CatBack Systems Losing Power

[Alien STI]

the system doesn't lose power, and even if by some chance you lost 5 hp, it would not be anything you can feel.

there isn't any system that we've seen / installed that looks like there is any reason it would lose power. Without a tune , with the same throttle response, car is going to feel exactly the same. Other than if it's pulling a bunch of timing for fuel, or really hot and pulling power.

I don't have dynos to show the difference if I'm not mistaken so I'm not saying it did. It did feel that way though.

 

[beefcake]

I don't have dynos to show the difference if I'm not mistaken so I'm not saying it did. It did feel that way though.

I know, statements like that are just frustrating, without back to back dyno's, track times, etc, or something to substantiate it

if that's how data was always provided, we'd never get anywhere in this hobby lol

I know in bg, when I went the 8.18, it felt like I had a good pass, and was hoping to see a .3 on the board, maybe even a high 20, never did I think it "felt" like a teen pass, but it was.

 

[Derek@Lethal]

I agree it should not pick up a ton of HP but picking up 2-3hp on average over the stock exhaust is showing either the stock exhaust flows really well or the SW is a restriction. The only way to verify that is with back to back testing like you said with other types of exhaust. Physics also factor in air flow turbulence not just size so something that is bigger doesn't always flow better. Definitely not calling you a liar but in all fairness you haven't done enough testing with different brands for comparisons. I don't like picking fights with you I just like people being told the truth about products so they don't waste money.

In the stock exhaust system, the restriction is not the mufflers, it's the cats. That's why if you open the exhaust up after the cats, the power will not go up much. As beefcake said, cat-backs AND axle backs will really only be for sound (same with all 05-14 models as well). Once you get rid of the cats, that's where you will see the largest power gains, then after that, adding headers will take you up further from there.

Now, if you already had long tubes, no cats and were still running a stock cat-back I can see an aftermarket cat-back then picking up a decent amount of power.