H-Pipe or Cat-back!!!!!!????
 

I have a 1999 Mustang Cobra 4.6L DOHC...Advise needed.

I am looking into either getting a Flomaster American Thunder Cat-Back system or an H-pipe to eliminate all 4 cats. I can't do both so what would be more benificial. I am looking for a good sound and some gain in performance. I have heard many different things from different people.. please give me your feedback and ideas! THANKS!

Get rid of the cats it will make a much greater power gain. Maybe twice as much as a cat back system. The cat back may give you better sound. I'd go for the power.

if i get the hpipe with my stock cat back, will it sound bad????

No, I think it will sound fine. It will be a heck of alot louder than stock. Get the h-pipe, power is better than sound anyway.

I don't see much debate in this subject, maybe some other people will chime in.

Good Luck!

I'd buy the H-pipe first. The '99 Cobra's sound pretty mean stock, so the H-pipe will really make it sound killer, and add a nice chunk of power at the same time. If you had the fix done, I believe the stock mufflers are pretty decent already.
BTW, is the stock cobra catback 2.25" or 2.5" (just curious?)

I havent checked but from what i have heard, my stock cobra has a cat back thats 2 and a quarter. Im not one hundred percent sure but i am almost positive. By the way, thanks for all the feeback, i am gonna go with the hpipe and see how it works out, anyone recommend any particular hpipes??

Get an H-pipe with cats if you live in a state with emissions testing. The cats quiet the car a little but the sound change is from the cat back system. I like the Flowmaster cat back for sound. If you're looking for sound go with the cat back. The H-pipe won't change the sound very much. Bassani or MAC H-pipes are pretty good if you go with the h-pipe.

This brings me to a question I have as well. I'm running a stock 97 GT (vert). I believe the stock exhaust components are all 2 1/4" diameter. I too am looking to change the stock-h first. Most aftermarket performance exhaust components come with 2 1/2" diameter pipes. Wouyldn't it be too restrictive to go from the stock 2 1/4" headers to the performance 2 1/2" h or x-pipe then back to the stock 2 1/4" catback? This seems like it would be a bad idea, yet I know lots of people have stock catbacks with their new x-pipes.

An H-pipe with no cats will make alot more difference in the sound than the catback with a stock H-pipe will, so for both sound and power you should go with the H-pipe.

You are much better off going with the H-Pipe, LONG AS YOU DO NOT HAVE TO WORRY ABOUT INSPECTION, I have the H-Pipe on my 1997 mustang gt it sounds great, it has a very healthy sound to it, had a cat back system before the H-pipe did not do the car much justice, The car sounds mean with the H-Pipe! Alot better than the cat back system, with that it just sounded average. Do not wory about the car being to loud I drive my car everyday. Everyone loves the way it sounds.

whats better... X-Pipe or H-Pipes? ... performance wise...

I had that same ? with my 96' GT. The only way to go is the H-pipe with no cats. The best sound and incredible power gain. It still wouldnt touch my new lightning.

Get the Mac Prochamber.
'Nuff said. Out.

Performance wise, X-pipes make slightly more top end horsepower (by only a few hp) and work best with straight-thru muffler designs, while H-pipes make a little more low- and mid-range torque and work best with chambered mufflers.

I just put my mac h-pipe on my stock 99 cobra today, i gotta admit, you guys were all right, it sounds amazing, thanks for all your help.

Nice to hear that you like it.
Did you go with offroad or cats? Do you feel any seat of the pants difference?

Go for the H-pipe first and then work on the cat back...

h-pipe all the way
 

I would get the h-pipe first , you get the most from removing the cat's. I would not get the cat back until I at least get a good set of headers. But for the money you have to spend I would want the power too and the sound from the h-pipe going thru the fac mufflers is not bad , sounds better than stock , but in the long run get SPINTECH mufflers , they are the newest out andn the number show that they out perform the flowmaster and the rest!!

Oh and I have headers , h-pipe and cat back system and I got my H-pipe first things first !!!!!!!!!

i got a straight hpipe with no cats and i love the thing, my car is so loud that i wake up the whole neighborhood at night, i love it. i thought it would sound like crap with my stock cat back but it sounds perfect. my only problem is that the idiots at ramchargers told me to put the mil elimiatiors on the wrong o2 sensors so my check engine light is on. thats a project for another day though, im used to the annoying yellow light now. As for power, i cant honestly say that i really noticed a big difference but then again, ill never be happy with my car until i get a supercharger. other than that, i love it. The only other complaint i have is that the acceleration in first doesnt seem as smooth as it could be, it seems like it misses out somtimes, its possible that its leaking, im gonna get it back on the hoist and check.

p.s. a word of advice for anyone putting one of these on, the stock bolts from the headers on the drivers side dont work. they leave a gap which causes a leak, you must change those bolts.