Megasquirt idea for the M120 V12! Will it work? - PeachParts Mercedes-Benz Forum

Turbo E320 · #1 12-11-2009, 03:54 PM

The M120 is quite literally two M104's put together and that got me thinking. An M120 will basically fit in the w210 engine bay mechanically according to Renntech, as the engine accessories like the ABS and the steering remain in the original position on the Renntech w210 V12's.

This allows my 19 year old self to go through with such a swap but engine management becomes a problem. While I was researching EDIS-6 modules and how to megasquirt a v12 I came across a marvelous piece of information I didn't think of. The M120 V12 fires every 60 degrees, twice as many times as the M104 which fires every 120 degrees. So if I had two VR crank triggers 180 degrees apart I could have a system that fires every 60 degrees IF megasquirt can support two VR triggers!

Then to illustrate my idea I spent an hour on MS paint:

What do you guys think?

Bluefang · #2 12-11-2009, 06:58 PM

Yes that sounds workable, or you could wait a month or so and get MS3 which will have ALOT more functionality and will be able to cope with a V12 with direct control wasted spark rather then having to wire in a EDIS system.

Another thing would be post on the www.MSEXTRA.com forum cause i am sure the M120 is not the first V12 to be megasquirted

Turbo E320 · #3 12-11-2009, 07:15 PM

I like EDIS systems though

simple as hell lol.

Here the V12 video I worked my ideas from:
http://www.youtube.com/watch?v=0ebxASWDBeI&feature=channel

I believe he must be running a similar setup.

whipplem104 · #4 12-11-2009, 10:32 PM

before you get to carried away. the v12 does not just fit in the engine bay. renntech had to make that custom intake manifold to get it to work. there is also a lot of modifications to the rear partitions. I am not saying it is not possible but it will require a great deal of hacking to get it in there. and after all that the engine only makes 389hp and is not very mod friendly. hell just getting the exhaust hooked up is not very fun on a car made by the factory.

Turbo E320 · #5 12-12-2009, 02:38 AM

The engine fit the bay pretty good with the throttle bodies taken off. The rear section was touching the fire wall but nothing a body hammer couldn't take care of. Also if you look at Renntech's modifications it was pretty medieval. they bolted block off plates to the original TB locations then welded new TB ports up closer to the front...

The m104 isn't mod friendly but we make it take way. With a megasquirt controlled M120 I don't see mods being a problem.

JayRash · #6 12-12-2009, 03:47 AM

As an art object, there is nothing sexier than the sight of an M120 in a small car like the W124 / 210 (not so small a car IMO).
But as a power house, well spend that same money on an M104 and it will make just abt the same power as a turbo charged stock M120. with almost 1/2 the weight on the front wheels.

Turbo E320 · #7 12-12-2009, 11:56 AM

The M120 makes 389hp and is not turbocharged it's N/A. The motor has 38K miles and was $1000 with all the accessories. With the transmission it's $1500 total so it was a pretty good deal.

Roncallo · #8 12-12-2009, 05:48 PM

Quote:

Originally Posted by Turbo E320

The M120 makes 389hp and is not turbocharged it's N/A. The motor has 38K miles and was $1000 with all the accessories. With the transmission it's $1500 total so it was a pretty good deal.

Thats a great deal. And 389 HP is nothing to sneeze at. Its also the smoothest and quietest 389HP available. And with the right pipes, sounds just so sweet.

Like others have pointed out, its not the best way to get power per dollar even if you got the engine for free. But it really is a very very very cool engine.

FLYNAVY · #9 12-12-2009, 11:16 PM

Are you doing this to you w210? If so, amazing!!!

