powertrain
Step-by-step Installation of the Jsm Supercharger Kit on a C63 M156
Table of Contents
The JSM Supercharger Kit is one of the most comprehensive forced‑induction upgrades available for the Mercedes‑Benz C63 AMG with the naturally aspirated M156 engine. When installed correctly, this kit delivers substantial power gains—often exceeding 600 horsepower—while maintaining excellent drivability and reliability. This guide provides a detailed, step‑by‑step installation process, covering everything from pre‑installation planning to post‑installation tuning. Whether you are a seasoned DIY mechanic or a professional shop looking for a thorough reference, these instructions will help you complete the job safely and correctly.
1. Kit Overview and Pre‑Installation Planning
Before you start turning wrenches, it is critical to understand what is included in the JSM Supercharger Kit and what additional components you may need. The kit typically contains:
- Supercharger unit (lyscrew or centrifugal, depending on JSM’s current design)
- Cast aluminum mounting bracket
- Drive belt (custom length) and tensioner
- Intake piping with silicone couplers and clamps
- Intercooler core and associated plumbing (air‑to‑water or air‑to‑air)
- Heat exchanger, coolant pump, and reservoir (for air‑to‑water systems)
- Injector adapters and larger fuel injectors (recommended)
- ECU tuning file or piggyback controller
- Detailed installation manual and belt routing diagram
Important: The M156 engine is sensitive to fuel quality and cooling. Ensure you have access to an experienced tuner who can calibrate the ECU after the hardware is installed. Without proper calibration, the supercharger can cause engine damage. Check the official JSM website for the most current kit version and any updates to the instructions.
2. Tools, Materials, and Workspace Preparation
Gather all the necessary tools before beginning. Using proper equipment prevents stripped fasteners and ensures components are torqued correctly. Below is a comprehensive list:
| Category | Items |
|---|---|
| General Hand Tools | Socket set (metric, 6‑point), combination wrench set (8–19 mm), Torx sockets (T25, T30, T45), allen keys, screwdrivers (flat and Phillips), pliers, wire cutters/crimpers |
| Specialty Tools | Torque wrench (5–80 Nm), belt tension gauge (optional), coolant pressure tester, multimeter, piston stop tool (for TDC verification), supercharger pulley puller (if needed) |
| Supplies | High‑temperature coolant (Glysantin G48 or equivalent), engine oil (5W‑40 full synthetic, per MB 229.5), anti‑seize compound, threadlocker (blue Loctite), new gaskets (intake, throttle body), new drive belt (check kit), shop towels, safety glasses, gloves, fender covers |
| Workspace | Clean, well‑lit area with a vehicle lift or jacks and jack stands. Have a fire extinguisher nearby. If working indoors, ensure adequate ventilation for exhaust and coolant fumes. |
Also, purchase a M156 intake manifold gasket set – you will need new gaskets for reassembly. If your C63 has high mileage, consider replacing the thermostat and water pump while the cooling system is open.
3. Engine Preparation – Disassembly for Supercharger Installation
Proper engine preparation saves time and prevents contamination. Work methodically and label all connectors, hoses, and fasteners.
3.1 Disconnect Battery and Drain Coolant
Disconnect the negative battery terminal (and positive if you want to be extra safe). Wait 10 minutes for the SRS system to discharge. Drain the coolant by removing the drain plug on the passenger side of the radiator and at the block (located near the starter motor). Capture the old coolant for proper disposal.
3.2 Remove Engine Cover and Air Intake System
Unclip the plastic engine cover. Remove the air filter boxes, intake ducts, and MAF sensors. Label the MAF connectors to avoid mixing them up during reassembly. Remove the throttle body (four Torx T30 bolts) and set it aside on a clean surface.
3.3 Remove the Intake Manifold
The M156 intake manifold is plastic and bolted with eight M8 bolts. Use a T45 socket for the outer bolts and a T30 for the inner smaller bolts. Carefully lift the manifold straight upward to avoid breaking the runner flaps. Discard the old gaskets. Inspect the intake ports for carbon deposits – if excessive, consider walnut blasting before proceeding.
