Clamton

So I am looking to improve and or upgrade so to speak my 94 jeep cherokee 4.0L xj and was wondering if you guys knew of any kind of performance upgrades just to make my jeeps life easier. I'm looking for upgrades along the lines of cooling, intake, exaust, and any other suggestions. This would be really helpful please and thank you

88CherokeeKid

Seriously, my best advice to you is just get lost in the forum. There is SO much information regarding ALL of those things, plus so much more on here.

extrashaky

As 88CherokeeKid suggested, you can spend hours and days on this and other boards researching this (I know I have), and what you decide to do will depend on what you want to do with the truck and how much money you want to spend. However, you don't know what to search until you know what to search. So here are a few ideas to get you started:

For cooling, you have a number of options. Heat wells up under that big flat hood and has nowhere to go. Adding the stock vents from an older Chrysler Lebaron turbo to your hood is a popular option for reducing the under-hood temperature and helping the engine run cooler. I have a set of Chevy Z34 vents ready to be installed in mine, which I selected because they have nice drip pans. Some people have simply put household heater vents on theirs, which looks kind of redneckish but does the job.

There is a popular hack involving swapping out the existing electric fan for the fan out of a salvage yard Taurus, because it moves more air than our stock fans. Some people go with aftermarket electric fans. Some remove the mechanical fan altogether and go with a dual or triple electric fan setup, which not only has cooling advantages but also gets the drag of the mechanical fan off the engine.

There are high-flow water pumps available, but from what I've read they don't appear to be worth the money. You can still research it and see if that's something you want.

I have a CSF 3-row radiator. The stock radiator is 2-row. The 3-row radiator gives you more surface area for cooling the water-cooled system.

For intake, an under-hood "cold air" intake system (the kind with the cone filters) doesn't do you a tremendous amount of good because you're still pulling hot air from under the hood. Many people get better results just using their stock airboxes with a freer-flowing drop-in filter. There has been plenty of discussion over whether to use a dry or oiled filter, so there's something else you can search and research.

To actually get cold air to the engine, some people have had good results with either commercial or home-made cowl intakes that pull air from the area right in front of the windshield, below the vents. Or you can go with a snorkel, which runs up the a-pillar and sucks in cold air, with the added benefit of getting your air intake higher than any water you are ever likely to attempt to cross. Both of those options require you to cut sheet metal, so you'll definitely want to do your research.

You can read discussion about throttle body spacers. I think those are stupid and useless, but some people swear by them. I don't think they actually do anything but waste your time and money.

However, you can upgrade the throttle body itself to a larger diameter. I'm running a BBK 62mm throttle body on mine, but I have a stroker that needs it.

Another popular mod is to get the intake manifold off a 2000 or '01, but to be honest I don't know what years of older Jeeps that works for since mine is already a 2000. The manifolds for those two years were the most free flowing, with the '01s being ever so slightly better than the 00s.

You also asked about exhaust. Headers are a subject all unto themselves. If you buy one, consider having it ceramic coated. Jet Hot is reputable, but I went with Swain Tech for mine and have been quite happy with the result. The ceramic coating holds in the heat and passes it further down the exhaust, making your exhaust more "active." By moving the heat, it can also reduce under-hood temps, but not really by all that much.

A freer-flowing catalytic converter is a good mod for the exhaust. I have a Magnaflow cat on mine. I would never tell you to replace a functioning cat, since that's technically illegal wink wink. But I don't live in a nanny state where they really care about that all that much.

And finally, a new muffler or cat back exhaust can make a big difference in the way your ride sounds. Whether that's a positive or negative difference will be up for debate. I personally think the Flowmasters that everyone likes so much make the XJ sound like a 6:30AM Saturday morning lawnmower. The Banks exhaust sounds a lot better, but I'm running a Gibson cat back on mine. I chose the Gibson because it's not obnoxiously loud, but it flows freely and has a deep rumbling tone. Personally I think it's the best sounding exhaust for the XJ, but you should listen to as many clips as you can on YouTube and find a sound you like.

So those are some things to get you started. As you go deeper down the rabbit hole, you'll see people discussing other mods that you'll find yourself wanting to research. Sometimes it can be overwhelming, so you might want to bookmark some of the pages you find to read them later.

Have fun!

