Gunn's How to Add Additional Fuel Pickups to a Stock Tank DIY

gunn

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95 T-bird with 5.0and m5r2 swap for lemons
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S4Gunn's DIY: How to add additional fuel pickups in your stock tank

Both Mad Mikey and I have experienced fuel cutouts when campaigning our MN12 cars in 24 Hours of Lemons when you make right and sweeping turns at speed with <1/4 tank left.
His solution was to add a second fuel pump at the end of 2-3' of submersible hose and tee that attaches to the stock pump assembly above the stock pump (there's hose you can cut into).

I decided to try something different b/c a) having two sets of wires in my gastank terrifies me 2x more than one set of exposed connectors b) I'm not sure if I really wanted to have the weight of a second pump flopping around inside the tank as well even if this hasn't cause Mikey any issues. The proper big money solution would be just to buy a crazy large fuel cell + a hydramat pickup but fuel cells that comply with Lemons rules are $1200+.

Current Status
I haven't done any on track testing yet but I've already installed this setup into my stock tank. Installation took <15 min b/c I already had an access panel cut in my tbird (because racecar). Two lessons learned:
- If you are being cheap like me and used nylon hose for the last segment instead of fuel hose, take particular care to place the pickups in the general area as you are feeding in to avoid kinking. If there is a kink in a remote pickup, it won't do what it's supposed to do.
- I should have cut the access panel an inch larger to avoid any kind of tweaking of the feed/return hoses (also the same nylon stuff) during installation on the pump since you have to pull them back ~2" to remove/reinstall
- After draining the tank dry, I swapped fuel pump assemblies and then ran it dry again to see how much additional fuel I could pickup. Without the pickups moving (which should hopefully allow it to scavenge more), I was able to pull out an additional 0.5-.75gal compared to what I had dumped in (measured approximately using the ticks on my 5gal fuel cans (I dumped 5gal in and then pulled out >5gal into one can + 0.5gal in a second can).

I'll know exactly how well this works after my next track day. As a baseline, I don't think it will be any worse than what I have now.


This is probably the third revision of my planned pickup design because I had to try several different things. For those of you that aren't aware, the fuel pump sits in the tank at an angle and there's only a small opening at the front passenger side of the tank for this stuff to fit through. This meant that my first plan to use MettleAir quick disconnects and 3/8" SS tubing didn't work. To further complicate things, there's a whitish colored plastic cup area that sits around where the stock strainer will sit to keep a little fuel around it when you make turns. The challenge though is that this sometimes runs dry.

I did this partially for the learning experience and partially because i really wanted to gain an extra 15 min of track time between driver changes. I probably have an extra $50 in unnecessary crap (MettleAir QD connectors and 3/8" SS tubing).


Parts Used in Final Install
Walbro GSL391 Fuel Pump: $83.91
- This fuel pump has threaded connectors at each end (without a threaded connector onthe intake side, there's no easy way to add anything BUT a strainer sock.
- Make sure to buy from a legit retailer as knockoffs exist
- I called and confirmed with Walbro that this pump will work in a submerged application (not just externally)
- This one is rated at 190LPH (up to 500HP). There's no reason for me to go to a 255LPH (GSL392) unless I wanted to heat up my gasoline.
(2) 2-3" SS clamps to attach pump to stock assembly: $4
(1) short piece of J30R9 submersible hose: came with pump or assembly
(1) M10x1.0 fitting to Barb from assembly to pump (Walbro #128-3012): $8
(1) M10x1.0 at pump w/ elbow to 1/8"" JIC (4M10C80MXS): $6.50
(2) 1/8" NPT male to 5/16" Barbs (125HBL-5-2): $2
(1) 1/8" JIC to 1/8" NPT (4-4 F6X-S): $8.50
(1) 1/8" Union Pipe Tee aka the "Tee Block" (2203P-2): $2.50
(1) Walbro Pickups (MP12) to fit underneath the fuel pump: $28
(1) 2" 90-piece of scrap submersible hose to place MP12 pickup underneath the pump in the stock strainer position (inside the baffle): FREE
(1) 12" length of J30R9 submersible fuel hose (to get over baffle w/o worrying that the hose will kink) - Thanks BLOWN38 & RAYO: ~$15/ft
(1) 5/16 Barb Tee (to feed combine passenger rear & driver's side pickups): cheapest is to Dorman #55109 (set of 3 barbs) - $8
(1) ~12" Length of nylon hose (Dorman #800-075) to place second Walbro MP12 pickup on rear passenger's side: 10ft for $11
(1) Walbro MP12 pickup for rear passenger side: $28
(1) ~22" Length of nylon hose (Dorman #800-075) to place third Walbro Pickup (MP13 w/ bleed hole since this will be the last to run dry IMO)
(1) Walbro MP12 pickup for rear passenger side: $28
(8) Bag of .75" max diameter (Size 4 IIRC) Hose clamps: $8
Total Cost (not including the stuff I bought extra): $240


Setup Explained
- I first found these pickups when researching the Holley Hydramat product. These walbro pickups were first used in snowmobiles (which find themselves needing fuel at all sorts of angles). They offroading folks then found them (which is how i found out about them - https://liquidironindustries.com/Walbro-In-Tank-Pickups.html)
- I was trying to understand if there was a better solution for use inside the stock tank. The baffle inside (seen in picture 0) makes the hydrmat product useluess unless you cut it out and you'll still need a way to attach the hydramat to the fuel pump (likely: threaded fitting fuel pump as I've chosen).
- Fuel pump is attached to stock assembly in stock position
- First fancy fitting takes the hose out at a 90 degree angle from the bottom of the pump. THis is because there isn't much room vertically at the base of the pump assembly. This fitting allows you to pick the angle you want the fitting to come out AND then tighten it.
- Second fancy fitting allows you to adjust the angle of the first Tee-block. This lets you aim one barb forward and place the first fuel pickup underneath the pump (in pretty much the stock position)
- From there, a 1' hose goes up and over the lip of the baffle. This hose is stock enough that even if it's resting on the baffle it won't get cut. I suppose I could go down there and notch the baffle but I dont' think that's necessary.
- At the end of the 1' hose I put a barb aimed backwards and placed two more pickups. One will flop around at the rear
- These two hoses are at the end of cheaper submersible nylon hose. I know this stuff is OK for being in fuel because it's what the offroad people (the people who FIRST introduced me to these snowblower pickups) use to attach the Walbro pickups to MettleAir quick detach connectors. Given how lightweight the pickups are and how thick this nylon hose is I don't anticipate any kinking b/c the weight gets thrown around.


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