Contour Enthusiasts Group Archives Forums Modifications Zetec Performance Single vs. Dual Exhaust

Got a question for all. And I already did a " Search ", so back off nazi's. There have been a ton of posts on duals and people installing them, my question is simply this.....On a 4 cylinder, which is the better way to go? Not talking about aesthetics, simply performance. I am not trying to start a pissing contest, just looking for the facts. I don't have enough background with 4 cylinder engines to make a good decision.

My background is with V8 muscle cars, headers, and dual exhaust. Building them from the ground up. My plans are to build one hell of an engine for this car.

Any and all advice and knowledge is appreciated.

Thanks in advance.

TOUR'ING

From a purely performance standpoint single will net you the best gains, but a quasi dual system will probably sound and look better.

If you use small enough pipe on the duals, then it would perform same as single exhaust. Dual exhaust actually helps your mid and high end better than single. So maybe you only care about low end... I doubt that though. And if you build an engine pushing over 150hp than a dual exhaust should be find even on the low end.

So then what is the recommended diameter for single exhaust, bigger isn't always better with 4-cyl engines right? Do you actually need a little backpressure in the system, so that 3in. wouldn't work?

Somebody didn't search.

it's all a matter if what you got for mods other than the Exaust... weather it's a single or a dual.... to keep a stock air box and a dirty paper filter and no matter what you did to mod the exaust it isn't gonna help you that much.

Posted by kremithefrog

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If you use small enough pipe on the duals, then it would perform same as single exhaust

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Umm, no, a dual exhaust has more bends(slowing down exhaust flow), more piping and an extra muffler(again slowing down exhaust flow and adding more wieght to your car).

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Dual exhaust actually helps your mid and high end better than single.

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Wrong again, the only reason paople are seeing better mid and high power(and a small drop in low end occasionally) from the SVT exhausts is because they are pretty much switching straight from the crappy stock exhaust right to the SVT quasi-dual. I can assure my single SCREAMS up top.

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And if you build an engine pushing over 150hp than a dual exhaust should be find even on the low end.

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The only thing that should change with increasing HP is pipe diameter, duals/single really doesn't come into play.

so what have i done? i switched to the svt exh with a magnaflow resonator, killed my low end? improved the mid range? i know it sounds better, but is that it, it felt like i picked up a bit in the mid range, but who the hell knows there is so much conflicting info here, the best way to have found out would have been to dyno before and after the exh, i wish i did to end these discussions