The 1999 Jeep Cherokee, particularly those equipped with the legendary 4.0-liter inline-six engine, enjoys a well-deserved reputation for reliability and off-road prowess. However, even the most robust engines can benefit from performance enhancements. For many Cherokee enthusiasts, a turbocharger kit represents the ultimate upgrade, unlocking significant horsepower and torque gains. This article delves into the world of 1999 Jeep Cherokee 4.0 turbo kits, exploring their benefits, considerations, installation complexities, and everything else you need to know to decide if forced induction is right for your XJ.
I. Why Turbocharge Your 1999 Jeep Cherokee 4.0?
1999 Jeep Cherokee 4.0 Turbo Kit: Unleashing Hidden Potential
The 4.0L engine is known for its low-end torque, making it a capable off-roader. However, it often lacks top-end power, especially at higher altitudes or when hauling heavy loads. A turbocharger addresses this limitation by forcing more air into the engine, resulting in:
- Increased Horsepower and Torque: Expect substantial gains, potentially pushing horsepower from the stock ~190 hp to well over 250 hp, and torque from ~225 lb-ft to over 300 lb-ft, depending on boost levels and kit quality.
- Improved Throttle Response: Turbocharging can significantly sharpen throttle response, making the Cherokee feel more responsive and eager to accelerate.
- Enhanced Off-Road Performance: The increased torque output translates to improved crawling ability and less need to downshift in challenging terrain.
- Better Highway Cruising: More power makes highway driving more comfortable and less taxing on the engine, especially when towing or climbing hills.
- Just Plain Fun: The sound of a turbo spooling up and the added performance is undeniably exhilarating.
II. Essential Components of a 1999 Jeep Cherokee 4.0 Turbo Kit
A complete turbo kit typically includes the following components:
- Turbocharger: The heart of the system, responsible for compressing air and forcing it into the engine. Different sizes and types are available, impacting performance characteristics and boost levels.
- Exhaust Manifold/Turbo Header: This component replaces the stock exhaust manifold and provides a mounting point for the turbocharger. It's crucial for directing exhaust gases to the turbine.
- Downpipe: Connects the turbocharger outlet to the exhaust system. It's typically larger diameter than the stock exhaust to reduce backpressure.
- Intercooler: Cools the compressed air from the turbocharger, increasing its density and further boosting performance.
- Intercooler Piping: Connects the turbocharger to the intercooler and the intercooler to the throttle body.
- Blow-Off Valve (BOV) or Diverter Valve: Releases excess pressure when the throttle closes, preventing compressor surge and potential damage to the turbo.
- Wastegate: Regulates the amount of exhaust gas flowing through the turbine, controlling boost levels and preventing overboost.
- Fuel Injectors: Larger fuel injectors are usually required to provide the increased fuel demand of the turbocharger engine.
- Fuel Pump: A high-flow fuel pump is often necessary to supply the larger fuel injectors.
- Engine Management System (EMS): A standalone ECU or piggyback system is essential for properly tuning the engine to accommodate the turbocharger. This controls fuel delivery, ignition timing, and boost levels.
- Air Filter: Provides clean air to the turbocharger.
- Oil Lines: Supply oil to lubricate and cool the turbocharger.
- Water Lines (if water-cooled turbo): Cool the turbocharger.
- Hardware and Fittings: All necessary nuts, bolts, clamps, and hoses for installation.
III. Choosing the Right Turbo Kit for Your Cherokee
Selecting the appropriate turbo kit depends on your budget, performance goals, and mechanical skill level. Here are some key factors to consider:
- Turbocharger Size: A smaller turbocharger will spool up faster and provide better low-end torque, ideal for off-roading and daily driving. A larger turbocharger will deliver more top-end power, suitable for drag racing or high-speed applications.
- Intercooler Type: Air-to-air intercoolers are the most common and cost-effective. Air-to-water intercoolers offer superior cooling but are more complex and expensive.
- Engine Management System: This is arguably the most critical component. A proper EMS is essential for safe and reliable operation. Options range from piggyback systems that modify the stock ECU to standalone ECUs that completely replace it.
- Kit Completeness: Some kits are more complete than others. Ensure the kit includes everything you need for a successful installation, including fuel injectors, fuel pump, and EMS.
- Budget: Turbo kits can range in price from a few thousand dollars to well over $10,000. Set a realistic budget and stick to it.
- Reputation: Research the manufacturer and read reviews from other users. Choose a reputable brand with a proven track record.
IV. Installation: A Step-by-Step Overview (Simplified)
Installing a turbo kit is a complex project best left to experienced mechanics. However, here's a simplified overview:
- Preparation: Gather all necessary tools, parts, and fluids. Disconnect the battery.
- Remove Stock Components: Remove the stock exhaust manifold, air intake system, and any other components that will interfere with the turbo kit.
- Install Turbo Header/Manifold: Install the new exhaust manifold/turbo header.
- Mount Turbocharger: Mount the turbocharger to the header.
- Install Downpipe: Connect the downpipe to the turbocharger outlet.
