BMW E90 LS Swap: Everything You Need to Know

Swapping a Chevy LS engine into a BMW E90 is a popular modification that can significantly increase horsepower and torque, while also adding reliability and affordability. This project is a popular choice among car enthusiasts, offering an excellent balance of performance and budget-friendliness. However, like any significant car modification, there are several considerations and steps involved that require proper planning and execution.

This comprehensive guide aims to provide you with all the necessary information about performing an LS swap on a BMW E90, covering essential aspects like choosing the right LS engine, selecting the appropriate transmission, adapting the engine to the BMW chassis, and tackling the electrical system integration.

Choosing the Right LS Engine for Your E90

The first step in any LS swap is selecting the right LS engine for your needs. This choice depends on your budget, desired performance level, and compatibility with the E90 platform. Popular choices include:

• LS1: This engine is known for its reliability and power output, making it a popular choice for LS swaps.
• LS2: Offering more power than the LS1, the LS2 is also a great option for performance-minded enthusiasts.
• LS3: The LS3 is the most powerful LS engine, delivering high performance and modern features.

Consider the following factors when choosing your LS engine:

• Horsepower and Torque: Determine your desired performance level and choose an engine that meets your needs.
• Compatibility: Ensure the chosen engine fits within the E90 engine bay and has the necessary mounting points.
• Transmission Compatibility: Select an engine compatible with the transmission you intend to use.
• Cost: Set a budget for your LS swap and choose an engine within your price range.

Transmission Options for Your LS Swap

The transmission is a crucial component in an LS swap, ensuring smooth power delivery and drivability. Here’s a breakdown of common transmission options:

• T56 Magnum: This six-speed manual transmission is a popular choice for LS swaps, offering excellent performance and durability.
• 4L60E/4L65E: These automatic transmissions are reliable and affordable, making them a good choice for street driving.
• 4L80E: This heavy-duty automatic transmission is designed for high torque applications and is a suitable option for performance-focused LS swaps.

Choosing the right transmission depends on your driving style and desired performance characteristics. Consider factors like gear ratios, torque capacity, and compatibility with your chosen LS engine.

Adapting the Engine to the BMW Chassis

Integrating the LS engine into the E90 chassis requires a specialized engine mounting kit that provides secure attachment points and ensures proper alignment. These kits typically include custom mounts, brackets, and hardware designed specifically for the E90 platform.

Here are essential considerations for adapting the engine to the chassis:

• Engine Mounts: The engine mounts need to be robust and securely attached to prevent vibrations and engine movement.
• Exhaust System: The exhaust system must be custom-made or modified to fit the LS engine and clear the BMW chassis.
• Cooling System: The cooling system should be adequately sized to handle the LS engine’s heat output.
• Electrical System: The LS engine’s electrical system needs to be integrated with the BMW’s existing wiring harness.

The Electrical System Integration: A Critical Aspect

The LS engine’s electrical system differs significantly from the BMW’s OEM system. This requires careful integration, ensuring proper communication between the engine control unit (ECU) and the car’s electronics.

Here are crucial aspects of electrical system integration:

• Wiring Harness: A custom wiring harness or adapter is required to connect the LS engine’s ECU to the BMW’s electrical system.
• Sensors: The LS engine’s sensors, such as the crankshaft position sensor and oxygen sensors, need to be properly wired to the BMW’s ECU.
• Gauges: Ensure the LS engine’s gauges, such as the oil pressure and temperature gauges, are integrated into the BMW’s instrument cluster.

“LS swaps are not just about engine power; proper integration is key to a well-functioning and safe build,” states Richard Lawson, a seasoned LS swap specialist.

Common Challenges and Troubleshooting

Like any major modification, an LS swap can present challenges. Some common issues and troubleshooting tips include:

• Electrical Problems: Ensure all wiring connections are secure and properly grounded. Troubleshoot any electrical issues with a multimeter and wiring diagrams.
• Engine Management: Properly configure the LS engine’s ECU to work with the BMW’s electronic systems.
• Transmission Compatibility: Ensure your chosen transmission is compatible with the LS engine and has the necessary adapter plates.
• Cooling System: Make sure the cooling system is adequate to handle the heat generated by the LS engine.

FAQ

Q: What are the benefits of an LS swap in a BMW E90?

A: An LS swap provides increased horsepower and torque, improved reliability, and a more affordable engine option compared to the original BMW engine.

Q: Is an LS swap legal in all states?

A: Laws regarding engine swaps vary by state. Consult local regulations to ensure compliance.

Q: What are the common costs associated with an LS swap?

A: Costs vary depending on the chosen LS engine, transmission, and the level of custom work required. Budget for engine and transmission components, wiring harnesses, engine mounts, exhaust system modifications, and professional installation labor.

Q: Is it possible to swap an LS engine into any BMW model?

A: While LS swaps are common in E90s, some models may pose significant challenges due to engine bay space limitations or electrical system complexity.

Q: Where can I find resources for LS swaps in BMWs?

A: Online forums, specialized LS swap websites, and social media groups dedicated to LS swaps are excellent resources.

Need more help? Contact us at [email protected] or visit our shop at 276 Reock St, City of Orange, NJ 07050. Our team is available 24/7 to answer your questions and assist with your LS swap project.