3.4 Remove Belts, Pulleys, and Front Accessory Drive
Remove the serpentine belt and the auxiliary belt. Use a belt tensioner tool to relieve tension. Remove the alternator, power steering pump, and A/C compressor (only if they interfere with the supercharger bracket – consult the kit instructions). You do not need to disconnect the refrigerant lines; just unbolt and hang the compressor out of the way using a zip tie.
3.5 Remove the Crank Pulley (Damper) – Optional
Some JSM kits require a larger crank pulley or a dedicated drive pulley. To remove the factory damper, you need a special puller. Use a crank holding tool and an impact wrench. Check the kit instructions to see if this step is necessary. If not, skip to the bracket installation.
4. Installing the Supercharger Bracket and Mounting the Supercharger
This is the most critical part of the install – the bracket must be seated flush and all bolts torqued to spec. Any misalignment will cause belt wear and vibration.
4.1 Mounting the Bracket
Clean the engine block mounting surfaces with brake cleaner. Apply a thin layer of anti‑seize to the bracket bolts (typically M10 x 1.5) to prevent galling in the aluminum block. Position the bracket over the front of the engine and hand‑tighten the bolts. Use a torque wrench to tighten them in sequence to 45 Nm (33 lb‑ft) for M10 bolts, and 25 Nm (18 lb‑ft) for any M8 bolts. Consult the kit manual for exact values.
4.2 Prep the Supercharger
If the supercharger comes with an internal oil supply, fill it with the specified synthetic supercharger oil (often supplied by JSM). For centrifugal units, check the gearbox oil level. Install the supercharger pulley onto the input shaft – use a press or careful heat application; never hammer the pulley onto the bearing.
4.3 Mount the Supercharger
With the bracket secure, lift the supercharger into place. It is heavy (about 20–25 lbs), so use a second person or a jack. Slide the supercharger onto the bracket studs or bolts. Tighten the mounting bolts in a cross pattern to the torque specified in the kit – usually 40 Nm for the main M12 bolts. Verify that the supercharger can rotate freely by hand.
5. Intake and Exhaust Piping – Connecting the Boost Circuit
Now connect the air inlet and outlet of the supercharger to the engine. For air‑to‑air or air‑to‑water intercooled systems, the piping may route through the front of the car.
5.1 Intake Air Filter and MAF Housing
Attach a filter to the supercharger inlet. The JSM kit usually includes a high‑flow conical filter and an aluminum duct. Ensure the MAF sensor (if retained) is installed in the correct orientation – the arrow points in the direction of airflow. Use silicone couplers and T‑bolt clamps, tightened to 5 Nm (do not overtighten or you will cut the silicone).
5.2 Boost Tube / Intercooler Plumbling
Route the charge pipe from the supercharger outlet to the intercooler, then from the intercooler to the throttle body. Trim silicone hoses as needed. Use lubricant (dish soap or silicone spray) to help slide hoses over the aluminum pipes. Secure all connections with clamps. If the system uses an air‑to‑water intercooler, mount the heat exchanger in the front grille area and run the coolant hoses to the intercooler core.
5.3 Throttle Body Adapter
The factory throttle body needs an adapter plate to fit the new intake pipe. Clean the throttle body mating surface and install a new gasket. Tighten the four bolts evenly to 10 Nm.
6. Drive Belt Installation and Tensioning
The belt drives the supercharger from the crank pulley. Incorrect belt routing will cause immediate failure or slipping.
6.1 Choose the Correct Belt
Use the belt supplied in the kit – it is cut to the exact length for the C63 M156 with the JSM bracket. Do not substitute. Inspect the belt for any tears.
6.2 Route the Belt
Follow the diagram from the kit. Typically, the belt wraps around: crank pulley → supercharger pulley → belt tensioner → idler pulley(s). Make sure the belt sits squarely in each pulley groove. Use a belt tool to pull the tensioner back while sliding the belt over the last pulley.
6.3 Set Belt Tension
If the tensioner is automatic (spring‑loaded), just verify that the tensioner arm is within its travel range. If adjustable, use a belt tension gauge and set to 45–50 Hz (about 120 lbs tension for a 6‑rib belt). Rotate the engine by hand two full revolutions and recheck alignment and tension.
7. Cooling System Integration
The M156 already runs hot from the factory. Adding a supercharger increases heat load significantly. The JSM kit includes either an air‑to‑air intercooler or a supplementary water‑to‑air system.
