About
Mods
The M113K responds well to modification. A stock car with a tune alone sees meaningful power gains, and the platform has been built past 600 whp with supporting modifications.
Power
ECU Tune
Remaps ignition timing, fuel delivery, boost targets, and supercharger clutch engagement in the ECU. Because each engine is hand-built, stock output varies from car to car. Real-world gains on a stock car are roughly 30–45 whp, scaling further as hardware modifications are added.
Supercharger Pulley
A smaller pulley increases supercharger shaft speed relative to the crankshaft, raising boost pressure. The stock pulley is 90mm and clutched. An 83–84mm pulley is the common street choice. A 77mm is a more aggressive step that benefits from upgraded cooling. Pulleys smaller than 77mm are generally reserved for track use. Clutchless pulleys are also available but produce significant chatter that can sound like the supercharger is failing. Beyond the noise, the clutched pulley provides the correct amount of preload to the supercharger snout and internal barrels. Clutchless units do not replicate this, which adds wear over time.
Headers
Long tube headers replace the factory cast manifolds, reducing exhaust backpressure. Installing them requires removing the catalytic converters, which is illegal for street use in most jurisdictions. Headers are used on dedicated track builds.
Cooling
Intercooler Pump
The M113K uses a separate electric pump to circulate coolant through the supercharger's water-to-air intercooler circuit. The stock pump is a known failure point on aging cars. Aftermarket pumps with higher flow rates are a common replacement, both as a reliability measure and to improve charge cooling.
Heat Exchanger
The front-mounted heat exchanger dissipates heat from the intercooler coolant loop. The stock unit saturates quickly under hard driving. Upgraded units offer more surface area and faster recovery between runs.
Split Cooling
From the factory, the intercooler coolant loop shares a reservoir with the engine cooling system. Engine coolant runs at approximately 180–200°F, which pre-loads the intercooler circuit with hot fluid before any boost is made. A split cooling kit adds a dedicated reservoir for the intercooler loop, isolating it from the engine circuit entirely.
Ice Tank
An ice tank plumbed into the intercooler coolant loop allows the system to run near-freezing fluid through the heat exchanger. The result is a dramatic drop in intake air temperatures, particularly useful during back-to-back runs where the stock heat exchanger saturates. Commonly paired with an intercooler chiller or used on its own at the track.
Intercooler Chiller
A refrigerant-to-coolant heat exchanger plumbed into the car's air conditioning circuit. Intercooler coolant runs through one side of the core and A/C refrigerant through the other, pulling the coolant below ambient temperature before it reaches the supercharger. Unlike an ice tank it needs no pre-loading and holds temperature for as long as the compressor runs, at the cost of some cabin cooling. Used on builds where consistent intake temperatures matter more than a short peak reduction.
Fueling
Fuel Injectors
The stock injectors are adequate through roughly 500–520 rwhp. Beyond that, duty cycle approaches unsafe levels and larger injectors become necessary. Injector upgrades require a corresponding ECU retune.
Fuel Pump
The W211, C219, W220, and C215 chassis also have an external inline fuel pump in addition to the in-tank unit. A common OE-style upgrade is doubling the stock external pump or swapping to the unit from the 65 AMG, which flows significantly more volume. An upgraded pump becomes necessary when running a Whipple supercharger swap or converting to E85, both of which significantly increase fuel volume requirements.
Water/Methanol Injection
Introduces a water and methanol mixture into the intake charge. The evaporation lowers intake air temperatures, and the methanol raises effective octane, allowing for more aggressive ignition timing on pump fuel.
Suspension
Coilovers
The W220 S55, C215 CL55, and R230 SL55 were equipped with Active Body Control hydraulic suspension from the factory. The W211 E55 and C219 CLS55 use AIRMATIC air suspension instead. The G55 uses conventional suspension. Coilover conversions on ABC cars require deleting the ABC system entirely, which involves capping hydraulic lines, disabling ABC faults, and fitting anti-roll bars not present on ABC cars. AIRMATIC conversions are more straightforward. Spring rate selection is critical. Incorrect rates cause handling instability.
