View Full Version : Fuel injecting a 50cc engine?

08-20-2011, 07:56 PM
Kicking this idea around. My main issue will be an ECU for sure. I would have to use a MS or something I guess. Still searching the webs but if you know something, chime in.

08-20-2011, 09:40 PM
Well I actually found some nice kits. Read a lot of reviews and installs on differant forums and its not that bad.
Can't wait to get my new scooter in now!
I think its a really cool idea to have a EFI small engine. I was looking at some John Deere garden tractors today at work, and some of them actually have a 2 cylinder
EFI engine on them. Pretty neat.

08-21-2011, 02:59 AM
Just curious.....


08-21-2011, 03:03 AM
Why not?

08-21-2011, 03:26 AM
Why not?

adding complexity and expense for little to no gain.

the juice just won't be worth the squeeze

If this is purely an engineering exercise to see what can be done, sure why not... but if you are doing this because you expect any gains, it's just not worth it. putting that money into a better pipe, gearing on the scooter, or even a displacement/stroker kit they have for them would be time/money better invested.

08-21-2011, 05:24 AM
Yeah but how cool would it be... cmon. For $300 I cant think of a cooler thing to do. Most people say power output is increased some, but the biggest differance is it gets rid of "flat spots" thru the rpms. more useable power.

08-21-2011, 06:15 AM
Yeah but how cool would it be... cmon. For $300 I cant think of a cooler thing to do.

"hookers and blow" seems to be popular on this site

Most people say power output is increased some, but the biggest differance is it gets rid of "flat spots" thru the rpms. more useable power.

you might get 1-2 HP at most , but you would get far more of a power increase by doing things such as better air filter, better exhaust and changing your slipper clutch. polish the intake manifold runner, and light port job on the exhaust side and you will get more power. If you want to go further, the kits to bump compression and displacement will get you FAR more power for the same cost.

As I said... if this was an engineering exercise to have fun and see what you can do, then go for it. I've done far more stupid things, wasting far more money. but I've done them for the enjoyment of the project, not because I expected any real benefit. My fiance calls me the mad scientist.

08-22-2011, 04:28 PM
Megasquirt makes a product called 'microsquirt' that would work well. I have seen it used on snowmobile engines in the past.

08-22-2011, 07:11 PM
Is it a 2 stroke or a 4 stroke?

08-22-2011, 09:41 PM
Breast stroke

08-22-2011, 10:33 PM
Freakin 4 stroke. I cant swim.

08-22-2011, 11:39 PM
Theres maths youre gonna have to know unless someones already figured them out for you. I honestly dont see it being worth it knowing what I do about small engines. One thing, you have to add more than a basic electrical system (Or find a way to make a mechanical fuel pump). Then you gotta install a fuel pump. Then you have to properly size the injector as well. Theres more to it than that also. You gotta install an inductance pickup system (so the engine knows how many RPMs its making, and a way of measuring air (like a map sensor or a MAF sensor).

If it was bigger than 50cc and was on like... a quad, then sure, but fuel injecting a small engine like that I dont feel would be worth it. I guess you could just use some maths, build some basic static tables, and not worry about dynamically reading air and adapting it to a table lookup system, but I just dont see it working better than a carb.

08-23-2011, 01:37 AM
Click the link up top. they sell kits ready to roll. But still. Not much power to be gained with this alone. One guy did a really detailed thread and reported going from 70mpg to 109mpg tho.

08-23-2011, 02:36 AM
sometimes ya just do what you want for the experience of it all. To be honest thats about as cheap an introduction to the ins and outs of custom FI as you are likely to get. Should pay off in spades in terms of experience gained and fun had.

I say go for it.

08-23-2011, 03:48 AM
I think it would be hella fun to mess with. Really an easy way to test engine stuffs doing it on one cylinder vs 4. If you can make one cylinder run amazing, a really good blueprint, then you can apply that to 3 more. They make high lift cams, titanium valve springs, other heads to swap on, ect. Cam is $60. Valve springs.... $12 a kit. The GY6 platform is kinda awesome.