Fuel Delivery - what's a better setup?

[mbuskuhl]

My fuel delivery system needs work. It was plumbed wrong and starves in corners with about 3.5 gallons left in the tank. I need to make a change, which do you think is a better way to go?

Current - 12 Gal ATL sport cell, AN plumbing, Bosch 044. Dual pickups into a Y then filter then pump then filter. This setup is wrong and will cause starvation in corners w/ about 3.5 gallons left. The pump will draw from the corner with the least resistance (no gas). I know, I had to pull into the pits the first and only race I have ever had pole position. I emptied the tank later to measure the gas remaining.

Option A - Add an ATL black box, put both pickups in the box, no plumbing change. About $200. BTW, anybody know where to get these below MSRP?

Option B - Add a 2nd pump and re-plumb so each pickup has it's own pump and then Y the lines. About $400. Would you run separate wiring and separate switches?

Ultimate Setup - Add a black box and dual pumps - About $600

I have to be conservative with money right now. I spoke to ATL and they couldn't say whether Option A or B would be better. Option B has the benefit of a backup pump in case of one failing. Would Option B still empty the tank as much as Option A? I am not ready to do the ultimate setup, maybe in the spring. I have 2 race weekends left this year.

Do I do Option A or Option B?

Thanks.

[chuck baader]

Had the same problem. Solved by making my own trap door surge tank. Mounted in the center of the cell with a door on each side. "V" wedge shaped with top partially closed. Pickup in center 1/4" off bottom. Have wings 2" tall off each corner to the corners of the cell. Have run to less than two gallons...lost nerve, but I think it will go lower. Ended up being about 4 hours fab work (and I have all the tools and welding equipment). I also cut the foam at a 45 and have a piece on each side of the surge tank to hold it in place.

I looked at the ATL and the Fuel Safe solutions, but each have a 3 door units which do no good under breaking...that is why mine have 4 doors. Also, their solutions are quiet pricey...total cost on mine was under 10$. I just love simple solutions. Chuck

[Knestis]

I got a black box with the used enduro cell I bought and it seems like a good answer. I've never run it OUT but I've run it way down - like adding 25 gallons to a tank with a nominal 25 gal. capacity. The FI return line goes into the top of the box so it's hard to imagine that it won't get every bit of fuel that's available. On the other hand, when it's out, it's going to be OUT, just like the stock MkIII VW set up - which is pretty similar.

K

EDIT - my system has only one pick-up. I'm struggling to understand how two pick-ups will be better, given the basic function of the "box."

[MMiskoe]

build or buy a box, use one pump.

I had a two pump, two pickup system, replaced it with one pump and a black box. Seemed to work better. In a 12 gallon cell, this system would run w/ a 1/2" of fuel in the cell.

Two pumps feeding the same line can have the tendancy to fight each other so you end up having to put check valves in. Then if one pump delivers a higher pressure than the other, the lower pressure one can just sit there & cavitate, leaving it pumping air for a while if the other has its pick up go dry and you're back to having the car skip in a corner.

I'd be curious to hear other theories on two pump or two pick up applications.

[mbuskuhl]

EDIT - my system has only one pick-up. I'm struggling to understand how two pick-ups will be better, given the basic function of the "box."
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Since the system is already plumbed with 2 pickups, for simplicity sakes I would put both pickups in the box rather than eliminating one and changing the plumbing (more $$ on AN fittings). The two pickups would not be of any advantage in my opinion. And yes, good point about putting the FI return line in the box as well.

Black box looks like it's in the lead, thanks for all the comments! Any other feedback on a 2 pump setup? I had not thought about the points you made Miskoe.

Chuck and the other homemades, you got any pictures of the box you made?

[seckerich]

Run with one high pressure pump. The only ones that do not feed back through each other are the low pressure facets and do not work with injection. Run one pickup in a surge tank (box) and have the return line empty into it. As an added feature you can install a second low pressure transfer pump (similar to stock RX8) that picks up from the second pickup line and just fills the box. Dirt cheap bosch for the RX8's work well. We use them in the Grand Am cars that have saddle tanks. Stock setup.

[chuck baader]

I use one pickup in the center of the tank. If you use two, one of them will always try to suck air if the level is low. I also use a Holley (red/blue?) pump for a lift pump and the stock BMW high pressure pump. Since the surge tank install, I have had no fuel starvation issues what so ever. Chuck

[koliver]

...another vote for keeping it simple with single pump and pick-up in a scavenge box. I run an 8 gallon Fuel Safe cell with the return (Bosch EFI) plumbed into the black box. The box is mounted centerline against the forward wall of the cell. Have run it down to less than a gallon with no starvation. Less than 1/2 gallon gave some stumble (never under only breaking or accel, only in a long corner).

[Conover]

One pump in a black box. Two pumps is just asking for problems if you ask me. Why would you need that? I could see it if your working with some giant fuel cell or something like 120gallons on a boat or something, but on a car with a 12 gallon cell and those pick up pumps will pump like 120 gallons an hour so it's basically pumping way more fuel to the engine than you need, returning most of it back into the pick up box, so that box will stay full for sure, until your slap out of gas. The draw back to pumping so much fuel up to the engine then back to the tank is that it heats the fuel to some extent.