SL/R230: Engine swap M273 to M278 ?
Thread Starter
Senior Member
Joined: Aug 2019
Posts: 340
Likes: 189
From: Europe
09 SL500, 03 E320 CDI Wagon
Engine swap M273 to M278 ?
This is one for the experts.
Is it possible to fit a M278 with Bosch MED17.7.- ECU ( R231 SL550 435 HP ) into a 2009 SL550 R230 with a M273 and Bosch ME9.7 ECU ?
Both ECU have the T58 connector car side, but pinout may be different ?
Will CAN BUS work ?
Will all K-Line connections work ?
Can Bosch MED17.7.- ECU be programmed with "old" engine ID ?
R230 7G-Tronic ( 722.904 ) should do the job as long as the engine don't crank out more than 530 lb/ft..
Other considerations ?
Could do swap with M156, but fuel economy and low range torque, is way better with the M278.
Is it possible to fit a M278 with Bosch MED17.7.- ECU ( R231 SL550 435 HP ) into a 2009 SL550 R230 with a M273 and Bosch ME9.7 ECU ?
Both ECU have the T58 connector car side, but pinout may be different ?
Will CAN BUS work ?
Will all K-Line connections work ?
Can Bosch MED17.7.- ECU be programmed with "old" engine ID ?
R230 7G-Tronic ( 722.904 ) should do the job as long as the engine don't crank out more than 530 lb/ft..
Other considerations ?
Could do swap with M156, but fuel economy and low range torque, is way better with the M278.
Last edited by SLcharge; Aug 5, 2019 at 12:57 PM.
Super Member
Joined: May 2015
Posts: 606
Likes: 88
From: North Cali
2005 SL500, 2015 CLS400
Not an expert but will give it a try - i would say it's possible.The problem you will run into most likely will be not the engine + transmission connection but the engine and all other systems programming. They are different generations and use different software to work with. All the sensors from the engine will (not maybe, but will) have errors transmitting data to ECU / CAN and related systems... Even if it is possible to make it work - not sure it worth the time and effort needed to do the job, and lots, lots of troubleshooting... 
Curious why would you want do go through such a workload? Don't like the R231 body style? Considering you have roughly same amount of power and same transmission - wouldn't say the difference is that much noticeable.
Curious why would you want do go through such a workload? Don't like the R231 body style? Considering you have roughly same amount of power and same transmission - wouldn't say the difference is that much noticeable.
Thread Starter
Senior Member
Joined: Aug 2019
Posts: 340
Likes: 189
From: Europe
09 SL500, 03 E320 CDI Wagon
Ghostty, thanks for your reply.
As you guessed I don't like the R231. I don't like the cabin layout, and I don't like the front / nose of it either.
I don't consider the mechanical work a problem, that is why I ask mostly for advice on the electrical system.
I guess that all engine related sensors go through the ECU, and will therefore not be a problem. I fear the problem will be the communication between ECU and other modules in the car, not using same protocol, or what ever.
I need someone with software knowledge to help me out here, give me a go or no go.
And your question why go through all this trouble ?
The 388 hp is a bit lame, and I miss the low end torque from my previous SL55. A healthy 500 hp would be nice.
Further I like to wrench, and see it as a challenge.
As you guessed I don't like the R231. I don't like the cabin layout, and I don't like the front / nose of it either.
I don't consider the mechanical work a problem, that is why I ask mostly for advice on the electrical system.
I guess that all engine related sensors go through the ECU, and will therefore not be a problem. I fear the problem will be the communication between ECU and other modules in the car, not using same protocol, or what ever.
I need someone with software knowledge to help me out here, give me a go or no go.
And your question why go through all this trouble ?
The 388 hp is a bit lame, and I miss the low end torque from my previous SL55. A healthy 500 hp would be nice.
Further I like to wrench, and see it as a challenge.
Banned
Joined: Jan 2006
Posts: 1,982
Likes: 393
From: Atlanta, unfortunately
'09 S600, (2) R129 300SLs, '03 SL500, '03 SL55
A major obstacle is Drive Authorization. As an anti-theft measure every engine ECU is married to a particular VIN, so your replacement ECU would need to be hacked in some way.
And if you were to get the M278 installed, it may not recognize the CAN message to start the engine sent from the ignition switch.
Those are just two problems I see. There may be other pitfalls that nobody outside the engineering staff at Daimler can anticipate.
I'd say the likelihood of Beto O'Rourke being elected U.S. president is an order of magnitude greater than the likelihood of you succeeding if you embarked on this endeavor. It's an interesting topic for discussion but completely nonsensical as a practical matter.
And if you were to get the M278 installed, it may not recognize the CAN message to start the engine sent from the ignition switch.
Those are just two problems I see. There may be other pitfalls that nobody outside the engineering staff at Daimler can anticipate.
I'd say the likelihood of Beto O'Rourke being elected U.S. president is an order of magnitude greater than the likelihood of you succeeding if you embarked on this endeavor. It's an interesting topic for discussion but completely nonsensical as a practical matter.
Thread Starter
Senior Member
Joined: Aug 2019
Posts: 340
Likes: 189
From: Europe
09 SL500, 03 E320 CDI Wagon
Bobterry99, I am aware of the VIN # transfer, but I believe I have seen a company on the web offering to do it, if you can prove legitimate ownership.
