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:
Pre-purchase
- 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
- Look for any issues that say something like misfire cylinder 5
- 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
- UPD air intake riser + K&N Filter
- 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
- Go on MBworld and wait for a sale
- 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
