Alright before you say anything I searched, and read the stickies.

My question was, I want to buy a catback exhaust for my new car. Its a 1990 formula firebird with the 305 TBI and single cat. It still has the stock exhaust, which is only lightly surface rusted because the car sat so long.

At first, I planned on buying the flowmaster american thunder from summit for like $350. Its full 3" mandrel, but funnels down to the stock size so it should bolt up right after the cat. (FLO-17234)

Then, I decided I didnt want to spend that much if i didnt have to. So I looked, and dynomax makes a cheap exhaust for my car. Like $180. Summit says its only 2.5" mandrel though. Has anyone had any experience with dynomax? I read they are too quiet, but some people say they are loud. Also, are they really only 2.5"?

Finally, I noticed something called the Pacesetter TFX. Summit lists 2 kits for my car, nut sure which one would work. Anyone tried this? How does it sound? I want a loud and throaty sound from my car, but it seems like every 3rd gen has a flowmaster.

Any help appreciated, thanks.

 

You dont want a 2.5" pipe, not even for an LG4 or a TBI. I dont know why they sell that small pipe as for a V8. Stick with a 3" pipe.

You're not going to find anything good that is cheap.
And nothing bolts up in your driveway, so plan on getting it installed at a good muffler shop.

Other than that, they're all the same except the sound. Pick one that you like the sound of. I have only heard the Hooker, the Magnaflow, and the Flowmaster, and I like the Magnaflow best.

 

actually i've installed a few cat backs with nothing but jack stands and a few wrenches. My car has never seen a shop and the only thing original is the front suspension and rear springs.

I always follow this

Good, Fast, Cheap, Pick Two. If it's good and fast it aint cheap. If its fast and cheap it aint good. And if its good and cheap it sure as hell aint fast.

Also, as long as you have stock exhaust manifolds i see no reason why a 2.5" wouldn't work. And I'd imagine with a TBI motor it would anyway, I mean these big companies do do some R&D right?


Also, there have been tests done that some mufflers from certain companies outflow other. PLus i had two buddies, both with 87 automatic l89s. The only thing either had done was a catback. ONe Dynomax, one flowmaster. The car with the Dynomax most definately pulled harder up top.

 

Yeah, thats kinda what I thought. I got a rough measurement of the stock pipe diameter with some string and Pi, and found that the stock intermediate pipe is only like 2.25" tubing. Why would GM do that? However, my stock tips are 2.5".

I wish there was a cheap cat-back system that sounded good and had 3".

 

I have the Texas Speed & Performance Rumbler cat back system.

I always get compliments on it, but to me, it's too tame. I'm a Flowmaster 2 chamber fan. I've been considering redoing mine, even though it is only a year old...or just doing a Boom Tube setup.

 

Do they make a TSP rumbler for the 3rd gens? I really dont want to have to do any custom fab / welding I would rather have it bolt up. But yeah, I bet that would sound nice with one of those chambered mufflers in a straight section behind the cat.

 

Get the hooker's catback system. I really never hear anyone complain about it and its only around $300, plus its 3" pipe and I hear they have a nice deep tone to them. I am going to be ordering mine tonight. Hopfully I will have it installed by the end of this week and a will post a sound clip.