Jeep Tech

You are currently browsing the archive for the Jeep Tech category.

There are really only two types of Jeep Cherokees in this world, those who’s headers have cracked and those who’s headers will crack. Unfortunately, the inline 6 cylinder, while still being bullet proof, has one huge flaw. Due to the nature of the inline 6 being quite long, it puts an abnormal amount of pressure on the header.

The Problem
Cracked OEM Header The break usually comes very close to where the two pipe from each side of the header meet. If you have not had a header crack on your inline 6 you are in one of the following positions: it already cracked and was replaced by a previous owner, your Jeep Cherokee was built after 1999 where they changed the casting, or you have just been lucky so far, so congrats.

The Solution

New Accordion Styled HeaderThere is only one solution to prevent this from happening.  Immediately replace it with one like this Exhaust Manifold from AutoParts123.com.  This design has two accordion like pipes connecting the last ports on each end to the rest of the header.

However, there are two solutions to fixing this after it happens.  You can again purchase and replace the header with this Exhaust Manifold from AutoParts123.com. Again this design will not have the same stress on the header as the OEM’s inferior design.

In some cases you can have Welded OEM Headerthe crack welded and not only with this fix the problem of the cracked header, but in most cases the extra weld will reinforce that area preventing it from cracking in the future.  Obviously the latter solution can generally be easier on the budget, especially if you have the expertise and equipment to weld it yourself.

Tags: , ,

SnorkelIf you’ve ever found yourself hood deep in water without a snorkel, you’ve found yourself  problems.  Want a quick way to ruin that bullet proof engine?  Try filling it with water.  The solution to this drowning problem is a snorkel.  Much like floating on your belly in the hawaiian tropics with your goggles, fins, and snorkel.  This DIY project uses the same basic principle.  Take the air intake of your engine and put it above the water level.  Simple enough.  Let’s get started.

All credit goes to jfiscus from TerrainStompers.com for the build and pictures for this article.

As far as brand names go ARB is probably the most popular.  Their snorkel kits sell from about $350-$400.  And as essential as this piece of equipment can be when traveling down into the river, we’re going to build it for way less.  Like $300-$400 less.

Build List:

  • 1 - 2″ PVC Pipe 10 ft Length : $6.00
  • 3 - 2″ 45 Degree PVC Elbows : $1.50 each
  • 3 - 2″ 90 Degree PVC Elbows: $1.50 each
  • 1 - Small Can PVC Glue: $3.00
  • 1 - Tube JB Weld : $7.00
  • 1 - Can Krylon Fusion Black Spray Paint : $4
  • 1 - 2-2.5″ hose clamp sheet metal screws (for attaching to A-Post) : $2

Total Project Cost: ~$30 not including tools

Tools Required:

2″ Holesaw

PVC, Sawzall, or Hack Saw to cut PVC

Sandpaper to make grit for paint to stick to PVC

Step One - Test Fit Assembly

Engine Snorkel Component

Click For Full Size

Coming off of the airbox, on the side closest to driver, you’ll want to use your 45 degree elbow.  Then attach a cut length of the PVC pipe to another 45 degree elbow.  Then you’ll want a cut length of PVC to through the fender.  You’ll need your 2″ holesaw to make this cut to fit it.

Once off the fender you’ll attach a 90 degree elbow to make the turn up the side of the Jeep.  Attach a cut length of PVC pipe leading up to a 45 degree elbow that will take 1 more cut length of PVC pipe all the way to the top of the A -Post.  I hope it’s not too confusing.  The pictures should clear it up.

Once you’ve test fitted everything it’s time to move on to actual assembly and installation.

Side Snorkel

Click For Full Size

Step Two - Assembly and Glue

Referring to the previous instructions and the pictures you’re going to assemble the PVC together using the PVC glue.  Use the included application brush an apply a decent amount to both the contacting parts of the PVC according to the directions on the can.  Assemble the inside engine piece first, not inlcuding the length of PVC going through the fender.  Then assemble the outside pieces.  Once the outside part is assembled and glued, use sandpaper to sand the entire outside assembly.