Jrozar

This will answer any engine mod questions you have and from a VERY reliable source..

http://www.fourwheeler.com/how-to/en...ing-true-lies/

Cold Air Intake
Myth: A cold air intake with an open dry or oil-impregnated gauze filter will increase power and mileage.
Our Thoughts: While not all aftermarket filter media are as efficient at trapping dirt as the factory-spec paper plate filters, there's no denying you'll see improved mileage and feel a definite seat-of-the-pants improvement.
Claimed Gains: 10-20hp and 1-3mpg
Actual Gains: 5-10hp
Notes: A good cold air intake will wake up any '91-up MPI HO 4.0L with snappier off-idle acceleration, improved top end pulling power, and a definite 1mpg increase. On some models, the major benefit comes from replacing the kinked, convoluted factory ducting.

Throttle Body Spacer
Myth: Adding a throttle body spacer will increase the intake plenum volume for more air and a higher velocity intake charge. Also, rifling an aluminum spacer helps air flow into cylinder head with less turbulence for more power.
Our Thoughts: Depending on the application, a spacer works wonders on a carbureted or a TBI-injected engine in which the air/fuel mixture atomizes and flows through a wet manifold, but results are less drastic on a MPI engine in which only air flows through the intake.
Claimed Gains: 10-15hp
Actual Gains: 0-3hp
Notes: With our Red and Mileage Master projects, the largest power increase we've seen on the dyno was 1hp.

62mm Throttle Body
Myth: The factory 60mm throttle body is a choking point in the stock engine. Boring the factory throttle body or installing a larger-bore aftermarket throttle body will allow the engine to breathe and make more power.
Our Thoughts: On most stock or slightly modified engines the factory 60mm throttle body isn't the cork, and is capable of supplying the engine with enough air to get the job done. Only on a vehicle with airflow modifications like a cold air intake and free-flow exhaust will you notice a difference.
Claimed Gains: 10-20hp
Actual Gains: 5hp
Notes: We did see a 5hp difference with a 62mm throttle body on a 4.0L with a cold air intake and exhaust modifications and believe the increase would be larger with other airflow enhancements, like a larger camshaft or high-flow cylinder head. It's a complementary component best used in concert with other products.


Ignition Hop-Ups
Myth: A hotter spark will allow you to run a bigger plug gap and burn more fuel more completely.
Our Thoughts: It's sound theory, but impractical in practice for most of the 4.0L engines running around out there. Not only is the 4.0L calibrated lean from the factory to aid in mileage and emissions, but most HO engines come with a pretty good ignition that will allow 0.045-inch plug gap with no trouble. It's only when forced induction or larger injectors and different camshaft profiles come into play that hotter aftermarket spark components prove their worth.
Claimed Gains: 15hp, 20 percent better mileage
Actual Gains: 0-3hp
Notes: You may see some big numbers from 4.0L ignition modifications, but it'll only happen if there was something wrong with the existing ignition system, in which cases even fresh factory replacement parts may garner the same results.



After-Cat Exhaust
Myth: Removing the restrictive muffler and exhaust pipe behind the catalytic converter will greatly increase drivability, performance, and mileage.
Our Thoughts: Car manufacturers often design exhaust systems to cancel out resonance and unwanted noise at some sacrifice to mileage and power. They almost always leave a little power and efficiency on the table as a result.
Claimed Gains: Up to 25hp and a 10-15-percent bump in mileage
Actual Gains: 5-15hp and 10-percent fuel mileage
Notes: We've realized very noticeable seat-of-the-pants improvements with after-cat exhaust systems, as well as bonefide dyno verification.



Header/Manifold Crack Issues
Myth: All 4.0Ls will crack the factory tubular exhaust manifold at the collector. The extra air getting to the O2 sensor will make the Jeep run rich, foul cat, and run like crap. The fix is to add an aftermarket header for more power, durability, and longevity.
Our Thoughts: We agree with the above. The exhaust system of a 4.0L Jeep has to deal with very high temperatures due to the 4.0L's lean air/fuel calibration that, when coupled with a long and inflexible intermediate tube that leverages the tubular header, is a perfect recipe for cracking. In fact, even some aftermarket steel and stainless steel headers may not prove immune.
Claimed Gains: 5-10hp and long-life
Actual Gains: 5-10hp and long-life
Notes: Despite its fairly efficient design, you will notice a seat-of-the-pants improvement with an aftermarket header when used in conjunction with an after-cat exhaust and a cold air intake. Just buy the header with the thickest gauge tubing you can.



