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Calculating fueling on alcohol EFI# ANOTHER QUESTION???

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speedster356 Plastic not Classic Racing

1,624 posts · joined Aug 2002 ·

#817874
How would I calculate fuel flow for puimp sizing, ejector size, and throttle body dia on an aircooled single cylinder of 600cc running on alcohol? This is EFI.
Not sure of HP, maybe 45?
At the stage of selecting electric fuel pump etc.









Spyder-WISD 07-09-05 11.6s @ 125 MPH

Speedster-WISD Nats 05 14.4s @ 89 MPH

Jet cruiser-Coogee 22-09-05 900 deg C @ 110,000 rpm

Weaseling out of things is what separates us from the animals....................Except the Weasel.

vlad01 Compulsive Aussie Vee Dubber

4,270 posts · joined Jun 2010 ·

#817877
I think 34% more than regular fuel.

71 notchback,
Past owner of, 70 NB, 73 SB and 72 FB TLE

mactaylor Custom Title Time!

1,005 posts · joined Aug 2007 ·

#817887
is that a lycoming cylinder head?
EVERLAST CONCRETE TANKS
1800 552 123

dangerous 23 Windows of Awesome

5,901 posts · joined Jan 2005 ·

#817890
900ml per HP per hour is what the engine will want.

So a 45 hp engine will want 40.5 lt in and hour.

If you flow through into a bucket it will need about 675ml in a minute,
or 112.5 ml in 10 seconds.

As a margin for error or other things,
you may like to make sure your pump can supply 50% more than this,
but through the nozzles, the engine will want around 112.5ml in 10 seconds.

An interesting comparison,
my supercharged engine flowed 3lt into the engine in 10 seconds at 7000 rpm.

If you are boosted you have to factor in any parts that use HP.
westi wrote:That's mad Alan.

speedster356 Plastic not Classic Racing

1,624 posts · joined Aug 2002 ·

#817898
Perfect, thanks Dave. A little Bosche will be fine then. What about compatability with Methanol? any problems there you think?
Head is a 1929 AJS bigport, engine cases are 29 roller bearing AJS, bottom end is BSA B50 with JE forged piston, the rest is made by me.
Spyder-WISD 07-09-05 11.6s @ 125 MPH

Speedster-WISD Nats 05 14.4s @ 89 MPH

Jet cruiser-Coogee 22-09-05 900 deg C @ 110,000 rpm

Weaseling out of things is what separates us from the animals....................Except the Weasel.

fast68 Commited Dubber

58 posts · joined Jul 2009 ·

#817906
looks pritty cool😎

SuperOwen Fahrvergnugen

868 posts · joined Jan 2009 ·

#817943
Cool project!! Are you going to try hide the system and make it look semi original or is this more of a custom build?
I know its not VW but keep this thread updated!

speedster356 Plastic not Classic Racing

1,624 posts · joined Aug 2002 ·

#817970
Stealth. ECU (check here microsquirt) is the size of a credit card. This is sitting between the tanks along with the pump etc. I'm machining a 32mm carb from billet and this will be the throttle body with original Amal float bowls hanging off it. I'll run the TPS (which is rotary) also under the tank cavity, so it will be pull cable from the throttle grip to a rotary quadrant with the TPS mounted (just off a nornal car carb) then it'll be a pull cable from the quadrant to the carb/throttle body so it should be all hidden. The frame is full 4130 CroMo.
Spyder-WISD 07-09-05 11.6s @ 125 MPH

Speedster-WISD Nats 05 14.4s @ 89 MPH

Jet cruiser-Coogee 22-09-05 900 deg C @ 110,000 rpm

Weaseling out of things is what separates us from the animals....................Except the Weasel.

speedster356 Plastic not Classic Racing

1,624 posts · joined Aug 2002 ·

#819071
I'm using a carb with a slide and not a throttle body with a butterfly.
How will this effect the perfromance (trying to maintain the original look with a carb). I've fabricated a 38mm carb. I guess the progression will be different with a slide carb? is that all do you think? Can anyone tell me what the cutout is on the front of a normal carb slide is and what is it's function?

Spyder-WISD 07-09-05 11.6s @ 125 MPH

Speedster-WISD Nats 05 14.4s @ 89 MPH

Jet cruiser-Coogee 22-09-05 900 deg C @ 110,000 rpm

Weaseling out of things is what separates us from the animals....................Except the Weasel.

speedster356 Plastic not Classic Racing

1,624 posts · joined Aug 2002 ·

#819077
Can anyone tell me what the cutout is on the front of a normal carb slide is and what is it's function?

From the crack of the throttle through 1/4 throttle openings, the slide cutaway determines how much fuel flows into the engine. It doesn't do this by allowing more air into the engine--that duty is handled by the straight, front edge of the slide. It does it by changing the velocity at which the air streaks under the slide; just like you do with your thumb over the hose.

So in a throttle body situation the slide cutout is not requred I guess as my carb/throttle body only regulates the airflow.
Spyder-WISD 07-09-05 11.6s @ 125 MPH

Speedster-WISD Nats 05 14.4s @ 89 MPH

Jet cruiser-Coogee 22-09-05 900 deg C @ 110,000 rpm

Weaseling out of things is what separates us from the animals....................Except the Weasel.