Building a mid-engine Volkswagen (VW) with a Subaru transmission is a great way to boost performance and create something truly custom. One of the biggest choices you’ll face is which transmission to use.
Subaru’s 4EAT and 5EAT automatic transmissions are both popular among car builders because they are reliable and work well with different setups.
This blog will break down the differences between the 4EAT and 5EAT conversion kits. We’ll help you decide which one is better for your build based on things like cost, power, ease of setup, and driving style.
Whether you’re new to engine swaps or have done a few, this guide will give you the clear information you need to choose the right setup for your project.
Understanding The Basics: 4EAT Vs. 5EAT Transmissions
4EAT (4-Speed Electronic Automatic Transmission)
The 4EAT is a 4-speed automatic transmission developed by Subaru, known for its durability and straightforward design. It has been a staple in Subaru vehicles since the late 1980s, offering a balance between performance and reliability.
Key Features
- Simplicity: Its design is less complex, making it easier to modify and maintain.
- Compatibility: Widely used in various Subaru models, ensuring availability of parts and support.
- Cost-Effective: Generally more affordable than newer transmission models.
5EAT (5-Speed Electronic Automatic Transmission)
Introduced in the early 2000s, the 5EAT is a 5-speed automatic transmission offering improved drivability and smoother gear transitions. It incorporates more advanced electronic controls than the 4EAT and was used in higher-performance Subaru models.
Key Features
- Enhanced Performance: The additional gear allows for more precise acceleration and RPM control.
- Advanced Electronics: Some versions include adaptive shift logic depending on the donor model and ECU.
- Higher Torque Capacity: Designed to handle more powerful engines, making it suitable for performance-oriented builds.
Conversion Kits Overview: Tailoring Transmissions For Mid-Engine VW Builds
4EAT 2WD Conversion Kit
Designed to convert the AWD 4EAT transmission to a 2WD setup suitable for mid-engine applications.
Included Components
- Large back cover plate compatible with VW Vanagon mounts
- Small AWD clutch solenoid passage cover plate
- Bypass resistor for AWD clutch solenoid wires
- Pair of 100 mm axle flanges
Advantages
- Ease of Installation: The kit’s design simplifies the conversion process.
- Cost-Effective: Generally more affordable, making it ideal for budget-conscious projects.
- Proven Reliability: The 4EAT’s track record ensures dependable performance.
Considerations
- Limited Gearing: The 4-speed configuration may not offer the same performance as newer transmissions.
- Older Technology: Lacks some of the advanced features found in modern models.
5EAT 2WD Conversion Kit
Tailored to convert the AWD 5EAT transmission to a 2WD setup for mid-engine configurations.
Included Components
- Large back cover plate with mounting holes
- Output shaft and gear
- Mounting bracket with bolts
- Thrust bearing retaining ring plate
- Pair of Subaru OEM stub axle shafts
- Pair of 100 mm standard-length axle flanges
Advantages
- Improved Performance: The 5-speed gearing offers smoother shifts and improved torque distribution.
- Advanced Features: Some variants support adaptive shifting depending on ECU and model configuration.
- Higher Torque Handling: Suitable for builds using more powerful engines or seeking enhanced road performance.
Considerations
- Complex Installation: The electronic controls may require specific wiring or tuning adjustments.
- Higher Cost: The kit and associated components are typically more expensive than the 4EAT setup.
- Fuel Efficiency: While better RPM management may result in improved drivability, fuel economy gains in converted VW applications may vary depending on weight, gearing, and aerodynamics.
Comparative Analysis: 4EAT Vs. 5EAT Conversion Kits
| Feature | 4EAT Conversion Kit | 5EAT Conversion Kit |
| Gearing | 4-speed | 5-speed |
| Performance | Adequate for standard builds | Enhanced acceleration and drivability |
| Installation Complexity | Relatively straightforward | More complex due to advanced electronics |
| Cost | Generally more affordable | Higher cost due to advanced components |
| Torque Handling | Suitable for moderate power outputs | Designed for higher torque applications |
| Technology | Older, proven technology | Incorporates more modern features in some models |
Making The Right Choice For Your VW Mid-Engine Build
When deciding between the 4EAT and 5EAT conversion kits, consider the following:
- Budget Constraints: If you’re working within a limited budget, the 4EAT kit offers a cost-effective and reliable solution.
- Performance Goals: For high-performance builds or heavier vehicles, the 5EAT provides the gear ratio and torque control needed.
- Technical Expertise: The 4EAT kit’s simpler design is ideal for DIYers. The 5EAT kit, however, may require a professional setup due to its complexity and electronics.
- Donor Vehicle Considerations: Depending on your transmission’s origin (e.g., Outback, Legacy, or Tribeca), electronic compatibility may vary. Confirm ECU and sensor requirements before committing to a 5EAT build.
About Us
At Specialised Parts, we are a leading manufacturer and supplier of VW and Subaru conversion auto parts. Our expertise lies in providing high-quality, custom-manufactured components that meet the needs of enthusiasts and professionals alike.
For more information or to inquire about our products, please visit our website or contact us directly. We’re here to help you get the most out of your Subaru conversion.
