What does your Dynon indicate for fuel pressure with the electric fuel pump on and the engine not running?
With the fuel tank with approx. 1 gal. of fuel, mine shows 1.8 psi.
With the fuel tank full of fuel, mine shows at most 2.2 psi.
My electric pump will pump 1 gal. under 180 secs. However, being wary about vapor lock problems that I've experienced in the past without the electric fuel pump running, I decided to do a pressure test. The Facet catalog shows that the min. press capable with this pump is 3.0 psi and the max. is 4.5 psi. So, I dead headed the pump (i.e. plugged the discharge) and only saw 2.2 psi on the Dynon with 1 gal. of fuel in the tank. If I correct for the sensor height relative to the level of fuel in the tank, I figure the most that the pump was putting out was approx. 2.5 psi. which is about .5 psi less than the min. Many would say, "Ah, but the 0 - 30 psi range sensor is probably not very accurate at the low pressures that we're at." And, you would probably be correct. However, I was dead heading against a mechanical pressure gauge with a 10 psi. range and correcting for its location (overflow tube in fuel tank filler neck), the pump was putting out 2.1 psi. That's an average between the two measuring devices of 2.3 psi. which is .7 psi less than the min. that the pump is supposed to attain. Now, I realize that even 2 psi is approx. four times as much head pressure needed to get fuel to mech. fuel pump and carbs. But, the pump not meeting the min. pressure specification of the catalog bothers me a bit. Thoughts?
Anyone ever perform this pressure test and if so, what were your results?
With the fuel tank with approx. 1 gal. of fuel, mine shows 1.8 psi.
With the fuel tank full of fuel, mine shows at most 2.2 psi.
My electric pump will pump 1 gal. under 180 secs. However, being wary about vapor lock problems that I've experienced in the past without the electric fuel pump running, I decided to do a pressure test. The Facet catalog shows that the min. press capable with this pump is 3.0 psi and the max. is 4.5 psi. So, I dead headed the pump (i.e. plugged the discharge) and only saw 2.2 psi on the Dynon with 1 gal. of fuel in the tank. If I correct for the sensor height relative to the level of fuel in the tank, I figure the most that the pump was putting out was approx. 2.5 psi. which is about .5 psi less than the min. Many would say, "Ah, but the 0 - 30 psi range sensor is probably not very accurate at the low pressures that we're at." And, you would probably be correct. However, I was dead heading against a mechanical pressure gauge with a 10 psi. range and correcting for its location (overflow tube in fuel tank filler neck), the pump was putting out 2.1 psi. That's an average between the two measuring devices of 2.3 psi. which is .7 psi less than the min. that the pump is supposed to attain. Now, I realize that even 2 psi is approx. four times as much head pressure needed to get fuel to mech. fuel pump and carbs. But, the pump not meeting the min. pressure specification of the catalog bothers me a bit. Thoughts?
Anyone ever perform this pressure test and if so, what were your results?
