According to Gibson's website, they state the single swept side exhaust is their best performing exhaust. That's one of the reason's I bought it.
My question: Why does the single pipe yield better performance than a dual pipe? I would assume the opposite, dual pipes allow more flow, producing more performance. :?:

This engine seems to require a bit a back pressure for best results. The duals seem to cut out too much back pressure. The single keeps enough but still flows good enough to get a performance increase. Least thats what I get from all the posts I read.
M4ck

Why can't you put in a smaller "X" pipe upstream of the mufflers to retain some of the needed back pressure, and still have duals?

This engine seems to require a bit a back pressure for best results. The duals seem to cut out too much back pressure. The single keeps enough but still flows good enough to get a performance increase. Least thats what I get from all the posts I read.
M4ck

M4ck,

I believe the old saying "needs a little back pressure" to preserve torque is an old wives tale. From what I've been told by many tuners that modify/dyno cars alot, you do not want any kind of back pressure. The freer flowing the more hp and torque created, but at a cost with more noise. An aftermarket cat-back exhaust will not lose any power. Where you will see the torque and hp curve shift upwards is in the design of the manifold (headers).

According to Gibson's website, they state the single swept side exhaust is their best performing exhaust. That's one of the reason's I bought it.
My question: Why does the single pipe yield better performance than a dual pipe? I would assume the opposite, dual pipes allow more flow, producing more performance. :?:

I asked them about that before I bought my exhaust system too. They said the same thing about the single making more power. What's funny though is I never told them what vehicle it was for. So did he mean every car/truck they make systems for? If so, I don't buy it. The corvette has duals and the camaro had single, but the vette always had more power.

m4ck,

I believe the old saying "needs a little back pressure" to preserve torque is an old wives tale. From what I've been told by many tuners that modify/dyno cars alot, you do not want any kind of back pressure. The freer flowing the more hp and torque created, but at a cost with more noise. An aftermarket cat-back exhaust will not lose any power. Where you will see the torque and hp curve shift upwards is in the design of the manifold (headers).

I wouldn't chaulk it up to an old wives tale. According to the dyno I had done several weeks ago, with JBA headers and no cats, I lost torque and gained hp. Now that I've got the factory cats welded on the headers all seems much better in the lower rpm range. I'll be headed back to the dyno soon to see.

m4ck,

I believe the old saying "needs a little back pressure" to preserve torque is an old wives tale. From what I've been told by many tuners that modify/dyno cars alot, you do not want any kind of back pressure. The freer flowing the more hp and torque created, but at a cost with more noise. An aftermarket cat-back exhaust will not lose any power. Where you will see the torque and hp curve shift upwards is in the design of the manifold (headers).

I wouldn't chaulk it up to an old wives tale. According to the dyno I had done several weeks ago, with JBA headers and no cats, I lost torque and gained hp. Now that I've got the factory cats welded on the headers all seems much better in the lower rpm range. I'll be headed back to the dyno soon to see.

Jet,
I was referring to cat-back systems where you wouldn't lose torque or hp. Headers is a different ball game (like in your case). Well, that's what I was told anyways.

The single pipe and back pressure theory probably has more to do with scavenging. If you have low exhaust gas velocity as in a low revving low end torque engine you will need the smaller pipe and some back pressure to keep the "pulses" closer together. The preceding pulse helps the following pulse escape the cylinder and travel down the exhaust. On higher revving engines you need more capacity and the high pulse rate of the engine being revved up keeps the scavenging effective.