Microsquirt EFI - Has anyone tried this?

[Dustin Mustangs]

For some reason I've always day dreamed about putting efi on a 2 stroke ski. I've seen the MRD systems and it's no surprise they are junk due to many shortcuts they take on the theory (imo they are more of an mfi, mechanical fuel injection).

So I came across this microsquirt last night which specifically lists pwc's as one of it's applications. It's basically a compact and 'weather proof' version of the megasquirt which has had huge success in the diy automotive aftermarket.

It just seems to me that the typical way to go on full effort skis is TL and about a grand worth of carbs. I can only imagine that this microsquirt could be put together for much less then that. I could go on and on about all the advantages and possibilities this would open up over a typical setup, but what I am more curious about is why there is no market for this type of thing? Is there a reason why you don't see efi on 2 strokes very often if ever??

Maybe I'll just have to be the first...

 

[SuperJETT]

(MRD is all mechanical, there's not a single electrical component on it, purely crankshaft driven with some valving)

Looks interesting...

 

[D-Roc]

megasquirt is used by those waterpumping VW's that don't want to run the cis/ cis-e /motronic fuel injection systems. i have heard good things about them.

 

[WaveDemon]

there is a guy who put one on a seadoo on one of the megasquirt forums. do a search you should find it. If I remember correctly it has a sampling rate issue.

 

[Dustin Mustangs]

I find the whole idea of this pretty intriguing. Here is a site with a TON of Microsquirt Info if anyone else is as curious as I am.

 

[#ZERO]

It says this unit is compatible with personal watercraft but it must be for 4-stroke engines because (MAP) manifold absolute pressure sensors won't work with the 2-stroke engines. It might work better with a (MAF) mass air flow sensor but the minute the sensor sees any water it's going to give false readings and the sensor could be damaged. Also the aluminum box doesn't appear to be too waterproof and the electronic components are not potted. If the unit cost 400 bucks not including any of the sensors, injectors, fuel pump etc. it will cost lot more once complete and it will be a big gamble if it even works. I like the idea of using fuel injection but the power gains would be very minimal unless you're able to squirt fuel directly into the cylinders and that won't work well on 2-stroke engines unless you use an external oil pump to keep the bearings lubricated.

 

[Dustin Mustangs]

Why no map on a 2 stroke? The reflected pressure waves from the exhaust?? If that's the case you'd have to resort to alpha n tuning because the maf is a deff no. I also had assumed an o2 sensor would be out the door (due to it's operating temp) so that means open loop only. Both big compromises but it would still read more into operating conditions then a carb.

I thought most of the brap gains would be on the ignition side. I am under the (maybe ignorant) impression that even the best pwc ignitions only reference rpm. That is leaving A LOT at the table.

I think you could add on a few bells and whistles that would be nice too... Water injection? No problem, referenced to rpm, throttle position or both?? How about a brap button on your bars that switches you to a real aggressive ignition curve and fuel trim? Nitrous perhaps?

Not that the wheel is broken, but there is definitely room for some improvement here...

Tuning with Alpha-N

MegaSquirt can be converted from speed-density to use RPM , temperature and TPS only. This is called "Alpha-N". Alpha-N uses the only throttle position and RPM to calculate the amount of fuel to inject as opposed to using the manifold absolute pressure and RPM to calculate the amount of fuel to inject.

With boosted engines, you MUST use the speed density algorithm with MegaSquirt® EFI Controller, because the throttle position bears little relationship to the amount of air going into the engine. Alpha-N is for naturally aspirated engines ONLY.

Using the speed-density algorithm, MAP is the main variable and VE is a 'tweak'. On alpha-N the VE table is the main variable, as TPS is used as a lookup into this table. Actually it is a fuel map rather than a VE table.

Alpha-N is useful for long duration cams where the resolution of manifold air pressure (map) would be small. It is also useful to get smother idle on engines that have erratic map values.

 

[Goose]

I would go with a mechanical fuel injection and have 2 injectors one in the case to lube the crank and one somewhere in the boost port

 

[madscientist]

been thinking about these myself

 

[#ZERO]

Why no map on a 2 stroke? The reflected pressure waves from the exhaust?? If that's the case you'd have to resort to alpha n tuning because the maf is a deff no. I also had assumed an o2 sensor would be out the door (due to it's operating temp) so that means open loop only. Both big compromises but it would still read more into operating conditions then a carb.

I thought most of the brap gains would be on the ignition side. I am under the (maybe ignorant) impression that even the best pwc ignitions only reference rpm. That is leaving A LOT at the table.

I think you could add on a few bells and whistles that would be nice too... Water injection? No problem, referenced to rpm, throttle position or both?? How about a brap button on your bars that switches you to a real aggressive ignition curve and fuel trim? Nitrous perhaps?

Not that the wheel is broken, but there is definitely room for some improvement here...

The MAP sensors were originally designed for use with 4-stroke engines with long tuned length intake runners with a log style manifold and a consistent vacuum signal. The problem is 2-stroke engines have very short intake runners and have essentially no manifold vacuum and what vacuum there is goes away real fast. Then there's the severe reversion problem on non reed valve engines that will drive a map sensors crazy. Also the oxygen sensors probably wouldn't last very long with 2-stroke oil going through the exhaust system.

 

[Kawastyler]

Hallo,i have it in my Lotus super Seven with VW R32 engine and in my Cobra (Chevy TPI). I think about to put it in my ski.......but the big problem is the energy supply. The Kawa/Sj chagecoil give you 2-3Amps but the electrical fuelpump needs 4-8amps alone, the complette injection/ignitation with pump needs 8-15 amps........


Thanks,Andy

 

[WRX Dave]

Hallo,i have it in my Lotus super Seven with VW R32 engine and in my Cobra (Chevy TPI). I think about to put it in my ski.......but the big problem is the energy supply. The Kawa/Sj chagecoil give you 2-3Amps but the electrical fuelpump needs 4-8amps alone, the complette injection/ignitation with pump needs 8-15 amps........


Thanks,Andy

I want your cars...especially the Super Seven.

 

[Nefarious]

megasquirt is used by those waterpumping VW's that don't want to run the cis/ cis-e /motronic fuel injection systems. i have heard good things about them.

Yup, I ran it on a 16V ITB GTI. My buddy runs it on an 8v turbo VW Caddy putting out 400 WHP. Megasquirt is the isht!!

 

[timoNZ]

I have been keen to try this too, What are the chances of getting the GPR1300 injection to work???

 

[Superjet3]

I have built and used the mega squirt on my 500hp eclipse.