Straight-Pipe Questions

A friend of mine is going to be buying an 02 Mustang GT and he had a few questions about the benefits and drawbacks of a straight-pipe exhaust. He mainly wants a very loud sound that is somewhat agressive. He just wanted to know if there were any hp gains to be had if he ran a straight-pipe from the cats back or possibly the exhaust manifolds back. And also what problems or annoyances he might run into, or if it is just a bad idea for this car in general. Any input would be greatly appreciated. THX

yes there are gains from catback and no exhaust is not a bad idea

10 hp just from just pipe that can be bought from any muffler shop, or from an actual brand-name cat-back system? Also what will a straight-pipe do to the sound? I'm assuming it will be pretty loud since the lack of the muffler, but will it be a nasty kind of loud?

If he gets rid of the cats totally it would be to his benefit (other than emissions of course). He will have to get the little eliminators though if he removes the cats. Aside from the power gains it will certainly change the sound for the better.

When I had my 89 5.0 I took off the mufflers and used straight pipes in place of them. The rest of the exhaust was all stock. I did the same with my 92 5.0. The only reason I used the pipes instead of performance muffs was because of cost. They sounded mean, not too loud untill I got on it then they screamed. I liked the sound of them, but when I got an offroad H-pipe and 2 chamber Flowmasters it sounded better and I noticed a little more power. The only drawback to straight pipes is if the engine is cold and you get on it they will cakle or backfire. DO NOT USE STRAIGHT PIPES FROM THE HEADERS ALL THE WAY BACK. Way too loud, not enough back pressure, and you'll hear each time a cylinder fires. Alot of guys with F150's or Dodge and Chevy trucks will use straight pipes. That's very close to what a Stang sounds like with them aswell.

blackGT, you really think i would be best? I would like my 02 to be a little louder. I've just always been afraid of losing too much backpressure. Please convince me to do it, because i would very much like to.

Well when I think strait pipes I may be thinking wrong. I was just thinking off road x pipe or H pipe. I think its definately good. I have been in several mustangs that have had this done and have compared before and after. I am not a professional so I can't really attest to any loss of back pressure but the sound certainly was better to me and it made it faster (well it seemed that way to me.) Like I said, i am no professional, but having multiple cats on one pipe can't be as good as no cats on a slightly larger, less bent pipe.

thanx. In my case it would be just stock exhaust with a muffler swap. I was thinking of just cutting the cat part of the pipe and replacing it. The daimeter would still be 2 1/4, so does anyone see me losing too much backpressure from a non-catted stock exhaust w/ flows?

thanx. In my case it would be just stock exhaust with a muffler swap. I was thinking of just cutting the cat part of the pipe and replacing it. The daimeter would still be 2 1/4, so does anyone see me losing too much backpressure from a non-catted stock exhaust w/ flows?


Read my reply a couple of boxes up. I had stock headers, stock H-pipe, removed muffs and put in straight pipes, stock tails. That was good. Then later I used an offroad H-pipe (no cats) and 2 chamber Flowmasters. THAT WAS AWESOME!! You will not lose too much backpressure with an offroad H-pipe as long as you use mufflers with it. The engine will thank you!! And you will thank yourself for it aswell.

Thanks. Those 4 bad boys will soon be gone. But first i gotta get a predator, so that stupid light won't come on.

handheld tuners turn off your check engine lights if you remove your cats?

don't know about all of them, but supposedly the diablo predator has like an offroad setting where the exhaust sensors are turned off or fooled or something.

If that works let me know because I heard that before I got mine but never used that feature.

Another question, if I get a catted x pipe, will the check engine light still come on?

It really shouldn't but I have heard of it coming on for people with really high performance cats. I don't know though what brands or if that is the norm. I do know that a good x pipe with cats costs considerably more than an off road pipe with the mil's.

Thanks. Those 4 bad boys will soon be gone. But first i gotta get a predator, so that stupid light won't come on.


When I installed my offroad H-pipe, I hooked up the O2 sensors and I had no problems with the Check Engine light. If you do this and the light still comes on, you may need new O2 sensors.


IS IT JUST ME OR AM I THE ONLY ONE THAT DOESN'T LIKE THIS NEW FORMAT OR WHATEVER YOU CALL IT?

I don't like it now, but i'll get used to it.

got a predator on the way. But this stupid ass holiday is slowing it down.

You shouldn't need any programer or anything to get the check engine light off. Just hook up the 02sensors and it should go off. If it doesn't go off, get new ones.