Cherokee Performance Upgrades

[jeeptime99]

Ok I’ve got a few questions. First I want to figure out what diameter tubing to use for my exhaust. JEGS has come out with a 2 1/2” cat-back for the Cherokee, but I’ve heard that using a 2 1/2” exhaust will create a loss in backpressure to the point of losing low end torque. I was planning on going with the Dynomax which is 2 1/4, but the JEGS cat-back is least expensive, and since it’s JEGS I didn’t think they would make a bad product so I figured I’d give their cat-back a chance. So I was wondering if anyone has heard the same thing about the diameter creating a loss in torque, and if so what diameter should I go with.

My second question is regarding the K&N FIPK. I have the replacement filter in my ‘99, but I just want a little more power and throttle response. But one concern I have is whether or not any water could get into the intake (since it would now be an open element filter.) I’m not talking about crossing 5’ water crossings or anything, just like if I
happened to run through a bunch of standing water. Also I’m worried if mud got up there would it have a detrimental affect on the open filter and engine as well. I was planning on buying the intake and one of K&N’sDrychargers (I believe it’s like a pre-filter but it has a silicon coating or something to help resist water and keep it out of the intake.)

My last question is about the throttle body. The Jeep’s narrows from 60 down to 55 (so I’ve read.) I know there are many different sizes to choose from, but I’m only debating between two of them, either the 60mm (which would be 60 all the way through) or the 62mm (which I believe is the size as the opening on the intake manifold on my ‘99.)
I’d go with the 62mm in a heartbeat, but I’ve read that having too much of a bore can create a loss in torque. So Iwas just asking this to anyone out there who might know something about this.

Ok well thats it for now lol . . . Any thoughts or comments would be greatly appreciated, thanks.

[vamc]

www.quadratec.com
they sell one, try them.

[gtmud]

Well as it goes on the K&N kit, I've had mine on since I bought it(00 XJ w/102K) done alkinds of wheeling and never had an issue with water or mud. The exhaust, I have heard good things about the dynomax systems, but if you can afford it look into BANKS exhaust. I installed a complete BANKS exhaust on a friends CJ-7 and it sounded and performs GREAT. Not to mentin the workmanship that goes into their headers, WOW! Banks sell the header and I believe the mid pipe and the cat back system for the XJ. Another performance upgrade is look into a programmer or a chip for the computer. Hoep this helps a little. Oh, dynomax and Banks both size thier pipe to give you optimum performance per your type of vehicle. Eliminates the guess work of backpressure loss. Good luck.
One thing to keep in mind, if you go with the K&N kit you cannot install a spacer, no room. so the larger bore TB would be the way to go.

[vamc]

8mm plug wires from summit racing. im down the street from them.

[sector95]

As for performance questions, check out:

www.hescosc.com

They have done a lot of performance reasearch on Jeep inline sixes. Check out their stroker engines...There's a tech forum to ask your questions..... they usually get answered by Lee Hurley himself.... go to the website and read about Lee and his racing and engine building experience with Chrysler.

Oh, they also sell their own performance parts... that they've checked out on one of the three dynos they have in the shop.

mike