BlitZs2000

lol. If you want double, go for it man. People are just letting you know single is better.

S2FARSI

Really? So far you have made an incorrect assumption that a dual exhaust is more "restrictive" than a single.

The only useful fact posted (with no backing mind you) is that the Y pipe is inefficient. How is this?

afwfjustin

If dual is more restrictive, here's what I would guess as to why:

Air velocity is important to exhaust flow - way more important than even backpressure. If a single 3" pipe is filled, then splits to two 3" pipes, half the amount of air would be pushed into each side, making each end of the dual split only have half the amount of air that it should, resulting in a slower velocity. The single would carry the same velocity all the way through.

Your cat is already going to be causing a bottleneck, so I don't think you'd want to cause the air to then slow down at the dual split.

IMO single looks better anyway. Everyone knows it's a 4 cylinder, so having a dual exhaust is kinda ricey... like the kids that add dual mufflers to their Civics.

jeremiah89

As the others have said a straight pipe will be slightly louder and give a little more power. Really though with all else being the same it won't matter much and is just what you prefer.

I believe a single pipe is better because of the fact that it provides ample room for air on a 4 cylinder and the Y to split into duels creates a slight amount of resistance. Straight paths are better when possible. Hope that helps.