Snorkel Outside

Step Three - Paint

Click For Full Size

Now you can paint the entire snorkel or just what will be visible on the outside.  Whichever pieces you want to paint, use the sandpaper and rough them up pretty good.  Then take your spray paint and get to painting.  Check the directions on the can to figure out drying times and exact methods for painting.

Step Four - Installation

Once everything is dry you’re going to begin final assembly and insallation.  Using the hole saw, cut a hole in the airbox. Place the engine piece in the hole and using JB weld bond the two pieces.  Once that is dry move on to the PVC pipe that will run through the fender.  If you haven’t already cut the fender through using the whole saw and cleaning it up with a sawzall if you’re not able to get clean through.  Glue the PVC piece to the engine compartment’s 45 degree elbow.

Then take your outside component of the snorkel and glue that to the PVC piece going through the fender.  The attach the outside snorkel piece to the A-Post with the clamps.  When you plan on going underwater, make sure you plug up the factory intake.

Completed Snorkel

Tags: , ,

Product Summary

Rubicon Express 2" Budget Lift

Manufacturer: Rubicon Express

Product: 2″ Budget Lift Kit

Price: $230 - $260

The Good:

It seems to be cliche for this class, budget, of product, but it doesn’t go without saying that this is a great price.  Most people I’ve talked to about this lift kit from Rubicon Express say they can’t get over the price.  And they’re right on with this lift coming in in the mid $200 range.

Unlike some budget Cherokee lift kits, one benefit to the Rubicon Express Budget Lift Kit is that it comes with shocks.  Unfortunetly, theres a lot of ‘budget’ kits out there that are either poor build quality or lack even the few necessary components to perform the simple lift, like shocks.

Even though it’s a budget kit, it is of the highest build quality.  The Rubicon Express Budget Lift Kit comes with great installation instructions that can be found on Rubicon Express’ website here.  I wouldn’t say installation is a breeze, because every install has it’s problems, however, installation is very straight forward and with those instructions provided by Rubicon Express, it makes installation just that much easier.

The Bad:

I can hear you saying it now, “what’s the catch?”.  Well, while this offer probably doesn’t sound like it’s too good to be true, it still has its catches.  For one, the ride’s definetly a bit rougher and stiffer than stock.  This is mainly do to the add-a-leaf stiffening up the back suspension.

Also, don’t expect to be able to throw 33″ inch tires under your XJ after you’re done with your install.  You’re looking at most at a 30″ tire with decent articulation.  (Checkout my article on Lift Kits and Tire Clearance)  Obviously because this is not a complete suspension kit you’re not going to get quite as much articulation as you would with say a 3″ suspension kit.

The Bottom Line:

The price speaks for itself on this one.  If you’re looking for a little extra clearance and don’t want to break the bank, then you should definetly consider this as an option.  If you’re looking to throw 33’s under your Cherokee, you should probably look at something a bit bigger.  Without the risk of sounding completely redundant, if this fits your budget and into your plans it’s a good deal.

Kit Includes:

  • 1.75″ Coil Spring Spacers
  • Add-A-Leaf 2″ Half LE
  • Replacement Center Pins for Leafs
  • 18″ Brake Line
  • 4 Twin Tube Shocks

Tags: , , , ,

Probably one of the most asked questions by new Cherokee owners or those who have finally decided to lift their Cherokee / XJ is: “What size tires can I fit under what size lift?”.  Well, maybe not that exact question, but a variation of it at least.

As always, here’s what you care about, the bottom line:

Lift Size and Tire Size:

Stock - 30×9.5 R15 or P255 70 R15 (The P255 is taller, but not as wide)Stock Jeep 30x9.5 R15

1″-2″ Lift - 30×9.5 R15

2" Lift with 30's

3″-4″ Lift -31×10.5 R15

3" Lift

4.5″ Lift - 32×11.5 R15 or 33×12.5 R15 (With Fender Modification)4.5" Lift

6.5″ Lif t- 33×12.5 R15 or 35×12.5 R15 (With Fend Mod + Bump Stops)6.5" Lift

8″ Lift - 35×12.5 R15

8" Lift

What else do I need?