A key hurdle could be the K-Line signals, to all the modules, like ABS,ESP,DST, etc. If they don't match I am Screwed.
Sometimes it's plug & play, other times it's a whole different animal. You never know with MB.
Beto O'Rourke, ? never heard of him.
A key hurdle could be the K-Line signals, to all the modules, like ABS,ESP,DST, etc. If they don't match I am Screwed.
Sometimes it's plug & play, other times it's a whole different animal. You never know with MB.
Beto O'Rourke, ? never heard of him.
Banned
Joined: Jan 2006
Posts: 1,982
Likes: 393
From: Atlanta, unfortunately
'09 S600, (2) R129 300SLs, '03 SL500, '03 SL55
I presume you have your reasons for not simply buying another SL55. Maybe you should swap the V-12 from an SL600 or swap your car for an SL600.
Trending Topics
This is one for the experts.
Is it possible to fit a M278 with Bosch MED17.7.- ECU ( R231 SL550 435 HP ) into a 2009 SL550 R230 with a M273 and Bosch ME9.7 ECU ?
Both ECU have the T58 connector car side, but pinout may be different ?
Will CAN BUS work ?
Will all K-Line connections work ?
Can Bosch MED17.7.- ECU be programmed with "old" engine ID ?
R230 7G-Tronic ( 722.904 ) should do the job as long as the engine don't crank out more than 530 lb/ft..
Other considerations ?
Could do swap with M156, but fuel economy and low range torque, is way better with the M278.
Is it possible to fit a M278 with Bosch MED17.7.- ECU ( R231 SL550 435 HP ) into a 2009 SL550 R230 with a M273 and Bosch ME9.7 ECU ?
Both ECU have the T58 connector car side, but pinout may be different ?
Will CAN BUS work ?
Will all K-Line connections work ?
Can Bosch MED17.7.- ECU be programmed with "old" engine ID ?
R230 7G-Tronic ( 722.904 ) should do the job as long as the engine don't crank out more than 530 lb/ft..
Other considerations ?
Could do swap with M156, but fuel economy and low range torque, is way better with the M278.
Is it possible to fit a M278 with Bosch MED17.7.- ECU ( R231 SL550 435 HP ) into a 2009 SL550 R230 with a M273 and Bosch ME9.7 ECU ?
NO
Both ECU have the T58 connector car side, but pinout may be different ?
YES
Will CAN BUS work ?
YES
Will all K-Line connections work ?
YES
Can Bosch MED17.7.- ECU be programmed with "old" engine ID ?
NO
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Thread Starter
Senior Member
Joined: Aug 2019
Posts: 340
Likes: 189
From: Europe
09 SL500, 03 E320 CDI Wagon
Forget it
Is it possible to fit a M278 with Bosch MED17.7.- ECU ( R231 SL550 435 HP ) into a 2009 SL550 R230 with a M273 and Bosch ME9.7 ECU ?
NO
Both ECU have the T58 connector car side, but pinout may be different ?
YES
Will CAN BUS work ?
YES
Will all K-Line connections work ?
YES
Can Bosch MED17.7.- ECU be programmed with "old" engine ID ?
NO
Is it possible to fit a M278 with Bosch MED17.7.- ECU ( R231 SL550 435 HP ) into a 2009 SL550 R230 with a M273 and Bosch ME9.7 ECU ?
NO
Both ECU have the T58 connector car side, but pinout may be different ?
YES
Will CAN BUS work ?
YES
Will all K-Line connections work ?
YES
Can Bosch MED17.7.- ECU be programmed with "old" engine ID ?
NO
Just that I understand why, would you please elaborate your answer :
Is it possible to fit a M278 with Bosch MED17.7.- ECU ( R231 SL550 435 HP ) into a 2009 SL550 R230 with a M273 and Bosch ME9.7 ECU ?
NO
If pinout is different, could a rewiring do it ?
Thanks.
Thanks pmercury for the answer.
Just that I understand why, would you please elaborate your answer :
Is it possible to fit a M278 with Bosch MED17.7.- ECU ( R231 SL550 435 HP ) into a 2009 SL550 R230 with a M273 and Bosch ME9.7 ECU ?
NO
If pinout is different, could a rewiring do it ?
Thanks.
Just that I understand why, would you please elaborate your answer :
Is it possible to fit a M278 with Bosch MED17.7.- ECU ( R231 SL550 435 HP ) into a 2009 SL550 R230 with a M273 and Bosch ME9.7 ECU ?
NO
If pinout is different, could a rewiring do it ?
Thanks.
You have many parameter in there, would be possible to rip the flash and make a custom but there you go into something crazy
It is much easy to swap from a same year group ex. 2003-2006 V8 to a V12
as the ecu would need just a few settings changes with xentry
from 2003-2006 group to 2006-2009 group change mostly always includes new ecu's, new ignition, new trans ecu ect
these devices are mostly not listed in other ecu's supposed to connect
but there is a 8.000$ solution
a standalone ecu
and lots of rewiring
If you would take the complete engine and ecu + trans and trans ecu
you would have the thing running probably i
What
