the hole-in-the-stock-exhaust-pipe mod for achieving a better, throatier sound, does it retard acceleration? How do aftermarket exhausts for the 996TT add HP? I'm not looking for the scientific answer. I'm just vaguely curious.

THanx.

JG 996T

Interesting, thanks for the pics... amazing how quiet these cars are....

pete95zhn

I can't give you a scientific answer, just a guessimate, but if you look closely the pictures you'll notice that there's not much direct flow through the muffler part. Change to slightly bigger ( in pipe diameter ) flow-through muffler and the back-pressure will be greatly reduced.
Also in OEM exhaust there's two dense cats ( 400 cpi or more ) each side, and that "Pack-Man" style opening from the aft one is not very big...

I really do not know how for example RUF ( or PBK ) has done their mod, but after opening this one I'd say that the Pack-Men are gone and those partially closed pipe ends are opened.

Last930

Thanks for posting these pics. What is the steel-wool looking stuff? Any idea what it's function is?

pete95zhn

That's the silencing stuff inside the silencer... There's actually two different styles of that inside. Just around those perforated pipes is an about 5mm thick layer of thread made out of S/S. I guess it's there to keep the actual silencing stuff ( which looks awfully lot like thick mineral insulation wool ) out of contact with exhaust flow and thus not to escape out of the silencer.

Macster

Can't help you with the hole in the exhaust pipe mod question. (Part of me believes this 'mod' is favored by those owners who can't figure out a way to attach cards to their car so as to slap against the spokes of the wheels.)

Generally if an aftermarket exhaust truly adds HP it does so by allowing the engine to flow more air. The engine is an air pump and the amount of power it can generate depends upon how much air it can pump in a given amount of time.

This requires of course that the stock system be overly restrictive to begin with and that other areas of the engine, the intake system mainly, does not then become the limiting factor. IOWs, a freer flowing exhaust ain't going to help much if the engine can't bring in more air through its intake system.

Sincerely,

Macster.

c32AMG-DTM

Turbo motors benefit from as little backpressure as possible... the stock exhaust trades higher backpressure for lower decibels. Aftermarket exhausts do the opposite, for greater responsiveness/spool and output.

The intake side of a well-engineered forced induction motor configuration rarely is a limiting factor, IMHO. At least, no where near as much as the exhaust side.

raineycd

All you ever wanted to know about the drilling out mod. I did it when I had a stock exhaust and loved it! When I put the cards in my wheels the rotors keep lighting them on fire under hard braking - can't figure that one out yet...

http://www.6speedonline.com/forums/9...ler-996tt.html

jcb-memphis

Cool. From the J of the TJW mod, this is cool stuff. You should post the photos in the 6so thread for completeness sake. I could if you allow me to do so.


Jeff

GaFFLe

LOL, fuNNy you are. So yeah, I'm one of mod-owners and boy, that well placed hole in the pipe makes the stock exhaust SING quite nicely; however, I do notice that in high-speed acceleration, my car doesn't pull as hard as it use to. The diameter of the hole I cut was about 2" so maybe I'll try increasing it for giggles. The only reason I did the mod was for the sound and I figured I'd focus $3300+ dollars on something like turbos or an larger intercoolers, etc. Looks like I'm still gonna get an aftermarket exhaust unit after all.

jpflip

Thanks a lot! Great information....

pete95zhn

Thanks Jeff! I've already done that^^