(and post pics)

JayRash · #10 12-13-2009, 05:13 AM

i have the chance to buy a 1994 600SEC for abt 5k USD here in lebanon, and i am really thinking abt it
and the main reason i am, cause i have always wanted a V12 W124. but i am only dreaming.
i still might buy the car and keep it, its a clean well kept SEC.

nick.ged · #11 12-13-2009, 05:45 AM

just a thought, if it fires every 60 degrees, and there is twelve cylinders, it must fire 2 at a time, so two six pin coils with the same wireing as we (i) use on a six cylinder but the split the input wires (not the earth) that come from megasquirt in two (to make six, three for each coil) and use one common earth for both, would in theory work?

Roncallo · #12 12-13-2009, 07:38 AM

Quote:

Originally Posted by nick.ged

just a thought, if it fires every 60 degrees, and there is twelve cylinders, it must fire 2 at a time, so two six pin coils with the same wireing as we (i) use on a six cylinder but the split the input wires (not the earth) that come from megasquirt in two (to make six, three for each coil) and use one common earth for both, would in theory work?

I don't think so. It fires every 60° over 720° of crank rotation. No two cylinders fire at the same time. I was looking into this a few years ago using 2 ECU just like MB does is for the later ME system. Looked to me like I could run 2 MS units and use all the existing COP coils and sensors. I would replace the ETA's with mechanical Ford 70mm throttle bodies. I would also plume in an idle control valve from an earlier 117 or 119 engine into intake manifold, plumed to both banks but controlled by one. It would also allow me to pickup all 4 knock sensors and all 4 O2 sensors.

The easy way around this is with an expensive MoTec system, which will even drive the expensive ETA's if that's your thing.

The only reason I did not go this rout was that I needed the Bosch ME computers to talk to the transmission ECU. This is not an issue if you go with the 722.3 4 speed transmission. Another option is to use an aftermarket stand alone transmission controller for the 722.6 which Whipplem104 has pretty much under control these days.

This is where I would really like to get with the M120 installations. Once you can get rid of the ME computers ETA's and transmission controller and the need for owning the Star Diagnosic System, owning an M120 powered vehicle becomes very practical.

nick.ged · #13 12-13-2009, 04:24 PM

are you saying that all the pistons on the v12 are spaced so as none of them are on the same ammount of degrees of rotation throught the 720 degrees needed for them all to fire? ie with the head off if you rotate the crankshaft, each piston comes to tdc seperatly? (if so, the engines must be really smooth when running)

in the 103/104 cylinders one and six, two and five and three and four rotate on the same degrres of rotation but fire 180 degrees spaced. this is why wasted spark works, it fires the one that is on compression stroke and also the one that is on exauste stroke. every 360 degrees the engine has three ignition events to produce power, but all six plugs will fire, and it takes 720 degrees for all six to fire on there power stroke.

Roncallo · #14 12-13-2009, 07:59 PM

It's the same way but I believe you will get 6 spark events. One MS system will run a 12 cyl in wasted spark. But not with COP. The M120 already has a 60-2 wheel with two separate pickups placed 60° apart. It can drive two MS units. The M120 is really smooth even when running on 6 cylinders.

Turbo E320 · #15 12-13-2009, 09:32 PM

Quote:

Originally Posted by nick.ged

are you saying that all the pistons on the v12 are spaced so as none of them are on the same ammount of degrees of rotation throught the 720 degrees needed for them all to fire? ie with the head off if you rotate the crankshaft, each piston comes to tdc seperatly? (if so, the engines must be really smooth when running)

in the 103/104 cylinders one and six, two and five and three and four rotate on the same degrres of rotation but fire 180 degrees spaced. this is why wasted spark works, it fires the one that is on compression stroke and also the one that is on exauste stroke. every 360 degrees the engine has three ignition events to produce power, but all six plugs will fire, and it takes 720 degrees for all six to fire on there power stroke.

The M120 fires all twelve cylinders in a 720 degree rotation yes but it does have piston pairs. 1-6, 2-5, 3-4, 7-12, 8-11, and 9-10. It is basically two M104's put together. The M120 had COP's and two ECU's so I guess it only fired six times every 360 degrees but it was because it was COP and not wasted spark.

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