I want to add more horespower to my XJ without stroking it or putting a new engine in. What do you recommend. Throttle body, exhaust, MSD ignition, electronic module, air intake system, performance plugs any other ideas? How much would that all help and is it worth the money?

sorry I forgot to mention it's a 2001 Jeep cherokee with the 4.0

 

Do not get any chips.... you lose power as the factory computer is set to the proper stats and is about 95% of the maximum HP/TQ

Remember that adding power is like an equaliteral triangle involving, air(in and out), fuel, and spark.

so when you open up the intake (63mm bored throttle body) you need to give more fuel (Ev6 style[4 pin] injectors) and to light all that up you need a good spark (8mm+ mires and a good coil). then you need to get that mixture out of the engine as fast as possible (2.5" exhaust)

 

Having a 2001 (like myself) I can say that you are limited on bolt-on horsepower. You have a wonderful cat/emissions system that is a complete pain. There are very few headers offered for 2000-2001, and because the ignition system uses a coil rail, you can't upgrade wires/distributor. I would advise a high-flow cat with 2.5'' piping, and a turbo-style muffler (or something along the lines of a Thrush Welded). A K&N cold air intake will help, but not much. Leave the plugs alone. Stick with copper.

 

I have the XJ completely stock and wanted to start by upgrading the drivetrain. So injectors, exhaust, throttle body and air intake is on my list. Now i have to do research for the products themselves. Thanks I really appreciate.

 

Helping the engine breath better is all you can do without cracking the engine open. Air intake and freer flowing exhaust, you might see some improvement.

 

I'm on the same boat as the OP. I have a 2001 Cherokee Sport and the problem i'm having is finding the right header for it. I believe it has duel pre-cats (y-pipe) and all i'm seeing are 6 to 2 to 1 type. Been really looking around online. I saw a couple of 6 to 2's but i don't think it comes with a y-pipe to the cat. Anybody have any info on headers for these 2001's?

I found these: http://www.car-stuff.com/carparts/je...istings+Page:1

Problem with these is what will happen to the pre-cat O2 sensors?

 

Haha... I feel like a rep for RP Oil lately...
http://www.royalpurple.com/motor-oil.html

 

I have the Banks Torque Tube header on my 01. It dosen't look like the one at your link though. Three pipes go to one of two precats then they Y together to a single under the engine and to a three hole header connector. It has two Oxygen sensors one after each precat.
I'm running a throttle body spacer and AirRaid intake and filter.
It had Dynoflo muffler and high flow cat. It sounded faster but I don't think it was worth it. I've since went with a quieter muffler. Some day the Throttle body spacer is coming off as my torque comes on at a higher RPM and I found out I don't like that.

 

On my ZJ (4.0L) I did a budget tune up 4 months ago. It got her running correctly but was quite sluggish and unresponsive. I added an MSD coil, Accell 8mm wires and gaped the plugs to .040 and it has noticeably more power, especially while pulling a hill. I'm not gonna say you'll see X amount of HP but I did see an improvement in idle, throttle response and overall "get up and go". Definitely worth the $100 I spent on everything.

 

I know which throttle body and air intake. Banks but finding the right coil packs, injectors, and headers is giving me a problem specifically because it's a 2001

 

Another thing I worry about is keeping the cooling temps low. I've had three cherokees and all of them ran relatively hot. Especially my last one because I was stationed in Camp Lejeune, North Carolina going through stop and go traffic daily. It sucked horribly

 

You can hood vents if you aren't afraid to hack up ur hood. I will probably be doing that on mine depending on how it maintains its temp as the weather gets warmer. Stop and go traffic here can be more like stop and no go. i'v head instances where it takes me 3 hours to get home from work and its only less than 10 miles away!

 

i dont know if y'all already covered this or not, but a decently priced flow-tek or pace-setter can be cut up to give you the option for dual exhaust but then you run into the issue of running a 2nd pipe all the way back and still retaining the "legality" of the OBD2 Emissions system that's installed from the factory, you can also try to find an aftermarket header for another jeep with the 4.0 or 4.0H/O depending on the application, but just my .02

 

you know there is one thing that will add horsepower...it varies from type to type. However it can vary from 5-100hp. They are super expensive to.

So go out and get your STICKERS!!!