Types of Mitsubishi Eclipse Engines
The Mitsubishi Eclipse engine is available in various four-cylinder or V6 configurations, each with unique performance characteristics designed for different driving needs. Below is a detailed breakdown of all Eclipse engine variants across generations.
| Engine Model | Production Years | Displacement | Configuration | Horsepower | Best For |
|---|---|---|---|---|---|
| 4G63T/G | 1988-1999 | 2.0L | Inline-4 DOHC 16V | 92-190 HP | High-speed driving, Performance |
| 4G64 | 1990-1999 | 2.4L | Inline-4 DOHC/SOHC | 135-150 HP | Highway driving, Everyday use |
| 6G72 | 1990-1999 | 3.0L | V6 DOHC/SOHC | 190-205 HP | High-speed driving, Power |
| 4B11T | 2005-2012 | 2.0L | Inline-4 Turbocharged | 265 HP | Highway driving, Performance |
| 4B12 | 2005-2012 | 2.4L | Inline-4 DOHC | 168-180 HP | Balanced performance |
| 4J11 | 2005-2012 | 2.0L | Inline-4 DOHC | 140-150 HP | Fuel efficiency, Daily driving |
4G63T/G Engine
A legendary 2.0L inline-four powerplant with double overhead cams and 16-valve design that established the Eclipse's performance reputation.
6G72 V6 Engine
A robust 3.0L V6 engine offering smooth power delivery and enhanced torque for drivers seeking premium performance without turbo complexity.
4B11T Engine
The modern 2.0L turbocharged four-cylinder that powers later Eclipse generations with impressive power-to-weight ratio and efficiency.
Expert Tip: The 4G63T engine is highly sought after in the tuning community due to its robust design and ability to handle significant power increases with proper modifications. Many enthusiasts consider it the most desirable Eclipse engine for performance builds.
Specifications and Technical Details
Understanding the technical specifications of Mitsubishi Eclipse engines helps owners make informed decisions about maintenance, upgrades, and performance expectations.
Key Technical Specifications
| Specification | Details | Impact on Performance |
|---|---|---|
| Engine Type | Inline-4 or V6, some with turbochargers/intercoolers | Defines power delivery characteristics and driving feel |
| Displacement | Ranges from 1.8L to 3.0L across models | Larger displacement typically provides more torque |
| Horsepower | Ranges from 92hp to 265hp depending on model | Determines acceleration capability and top speed |
| Torque | Ranges from 122Nm to 265Nm | Affects low-end power and pulling capability |
| Fuel Type | Unleaded petrol (91 octane or higher) | Higher octane required for turbocharged models |
| Transmission | 5/6-speed manual or automatic CVT | Manual offers more control; automatic provides convenience |
| Ignition System | Electronic with coil-on-plug in later models | Modern systems provide better reliability and efficiency |
Important Note: Turbocharged Eclipse engines (4G63T, 4B11T) typically require premium fuel (93 octane recommended) to prevent engine knock and ensure optimal performance. Using lower octane fuel can trigger the engine computer to reduce power output as a protective measure.
Maintenance Requirements and Best Practices
Proper maintenance is crucial for maximizing the lifespan and performance of your Mitsubishi Eclipse engine. Following these manufacturer-recommended service intervals will help ensure reliability and prevent costly repairs.
Engine Oil
Regular oil changes are the most critical maintenance task for any Eclipse engine.
- Interval: Every 5,000 miles or 6 months
- Type: 5W-30 (non-turbo) or 5W-40 (turbo) synthetic oil
- Filter: Replace with every oil change
Low oil levels are especially dangerous for turbocharged models!
Air Filter
Clean air is essential for proper combustion and engine performance.
- Inspection: Every 10,000 miles
- Replacement: Every 15,000-20,000 miles
- Signs of need: Visible dirt, reduced power
Spark Plugs
Critical for proper ignition and fuel efficiency.
- Inspection: Every 30,000 miles
- Replacement: Every 60,000 miles (non-turbo), 30,000 miles (turbo)
- Type: Iridium for best performance
Cooling System
Prevents overheating and protects engine components.
- Coolant change: Every 60,000 miles
- System flush: With coolant change
- Inspection: Check hoses and radiator annually
Fuel System
Ensures proper fuel delivery and engine performance.
- Fuel filter: Replace every 30,000 miles
- Injector cleaning: Every 45,000 miles
- Fuel additive: Every 10,000 miles to prevent deposits
Timing Belt/Chain
Critical component that synchronizes engine operation.
- Inspection: Every 60,000 miles
- Replacement: 60,000-90,000 miles (varies by model)
- Warning: Failure can cause catastrophic engine damage
Maintenance Tip: The 4G63T engine in particular benefits from more frequent oil changes (every 3,000-4,000 miles) when driven hard or used in performance applications. Using high-quality synthetic oil designed for turbocharged engines will significantly extend engine life and protect the turbocharger.
How to Choose the Right Mitsubishi Eclipse Engine
Selecting the appropriate engine for your Eclipse requires careful consideration of several factors including vehicle requirements, compatibility, and long-term objectives.
