Home » M157 M278 CLS 550 CLS 63 E 550 E 63 Build Thread

M157 M278 CLS 550 CLS 63 E 550 E 63 Build Thread

If one (yo Gilles this is for you bro! ) were going to buy a completely stock M278 based E class or CLS and build it out, here is some guidance:


  • Open up the hood, take off the engine cover, lifts straight up with tabs but take it slow, look for a coolant tank in the middle of the V
    • This denotes there is split cooling and it will be easier to build from
  • Check out the tires
  • Read the codes
    • Look for any issues that say something like misfire cylinder 5
      • There is an issue with some of these and Mercedes put out a TSB and is aware of it
      • Consider contacting them if you have an issue, it should be a service campaign
  • Ask to see the car cold and unmoved
    • See if it is level
    • Check air springs
    • Rears are cheaper, valve block, leaking lines, compressor are easy to fix
  • Check the condition of the accessory belt
  • Drive the car warm it up, park on an incline nose up.  Wait 10 minutes start the car again.
    • Listen for a few seconds of noise -- if it is likely need the check valve/tensioner fix
  • Open the oil cap, look at the timing chain.  Ones that have thicker center links (than outside) are stronger

Initial Tuning Steps

  • Change the spark plugs
    • Change every 15-30k miles
  • Take out the air dams
  • Change the air intake with
    • UPD air intake riser + K&N Filter
      • I like K&N better in this car, there have been some reports of pulling media through the BMC
    • BlackBoost
    • Adds approximately 23 awhp
  • Change the oil 
    • Change every 2-3k miles
  • Add blow off valve that has the methanol injector ports in it
    • I like Weistec, VRP is cheaper, you may also be able to bring it to a aluminum guy and have him fabricate it
  • ECU Tune
    • Go on MBworld and wait for a sale
      • Or ask Eurocharged, OE
    • Bring the car to a dyno and have them custom remap it if you can
    • Some people actually buy a second ECU and have it copied and updated this way
    • The ECU if physically updated I believe is a bit stronger, more like a firmware update
  • Reset some of the tranny adaptations
    •  Hold down gas pedal 10s, put car into 2nd on position continue holding gas pedal to floor for 30s, turn off car continuing to hold gas pedal for a few seconds.  Chill in your car reading reddit for a few minutes
  • Resonator delete
  • If it is a track car, bring to the exhaust shop ask them to make and install the "down pipes" about $200 per side
    • OR higher flow cats for the street, each side is 2 cell, 200 cell would be much better.
  • Change Tranny oil
  • Consider upgrading the navigation and entertainment now with the best specified Android 10 screen, buy a usb external sound card, the caralink usb adapter for carplay/android (included is junk), and external microphone
  • Get better tires (the stock MB contis are pretty bad, go for ultra high performance
  • Consider adding 10mm or so H&R spacers to improve handling for this platform
  • Add oil catch cans
  • Update batteries
  • Wire the IC pump to always on

Next Steps

  • Gold heat wrap intake and charge tubes
  • Update the IC pump with part # Pierburg: 7.06754.05.0
    • For M278 split cooling, 157 will have a similar pump
  • Drop Engine (for 4matic)
    • Bridge pipe/turbo back pipe for additional 20-40hp
    • Upgrade turbos
      • Either 157 or aftermarket (like Weistec)
      • Or billet turbo upgrade
    • Upgrade motor mounts

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