Anyone heard of someone retrofitting efi onto a 2-stroke? MAF or SD? I've thought about giving this a try. Give me some info or advice.

 

For one, the stock P4 code tables are only good tuning wise to 6400 rpm. I don't know of a 2 stroke that doesn't go higher except for diesels. Might be able to fudge the cal some.
Well, some people can.
Then you have the vibration problem.
Lots of things to overcome.

 

the motor I plan to use this on is a twin cyl rotax 720 in a seadoo that peaks at 6500-6600 anyway.. so that is very close. I think an O2 is out of the question so it will just have to have well tuned VE tables. I read somewhere that 2-strokes have very small manifold vacuum so a SD ecm probably wouldn't work well "I wanted to use the 727 because of its waterproof case" so a MAF ecm such as the 165 might be the way to go. Ignition shouldn't be too much of a problem, this motor has a CDI igntion so there is a stator that gives a pulse every 180 degree crank rotation, as far as the ecm is concerned I should be able to set it as a 4-cyl to get the proper RPM input. I was hoping to use a 1-bbl TBI but possibly could build a port injected intake. I think the spark and MAF tables should be mostly linear, since in this motors application there is always a constant load.

 

Nope, it's just water resistant.
It's a whole new world when you take to marine applications.

 

I'm sure it would survive inside the hull.... but back to basic engine operation, would SD even work on a 2-stroke?

 

I have a 90 HP mecury 6 cylinder that pulls 12 in/hg at idle. Apparently some two strokes pull pretty good vacuum. That might or might not be enough for SD. I am willing to bet that MAF would be a better setup.