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Raising and lowering voltage on a fuel pump
Posted: Fri Oct 02, 2015 6:25 pm
by Hodge
Hey guys
I'm fitting a Weldon external pump to a supra but it's insanely noisy. Is there a way for the Syvecs to run the pump on 7 volts maybe and then switch to 12v when the car hits say 7psi as a stock fuel pump ECU does. I've currently got the pump on a 4 pin 12v relay.
Cheers
John
Re: Raising and lowering voltage on a fuel pump
Posted: Fri Oct 02, 2015 6:39 pm
by stevieturbo
Hodge wrote:Hey guys
I'm fitting a Weldon external pump to a supra but it's insanely noisy. Is there a way for the Syvecs to run the pump on 7 volts maybe and then switch to 12v when the car hits say 7psi as a stock fuel pump ECU does. I've currently got the pump on a 4 pin 12v relay.
Cheers
John
You can PWM the pump output which in turn either drives a proper motor speed controller or some use a solid state relay to turn the pump off/on very fast so you can reduce its output duty
Reducing voltage by means of a resistor for example is an ancient and terrible way of controlling such a pump.
Other option is to fit much quieter and more reliable pumps, say a couple of 044's or something.
Here are a couple of threads.
viewtopic.php?f=4&t=638&p=3335
viewtopic.php?f=4&t=503&p=2780
If you want to do it externally, Aeromotive offer a simple PWM controller based on say an rpm input and their controller is rated to something like 40A.