Hi Mark,
I looked into installing the same kind of system early on, but did not. I came to the conclusion (that for me and my type of flying) that this system added no safety factor for me that running both pumps on take off and landing did not do.
If the "automatic" system failed to turn on your second pump (sensor failure, wiring failure, relay failure, etc), you could spend precious seconds figuring out what is wrong and hitting your manual override - I presume it does have that. I would assume it also has some means of letting you know that a pump has failed, warning light? tone?
I always take off and land with both EFI high pressure pumps (and boost pump) running. Once at cruise altitude I switch one EFI and the boost pump off. If pump failure should happen in that regime of flight, I have plenty of time to observe the decreasing fuel pressure and/or stuttering engine and switch on the other pump.
Not knocking that set up ( if designed and implemented well), but I have a dislike of having anything critical being automatically done for me - I'd rather do it myself. I never like talking cars either {:>)
Ed
----- Original Message -----
Sent: Tuesday, July 24, 2007 4:24 PM
Subject: [FlyRotary] Re: FUEL SYSTEM PRESSURE
Dave,
You've got much more actual experience than I do, but I set my system up like the Eggenfellner guys do. They use a pressure sensor coupled to a relay to monitor the fuel pressures. The relay automatically turns on the second efi pump if the pressure drops below a certain limit (determined by the pressure sensor). That way the engine won't falter, skip, run lean, etc. due to low fuel pressures.
The good thing about an efi system such as you have described is the fuel in the fuel rails is always cool. Hot starts should be a non-issue.
Mark S.