MicroSquirt.com read only forum (Jan.15,2018)

There was talk a while ago about small fuel pumps.. Did anyone find a donar for small low current fuel pumps?

Its looking like i'll use an R6 (or similar) pump, but most of those pumps are for 120+ hp.. I'm after one for about 25 hp!

Are any of the modern bike fuel pumps designed to run at under 12V? I was reading about a nissan that ran the pump from 8V to 12V (idle to redline). A 600cc pump at lower voltage might be better..

Any ideas welcome

andrew

Hey Andrew -

I don't know sources for the little pumps (check here http://www.msefi.com/viewtopic.php?p=10 ... ump#107407), but I would think using the R6 pump would be better with PWM than reduced voltage. I would set it by energizing the injector(s) to 100%DC and turning up the pump PW until you just start getting bypass from the FPR. This should be good for establishing minimum flow and pressure at maximum demand to allow the least burden on the electrical system. Your falling voltage at idle may be your biggest obstacle.

BTW - what are you building? I have a tiny turbocharger for something in the 25-30 n/a base HP range...

David

I'm squirting a 250cc single cylinder motorbike. Thanks for that link.. I didn't think of looking at engines the orbital engine companys worked on.. I might email them or go in and see them..

PWM probably would be better but i'm not sure how i'd go about it?

You'll need a guru to tell you if something like the FIdle PWM circuit could be adapted to drive the FP. In the meantime you could poke together a simple PWM circuit on stripboard from the local electronics house. Although there are advanced tiny controllers out there for electric model cars and planes, the circuits are simple to build.

A quick search found a zillion circuits for PWM but this link explains the benefits http://www.solorb.com/elect/solarcirc/pwm1/, while this one http://www.cpemma.co.uk/555pwm.html gives a detailed build of one that is cheap, simple and more than capable.

Perhaps others will provide other sources or circuits that you could use - but it's a start.

David

Andrew,
Jaycar have a small kit for PWM control from the Silicon Chip magazines "high perf projects for cars". Might do the job or at least give some inspiration.

Ian.