Fuel Injection "expert" required

[grindella]

I am after someone who knows how to set up fuel injection. Timing, delivery ammount and fuel air ratios.

[Booster]

Big topic mate, and each ecu type has its own language, let us know some particulars of what you have or what your thinking of getting and the application

[grindella]

I know the dificulty, I want to inject a two stroke. Need someone that undestands the computer side really well. May even need to build one thats suitable. I need to inject the fuel when the piston is before 2mm btdc. The rest is an experiement until i get it right.

[EXBEN]

High end ECU's ( Autronic & Motec) can inject fuel whenever you like.Im not sure about the cheaper ones though.

In my opinion, you're leaving it fairly late in the stroke to be injecting fuel. Not much opportunity for the squish band to do its thing and ignition should be happening about then. Depending on stroke length, of course.

[Booster]

Could probably do it with a cheaper one just have to take a lot of time setting up your ref signals

you looking at direct injection into the cyl ? supercharged or crankcase compression ?

[pommie02]

have a look a microsquirt, the forum is pretty good

[grindella]

fuel direct injection into the cylinder via the head, air though crankcase and tranfer ports into cylinder. I agree 2mm might be a bit late, perhaps just after transfer port is shut off.

[Booster]

Injection timing is going to effect required fuel pressures a lot as will duty cycle , whats cranking pressures and what do they rise to when the engine is in the power band and operating at peak efficancy ?? also is mixture distribution going to be adequate
Although total distribution is not necessarily needed, i think gmh are treating there direct injection like a jet engine combustion chamber where the ign and burning takes place inside a pocket of air and you don't get the very lean mixtures burning near the temp critical parts like pistons

also how are you lubricating the bottom end ? just leaving the oil injection in place ? is it likely to be influenced by the lack of fuel

[Stocky]

2 stroke injection...... big can of worms......Bottom end lube is the trick really.

If you had a rotary valve it'd be easy but......


If you want to do direct injection then it'll be a huge project.

If you want to replace a carb with FI then it'll be pretty easy.

Also depends how hard to intend to rev the engine. Up to 10,000 rpm it's still a pretty normal setup but after that it's much more like a jet engine in the way it's moving and burning air.
Oil delivery also becomes much more critical.

Personally I'd be having a look at the carby technolgy on really high end kart motors before I went injection.

How many cylinders ?

How many cc's ?

[grindella]

1 cylinder, 400cc, I am aware of bottom end lube problems and I think I have that covered with a few crank mods. I am leaning towards just replacing card with injection system but I would like to direct inject it through head.

I have been looking at yamaha (proto type)fuel injected two stroke technology and would like to mimic it.

like this

http://www.asfphotos.com/upload/1262572123.jpg