Tuning the Jeep Cherokee
"Thank you for reading this Jeep Cherokee tuning article."
The Cherokee is a great car modification project to execute. If you do your research then you can create an awesome Cherokee but don't be fooled there are lots of performance parts out there that will simply not suit it read our unbiased guides first.
Handling/Suspension upgrades
Improving the handling for car owners first priority in your Cherokee tuning project.
Fully adjustable suspension allows you to fine tune the handling of you Cherokee dramatically improving your drive.
We suggest that you fit performance suspension and lower the car by 28mm - 40 mm. Larger drops require arch work - especially on models already equipped with uprated suspension.
Our aim in engine tuning should be to increase peak torque at the top end.
Sadly with smaller engine sizes you are wasting your time spending money on modifications, so if this applies to you get yourself an engine swap then apply the following mods.
Engine tuning mods
Engine
- 2.1 L (126 cu in) Renault J8S I4 (turbocharged diesel)
- 2.5 L (150 cu in) AMC i4 (gasoline)
- 2.5 L (153 cu in) VM Motori 425 OHV i4 (turbocharged diesel)
- 2.8 L (173 cu in) GM LR2 V6 (gasoline)
- 4.0 L (242 cu in) AMC I6 (gasoline)
- 4.0 L (242 cu in) AMC H.O. I6 (gasoline)
- 4.0 L (242 cu in) PowerTech I6 (gasoline)
1984-1996
- 2.5L AMC 150
- 2.8L V6
- 2.1L TurboDiesel Douvrin J8S
- 4.0L AMC 242 2.5L TurboDiesel VM 425
1997-2001
- 2.5L AMC 150
- 4.0 Litre AMC 242
- 2.5 TurboDiesel
These are the kits are usually carried out by our members, decide how far you want to go before you start.
Getting the best uprated mods for your planned usage of the car is vital. Stage 3 motor sport mods just don't work well on the road making the car difficult to drive.
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How to tune your car
- Improve the handling
Focus on Suspension improvements, such as coilovers and make sure the bushings are in good order and that the alignment is correct. Then focus on improving the brakes, with a big disk brake conversion kit and fast road brake pads.
- Remove restrictions
Focus on the intake and exhaust with filters being the common point of restriction in a tuned car. Intercoolers may also become restrictive on turbo engines so this may also need to be uprated.
- Burn more fuel & air
Increase the fuelling so it matches the air coming into the engine. The ratio is important so you need to improve the fuel pump and injectors, so the head mods, big valve conversions, fast road camshafts and forced induction upgrades extra supply of air is adequately met.
- Test and replace any weak parts
Weak areas are commonly the clutch, the turbocharger and pistons and crankshaft in a highly tuned engine. Makes sure these components will cope with your power aspirations.
- The Tune or Remap
A cars ECU controls the fuel, timing, spark and even the turbo in some cases, so to fully extract your gains you should remap the car last and this will fully release the power. Some cars are easy to map, and others require piggyback ECU's or aftermarket ECU's but this is the most vital step of your tuning project.
Modifying to Stage 1:
Suspension upgrade (drop 28mm - 40 mm.), Sports exhaust, Panel air filter, Lighter flywheel, Remap, Alloy wheels.
Modifying to Stage 2:
Ported and polished head, Power/Sport clutch, high flow fuel injector, Fast road cam, fuel pump upgrades.
Modifying to Stage 3:
Competition cam, Adding or upgrading forced induction (turbo/supercharger), Engine balancing, Internal engine upgrades (pistons/head/valves), Sports gearbox.
Your targets when tuning should be a nice flat torque band. You don't want all the torque to be at the top end unless you are creating a competition car.
The whole point of our pointers is to give a starting base of customizing performance parts and point you in the right direction, our forum is where you can ask for more detailed advice and tips on your modified car project, the best uprated upgrades and all aspects of modding cars.Fast road cams offer one of the biggest torque gains for your money as far as a bolt on performance mods goes on a NASP engine.
The exhaust and intake valve timings play a major role in your cars power band, but be careful here, getting this wrong can upset the idle and make the car hard to drive in traffic. You'd need to follow a camshaft upgrade with other mods and finish with a performance chip to fully realise your gains.
Don't forget to increase the fuelling when you are increasing the power - it makes the car more thirsty.
Using higher octane petrol is another option if you find you are suffering from detonation or premature ignition on your Jeep project after fitting other uprated mods. Increasing the injectors is another beneficial modification and will deliver sufficient fuel.
Uprate the fuel pump to cope with the extra fuel requirements of your tuned Cherokee's uprated injectors.
Intake and Exhaust Tuning.
The next area for modification is the intake and exhaust. Please note that WE DO NOT FIND IMPROVEMENTS WITH INDUCTION KITS, unless you have tuned your car massively and are finding that the standard air intake has become the bottleneck.
Induction kits can work well on turbo engines and larger engines (if supplied with a suitable cold air feed or air box), generally though we'd just recommend for Cherokee engines you should go with a sports panel air filter preferably made from cotton.
Do not go with the largest exhaust you can get this will slow the exhaust rate - the best exhausts for power gains are usually between 1.5 to 2.5 inches. It is the shape and material more than the bore size.
Head work including a polish and port and 3 or 5 angle valve job will really help to release the potential of the engine. A good fast road performance clutch will help to keep that power going where it should. Never cut corners or expect a standard clutch to cope. The best mods we recommend for your Cherokee are fast road camshaft, remap, induction and exhaust, suspension.
NASP engines do not achieve big power gains if you remap them, unless you have done extensive modifications. With turbocharged engines this is another story. A remapped turbo will give significant power gains and fully release the potential power of the engine.
We've also come across some owners playing with twincharging conversions and making some very high power hikes.
Adding forced induction will see significant power gains but this is usually too expensive to be cost effective. Superchargers are generally easier to add than a turbo. Turbos increase power in increasing proportion to increasing engine speed and this can make mapping difficult.
It is simpler to map a supercharger because the boost is correlating to engine speed on a linear curve. To cope with forced induction you will usually need to decrease the engine compression ratio .
Alloy wheel upgrades.
Due to the fact that alloy wheels are less heavy they improve performance and they can help to cool the brake disks. Don't forget that your choice of rubber greatly affects your cars grip and handling. It is not worth compromising performance with cheap tyres when you can buy directional tread pattern performance tires.We should point out that although they can look cool on the Cherokee big alloys will actually decrease your performance. The larger you go the lower your acceleration will be - this to the change in your effective final drive ratio.
Because of this we would advise sticking to a maximum wheel size of 18 inches, although we know some of our members have fitted larger wheels with no problems.
For more information on Tuning your car please join us in our friendly forum where you can discuss Cherokee options in more detail with our Cherokee owners. It would also be worth reading our unbiased Jeep tuning articles to get a full grasp of the benefits and drawbacks of each modification.
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