The notes to the side of those tire sizes are only what is required to fit the tire under the Cherokee / XJ, not other necessary modifications.  There are other things that need to be done in order to drive the vehicle at certain heights.  For example once you go about 4.5″ of lift you absolutely need a slip yoke eliminator.  Above or at 3″ of lift and you need to relocate the brake lines or buy new longer brake lines.  Even at 4″-4.5″ of lift you’ll need to drop the transfer case with a transfer case drop kit.

This should be a good starting point to figure out how much lift you want and how big tires you will be able to fit under your Cherokee.  In the future I’ll post a couple articles on installing lift kits.

Tags: , , ,

BreathingOne of the best things you can do for your XJ to increase horsepower and MPG is to allow your XJ to breathe better. Yes, your Jeep breathes. It breathes in through your air-box and out through your exhaust. You can help your Cherokee breathe by removing restrictions in the flow of this breathing process.

So, how do you remove restrictions? First things first, check your catalytic converter.  If this is going bad or broken then you’re already losing horsepower, wasting gas, and hurting your engine.

You can tell your catalytic converter is bad if:

  1. You’ve recently failed an emissions test.
  2. You’ve had a significant decrease in gas mileage.
  3. You’ve had a significant loss in horsepower, up hills, on the freeway.
  4. It feels rough during idle.
  5. You’ve experienced it stalling at idle.

If you’ve experienced any of these things you need to have an exhaust back-pressure check.

Performance Catalytic Converters

catconPrice: $100-$150

Performance Gains: 5-10 HP Increase

Websites like SummitRacing.com sell “performance” or “high flow” catalytic converters.  These have better flow than OEM catalytic converters and will reduce back-pressure throughout the engine.  Reduced back-pressure means increased flow and increased flow means more horsepower.  Upgrading your catalytic converter is a great way to help your Cherokee breathe better.

High Flow and Performance Mufflers

flowmaster_40_seriesPrice: $100-$450 Full Exhaust Systems

Performance Gains: 7-15% Increase HP

A great way to increase your vehicles “breathability” is to replace your OEM muffler.  OEM mufflers are designed to decrease sound more than they are to make sure your Cherokee is running at top performance.  You can purchase just a muffler or an entire exhaust system that contains a muffler, tail piping, tips, and hanging brackets.  The systems make replacing your exhaust a cinch and can be done in a matter of hours.   And again, this will reduce back-flow, increasing horsepower, and adding a great sound to your XJ.

Air Intake

Price: $30-250

Performance Gain: 5-10 HPxjairintake

Last but not least is your air intake.  What good is reducing all the backpressure if your not getting enough air into the engine in the first place.  Replacing your air intake with an open cone and tube design like the one on the right can take less than 10 minutes and give you a gain of 5-10 horsepower.

The stock box is restrictive and doesn’t allow the engine to get as much air as an aftermarket design.  Going with a company like K&N for your filter allows you to wash your air filter as well.  No more purchasing air filters every time you go off roading only to clog up your air filter with horsepower destroying dust and mud.  Check out Rustys Airtube it’s only$29.95 + $29.95 for the K&N Air Filter.

If you plan on going in some deep puddles, snorkels are also available.

All in All

Total Pricing:

  1. XJ Cat-Back Exhaust $150
  2. XJ Cat-Converter $100
  3. Air Intake $100
  4. Total Price: $350     Increased Horsepower: ~30 HP

Bottom line is reducing restrictive OEM parts and replacing them with aftermarket performance parts cannot only give you performance increases, but significantly increase your gas mileage as well.

Tags: , ,

It can be helpful to know what the VIN Number on your XJ or on a Cherokee you’re looking at purchasing means. It can help determine the engine type, transmission/transfer case type, trim package, and other helpful information. At the very least it will let you know what to expect if it’s still stock.

So here’s a guide to breaking down the VIN Number on a 1984-2001 Jeep Cherokees:

- Jeep Fan’s XJ - VIN Guide -

Tags: , ,