2.5" vs 3" header collector

[Desertjr]

I've gotta cut off my collector and weld up a new one. I was thinking I could do a 3" collector and a 3" s-pipe/down pipe, into a 2.5" cat back. Or just a 3" header collector into a 2.5" down pipe. My thinking was gasses would be the hottest at the collector and thus be moving the fastest. So a 3" collector would be beneficial. The gases slow as they get to the rear of the jeep, so a 2.5" piping would be best.

It's a matter of pennies more, so that's not an issue. Any reason to not go 3"?
3" collector to 3" downpipe.
http://www.jegs.com/i/Hedman/500/21121/ ... tId=753418

Or 3" collector to 2.5" downpipe.
http://www.jegs.com/i/Hedman/500/21143/ ... ProductId=


Motors a 4.2l mini stroker. High 9s for compression.

[Cheromaniac]

Sunds like you're trying to copy my exhaust set-up but since your engine will have a smaller displacement than mine, I reckon 2.5" from the collector back will suffice.

[Desertjr]

Bingo:)
My collector now is just shy of 2 1/4 so I figured if I'm welding in bungs and what not then I may as well spend another 30 for the collector. Downpipe has to be remade anyway. Thanks Dino.

[gradon]

My current setup is borla header w/ 2.25" slip fit to included s-pipe, a custom 16" long 2.25" SS pipe with 2 o2 bungs, then 2.5" Borla muffler and 2.5" mandrel-bent tail. I know my stroker would love to be at least 2.5" all the way, but I'm leaning towards a different header instead of chopping up the Borla. I have a line on some unused Cliffords so who knows how it'll end up(they have dual outlets).

[Muad'Dib]

2.5" is plenty for any stroker. Additionally, if your not lifted, anything that you put under there will get bent by the front driveshaft unless your creative with the routing.

[Desertjr]

2.5" is plenty for any stroker. Additionally, if your not lifted, anything that you put under there will get bent by the front driveshaft unless your creative with the routing.

Ya that should be made clear because I know some aren't. Myself at 3.5" but I plan to pull my srpings and make sure it clears the right way