0-5v OUTPUT

[T04GTR]

Hello, i have an older s12, and have a very large fuel pump. (hand me down from the shop racecar) (20L/min@80psi) i have a speed controller for it. its a 60 amp dc motor speed controller via pwm. but i will need a 0-5v output from the ecu to replace the trimpot that is on the controller.

how would i go in setting up an output for this?
should i use a pwm fuel pump strategy and wire in a 470ohm and the 5v out from the controller?
Dave.

[stevieturbo]

A single pump that large would be very uncommon ?

What sort is it ? Is the controller a DIY thing or supplied by pump maker ?

Would the PWM output option for controlling a fuel pump be usable ? Some people just seem to hook this up to a solid state relay to drive the heavy load.

Although with a pullup resistor you could probably work something to create a sort of 0-5v output

[T04GTR]

its a kinsler 0.7" spur gear pump that i have put a 3000rpm 12v motor on the back of.(1hp) the motor mimics the back of a dry sump oil pump with a hex drive pump option.
we have found that with 1200hp+ atw with e85. the magnafuel efi 750 just doesnt quite do it. ( low hp low rpm motor) and having multiple pumps, having one fail can have all sorts of piston melting issues at 45+psi boost.
and yes, if they had a syvecs that wouldn't be an issue with a trip setting. and drag racers are slow to adopt more modern tuning strategies.
the problem is there is nothing that bridges the gap between a belt drive/full mechanical pump. and a single electric pump. (4 bosch 044's or walbro e85 pumps pull in excess of 60-70 amps. and with most of the alternators we use tapped out at 100-120 amps its to much.

15L/min is the minimum for a 2j making this sort of power.

this pump i have "made" outflows all of them but only draws 45 amps all in. but is WAY to big to be running flat out all the time.

there has been a massive surge in "road registered" cars that can do a sub 8 sec 1/4. and roll racing has really taken off.

will a ssr be able to switch quick enough?

[stevieturbo]

SSR will switch as fast as you tell it to switch really. No reason they cant do a few thousand Hz without difficulty, Syvecs offers up to 10kHz output on the fuel pump outputs and control for up to 3 pumps


Some people are using them already to drive various motors. I did buy a couple myself, but it just isnt something I ever got around to doing. I did just buy cheap ones as it was only going to be for a test. So there probably are some more suited to such things than others and no doubt they are a little more expensive.

I've seen some people in the US use OEM Fan controllers that take a PWM signal to drive either fans or pumps etc in a similar fashion, although these may not carry the same current as some SSR's could.

[stevieturbo]

Or as said, if you wired a pullup resistor across the output to 5v that would allow you to effectively create a 0-5v on that output line although pretty sure it would end up 5v to 0v with 0 to 100% duty rather than 0v to 5v with 0 to 100% duty.

Another couple of threads here

viewtopic.php?f=6&t=737&p=3892

You can also buy cheapish DC motor controllers that run off a PWM input. Again I've one sitting beside me here, but never got around to ( or figured out ) how to work it exactly.


It would be worth emailing Syvecs support as they might get you a better answer directly.

[stevieturbo]

viewtopic.php?f=6&t=907

And I also wonder can one of the H Bridge outputs be configured to give you a variable 0-5v output ?

[T04GTR]

thanks for the replies. good info.
the other option is sending the pwm to the on switch of the controller. was on $26 aud. il have a play with it when im closer to starting the engine.. cheers.