'99-Up Horseshoe Intake
Myth: According to that great wealth of information that is never wrong, the Internet says you'll get a 5-30hp gain thanks to the '99-up 4.0L's swooped, equal length runners and larger plenum volume.
Our Thoughts: While a free-flow intake manifold can deliver more power, it's only going to allow as much air to flow as the cylinder head and camshaft will call for. Upping the intake runner volume too much will cause the intake charge to lose velocity, killing low- and mid-speed power and torque. On a '98-earlier engine running a stock camshaft and unported cylinder head, it's wasted effort.
Claimed Gains: 5-30hp
Actual Gains: 5hp loss on Trasborg's '98 XJ (Project Mileage Master)


This should give you a good start

Clamton

Okay guys thank you so much this forum is amazing and my jeep at the moment is a work in progress it's actually a salvage. I will defiantly dive deeper into te forum just wanted to show some appreciation for the responses.

extrashaky

Now let's be serious. Nobody really changes the exhaust for performance. They change it for sound and use any actual performance gains as justification for doing it. When you read the muffler threads, they focus almost entirely on how they sound, not how many hp they add. I'm not embarrassed in the slightest to say that my number one goal in selecting an exhaust was that I wanted my Jeep to sound good.

XJlimitedx99

Well, the ultimate questions are what do you plan to use your jeep for the most, and how much are you comfortable spending?

As far as cooling goes, the stock xj system is satisfactory as long as it's maintained well. A lot of people change the fans out, put in a bigger radiator, a more expensive water pump, and thermostat. Looking into a transmission cooler would be a great idea.

For performance, these 4.0s don't respond well to one mod alone. Not saying they won't function properly, but to see any kinda of decent gain it helps to open up the intake, exhaust, and fuel system.

Intake- a cowl intake will pull cold air from under the wipers, or you could do an expensive k&n style unit with a heat shield. A 62mm throttle body will open things up quite a bit. As some others mentioned, there are a few intake swaps people do. A port and polish would get a few ponies.

Exhaust- again with saying these parts work together; headers are expensive and don't get much as far as power with these motors, but a full header back exhaust system would really open everything up and let that air get out.

Fuel- injector swap from injectors with 1 hole to 4, cheap and easy.

IMO throttle body spacers and computer chips are a waste, atleast on these.

There are many many more areas to upgrade on your jeep, you'll find it's a never ending project. Some other upgrades you may be interested in are upgraded main wires under the hood and a bigger alternator, and upgraded headlights to start. Have fun getting lost in the forum!

extrashaky

I have one of Kelley's 1 AWG wire kits and a Mean Green alternator waiting to go in mine, but I wouldn't bother with that if I weren't planning to load that sucker down with a bunch of lights, a compressor and a winch.

The headlights are a very good suggestion. The headlights on these trucks kinda suck. One good upgrade is to replace the headlight wiring harness, which gets a lot more juice to the lights and brightens them up. Another good upgrade is to change over to e-code housings, which have a much better pattern and cutoff. I've seen the results on other Jeeps and have the whole kit waiting to go into mine. Too many things to do and too much day job to do them.

Jrozar

Uh.....if you notice those weren't my words but copied from the link by fourwheeler.com

Personally I go for performance and quiet if I can get it...over loud any day...my 4.0 ish in my YJ was built for performance...but then again mine is ported, bored, polished, balanced, blue printed, roller rockers, ceramic coated intake, header, etc....

Oh but it does sound good...

Now I'm getting ready to build my XJ....let's see what I come up with this one..maybe a turbo.

extrashaky

I did. It was still worth commenting on though. I don't think there's any shame in making a mod just because it looks or sounds good. I just find it funny that people say they're swapping exhausts for performance, when in reality it's for the sound, and the performance claim is just a justification for doing it.

Jrozar

The sound is a consideration...I would agree, don't want to sound like an teenagers import

Clamton

I here you completely haha. I think I may have a crack in my muffler so I mean instead of replacing the stock one I might as well upgrade it.

Fred/N0AZZ

Plan on spending your first $1k-1.5 on just RR all the worn, broken parts, tune-up, filters, fluids, steering, etc.

You get the point, if you don't have a solid basis to work up from and know what you have to work with, starting upgrades are useless.

XJlimitedx99

Every time something breaks on your jeep, spend 20 minutes or so reading online about upgraded parts people replace them with. There's an upgrade for a lot of major components. "If it breaks, upgrade!"