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Just wondering what benefit if any would come of this

Getting the MX6 headers and instead of using the 2 to 1 downpipe get a custom jobby of having 2 pipes coming down straight through to the backbox, Either 2 pipes into 1 back box or dual

Just reading the exhaust pressure thread I noticed a few people saying that exhaust size should be around the engine size so a 1Litre should have a 1" pipe

say the exhaust is for the 2.5 v6 for this to show good gains the 2 pipes should be around 1.25" correct?

and if it was indeed just the single pipe going down the recomended size should be 2.5"

Just wanting to make sure my measurments are correct for future plans

That seems about right. I thought about this myself, as seperating the two exhausts will get rid of any turbulence they create when they merge at the y-pipe. It would be pretty difficult though because it's FWD layout and because we only have a path for a single exhaust.

The 'displacement = exhaust size' logic isn't perfect. Two 1.25" exhaust pipes have about half the area of a single 2.5" exhaust pipe. You'd need to run dual 1.75" pipes to have a similar amount of exhaust flow.

SE MX-3 wrote:The 'displacement = exhaust size' logic isn't perfect. Two 1.25" exhaust pipes have about half the area of a single 2.5" exhaust pipe. You'd need to run dual 1.75" pipes to have a similar amount of exhaust flow.

Exactly. Only thing missing here is that with 2 x 1.75" pipes, you've got more radial surface area of pipe, as opposed to the 2 x 1.25" or 1 x 2.5" pipes.

More surface area friction = slower exhaust flow. That being said, it'd be pretty damn minimal on the length of pipe that we're talking about here. Where's the nerd smilie??

I've thought of this too but my friend told me something that made it seem useless.

Because I think our firing order is 1-2-3-4-5-6. Then only 1 cylinder from each exhaust header is actually pushing exhaust gas through at one time if that makes sense.

So when you have two headers and it goes into 1 pipe - you have all the gas pushing through that one pipe.

But with two completely separate pipes you have only 3 cylinders firing to each pipe. I dunno how well it would work for a small V6 like ours (I'm talking about the ZE too here...). It's like having a 1.25L 3 cylinder engine, you'd need a real small pipe otherwise there'd be no power down low.

Then again I don't know too much about this stuff so I'm just making theories here. Take it with a big grain of salt. I would be interested to see someone do it though.

You also might want to keep in mind smog emission laws. California is pretty hard on their smog not too sure if dual pipes will pass. That's assuming you're splitting the pipes right off the head, you'd need two cat.s, meaning it takes even longer for them to warm up and do their job, IE, wont pass smog. (I think). If you have the heads meet up at the cat and split there, you'd probably be fine but than you'd be bottle necking at the cat and would really be doing the dual exhaust pipes for looks and sound.

As RX8SE8P said, take this with a big grain of salt.