This may be too little too late, but it's good helpful info. Something to thing about anyway.
With the Turbo cars that I have been involved with recently, most of them have gone the mechanical fuel pump route for a number of good reasons.
With the kind of power a turbo engine can make, supplying the engine with fuel can be very demanding and sometimes tricky. An electric pump is triggered and runs at a certain RPM, which usually differs from Engine RPM. A mechanical pump runs linear with Engine RPM, supplying the engine with an adequate fuel supply all through the Engine RPM range. An electric pump is usually mounted at the rear of the racecar, with added weight of fuel line. A mechanical pump is usually mounted off the back of a dry sump oil pump with shorter fuel lines and the fuel cell mounted up front.
Perhaps one of the best reasons to run a mechanical pump is for the flexibility of fuel supply a mechanical pump can provide at all engine RPM levels. Undoubtedly the Turbo cars have the ability to max out the supply of an electric pump. Usually this shows up in the duty cycle numbers within the fuel injection, even with two electric pumps set up on a turbo car, it isn’t uncommon to see duty cycle numbers in the 95% to over 100% range, straining injector drivers like this will more then likely end up in injector driver failure. You could always add two injectors per cylinder, but again, the added strain on the injector drivers will undoubtedly result in failure. The duty cycle numbers I have seen from running a mechanical pump on one of the fastest turbo cars in the country were nothing over the 80% range. This year we experimented with running a mechanical fuel pump on a two stage N20 and EFI set up, with a lot of success, the car ran 7.25 @ 200.6 MPH at 2800 lbs and only 445 cubic inches.
Another advantage of running a mechanical pump is the reduced strain on the electrical system. In fact some of the Turbo cars are only running one 16 volt battery, which results in less weight.
I hope this helps
Sparky
