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more power out of my xj

Y

yamahadrummer

NAXJA Forum User
Location
Lincoln, Nebraska
I'm looking to get more power out of my 2001 xj. I was wondering if any of you guys have experience with cams, full exhausts, and intakes..
Putting a more aggressive cam in would be pretty sweet, but im having trouble finding the right one, and finding a list of other parts i would need to replace with it. I want this to be a reliable upgrade, so i need to know what other parts i need to replace in order to make it reliable. The intake and exhaust is pretty self explanatory, I have done tons of them on other vehicles.. what are some header companies you guys like for the 4.0's? And what intakes do you guys like? I've been told by my resident jeep fanatic friend that the aisin aw4 is quite capable of handling ~400hp (i would like some other opinions to back this up) so that doesnt seem to be a problem...not like i would be anywhere near that even with upgrades. torque>hp in my book, anyway. What are the capabilites of the aw4 for torque?

I know that's a lot of questions, and some of them probably make me sound like i dont know much (I do know my fare share about engines, just nos as much as i would like to about jeeps) heh... but any help would be nice!
thanks in advance
 
For power upgrades i got a rusty's air tube and cat back with a flowmaster 50 and pacesetter headers ( they're cheap but they get the job done) Banks has a line of exhaust stuff out and i'd take a look at Edge trail jammer kits as well. I can't help you with cams but this is what i know. For heat sheild i made one out of some metal and pink insulation lol ghetto but hey, it really works... Oh and don't forget a high flow cat if you're doing a whole exhaust build. Also there's always a throttlr body spacer and/or larger bore throttle body someone makes a 62mm one i think. I know both Rusty's and Quadratec and summit racing too, they're not just for drag racing ya know! Hope i helped!
 
How much money do you want to pay Mischief Performance Engineering? <my little 'company' that modifies everything from briggs engines to Jeep engines to computers.

Well, do you want low end torque, high speed power, or a more balanced combo?

edit: if you want it to really haul, get a turbo or supercharger. You'll need to run premium fuel, but it sure would be neat.
 
I,m interested in some more info about cam's myself.I went to the Mopar Performance site today and there was one listed for the 4.0L but no info.For headers I,d say Banks,Edelbrock,Gibson,and Borla to start.Get an intake that dos'nt use the factory rubber tube.You might want to check out Performance Distributor for ignition and Level10 about the AW4.
 
Back when my jeep was my dad's he bought an aggressive cam for it but had to send it back because it would have voided the warrenty on our replacement engine. I'll ask him tommor if he remembers anything about it.
 
nochance9 said:
Suppercharger sounds like more your thing... Silly me, i was talking little powe adders lol
Click to expand...
how much do supercharger kits run for the 4.0?
ChevelleSSLS6 said:
How much money do you want to pay Mischief Performance Engineering? <my little 'company' that modifies everything from briggs engines to Jeep engines to computers.

Well, do you want low end torque, high speed power, or a more balanced combo?

edit: if you want it to really haul, get a turbo or supercharger. You'll need to run premium fuel, but it sure would be neat.
Click to expand...
im looking more for torque. Obviously for when im on the trail it will be helpful, but I also want people to be like "wtf is this a jeep?" when i step on it :D
dakineJ said:
I,m interested in some more info about cam's myself.I went to the Mopar Performance site today and there was one listed for the 4.0L but no info.For headers I,d say Banks,Edelbrock,Gibson,and Borla to start.Get an intake that dos'nt use the factory rubber tube.You might want to check out Performance Distributor for ignition and Level10 about the AW4.
Click to expand...
yea, that's the problem I keep running into. I can't find much info on cams. I found one on oreilly's but it says you dont need to do any other mods for it, but i find that a bit odd

nochance9 said:
For power upgrades i got a rusty's air tube and cat back with a flowmaster 50 and pacesetter headers ( they're cheap but they get the job done) Banks has a line of exhaust stuff out and i'd take a look at Edge trail jammer kits as well. I can't help you with cams but this is what i know. For heat sheild i made one out of some metal and pink insulation lol ghetto but hey, it really works... Oh and don't forget a high flow cat if you're doing a whole exhaust build. Also there's always a throttlr body spacer and/or larger bore throttle body someone makes a 62mm one i think. I know both Rusty's and Quadratec and summit racing too, they're not just for drag racing ya know! Hope i helped!
Click to expand...
I was looking at rusty's for intakes...what exactly does a throttle body spacer or bigger throttle body do for you?

thanks for the help from everyone so far!
 
Last edited:
yamahadrummer said:
I was looking at rusty's for intakes...what exactly does a throttle body spacer or bigger throttle body do for you?
Click to expand...


On the fuel injected 4.0's the throttle body spacer wont do anything. It will probably just make a whistling noise. a bored out throttle body will let more air in I believe. that will do something on the fuel injected 4.0s.

I have rusty's air tube for a while now, and im still not sure how much I like it. I feel like my throttle is a little more responsive, but I dont really see any power or mpg gains. also I am worried about it taking in water if it gets splashed under the hood. so when I wheel somewhere I expect to see water I swap it out for the factory airbox.
 
I think the stock cams (1996 is my XJ, earlier HO cams are supposedly different) are good for decent high end power and lots of torque. Some high ratio rockers might be of interest to you- it keeps current cam specs but increases lift.
 
Just go this route...

DSC04132.jpg


DSC04135.jpg
 
robsjeepxj said:
If I was you I'd regear the axles. You can raise you gear ratio and in turn increase your HP and torque in direct proportion.
Click to expand...

regearing in no way, shape, or form increases horsepower or torque. It increases the mechanical advantage over the tires, but at a cost of lowering the top speed. The jeep would be quicker off the line but have a lower trap speed.

Raising the gears will have the opposite effect, higher top speed but a slug off the line.

thanks for playing
 
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