All modifications and tuning are undertaken at the vehicle owner's risk. Damage resulting from misuse or improper installation is not covered under warranty. Thorough troubleshooting is recommended before assuming turbo-related faults.
This guide pertains to turbo conversion of the Mercedes straight six engine. However, the principles outlined herein are also applicable to turbo conversions for various other vehicles lacking a turbocharger from factory. To make your life easier here is a comprehensive list for your convenience and time-saving benefit.
By adhering to these guidelines, turbo installations can be conducted effectively and reliably, ensuring optimal performance and longevity.
General requirements for tuning:
Replace your old and stock EFI/ECU/EMU/EMS or whatever you wanna call it. Installation of a new engine wiring harness is recommended but old wires are prone to electrical failures and are potential fire hazard. Stock computer does not understand boost pressure. Choosing a right platform for you may greatly hinder or boost your abilities to further improve your car and here is bare minimum of things that you need to have.
- Standalone engine management system - Upgraded fuel injectors - Ignition coils (Basic/wasted spark/Coil on plug) - Power supply station with relays - Coolant temperature (CLT) sensor - Intake air temperature (IAT) sensor (installed near the throttle body) - Throttle position sensor (TPS) - Wideband Lambda sensor. - Crankshaft position sensor (VR/Hall). - Camshaft position sensor (VR/Hall). - Trigger wheel 60-2. (Many ECU's have various trigger models supported).
For non-EFI systems such as carburetors or K-jet, upgrading to a modern fuel system including a fuel rail, fuel pressure regulator, new fuel lines, and a stronger fuel pump is necessary.
Basic Turbo Kit Components:
- Turbocharger - Exhaust manifold - Wastegate - Blow-off valve - Oil feed support for the turbo - Oil drain return from the turbo to the oil pan - "Open-air" air filter - Intercooler - Intake pipes between turbo and intercooler, and between intercooler and intake manifold - Silicone hoses and clamps for intake pipes - Downpipe and exhaust system.
Recommended Additions:
- Fuel pressure sensor for fuel pressure control. - Knock sensor for detecting detonation.
If you are not experienced in engine tuning do not attempt tuning without knock sensors. You will destroy your engine or something else along with it.
Differential and Transmission Considerations:
The capacity of the differential to handle power largely depends on the characteristics of the power curve. Factors such as turbo lag and the type of gearbox and clutch also influence its durability. Automatic transmissions, particularly those paired with larger differentials like the ASD 210mm, tend to withstand higher power outputs more effectively.
For transmissions, the 722.6 automatic transmission is preferred due to its reliability and strength, capable of handling up to 500-600 hp without modification. Blueberry has modified 722.6 transmission capable of holding over 1000Nm and still in perfect condition after 10,000 km of hard driving.
Engine Modifications:
The M103 or M104 engines, if in good condition, can accommodate up to 600 hp without major modifications. It is advisable to replace the head gasket, particularly for M104 engines boosting over 0.8 bar on regular gasoline and 2.0 bar on E85. Compression adjustment may be necessary for M104 engines exceeding these boost levels. Pistons can be machined or thicker gaskets installed for this purpose. For power outputs exceeding 500 hp, upgrading to H-Beam rods is highly recommended.
Budget Concerns:
The cost of turbocharging remains consistent regardless of desired horsepower output. A complete turbo kit and EFI system installation are essential for both 300 hp and 600 hp configurations.
General Recommendations:
Novices in turbo installation are advised against tackling larger projects independently. Proper adaptation of the vehicle's EFI system to accommodate increased pressure, fuel requirements, and ignition adjustments is crucial for successful turbo installations. Trial and error without proper monitoring equipment often leads to engine and turbo failures.
Important Maintenance and Troubleshooting Tips:
- Proper oil feed and drainage are critical for turbo longevity. Adequate crankcase ventilation is essential to prevent seal and bearing damage. - Rotating the compressor housing requires removing the O-ring to prevent damage. - After installation, the engine should be idled and checked for leaks before extensive driving. - Regular servicing of oil, oil filters, and air filters is necessary to maximize turbo service life. - Ensuring proper oil flow into the turbo is paramount.
