Dual Tanks - EFI - Check Valve Question

[gtpvette]

Guys,
I'm planning to run a dual fuel tank/pump/regulator setup on my LS1 that will run one side at a time (note no crosover hoses between tanks). The though is to run one tank/pump setup to the fuel rail on one side,,,, the other to the other with a crossover on the front of the fuel rail.

My quetion concerns the inline check valve that should keep the unused tank from being overfilled. WHen switching from one tank to the other, I'm wondering if the check valve will stay open due to the residual pressure in the line.

Any Thoughts??? Concerns? Comments???

Thanks!
Fred

[Steve_D]

Hi Fred
I assume the regulator has a return pipe to its supply tank.
I believe the check valve will close as I’m assuming it’s spring loaded. At the point you switch over there may be pressure both sides of the valve but it is more than likely equal. If your supply pressure drops then the valve may let the out of service side to release some of its pressure but that is all.

Can’t help thinking this is an expensive route as high pressure EFI pumps, filters and regulators are V expensive. A single HP pump etc fed from a supply pot fed by cheap and cheerful low pressure pumps has been discussed here at length.

Steve

[GreenV8S]

Are those regulators designed to be used in a dead-end configuration? Some are, but there's another sort which are essential a constant pressure blow-off valve at the *return* end of the fuel rail. The advantage of this is that it keeps fuel circulating through the rail. Disadvantage is mainly cost of installing the return hose I think.

[ROWDYRENAULT]

Yo Fred: A good sized crossover connected to the very bottom of each tank, mine is 1.25 inchs avoids the problem of filling the tanks or getting the fuel tanks uneven. I then draw from both tanks at the same time through a Y to one filter, then on to one pump, out of the pump to a Y that feeds both fuel rails. Then out of the two rails to the fuel regulator then one return line back to one of the tanks. Total 1 pump 1 filter 1 regulator 2 Ys. Just a thought. Lee

[GTR-TT]

ROWDYRENAULT said:

Yo Fred: A good sized crossover connected to the very bottom of each tank, mine is 1.25 inchs avoids the problem of filling the tanks or getting the fuel tanks uneven. I then draw from both tanks at the same time through a Y to one filter, then on to one pump, out of the pump to a Y that feeds both fuel rails. Then out of the two rails to the fuel regulator then one return line back to one of the tanks. Total 1 pump 1 filter 1 regulator 2 Ys. Just a thought. Lee

I have the same configuration (but I "Y" the return to both tanks) but I have problems with fuel starvation when acceleration out of long turns if the tankt are less then 2/3 full.

[GtrSimon]

On my LS2 I have gone a bit over the top! however it makes a failsafe system, I use 2 X fuel 1.5L swirl pots each fed via a pump from one fuel tank whith its own return, the 2 outlets are then fed to valves then the high pressure pump. this way no non return valves are required and there is no chance of fuel returning to the wrong tank.

[wherzmespana]

Reading GTR-TTs post, I am running an LS1 that was set up with twin tanks each with a low pressure pump to a swirl pot and on to a high pressure pump to the fuel rail with a bleed to the regulator. I tried every config of return hosing and link hosing before giving up due to fuel starvation after long track corners - the fuel pressure would momentarily drop to nothing and then pick up again. I have now reverted to a single tank with twin lift pumps to a swirl pot and on to the high pressure system. I had the world and his wife looking at it with me and I couldn't get any sense out of anyone - including a race mechanic at Spa running an Ultima in race spec. I find a single tank is good enough for the track and is OK for the road as long as there is a filling station every 50 miles or so!!! The twin tank system was perfect for the road but showed problems the minute it saw a track. If you get a system that works pls let me know how you did it.