Fuel system designs
 

Hey guys can you post some pics of some neat fuel system in boot systems. Need some ideas.. The fuel setup that i have had needs a fuel filter after the surge tank and its too cramped where it is to do.

here is the parts.. Now need to put them together. The pumps etc will be going in wheel well. The surge tank outside the car just behind the rear fender as usual.

Lines will enter underneath the fender well then setup assembled there. A blanking plate will go over fender well to seal it. Just trying to get idea of how to assemble it..

[URL=http://img248.imageshack.us/i/tinofuelsystem1.jpg/][IMG]http://img248.imageshack.us/img248/6687/tinofuelsystem1.jpg[/IMG][/URL]

I'm assuming it's just for street? I've never liked the idea of putting pumps in the wells, or having anything outside the structure really. Too easy to get damaged.

Okay so i have sorted out my design.

Another question though, im running twin walbro intank pumps feeding a 5ltr surge tank. which have two bosch 044 pumps drawing the fuel to the fuel lines.

Now is two walbro pumps going to fill the surge tank too quickly and therefore put pressure back onto the walbro pumps??

There is the bosch pumps which can out pump the walbros however there is also the return line filling the surge tank up also.

[URL=http://img694.imageshack.us/i/fuel002.jpg/][IMG]http://img694.imageshack.us/img694/2079/fuel002.jpg[/IMG][/URL]

No return line from the top of the surge tank back to the main tank Tino?

Won't the walbros pressurise the surge tank whilst the cars off boost / idling?

Tino, remember that the head requirement on the Walbro pump will be far less than pressurising a fuel system, as a result your flow will increase significantly.
Go back to first principles and estimate your maximum fuel consumption based on injector duty cycle from your previous tunes and etc and see if you can get a head vs flow chart for your Walbro. You do not want to be needlessly generating heat with additional pumps....
Not sure if its worth considering a pressure sensor in the line so that if fuel pressure is not above a predetermined limit Motec won't let you mash the go peddle?
Al

[QUOTE=Rossco;414980]No return line from the top of the surge tank back to the main tank Tino?

Won't the walbros pressurise the surge tank whilst the cars off boost / idling?[/QUOTE]

Yeh up the top theres three lines..

Thats the question too much pressure?? bad on the pumps.

[QUOTE=stinga;414983]Tino, remember that the head requirement on the Walbro pump will be far less than pressurising a fuel system, as a result your flow will increase significantly.
Go back to first principles and estimate your maximum fuel consumption based on injector duty cycle from your previous tunes and etc and see if you can get a head vs flow chart for your Walbro. You do not want to be needlessly generating heat with additional pumps....
Not sure if its worth considering a pressure sensor in the line so that if fuel pressure is not above a predetermined limit Motec won't let you mash the go peddle?
Al[/QUOTE]

Thats right Al, a single walbro or even standard sti pump should be able to fill a 5ltr surge tank as it can provide enough fuel for atleast 350 hp atw. All the walbro is doing is acting as a lift pump. Because there is a return line back to the surge tank there should be more than enough fuel that the twin boschs can pump??

Yeh im sorting something out with the motec when the car goes to sean..

Cuz, get a stop watch and bucket out and simulate the flow / height / pipe losses (restrictions from fittings and tube) requirements and see what you get from the Walbro.

Work out how much fuel your car needs at full boost / noise, add 30% ? and away you go:)

If you are plumbing the surge tank return into the normal fuel sytem return you may need to consider a vacuum breaker so it does not drain the surge tank when the car is off? or are you running straight back to the fuel tank up top somewhere?

Usually the surge return is just threaded through the top of the surge tank, there's no way for it to siphon the fuel back to the main tank.

(Is see you've changed the line drawing to include the surge over flow/return line)

The setup I ran on my series 2 RX-7 (ported 13b, To4e, 8 x 1000cc injectors).
2 x Bosch 010's inline (there was no intank pump) as lift pumps feeding a 4 litre swirl pot (mounted under bonnet), the return line to the main tank was tapped into the top of the swirl pot.
The High pressure side consisted of 2 x Bosch 979's, 1 feeding the primary injector rail, the second feeding the secondary injector rail. Both pressure regulator returns fed back in to the top of the swirl pot.

Set up was good for 440hp atw @ 1.1 bar, never ever had any surge issues.