Before I cut into my fuel tank

[derek]

I need to add an intank fuel pump to my fuel tank, unfortunately I will have to recess a section of the tank to fit the top of the fuel pump assembly.

I was going to buy one of these:

http://www.tanksinc.com/index.cfm/page/ptype=product/product_id=84/mode=prod/prd84.htm

and then recess part of the fuel tank about 1-2 inches.

I then had a crazy thought about making the tank larger by a 12 inch wide / 10 inch long / 7 inch high section. I would remove the fuel tank outriggers current location and move it forward or attach it somehow to the other outrigger.

The black box would be the section added, of course that is not to scale. This new section would fit under the floor boards

9522

That would only gain me about 4 gallons, but for a 11-12 gallon tank that would all of a sudden be 15-16 gallons.

Is there a better solution out there for the fuel tank? Has anyone added a section like this to their fuel tank?

People with a EFI setup what have you used for your fuel tank / pump setup.


Here is my current setup:
1973 series III 88, Vortec Chevy 5.3L V8, NV4500.

[SafeAirOne]

Has anyone added a section like this to their fuel tank?

Uh-huh. Lots of times. Well...30 times, to be exact:

http://farm9.staticflickr.com/8046/8149003766_cc5e5d44ed_z.jpg

http://farm9.staticflickr.com/8202/8246061476_5654a0ce52_z.jpg

Even some that slope upward at the same angle as the bulkhead outrigger:

http://siteground237.com/~gunsandr/attachment.php?attachmentid=6577&d=1391650647

If you're thinking of putting the in-tank pump up in the section that you add on, well...I wouldn't recommend it, You'll risk running out of fuel with two (or more) gallons still in the tank.

[greenmeanie]

Leave the tank alone. For your EFI you can use a two pumps. The first pump is a low pressure part Carter 1070 IIRC that is there to lift the fuel out the tank and supply it to a remote spin on fuel filter. The second is the high pressure pump for the second circuit supplying the EFI. Your fuel filter head should have 4 ports so that you have a feed to and from the tank and a feed to and from the EFI. I also added a pick up tube inside the filter head so it sucks for the high pressure circuit from low down in the filter itself.

The circuits will self bleed of air and the fuel filter acts as a reservoir in the same way a baffled tank for EFI normally works off road.

[TeriAnn]

I too used an external fuel pump. I use an external fuel pump from a late 1980's F250. I have it mounted at the side of the frame. There is no low pressure booster pump in front of it and it doesn't need to be primed. I grabbed the fuel pump mount and the fuel filter mount off a truck in a wrecking yard which makes mounting easy.

I did need to have a fuel tank top inlet brazed on for the fuel return in the EFI system.

[stomper]

I still get excited every time I see those tanks Mark! I just picked up the brass fittings so I can install mine this spring.

[greenmeanie]

I too used an external fuel pump. I use an external fuel pump from a late 1980's F250. I have it mounted at the side of the frame. There is no low pressure booster pump in front of it and it doesn't need to be primed. I grabbed the fuel pump mount and the fuel filter mount off a truck in a wrecking yard which makes mounting easy.

I did need to have a fuel tank top inlet brazed on for the fuel return in the EFI system.

This may or may not work depending on what EFI system the OP supplies. A good link from the Megasquirt crowd (http://msextra.com/doc/ms3/fuel.html)with a bucket load of info on retrofitting EFI fuel systems.

The LP/HP system has the advantage in Rover installs of eliminating surge because the tanks lack any kind of baffling around the fuel pickup. Given the amount of crud in the typical Rover tank I have a Rock stopper strainer on the pickup, an inline filter before the lp pump to protect that and then my big spin-on acting as both the surge tank and a fine filter. Injectors don't like dirty fuel.

[TeriAnn]

The LP/HP system has the advantage in Rover installs of eliminating surge because the tanks lack any kind of baffling around the fuel pickup. Given the amount of crud in the typical Rover tank I have a Rock stopper strainer on the pickup, an inline filter before the lp pump to protect that and then my big spin-on acting as both the surge tank and a fine filter. Injectors don't like dirty fuel.

I have the advantage in that Ford used both in tank fuel pumps and external fuel pumps with its 5.0L EFI vehicles.

I started out as you suggested. A high capacity fuel filter then low pressure pump, then a fuel accumulator that was about a half gallon reserve for steep climbing then the high pressure pump to the EFI rails. It took up a LOT of space and everything mostly worked fine along the coast where the average air temp was usually in the 50s. When all the part temperatures equalized with the vehicle running I'd sometimes get an engine hesitation when I suddenly pressed the accelerator pedal. When the ambient temperature got into the mid to high 70's vapor lock became an issue once everything got up to full running temperature. At warmer inland summer temperatures vapor lock was a frequent certainty. I spend time under my truck and in the engine bay with an infra red heat gun measuring temperatures.

Hot components came off and the vapor lock frequency decreased. The last thing to go was the fuel accumulator. I ended up with the same fuel delivery system that Ford used on its 5.0L late 1980s pickups. I mounted the pump & filter to the outside of the frame rail for cooler air & my vapor lock problems became a thing of the past.

Yes, no baffling inside the fuel tank is an issue with a near empty tank at steep angles. However I have multiple fuel tanks with the secondary tanks being transfer tanks. I just anticipate a steep angle when I'm down to a quarter tank or lower and transfer fuel into the tank that drives the EFI system.


BTW - if you add a second fuel level sender gauge hole to the top of your fuel tank you can mount an early RRC internal fuel pump. And of course if you are building a fuel tank from scratch you can just build in baffles.

[derek]

I really like those tanks, any more available? It would be great if I could throw a fuel pump into one of those. I would really like to get my rig running sooner rather than later.

I am really stuck on the idea of having the fuel pump in the tank, but I appreciate the ideas.

[greenmeanie]

There was something very poor about your original install. It has to be something badly wrong as your fuel rails should be regulated to 30-45psi and at this pressure it is almost impossible to boil the fuel to generate vapour lock. There are ways to create problems in the HP loop but again that is down to poor system design allowing the LP system to generate vapour bubbles that are sucked into the HP pump but even then the combination of pressure and bypass flow should take care of it. Your revised design is most likely moved the intake back into the tank where the fuel is cooler so no bubbles in the system but resulting in the other compromises you describe.

For comparison I used to ride in my mates Chevy C10 TBI Megasquirt conversion using the LP/HP (Used as a design pattern my Rover later). We would sit in the stop/go traffic on the I10 going through Phoenix in 115°F summer days with all the heat reflected off the concrete and it wouldn't have any issues. Niether, for that matter, did my carb fed 101 or my 88 with electric fuel pump. I

f you work on your design vapour lock should not be a concern in either system layout. In any case we still don't know what he is trying to supply.

[SafeAirOne]

I really like those tanks, any more available?

I had them made on a pre-paid basis, so just enough to fulfill the orders, unfortunately.