Key Selection Criteria
| Selection Factor | Considerations | Recommendation |
|---|---|---|
| Vehicle Requirements | Original design specifications and chassis compatibility | Stay with original engine type when possible for best fitment |
| Engine Codes | Specifications and configuration identification | 4G63T for performance, 4G64 for reliability, 6G72 for smooth power |
| Compatibility | Physical dimensions, mounting points, electrical connections | Confirm all connection points match before purchase |
| Modifications Required | Changes needed for installation of non-stock engines | Budget for wiring harness adaptors, custom mounts if swapping |
| Maintenance & Support | Parts availability, technical support, reliability | 4G series engines have excellent aftermarket support |
Understanding Engine Codes
Mitsubishi engine codes provide critical information about the engine's design and specifications:
- 4G63T: 2.0L inline-4 with turbocharging (legendary performance engine)
- 4B11T: 2.0L inline-4 with turbocharging (newer generation, aluminum block)
- 4G64: 2.4L inline-4 naturally aspirated (balance of power and reliability)
- 6G72: 3.0L V6 (smooth power delivery, more complex design)
- 4B12: 2.4L inline-4 with DOHC (modern design with good efficiency)
- 4J11: 2.0L inline-4 with DOHC (focus on fuel economy)
Warning: V6 engines (6G72, 6G75) are significantly more complex and may require substantial modifications to fit in vehicles originally designed for 4-cylinder engines. These swaps typically demand professional installation and custom fabrication.
Engine Replacement Guide
While professional installation is strongly recommended for engine replacement, understanding the process helps owners make informed decisions and communicate effectively with mechanics.
Professional Recommendation: Engine replacement is a complex procedure requiring specialized tools, knowledge, and equipment. For most owners, professional installation will save time, prevent costly mistakes, and ensure proper operation.
DIY Engine Replacement Process
For those with advanced mechanical skills and proper equipment, here's a simplified overview of the replacement process:
- Preparation and Safety: Disconnect the battery and ensure the engine is cool before beginning work. Use proper safety equipment including gloves and eye protection.
- Fluid Drainage: Properly drain and dispose of engine oil, coolant, and other fluids according to local regulations.
- Component Disconnection: Systematically disconnect electrical connections, fuel lines, cooling hoses, exhaust components, and transmission linkages.
- Engine Removal: Use an engine hoist rated for the weight of your engine (typically 300-500 lbs). Unbolt motor mounts and carefully lift the engine from the vehicle.
- New Engine Preparation: Transfer necessary components from old engine to new (if applicable) including intake/exhaust manifolds, sensors, and accessories.
- Installation: Carefully lower the new engine into position, align with motor mounts, and secure all mounting bolts to specified torque specifications.
- Reconnection: Methodically reconnect all systems including electrical, fuel, cooling, and exhaust components.
- Fluid Refill: Add fresh oil, coolant, and other fluids to appropriate levels using manufacturer-specified products.
- Testing: Before full operation, perform preliminary checks including turning the engine by hand to verify free rotation and checking for fluid leaks.
- Initial Start and Break-In: Follow proper engine break-in procedures including gradual warm-up and avoiding high RPMs for the first 500 miles.
Critical Warning: Improper engine installation can result in catastrophic failure, vehicle damage, and personal injury. Only attempt this procedure if you have extensive mechanical experience and the proper tools.
Frequently Asked Questions
To determine engine compatibility with your Eclipse chassis, consult the vehicle's service manual for specifications. Direct replacement engines from the same generation will offer the best fitment. For engine swaps, you'll need to consider mounting points, wiring harness compatibility, transmission mating surface, and clearance issues. Mitsubishi Eclipse enthusiast forums can provide valuable information about specific engine swaps that have been successfully completed by other owners.
The 2.0L turbocharged engines (4G63T) in GS, GST, and GTS models are known to experience connecting rod failures ("throwing rods") when not properly maintained or run with insufficient oil. This catastrophic failure typically occurs due to:
- Inadequate oil change intervals
- Operating with low oil levels
- Excessive boost pressure from modifications
- Detonation from improper fuel octane
Regular oil changes with high-quality synthetic oil and maintaining proper oil levels are essential preventive measures, especially for turbocharged models.
Yes, Mitsubishi Eclipse engines, particularly the 4G63T and 4B11T models, respond well to performance upgrades. Popular modifications include:
- Improved air intake systems
- Upgraded exhaust systems
- Performance ECU tuning
- Larger turbochargers (for turbocharged models)
- Upgraded fuel injectors and pumps
- Forged internal components for high-power builds
When upgrading, ensure modifications are compatible with other vehicle systems, particularly the transmission and cooling system. A balanced approach to modifications will yield the best reliability and performance.
If your Eclipse engine fails to start, follow this systematic troubleshooting approach:
- Check the basics: Verify battery voltage (should be 12.6V+), inspect battery terminals for corrosion, and ensure the starter is engaging
- Test fuel delivery: Listen for the fuel pump priming when the key is turned to "on" position
- Check ignition system: Inspect spark plugs for fouling, verify ignition coil operation
- Scan for codes: Use an OBD-II scanner to check for diagnostic trouble codes
- Examine timing: Verify timing belt/chain hasn't slipped or broken
If basic troubleshooting doesn't resolve the issue, consult a certified mechanic with experience in Mitsubishi vehicles for professional diagnosis and repair.