Smallest injectors available?

bigandy · Post by **bigandy** » Sun Jan 08, 2006 6:35 am

Good afternoon all.

I am just tossing a few ideas around at the moment for a large scale RC model glider tug (about 2.4m wingspan) that is going to be powered by a 45cc petrol engine. I am interested in converting the engine from a carburettor and magneto ignition, to something a bit more advanced.

Anyway, to cut a long story short, The only real bits that I am struggling with is the slection of an injector. Or to be more precise, I don't have a clue what smaller sized fuel injectors are out there! Does anyone have any knowledge of fuel injectors suitable for use with a smaller engine?

Any input would be appreciated, as would links to other resources etc etc. I've already emailed a few suppliers with no responses as yet, and I'm also settling down for a bit of research on the net now!

Cheers
Andy

the bubbler · Post by **the bubbler** » Tue Jan 10, 2006 8:02 am

Honda have produced a small EFI powered 50cc 4-stroke scooter. I'm not sure if it's in production yet.

Over the coming year or two, I think you'll start to see a big increase in the availability of small injectors and associated pumps etc.

This is owing to ever tightening motorcycle emission regulations leading to manufacturers developing small EFI systems for mopeds and scooters, in addition to their range for larger bikes.

Andy

efahl · Post by **efahl** » Tue Jan 10, 2006 12:00 pm

Andy,

How much power does your airplane motor make? How fast does it spin? I'm guessing the high speed of the motor is going to require that your injectors be a lot larger than they would be for a motor of similar power running much slower. Andy Whittle has a spreadsheet that should help you out, I think it's on the Hi-Tech forum.

Your other big challenge is going to be finding a light fuel pump that can supply sufficient fuel pressure, and then suppling it with power... Bike parts are probably sized appropriately, but they are dense lumps, not really optimized for weight in the way aero pieces are...

Eric

frez · Post by **frez** » Thu Jan 19, 2006 2:36 pm

If you find a small injector that would fit, I would gladly want to be informed of it.

I tried to contact a couple of place but really I'm lost.

frez · Post by **frez** » Thu Jan 19, 2006 3:10 pm

On the Stan Weiss' Website, there's an injector for a peugeot 4 - 2.5L BOSCH 0-280-150-255

any idea on this injector. It's rated 2.35 which is pretty low.

BentRods · Post by **BentRods** » Thu Jan 19, 2006 6:28 pm

How much HP ?
max RPM's ?
Gas, Alcohol, or what ?

frez · Post by **frez** » Fri Jan 20, 2006 11:32 am

Let's see (sorry I should have said it earlier),
How much HP ? Around 1-2 HP, 1 cylinder, 4 strokes. First objective is to make it fit to a 50cc motor...
max RPM's ? Around 6000.
Gas, Alcohol, or what ? Gas.

H2Advocate · Post by **H2Advocate** » Wed Jan 25, 2006 5:51 pm

KISS. Stay w/ the carb and mag. But if you insist, take a look at
MegaBaro.

Came across an email msg, a guy was FI'ing a 17cc engine for an
economy contest. Said they used a 0 280 155 731 - 750, which he
thought was 75cc/min.

Putting into Google "60 * 6.5 * 75cc in gallons" shows 7.73 (lbs/hr)
My math is 75cc/minute times 60minutes/hour times 6.5lbs/gallon,
and let Google convert cc's to gallons, answer in pounds/hour.

BTW, they got around 650MPG, record is about 10 thousand.

regards,
phil