- Install Intercooler and Piping: Mount the intercooler and run the piping to the turbocharger and throttle body.
- Install Blow-Off Valve: Install the blow-off valve or diverter valve.
- Install Wastegate: Install the wastegate and connect it to the turbocharger.
- Install Fuel Injectors and Fuel Pump: Replace the stock fuel injectors with larger ones and install a high-flow fuel pump.
- Install Oil and Water Lines: Connect the oil and water lines to the turbocharger.
- Install Engine Management System: Install the EMS and connect it to the necessary sensors and actuators.
- Connect Air Filter: Connect the air filter to the turbocharger inlet.
- Double-Check Everything: Carefully inspect all connections and ensure everything is properly installed.
- Start the Engine: Start the engine and check for leaks.
- Tune the Engine: Tune the EMS to optimize performance and ensure safe operation. This often requires dyno tuning by a professional.
V. Important Considerations and Potential Challenges
- Engine Condition: A turbocharger will put increased stress on the engine. Ensure your engine is in good condition before installing a turbo kit. Consider a compression test and leak-down test to assess its health.
- Cooling System: Turbocharging generates more heat. Consider upgrading your radiator and cooling fan to prevent overheating.
- Transmission: The stock transmission may not be able to handle the increased power. Consider upgrading to a stronger transmission or reinforcing the existing one.
- Drivetrain: The increased power can also stress the drivetrain components, such as the axles and differentials. Consider upgrading these components as well.
- Tuning: Proper tuning is crucial for safe and reliable operation. Work with a qualified tuner who has experience with turbocharged 4.0L engines.
- Emissions: Turbocharging may affect your vehicle's emissions. Check your local regulations before installing a turbo kit.
- Cost: Turbocharging can be expensive. Factor in the cost of the kit, installation, tuning, and any necessary upgrades to the engine, transmission, and drivetrain.
VI. Table Price 1999 Jeep Cherokee 4.0 Turbo Kit
| Component | Description | Estimated Price (USD) |
|---|---|---|
| Turbocharger | Garrett, Precision, or similar brand; Size depends on HP Goals | $800 - $2,000 |
| Exhaust Manifold/Turbo Header | Fabricated steel; designed for turbo mounting | $300 - $800 |
| Downpipe | Stainless steel; 3" diameter recommended | $200 - $500 |
| Intercooler | Air-to-air; Front-mount or side-mount options | $200 - $600 |
| Intercooler Piping | Aluminum or silicone; Includes couplers and clamps | $150 - $400 |
| Blow-Off Valve (BOV) | Prevents compressor surge; Adjustable spring pressure | $100 - $300 |
| Wastegate | Controls boost pressure; External or internal options | $100 - $300 |
| Fuel Injectors | Upgraded; Required for increased fuel delivery (e.g., 30lb/hr or higher) | $200 - $400 |
| Fuel Pump | High-flow; Walbro 255 or equivalent | $100 - $200 |
| Engine Management System (EMS) | Standalone ECU (e.g., Megasquirt) or Piggyback system (e.g., AEM FIC); Tuning required | $400 - $1,500 |
| Air Filter | High-flow; K&N or similar | $50 - $100 |
| Oil Lines & Fittings | Stainless steel braided; Includes all necessary fittings | $50 - $150 |
| Water Lines & Fittings (if applicable) | For water-cooled turbos | $30 - $100 |
| Miscellaneous Hardware | Nuts, bolts, clamps, hoses, gaskets, etc. | $50 - $200 |
| Total Kit Cost (DIY) | Estimated Range | $2,730 - $7,650 |
| Professional Installation | Estimated Additional Cost (Highly Recommended) | $1,500 - $4,000+ |
| Dyno Tuning | Essential for Proper Operation and Longevity | $500 - $1,000+ |
VII. Frequently Asked Questions (FAQ)
- Q: Is turbocharging a 1999 Jeep Cherokee 4.0 reliable?
- A: Yes, if done correctly. Proper tuning, quality components, and regular maintenance are essential.
- Q: How much horsepower can I expect to gain?
- A: Gains vary depending on boost levels, turbocharger size, and tuning. Expect anywhere from 50-150+ horsepower.
- Q: Do I need to upgrade my transmission?
- A: It's highly recommended, especially if you plan to run high boost levels.
- Q: Can I install a turbo kit myself?
- A: Only if you have extensive mechanical experience. Professional installation is recommended.
- Q: Will turbocharging affect my fuel economy?
- A: Fuel economy may decrease slightly under normal driving conditions. However, it may improve at highway speeds due to the increased power.
- Q: What kind of maintenance is required?
- A: Regular oil changes, air filter cleaning, and inspection of all components are essential.
VIII. Conclusion
Turbocharging a 1999 Jeep Cherokee 4.0 can dramatically enhance its performance, transforming it into a true powerhouse both on and off the road. However, it's a complex and costly project that requires careful planning, quality components, and professional tuning. By understanding the considerations outlined in this article, you can make an informed decision about whether a turbo kit is the right upgrade for your XJ. If executed properly, the rewards – increased power, improved throttle response, and undeniable fun – are well worth the effort.