About
Mods
The M113K responds well to modification. A stock car with a tune alone sees meaningful power gains, and the platform has been built past 600 whp with supporting modifications.
Power
ECU Tune
Remaps ignition timing, fuel delivery, boost targets, and supercharger clutch engagement in the ECU. Because each engine is hand-built, stock output varies from car to car. Real-world gains on a stock car are roughly 30–45 whp, scaling further as hardware modifications are added.
Supercharger Pulley
A smaller pulley increases supercharger shaft speed relative to the crankshaft, raising boost pressure. The stock pulley is 90mm and clutched. An 83–84mm pulley is the common street choice. A 77mm is a more aggressive step that benefits from upgraded cooling. Pulleys smaller than 77mm are generally reserved for track use. Clutchless pulleys are also available but produce significant chatter that can sound like the supercharger is failing. Beyond the noise, the clutched pulley provides the correct amount of preload to the supercharger snout and internal barrels. Clutchless units do not replicate this, which adds wear over time.
Headers
Long tube headers replace the factory cast manifolds, reducing exhaust backpressure. Installing them requires removing the catalytic converters, which is illegal for street use in most jurisdictions. Headers are used on dedicated track builds.
Cooling
Intercooler Pump
The M113K uses a separate electric pump to circulate coolant through the supercharger's water-to-air intercooler circuit. The stock pump is a known failure point on aging cars. Aftermarket pumps with higher flow rates are a common replacement, both as a reliability measure and to improve charge cooling.
Heat Exchanger
The front-mounted heat exchanger dissipates heat from the intercooler coolant loop. The stock unit saturates quickly under hard driving. Upgraded units offer more surface area and faster recovery between runs.
Split Cooling
From the factory, the intercooler coolant loop shares a reservoir with the engine cooling system. Engine coolant runs at approximately 180–200°F, which pre-loads the intercooler circuit with hot fluid before any boost is made. A split cooling kit adds a dedicated reservoir for the intercooler loop, isolating it from the engine circuit entirely.
Ice Tank
An ice tank plumbed into the intercooler coolant loop allows the system to run near-freezing fluid through the heat exchanger. The result is a dramatic drop in intake air temperatures, particularly useful during back-to-back runs where the stock heat exchanger saturates. Commonly paired with an intercooler chiller or used on its own at the track.
Intercooler Chiller
A refrigerant-to-coolant heat exchanger plumbed into the car's air conditioning circuit. Intercooler coolant runs through one side of the core and A/C refrigerant through the other, pulling the coolant below ambient temperature before it reaches the supercharger. Unlike an ice tank it needs no pre-loading and holds temperature for as long as the compressor runs, at the cost of some cabin cooling. Used on builds where consistent intake temperatures matter more than a short peak reduction.
Fueling
Fuel Injectors
The stock injectors are adequate through roughly 500–520 rwhp. Beyond that, duty cycle approaches unsafe levels and larger injectors become necessary. Injector upgrades require a corresponding ECU retune.
Fuel Pump
The W211, C219, W220, and C215 chassis also have an external inline fuel pump in addition to the in-tank unit. A common OE-style upgrade is doubling the stock external pump or swapping to the unit from the 65 AMG, which flows significantly more volume. An upgraded pump becomes necessary when running a Whipple supercharger swap or converting to E85, both of which significantly increase fuel volume requirements.
Water/Methanol Injection
Introduces a water and methanol mixture into the intake charge. The evaporation lowers intake air temperatures, and the methanol raises effective octane, allowing for more aggressive ignition timing on pump fuel.
Suspension
Coilovers
The W220 S55, C215 CL55, and R230 SL55 were equipped with Active Body Control hydraulic suspension from the factory. The W211 E55 and C219 CLS55 use AIRMATIC air suspension instead. The G55 uses conventional suspension. Coilover conversions on ABC cars require deleting the ABC system entirely, which involves capping hydraulic lines, disabling ABC faults, and fitting anti-roll bars not present on ABC cars. AIRMATIC conversions are more straightforward. Spring rate selection is critical. Incorrect rates cause handling instability.