I'm thinking about going with the after cat 3" pipe, with the dual 2.5" tips with the 80 series Camaro Muffler (crossflow, 3" in / dual 2.5" out) . Is anyone running this combo, any draw backs I should know about?

 

Has anyone tried this setup?

 

i think i saw this set up on youtube on a JK,

i liked it, just havent got around to getting it done yet, weighing all my options first

 

I had 3" to a magnaflow and 3" straight out the back high clearance. I had a ton of popping and seat-of-the-pants LOSS of power. I would talk to some of the exhaust manufactures and see what they have to say, but I think the 3.8 likes alittle back pressure.

I now have a 2 1/2" to a walker "quietflow 3", sounds and runs great...

 

Indeed, you need some back pressure (resistance) or you loose more than you're trying to achieve. Even a monster diesel needs a little, without they loose as much as 10% on the bottom end.

 

It isn't back pressure that is needed it is a size of exhaust tube that assures exhaust velocity.

There isn't any reason to have anything larger than a 2.5" pipe, single in and single out. Anything larger and you lose exhaust velocity and exhaust gas scavenging from the cylinder. A 2.5" single outlet system is good to about 250hp and you need to do a lot of work to push that kind of power out of the JK's 3.8l engine.

 

to do a dual exhaust like that you may want to think of doing a 2.5" inlet with 2" or 2.25" dual outlet. And at that those diameter outlets may be to big. You will get loss of back pressure and reduce torque and hp. I wouldn't do a dual exhaust. I relocated my muffler with a flowmaster super 44 and i noticed a drop in power due to backpressure.

 

It isn't back pressure but exhaust velocity. You are correct in your assertion that those diameter outlets would be too large for a dual outlet exhaust for the JK. The correct diameter outlets for a dual outlet exhaust would be 1.75" diameter which would totally remove any cool factor.

 

Might wanna stick to gasoline performance theory.

 

Yes, in a normally aspirated engine.