Question about Stillen cat backs single and dual wall

[Steeeve]

Im assuming there is a difference in sound, correct? What does the single wall sound like and what does the dual wall sound like? Im also wondering something too, the stock horsepower of the auto G is 280, when an aftermarket exhaust is added and it says it adds 15hp, does this mean that it gives the car 295? It seems like a dumb question, but Im just wondering cause after you take the stock exhaust off, the hp may be rated then at 270 or so, and then adding a 15hp gain back on would only make 285hp. Its probably a difficult question to understand, Im probably not explaing too well, but if someone can clarify Id appreciate it

[NWG35]

Any claims on HP gain are with the new componants replacing the old, so theoretically it woulf give you 295.

[mav555]

As far as my experience, the real world HP gains are never up to what the manufacturer claims. Look at the dynos run in all the tuner magazines and the gains aren't as impressive as stated.

And just because you take the stock exhaust off, it doesn't mean that you automatically loose the 10 HP. Exhaust systems are restrictive. Cats and mufflers all reduce exhaust flow, as well as the bends in your piping.

The HP rating is as NWG35 said, based upon replacing your stock system. If you took off the your exhaust system, i would think you have more HP rather than less. All the aftermarkets basically make the exhaust freer flowing than stock and reduce the sound muffling. (of course theres more to the design overall).

So no exhaust would be the freest flowing of them all? Just have straight pipes shooting straight up from the headers or exhaust manifolds like the old hot rods.

[Steeeve]

ahh good point, never thought of it like that. thanks to both of you. what about the dual vs single wall sound, im gonna guess that the dual wall has more of a higher pitched sound to it and the single wall has a lower end sound, am I right or do I have em mixed up? I play drums, and im kinda thinkin the pipe thickness is like the plies on a drum. The more plies of wood a drum has, the pitch gets higher and also it gets louder.