Custom X-pipe exhaust.

[A Quiet Boom]

Just completed this exhaust (the silver one)the other day, I had it off tonight to weld on some chrome tips so I thought I'd take a pic, what do you guys think? It's quieter and has a little more midrange feel than the other one which is a 2 in 2 out 2.5 inch Flowmaster with Pacesetter tips. Only downside is that it seems a little softer up top but that could be the cooler weather with jets optimized in 90 degree July. I'm gonna dyno test both as soon as possible for comparisions sake. The only thing I don't like is that I used cheap Summit racing turbo-style mufflers and they're a little raspy at full throttle, I'm looking at other options such as Hooker Aerochamber, Walker Dynomax and Edelbrock. Any ideas or thoughts?

[Bill Verburg]

Interesting, sort of reminds me of the old Ansa and Manta muffs

[TimT]

How about one of these?

[A Quiet Boom]

Actually, I've been finding that most performance mufflers are more geared and cutting down the lower rumble of V8 engines and do little for the higher pitched flat six. I plan on cutting these mufflers off and putting flanges there so I can test several different mufflers so I can get the sound AND performance I like. What will I do with the slighty used mufflers I don't like? Sell them to my drag race buddies, as long as it's loud and flows well they're happy

P.S. Where did you find those?

[TimT]

Those mufflers are from coast fabrication you could get some v clamps and mix and match mufflers from different sources to to suit particular tracks noise regs...

Bill originally posted the Coast link

[A Quiet Boom]

Yeah I saw those that rsr.Guru used, that's what I meant by flanges. I haven't tracked the car yet so right now I'm aiming at street noise and performance without making the neighbors too mad. (I can't run my dragcar in the driveway anymore )

[Chuck Moreland]

Looks clean.

How do the twin mufflers compare to the flaumeister weight wise?

Does the crossover create any restriction due to reduction in total cross-section?

[A Quiet Boom]

Originally posted by Chuck Moreland
Looks clean.

How do the twin mufflers compare to the flaumeister weight wise?

Does the crossover create any restriction due to reduction in total cross-section?

Thanks

As for weight, I couldn't believe my eyes when I put them on the pallet scale, both exhausts weight 25lbs +/-1lb

I'm sure the crossover creates some restriction, I've seen them with varying "merge" areas for different rpm/hp levels with smaller merge sections for higher rpm HP. I used 2.5 inch pipe though so it's definately far less restrictive than a stock SC exhaust with it's single pipe to the muffler. Like I said it feels a little softer up top but I jetted my car in the July heat so it might be a little lean with the cool weather we've been having in Ohio lately. I'm gonna check the A/F ratio and possibly install larger jets.

[RSR.guy]

QB,

I like 'em! This is a cool and clever way to get the crossover in. Reminds me of the Dr. Gas components. (www.drgas.com). I'm a big fan of crossovers on 911 motors. Definitely knocks down the db level, and seems to particularly help midrange power. Have you experimented with secondary (distance from header to muffler inlet) length? I haven't done nearly enough testing, but it seems like the longer the better.

Thanks for sharing. Lemme know how it works out on the dyno.

Cheers, Chris

[Two Oh]

Boomy, Very nice. You've discovered a good location for the crossover pipe. Care to make me a set without the mufflers?

I've always wondered why, on the 917's, they never used a crossover pipe. Any idea?

Looks like a lot of fun. The work you're doing that is.

[A Quiet Boom]

Thanks RSR, actually you inspired me to practice more with my new Tig so I could do a better job than the old exhaust that I did with my Mig. I got the idea from the Dr. Gas pipes used on 5.0 mustangs. Due to packaging I haven't experimented much with secondary length although these are longer than the flowmaster setup and the midrange does feel stronger, the dyno will tell.

[A Quiet Boom]

Two Oh, I'd love to make you a set but... I'd need a car to fit it to. I cut the factory collecters off my early Triad Headers and installed 2.5" collectors so I don't have an exhaust to match up to. Anyone with some spare time and an early car in the Akron/Cleveland area of Ohio that would like a crossover? I'll do the first one free if the owner supplies the materials (about $90 for the crossover and flanges) That way I could make a jig and sell them cheap. I really enjoy welding and metal work as a hobby so this would be a fun little side job for me but of course small production since they're handmade.

[A Quiet Boom]

Thanks for the PM Two Oh

Anybody think there's a market for these crossovers? Should I protect my idea from "theft" by the big, bad exhaust manufacturers? Does posting it here prove a timeline for my idea? In other words, who's an attorney? and do I need one? [hint] patent or trademark? [/hint]

Am I an idiot for sharing a pic of my idea? I just wanted response as to whether or not I could make these for others.

[Steve W]

QB,

Interesting concept and I like it much better than the single Flowmaster. I heard once the larger the can, the better the sound attenuation - so two must be better than one, and since they share the flow, you get half the backpressure in each. Probably the straight through mufflers will net you the best performance, such as the Edelbrock RPM series, Borlas with the lazy S core, and Ultra-Flos. I would imagine a controlled burble at idle, and a straight shot out at full throttle rpm.

[Steve W]

Hey, and what about a pair of used 993 mufflers? Supposedly their exhausts are so efficient, yet quiet that tuners can barely extract more than 5 hp extra out of them. The entrys and exits are probably in the wrong place, but with all the creative minds here, maybe something could be rigged.

[smestas]

That exhaust looks SWEET! I'd like to see a pic of it all mounted up.

Keep up the good work!

[A Quiet Boom]

Steve W,

I can certainly see why the 993 mufflers flow so well, might be worth a look but probably much more expensive than aftermarket. I'll keep you guys posted with my progress and hopefully some more pics of it mounted once I'm satisfied with the fit and finish. My plan is to get them fit just right and then remake them using these as a template, everythings a tight fit so I've had to tweak here and there. BTW my car doesn't have a factory bumper just a fiberglass replica so I'm not sure such large mufflers would work on a stock car but some glasspack style mufflers angled down should fit no problem or even narrower (shorter) turbos. Thanks for the replies guys, keep 'em coming.

-Chris

[Steve W]

I've seen used 993 mufflers go up for sale pretty often for reasonable, and see them all time at Porsche swap meets, not to mention, they're stainless. Check out an old listing:

996 / 993 oem rear mufflers

Now, I think the hot set up would be a pair of 993 heat exchangers mated with a pair of stock 993 mufflers - imagine the potential! If the're good enough for a 3.6, then . . . . . . And those come up for sale all the time too. You only need to cut off and rotate the flanges of the right(?) heat exchanger because Porsche decided in their wisdom to do so. But that should be cake, with the new TIG.

[MIK911]

Steve W,
I like your idea of a 993 muffler mod. A hot muffler set up amongst 993 enthusiasts is a mod to the stock 993 muffler by Robin Sun (P-car.com), called a RSR conversion. It sounds SWEET on 993's . Wonder how it would sound on my 3.2?
Anyone have thoughts on Steve's idea of a 993 muffler on earlier 911's?

Mike
'86 Coupe

[Doug Zielke]

The Secret Weapon......



(Thanks to Randy Wells....a guy who knows his stuff).