Bill Verburg

an even fire engine like a Porsche H6 doesn't profit from a x-over connection like odd fire v8s. The factory knows this and correctly plumbs it's race and street/race exhausts like on a GT3

GT3

997S

onefastviking

Exactly !
An X only changes the sound on our motors. There also isn't enough pipe length for us to make an "x" work even if it would on our cars.

Larry Herman

That could be just 2 small side inlet/outlet mufflers put together in one housing. That is the way the Flow-Masters are done, and on my old Carrera, the difference between that and straight pipes was about 3/4 of a HP.

onefastviking

Yes the Flowmasters use multi chambers with internal baffling which is a little different than the Magnaflows with straight thru perforated cores and fiberglass baffling. Neither are really set up for a dual in/dual out for our cars.

Larry Herman

I thought that the Flowmaster was the right way to do it, seeing as how in the one that I had the left side was separate from the right side.

onefastviking

I didn't realize Flowmaster had a dual/dual with opposing sides like that. Not bad. How was the sound from it ?

fletcherdave

If extended straight pipes work without head damage......get the plasma cutter out and lets lose some weight out of the back of this thing.

Flyin Finn-where did you get that pic? I am trying to build a 996 RSR (clone) and need all the pics I can get.

Larry Herman

On my 3.2 Carrera it was awesome. Along with the resonator tips that I had, it made the motor sound more like a V8 Ferrari than a flat 6 Porsche. Had that little shriek when you wound it up. Pretty cool.

Bill Verburg

Both Flowmaster and Magnaflow have 2x in/2 out xflow mufflers. Like Larry I have a Flowmaster on my '76 hotrod, it sounds great but is loud and would never be allowed to run a a palce like Lime Rock. you are coprrect about the internal designs, the Flowmaster just uses baffles and internal reflection to damp noise, the Magnaflows ate a glasspack desiign w/ perforated cores wrapped w/ ss ot f/g strands. The Magnaflow is quieter.

Fabspeed also makes a 2x2 crossflow muffler, here's a pic of it's internals, inlet is the lower pipes

onefastviking

Thanks for the pics, for me personally, I'll stick with 2 individual mufflers. I'm not sold on "x"s working for us and it's just as easy, maybe easier, to design and work 2 separate mufflers into the car than one big one. Just my preference.

fletcherdave

ltusler - getting ready to do this and started wondering about the O2 sensors???? I don't see any at all in your pics. Are you running stand alone EMS or ?????

Gary R.

Thanks Bill, great shots. I think I may build a Magnaflo to try and meet Limerocks db standards this year as my old busted up Flowmaster 80 with the baffles pounded into the tail pipes just won't hack it anymore..

Bill Verburg

I know, once the Flowmaster went on my '76 any thought of LRP went out the window.

I hope that the Magnaflow works for you but suspect not, given how tough they have been getting. I do have some other ideas for someone with some welding skills.

The key to a good flowing muffled exhaust is to get muffler volume. the Fabspeed is better because it is bigger. The wrapped perforated core is going to silence better than the baffled core but flow worse, Viking is correct 2 long separate cores will be better, even if they are in the same case. The Fabspeeed would be much quieter if the 2 cores were extended so one internal turn up is at one end and the other at the opposite end. The external plumbing will also be asymmetric. The next thing to try is a trick that I knew of but had never seen implemented, It was on a BMW exhaust. Your BMW may have the same thing, look for an exhaust can that only has an Inlet, no outlet. It does work.

Gary R.

Another thought is separate "tube" mufflers running straight back off the headers like the (expensive as hell) 22" ones Burns sells now.

Bill Verburg

The problem w/ those is how short they are, the longer the better, a transverse install gives you the most length.