Dynomax cat-back

[Guido]

I've decided to go with Dynomax Super Turbos because from what I hear (from you guys) they do the job and are the most quiet. Does anyone have part #'s they used? Or at least dimensions (length, pipe offset)? I'm going with 2.5 inch.

Otherwise...I'm also considering modifying a Mustang cat back system but when looking through catalogs they specify GT and LX models. What's the difference? Which one would be better for a Mark?

[pro-five-oh]

GT or LX: a personal preference.

If you want the understated look, the GT's are better. The GT's gigantic rear valence panel won't permit the big shotgun pipes of the LX.

Screw understatement, get the nice double barrel shotgun duals for the LX and lengthen them to fit a Mark.

I went with a GT-style 2 1/2" cat back (ideal size, I might add) just because my Cougar is monochrome, but on a chromey Mark you'll do fine with them!

[Lscman]

Oh boy! Cat back Dynomax Super Turbo's with stock H-pipe & cat setup will literally blow your eardrums out. They will be louder in the driver's seat than 2 chamber flowmasters on a ponycar. I specified STOCK replacement '88 Mustang mufflers for a custom Mark VII system. When I got to the shop, he said "take it for one day" and let him know what I thought. What a jerk. It took 15 minutes to decide to hack the SuperTurbo's he substituted off and throw it in the dumpster. The stainless Dynomax UltraFlo's are barely liveable in my opinion. They are much quieter than their Super Turbos but really the Mustang OEM replacement mufflers are needed to prevent resonance. The longer wheelbase in the Mark VII makes systems MUCH louder than the same system on a Mustang. Sound is neutralized when the crossover is moved toward the muffler inlets and the long driveshaft makes that impossible. Alternatively, a X-pipe will reduce the resonance if local emissions rules allow it. An x-pipe might make Super Turbo's liveable. By the way, a Mustang or T-Bird cat back system will not fit a Mark VII right. The 21 gallon gas tank is much wider than the 16 gallon version on the other's and there is more trunk overhang. The right side pipe must be custom bent to fit properly. You might get the left one to fit. Custom is the only way to go, although you can hack a Mustang pipe and use the small section that passes over the rear differential. As the pipe nears the gas tank, you should cut it off and bend a custom tail section.

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Rick, Road Track Terror in my '88 Mark VII LSC. See ya at Northeast Events! Pgh, PA

[This message has been edited by Lscman (edited June 16, 2001).]

[Lost Boy]

you can run super turbos hemi...about as quite as stock but awesome breathing

part number for the super turbo:

the super turbo is off set in/out model WLK-17734 for a 2 1/2 in setup( I am 90% sure this is correct) anyone want to confirm this

I would throw a MAC pro chamber h pipe on with the rest of the exhaust(GT that way it looks stock)...

[pro-five-oh]

Guido, I forgot about the stock H-pipe...yes, it is still a big restriction even with headers and cat-back modifications you are making.

Though I haven't seen a Mustang cat-back setup on a bird/Cougar/Mark but they should fit with the right amount of bending. Hell, I got a 5-speed Mustang H-pipe to fit my AOD cougar with a little cutting, welding, and bending!!!

If the Mustang cat-back doesn't work, just find a smart exhaust guy to make one for you out of 2 1/2" aluminized (sp?) pipe. I had a custom cat-back added to my car, and it clears the 22 gallon tank easily (us birdcats get the mondo tank too!)

[Lscman]

I'm a little confused, Lost Boy. Are you suggesting Walker's physically huge Hemi Turbo mufflers or their Super Turbo's? They are entirely different and the Hemi's are far quieter. X-pipes are quickly making H-pipes obsolete. They use crossover flow to create a negative pressure that sucks exhaust out and creates less resonance and more HP. I would suggest an X-pipe if you're going to the trouble of a swap. Many owners of newer sports cars are sawing off nice H-pipes and installing X-pipes after seeing dyno results. The MAC chamber pipe is quality built, but pre x-pipe era & late 80's technology.

[90LSC]

Last year I had the Dynomax SuperTurbos installed. Did not modify the exaust in any other way. I am happy with them. There is a little resonance in the 1500-2000 rpm range but since I have 3:55s in the rear it doesn't stay in this rpm range very long. They can get a little loud under hard throttle but otherwise sound very good.
Keep in mind I am NOT a believer in loud makes fast. I prefer to walk softly and carry a big stick.

[Papayogi]

Redneck muffler tip!

New flowmaster catalytics, then elimatted the mufflers all together! Not bad inside, but really sounds off outside!

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[Lost Boy]

When comparing the bassani x pipe to the MAC pro chamber h pipe W/O CATS, the MAC had a better flow and producted more HP. Again this is ONLY the MAC PRO CHAMBER...it is a modified h pipe...more like a x pipe but they still call it a h.

This is what I would do:

If you need cats Bassani X pipe-best flowing pipe with cats

NO CATS MAC pro chamber

If you want a like stock sound until WOT Dynomax super turbo hemi muffs WLK-17749 @ summit

If you want a nice low rumble at idle and then louder @ WOT Dynomax super turbo muffs WLK-17734 @ summit

2 1/2 the rest on the way out.

look the muffs up at www.summitracing.com (http://www.summitracing.com) both are under the Dynomax super turbo section The super turbo might be a hair louder than a mustang 5.0 stock, but not much and the hemi is quite as stock until WOT

choose your poison both will get the job done well


here is the size of both of the above listed muffs: Super Turbo Muffler: 4 1/4 in. x 9 3/4 in. oval, 2 1/2 in. offset inlet/2 1/2 in. offset outlet, 14 in. body length, 18 1/2 in. overall length. Universal fit.

have fun and good luck

[my88lsc]

if i were you i'd say to hell with the fancy exhaust and just do old school cat back...that's what i have and it sounds awesome!!! then again i don't have emission testing either

[Lscman]

I think the rear gear ratio means everything, as "90 LSC" noted. OD Cruising below 70 MPH will be deafening with stock gearing but quiet with 3.55's. The stock Walker OEM replacement mufflers for a Mustang are every bit as loud on a Mark VII as Super Turbo's are on a Mustang. Mark VII's are MUCH LOUDER with the same exhaust setup, not quieter. I have owned and driven both cars and both setups for years. It is surely not fair to compare HP output for the ancient '80's MAC PRO Chamber without cat's to a Bassani with cat's. An X-pipe with "equivalent pipes (and equivalent cat setup or no cat setup)" will produce more power than an H-pipe or MAC PRO chamber. With an X-pipe, the previously fired cylinder scavenges the subsequent one. This phenomenon does not occur with a conventional H crossover or PRO chamber. This is why owners of many sports cars like the Corvette are seeing dyno tests & cutting off huge chambered factory crossovers and replacing them with X's. In the Corvette, the OEM chamber within the intermediate muffler crossover is almost a foot long!! Like the MAC, it does not provide subsequent cylinder scavenging. It only provides exhaust pressure balancing.

[This message has been edited by Lscman (edited June 18, 2001).]

[Guido]

Thanks for all the info guys, and thanks Lost Boy for the dimensions.

If the price isn't much more then I'll get an x-pipe. I'm not worried about emissions because I'll just install the stock h-pipe every 2 years before the test (I guess it'll take 1-2 hours to swap, every 2 years isn't bad). As far as I know besides the AIR pump connection it should be a direct swap right?

Right now I have 3.23 gears but will install 3.73 eventually.

I know the Mustang cat-back will have to be modified, I was just wondering if it would be easier to do that or just start from scratch? I like the chrome shotgun look.

Lscman do the OEM 'stang mufflers flow better than the OEM Mark ones?