New Exhaust

[B192734]

So I'm looking at putting a new exhaust on the 2000 XJ. I was looking at Rusty's, and had a question. What's the deal with "Mandrel" Bent? How does that differ from the stock pipe.

2nd question...Am I right in thinking that the stock tubes are 2 inch as opposed to the 2.5 inch of the Rusty's?

 

[fast_Z28_guy]

mandrel bends are smooth and maintain the same diameter through the bend. compression bends have to neck down the actual diameter of the pipe to make up for the angle change. these "kinks" from the compression bend not only decrease the effective diameter, they also increase turbulance and hinder flow.

flow makes power

stock pipes on my 03 wrangler are 2.25"...at least the tubing around the muffler.

going from 2.25" tube to 2.5" tubing results in nearly a 20% increase in cross sectional area...so much better flow.

 

[B192734]

So then changing then size of the pipes and the size of the bends, opens everything up. What happens if you just put on a cat back system. If your headers and everything up front including the cat is stock, you have that new 20% in the back, but will that allow the front end to "breathe" as well, or will that actually change anything? And are those high flow cats productive?

 

[Bounty__Hunter]

Late-model catalytic converters aren't very restrictive, I don't think you'll gain much by changing it. It's illegal to change under federal emissions laws unless it is faulty.

Jeeps need some back-pressure to maintain torque, I would go larger than 2.25" and get a decent muffler or cat-back system.

 

[dingus]

i have the rusty's kit on my XJ - sounds great! i replaced my cat at the same time as when I put the thing on, and she FLEW right through emissions. highly recommend.

 

[B192734]

i have the rusty's kit on my XJ - sounds great!

You're talking about just the Rusty's exhaust with a normal cat, or the exhaust with the hi-flo cat that they sell?