Single or dual exhaust?

[Yeret]

Howdy, all. Just as the title says! I'm going to completely redo the exhaust in my truck. I'm pretty set on keeping to a single pipe and splitting from the muffler into two for the "cool" factor.

But...maybe? To avoid going into a wall-o-text, personal theory of why I THINK a single exhaust setup would be better, I'm just gonna say that my personal theory with what I've read is fairly contradictory.

As a quick rundown of what I'm doing, I've got a pair of Pacesetter long-tube headers and an FI Air Gap. The objective is a substantial boost to mid-range power. I fully expect some loss of low-end torque (although I hope that a tune from Ryan will offset at least some of that), however I believe a gear swap would regain any losses and more (that's another story for another day).

Also, I want my exhaust to have a nice, low, meaty rumble. High-pitched, raspy exhaust sounds good on a car, but a full-size truck just wants something..."big," for lack of a better word. I'm thinking a single, 3" pipe will produce a deeper tone than a pair of 2.25" or 2.5" pipes (reduction of velocity, a result of a gas travelling through a wider diameter pipe, seems to reduce the "high" and increase the "low" sounds).

I'm under the impression that anything a dual exhaust can do, a properly setup single exhaust can match, but maybe I'm wrong? I'm thinking I've read a few posts here years back of people dual-piping their trucks and regretting it.

 

[Compu-Doc]

Funny that you should ask this I just finished watching an episode of Engine Masters where they dyno tested all different exhaust configs and the best performance by far was a single 3" coming from the headers into a free flowing muffler
Turns out that's pretty much the setup I have on my Ram but without headers

 

[Nealuss]

I have the Pacesetter long tubes and their 3" y-pipe into a single Flowmaster Super 40 and it definitely has a nice, deep rumble. I get compliments on it all the time. I also don't have a cat, but a high flow cat if you have to have it won't change the sound much.

 

[dapepper9]

Single exhaust is more efficient. Proper equal length duals of proper size vs proper size Y pipe, the y pipe is more efficient at scavenging. The problem you run into with single exhausts is size limitation vs volume. 1000hp supercharged big block street car (unrealistic I know but it's for visual) is going to need a very large single exhaust, 4inch on up. That's hard to fit, hard to find good mufflers for and simply isn't realistic whereas utilizing 3inch duals is easier to fit with a much wider selection of available mufflers.

But, single 3" will more than handle what you're doing. With or without a good catalytic converter. Below about 500hp NA, single 3" is sufficient. Especially if, when utilizing cats, you use one on each bank instead of a single to minimize any restriction. With a supercharger, you can even push that to like 600hp at the tire. Coyote powered F-150s have shown over and over that it's sufficient, some guys run large 4" singles or dual 3" or run cutouts on their collectors when running Whipple blowers and are seeing no difference in 1/4 times or MPH vs the stock catback. And the stock catback on those is a 2.5" resonator pipe before going into a straight through 3" muffler

TLDR; pick your setup based on what sound you want. Duals can sound great, sure. They're heavier though and harder to package. Ypipe and single 3" is far easier and still sounds great

 

[Rob2gen]

Super Happy with my 3 inch single flowmaster cat back setup

 

[Jkidd]

I run a single in duel out flowmaster super 40 on my 2500. I have cut my cats off, due to clogging, and Y pipes my pipes from the headers. I cut the factory muffler of and welded in the flowmaster. I didn't however, run the pipes to the rear of the truck. But the sound is amazing,but a little load in the cab.

 

[GTyankee]

the exhaust should never end before the cab ends
too much chance of the exhaust entering the cab

I ran my exhaust from the headers back to an H pipe, almost the same as a Y pipe, into a 18" magnaflow 2 chamber
Then dual pipes back almost to the rear tires, where i had Dump Tubes that were aimed at a point where the ground & the tire met.

That was in a pre 2000 model vehicle

The noise was just right, if a person stood next to the truck, you could feel it in your private parts

For information, a 3 chamber Magnaflow is factory quiet

 

[Jkidd]

the exhaust should never end before the cab ends
too much chance of the exhaust entering the cab

I ran my exhaust from the headers back to an H pipe, almost the same as a Y pipe, into a 18" magnaflow 2 chamber
Then dual pipes back almost to the rear tires, where i had Dump Tubes that were aimed at a point where the ground & the tire met.

That was in a pre 2000 model vehicle

The noise was just right, if a person stood next to the truck, you could feel it in your private parts

For information, a 3 chamber Magnaflow is factory quiet

True. Mine ends about 2 feet behind the front of the bed. But still get a lot of noise in the cab. Muffler guy said it would cost me around $200 to run it the rest of the way to the rear of the truck. So I deal with the noise. LOL.