EFI Fuel System

Peter D · 01-09-02, 07:30 AM

Hi Guys, I just picked up most of the components for the EFI fuel system today - LP pump, HP pump, changeover switch, regulator, 3 x filters, surge tank, charcoal tanks, etc.

I have now finished some 2 hours sitting on my little chair beside the car, playing 3-dimensional chess with all these bits ! Checkmate each time ! Whenever I think I have got it right, the last outlet is totally out of reach of the inlet that it needs to connect with.

Has anybody worked out a bracket/support system which allows all of these bits to interconnect logically ? Any pics would be soooo much appreciated.

Kind Regards,

Peter D.

01-10-02, 12:24 AM

Hey Pete,
And I thought I was the only one that had that chair in the shed for 3D chess. I know exactly where you are coming from on this one as I am doing the same my self with the fuel system.
I guess the DRB is a bit different to the RF so can only offer Good Luck. Have fun,
RV

BuzzClarke · 03-21-04, 07:17 PM

Here are some pics of the fuel system that was designed for my car. Since I didn't do this myself I'm a little on the thin side with the knowledge, but here goes.

The tank selector switch on the dash picks one of the two small black relays on the left which in turn controls the feed and return valving for that particular tank.

BuzzClarke · 03-21-04, 07:22 PM

The fuel flows from the tank through the valve mechanism, into the filter and up to the pump and regulator.

BuzzClarke · 03-21-04, 07:25 PM

It exits the regulator going into the fuel rail. (The black hose in the picture goes down and loops back up making the connection)

BuzzClarke · 03-21-04, 07:31 PM

I gather this six-way valve to the right of the filter is part of the solution. A relay can select the left or right tank. The valve then works with the feed and return for that tank while having a main feed through the filter, and a main return from the fuel rail.

I know I'm missing a bit, and I know there are a few other ways to do this, but this is what I have for now and the packaging seems acceptable.

Paul Thompson 'Hooligan' · 03-21-04, 07:59 PM

Hi Buzz -

Do you have a swirl pot (surge tank) before the high pressure pump to provide it with a reserve of fuel under hard braking/cornering? Without one we had loads of problems for a long time on Roy's GTD until we determined the problem.

Your pics look good, have you done many miles yet?

BuzzClarke · 03-21-04, 08:33 PM

Thanks Paul,

That's just the kind of response that makes this Forum so valuable.

The first time this car hesitates at the track under heavy cornering or braking loads I will be asking about surge tanks. For now the car is a week from completion with a month to follow of shakedown for the Cannonball (including some track time). It is hard to believe that within approximately eight weeks of today I hope to have 10,000+ on the car.

mlevea · 03-21-04, 09:03 PM

Peter,

Here's an excerpt from my website:

"Our solution was to design a surge tank that is filled from a low pressure pump located near each fuel tank. A high pressure fuel pump feeds from the bottom of the surge tank and circulates fuel around the rails to a fuel pressure regulator. Bypass fuel is diverted through a relay controlled shuttle valve and returned to the feed tank. Discreet indicator lights are installed in the dash to monitor proper fuel distribution."

So the flow goes:

Tank->LP Pump->Filter->One-way Valve->Surge tank->HP Pump->Filter-> Loop around the fuel rails->Bypass Regulator->Fuel Return Selector

The reason you should run a loop around the rails is for fuel temperature (constantly circulates back to the tank) and so no air gets trapped in a dead end fuel rail (could cause a lean situation on some cylinders)

Check this if you need more confusion:

mlevea · 03-21-04, 09:23 PM

Another pic showing the whole system:

BuzzClarke · 03-21-04, 09:43 PM

Mark:

That is some beautiful workmanship!! I'm looking forward to getting on the road and heading your way in a couple of weeks. I hope you have the headers worked out.

Regards, Buzz

bclough · 03-22-04, 01:05 AM

Good show, how long before the TEC3 goes in?

edit: (hey look, I got a "tenth". I'm no longer a noob.)

mlevea · 03-22-04, 10:23 AM

Brian,

The TEC3? It's in there. Check the battery box on the left side. A DB9 connector and the top face is visible. All wired, firmware updated and base maps ready.

Mark

JP · 03-22-04, 12:14 PM

Here is a shot of my setup.

Low pressure pumps to swirl pots via fuel filters.

Swirl pot to 2 x high pressure pumps via fuel filters.

Fuel rail - Pressure regulator>return to swirl pot.

Overflow in swirl pot>returns to fuel tank.

I believe this is almost standard practice for serious fuel injection systems. Especially those that will be exposed to hard braking and cornering.

The swirl pot is 1.5 litres.

Regards,

J.P