W204 c250 m273 swap
Thread Starter
Newbie
Joined: Oct 2023
Posts: 1
Likes: 0
w204 c250
W204 c250 m273 swap
Hello, I have a 2012 w204c250 4c turbo with almost 130k miles that I am really wanting to swap with a m273 engine, I have seen people do the c300 v6 but I noticed The ECU is not in the same location as the one I have and I was wondering if I would need to get a new ECU, Engine wiring harness, ect… if anyone has any answers or suggestions it would help a lot.
Newbie
Joined: Apr 2025
Posts: 4
Likes: 0
c350 coupe
Swapping a 2012 W204 C250 4-cylinder turbo engine with an M273 V8 is ambitious, but it’s definitely possible with the right planning and resources. Here are some key considerations based on similar swaps:
- ECU Compatibility: Yes, you will likely need a new ECU that is compatible with the M273 engine. The existing ECU for your 4-cylinder turbo won't be able to manage the V8's parameters. Additionally, the ECU may need to be reprogrammed or tuned to work with your car's systems.
- Engine Wiring Harness: A new engine wiring harness is essential. The wiring for the M273 will differ significantly from your current setup, so you'll need a harness specifically designed for the V8.
- Transmission: Ensure your current transmission can handle the increased power and torque of the M273. If not, you may need to upgrade to a compatible transmission.
- Mounting Points: Check if the engine mounts for the M273 align with your W204 chassis. Custom mounts may be required.
- Cooling System: The M273 will generate more heat than your current engine, so upgrading the cooling system (radiator, fans, etc.) is advisable.
- Exhaust System: A new exhaust system tailored to the V8 will be necessary.
- Drivetrain and Suspension: The added weight and power of the V8 may require upgrades to the drivetrain and suspension for optimal performance and safety.
- Professional Assistance: Consulting with a professional mechanic or a shop experienced in engine swaps is highly recommended. They can provide insights specific to your vehicle and the M273 engine.