7.1 Air‑to‑Water Intercooler Setup
Mount the intercooler core in the lower intake tract. Connect the coolant pump (often a Bosch or Davies Craig unit) to the heat exchanger. Wire the pump to a switched 12V source (e.g., the engine fuse box). Use a relay and inline fuse. Fill the system with a 50/50 mix of distilled water and antifreeze – use no coolant corrosion inhibitors that are incompatible with aluminum.
7.2 Bleeding Air from the Coolant System
After plumbing, elevate the reservoir (if possible) and run the pump while slowly adding coolant. Tap the intercooler lines to dislodge air pockets. For the engine cooling system, recharge with the correct MB coolant and manually bleed the air using the radiator bleed screw and the heater valve.
8. Reassembly and Final Electrical Connections
Now you can put the engine back together.
8.1 Reinstall Intake Manifold (If Kept) or New Manifold
Some JSM kits delete the factory intake manifold and use a fabricated plenum. If retaining the factory manifold, install a fresh gasket set. Torque the intake manifold bolts in sequence: inner bolts 15 Nm, outer bolts 25 Nm. Reconnect the vacuum lines and the intake runner flap motor.
8.2 Connect Injectors and Fuel Rails
Install the larger injectors (if supplied). Lubricate the O‑rings with clean engine oil. Seat them fully into the fuel rail and intake ports. Torque the rail bolts to 20 Nm. For safety, pressurize the fuel system with the key on (engine off) and check for leaks.
8.3 Reattach Throttle Body and Air Intake Tubes
Reinstall the throttle body with a new gasket. Connect the charge pipe to the throttle body. Tighten all boost hose clamps to 5 Nm. Reconnect the MAF connectors and all engine harness plugs that were disconnected.
8.4 Check All Wiring and Hoses
Ensure no hoses are kinked and no wires are rubbing against pulleys or belts. Use wire ties to secure loose cables. Reinstall the engine cover (if it still fits).
9. First Start, Tuning, and Break‑In Procedure
Before starting, double‑check that every fastener is tight and all fluids are at the correct levels.
9.1 Initial Start
Reconnect the battery. Turn the ignition to position 2 (without cranking) for 10 seconds to prime the fuel system. Then start the engine. It should fire immediately. Let it idle for 10–15 minutes, monitoring temperatures and listening for any unusual noises. Watch the boost gauge – it should read vacuum at idle. If the engine runs rough, check for vacuum leaks.
9.2 Load Tuning and Wideband Tuning
Do not drive the car aggressively until the ECU is tuned. Load the custom JSM calibration file using a flash tool (Cobb Accessport, ECUTEK, or similar). If you do not have a pre‑loaded tune, contact a reputable M156 tuner. A wideband O2 sensor is recommended to confirm air‑fuel ratios; target 11.5‑12.0 AFR under boost.
9.3 Break‑In Period
For the first 500 miles, avoid sustained boost over 5 psi. Vary the engine speed and do not exceed 4000 rpm. This allows the supercharger bearings and belt to seat. Change the engine oil and filter after this break‑in period.
10. Maintenance and Long‑Term Care
Supercharged M156 engines require more frequent maintenance than stock.
- Oil Changes: Every 5000 miles with high‑quality synthetic oil. Consider oil analysis if running high boost.
- Belt Inspection: Check belt condition every oil change. Replace every 20,000 miles or if any fraying appears.
- Supercharger Fluid: For centrifugal units, change the gearbox oil every 30,000 miles (use supplied oil).
- Intercooler System: Check coolant level and pump function monthly. Flush and replace coolant every two years.
- Boost Leak Test: Annually, pressurize the intake system to 15 psi and check for leaks at all connections.
For more detailed guidance, refer to the MBWorld C63 forum where experienced owners share their supercharger build threads and troubleshooting tips.
Conclusion
Installing the JSM Supercharger Kit on your C63 M156 is a rewarding project that transforms the character of the car. By following this expanded step‑by‑step guide and paying attention to every torque spec and sealing detail, you will achieve a clean, reliable installation that delivers outstanding horsepower and torque. Always remember that proper tuning is the key to longevity – do not skip the dyno session or the break‑in period. With care and maintenance, your supercharged M156 will provide many miles of exhilarating performance.