M20 - e2i Conversion: Difference between revisions
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Created page with "The '''M20 "e2i" conversion''' is a popular modification for BMW enthusiasts seeking to enhance the performance of the M20B27 engine found in "eta" models by integrating components from the higher-revving M20B25 "i" engine. This conversion combines the torque-rich characteristics of the eta engine with the improved airflow and higher RPM capabilities of the "i" engine. ---- === Key Features === * '''Increased Displacement''': Retains the 2693cc displacement of the M20B..." |
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[[File:M20B27 e2i Swap.jpg|thumb]] | |||
The '''M20 "e2i" conversion''' is a popular modification for BMW enthusiasts seeking to enhance the performance of the M20B27 engine found in "eta" models by integrating components from the higher-revving M20B25 "i" engine. This conversion combines the torque-rich characteristics of the eta engine with the improved airflow and higher RPM capabilities of the "i" engine. | The '''M20 "e2i" conversion''' is a popular modification for BMW enthusiasts seeking to enhance the performance of the M20B27 engine found in "eta" models by integrating components from the higher-revving M20B25 "i" engine. This conversion combines the torque-rich characteristics of the eta engine with the improved airflow and higher RPM capabilities of the "i" engine. | ||
== | == e2i Forum Threads == | ||
* [https://www.mye28.com/viewtopic.php?t=131610 Maytag's M20B27 'e2i' Engine Build Thread (87 528e)] | |||
== Key Features == | |||
* '''Increased Displacement''': Retains the 2693cc displacement of the M20B27. | * '''Increased Displacement''': Retains the 2693cc displacement of the M20B27. | ||
* '''Higher Compression''': The conversion often results in a compression ratio of approximately 9.4:1 when using the stock eta block and pistons with an "i" cylinder head. | * '''Higher Compression''': The conversion often results in a compression ratio of approximately 9.4:1 when using the stock eta block and pistons with an "i" cylinder head. | ||
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* '''Notable Identifiers''': Combines the "eta" bottom end (long-stroke crank) with the "i" head, which features larger intake valves and improved flow. | * '''Notable Identifiers''': Combines the "eta" bottom end (long-stroke crank) with the "i" head, which features larger intake valves and improved flow. | ||
== Required Components == | |||
# '''M20B25 '885' Cylinder Head''': Includes the camshaft and intake valves from the "i" engine for better high-RPM performance. | |||
# '''M20B25 Cylinder Head''': Includes the camshaft and intake valves from the "i" engine for better high-RPM performance. | |||
# '''"i" Intake Manifold and Throttle Body''': Provides increased airflow compared to the eta components. | # '''"i" Intake Manifold and Throttle Body''': Provides increased airflow compared to the eta components. | ||
# '''"i" ECU (Motronic 1.3)''': Enables proper engine management and fueling for the higher-revving setup. | # '''"i" ECU (Motronic 1.3)''': Enables proper engine management and fueling for the higher-revving setup. | ||
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#* Appropriate gaskets and seals for assembly. | #* Appropriate gaskets and seals for assembly. | ||
== Performance Gains == | |||
* '''Low-End Torque''': Retained from the eta engine's long-stroke design. | * '''Low-End Torque''': Retained from the eta engine's long-stroke design. | ||
* '''Improved Top-End Power''': Provided by the "i" cylinder head and intake system, allowing the engine to rev freely to higher RPMs. | * '''Improved Top-End Power''': Provided by the "i" cylinder head and intake system, allowing the engine to rev freely to higher RPMs. | ||
* '''Versatility''': The e2i conversion offers a balance of low-end drivability and higher-end performance, making it suitable for street and light track use. | * '''Versatility''': The e2i conversion offers a balance of low-end drivability and higher-end performance, making it suitable for street and light track use. | ||
== Considerations == | |||
* '''Tuning''': Optimizing the ECU and ignition timing is essential to fully realize the performance gains. | * '''Tuning''': Optimizing the ECU and ignition timing is essential to fully realize the performance gains. | ||
* '''Compatibility''': Ensure the "i" head is compatible with the eta block, especially in terms of cooling channels. | * '''Compatibility''': Ensure the "i" head is compatible with the eta block, especially in terms of cooling channels. | ||
Revision as of 16:35, 1 January 2025
The M20 "e2i" conversion is a popular modification for BMW enthusiasts seeking to enhance the performance of the M20B27 engine found in "eta" models by integrating components from the higher-revving M20B25 "i" engine. This conversion combines the torque-rich characteristics of the eta engine with the improved airflow and higher RPM capabilities of the "i" engine.
e2i Forum Threads
Key Features
- Increased Displacement: Retains the 2693cc displacement of the M20B27.
- Higher Compression: The conversion often results in a compression ratio of approximately 9.4:1 when using the stock eta block and pistons with an "i" cylinder head.
- Power Output: Depending on tuning and supporting modifications, the e2i conversion can achieve power outputs of 170–190 hp and similar torque figures.
- Notable Identifiers: Combines the "eta" bottom end (long-stroke crank) with the "i" head, which features larger intake valves and improved flow.
Required Components
- M20B25 '885' Cylinder Head: Includes the camshaft and intake valves from the "i" engine for better high-RPM performance.
- "i" Intake Manifold and Throttle Body: Provides increased airflow compared to the eta components.
- "i" ECU (Motronic 1.3): Enables proper engine management and fueling for the higher-revving setup.
- "i" Wiring Harness: Simplifies the installation and integration of the "i" electronics.
- Additional Items:
- New timing belt and water pump.
- "i" injectors for proper fueling.
- Appropriate gaskets and seals for assembly.
Performance Gains
- Low-End Torque: Retained from the eta engine's long-stroke design.
- Improved Top-End Power: Provided by the "i" cylinder head and intake system, allowing the engine to rev freely to higher RPMs.
- Versatility: The e2i conversion offers a balance of low-end drivability and higher-end performance, making it suitable for street and light track use.
Considerations
- Tuning: Optimizing the ECU and ignition timing is essential to fully realize the performance gains.
- Compatibility: Ensure the "i" head is compatible with the eta block, especially in terms of cooling channels.
- Additional Mods: Complementary upgrades such as a freer-flowing exhaust, a lightweight flywheel, or a performance camshaft can further enhance results.
