Old Fuel Tank Issues

[lpmagruder]

Hi all,

Got 3 autocrosses on my car and absolutely loving the car and having a blast, but I'm starting to get pretty frustrated with my fuel tank. I have the "old" style tank that was before they made the firewall cut for more driver room. The connections for the fuel pump and level sender are the style that use a 1/4 turn ring, not using the Subaru tank top mount. I had to hack together the Subaru pump to the supplied top bracket. I think this is the tank that shipped with the earliest kits, with the older front-end.

I cannot seem to get the 1/4 turn flanges to consistently seal. I've had them both on and off many times. The O-ring (not really an O-ring, looks more like a rectangle section) doesn't really index well into the hole, and the diameters of the mating flange vs the O-ring are such that it is very easy for the o-ring to slip out on one side. I have had this happen over time too, so even if I pressure/smoke test and verify it's all sealed up, there's no guarantee it will be tomorrow.

Second but more minor issue, the fuel level sender is either getting its float stuck or just has intermittent shorts/opens. My fuel gauge is pretty much a random number generator between totally full and totally empty. At one point it sorta worked, but lately I've had it on and off like 5 times and I can't seem to get it to stay consistent. It'll be reading ok, then I'll go around a corner and then it'll jump to some random position (usually 100% or 0%, but sometimes somewhere in-between) and just stick there until I take it out and back in again. I've tried a ton of different orientations.


Has anyone gotten to a point where they're happy with this tank? I'm wanting to get it reliable before my next autocross mid-May so I don't have the lingering fear of fuel spilling onto the hot headers constantly in the back of my head. I was going to start with pulling the fuel pump and level sender both out, measuring the O-ring groove, and ordering a better set of O-rings from McMaster. For the sender, I guess I'm just going to keep iterating with orientation of the float and maybe try bending the wire and try to find a spot where it doesn't bind up. But this kinda seems like something that could be a never-ending battle, I'm wondering if I should just consider either the Boyd tank or a fuel cell and know I have a solid solution.

[BigDanSubaru]

I have the updated FFR fuel tank that gives the driver more leg room. It is unused because I went with a Boyd tank right from the start. I am in PA, so shipping that tank to you would cost more than just buying a Boyd tank (probably). Otherwise I would sell you my tank for cheap. It just takes up space in my basement. I too am struggling with the fuel gauge, but I am using the Boyd fuel level sensor which comes with its own problems. Good luck, you will get it figured out.

[lpmagruder]

Other than the level sender are you pretty happy with the Boyd tank? They have a "Not for Racing" disclaimer on their site that concerned me. I don't do anything serious (no wheel-to-wheel racing) but I do autocross my car regularly and plan to do some track days.

Wondering if I'm better off just spending a little more and getting a fuel cell.

[BigDanSubaru]

There is probably some safety regulation that requires them to state that it is not for racing. I have only just driven my 818 in go-kart stage this month, so I cannot speak much about the fuel tank yet in terms of performance. However, I have watched videos from other builders who have raced with it in autocross and have been fine. They added baffles inside to prevent fuel from sloshing around so much. Apparently the original Boyd design had a problem with that. The fuel filler inlet is in a different spot than the FFR tank, so you will have to modify that filler neck a little. Not a huge deal and I did not have to purchase any additional parts to make it work. I used the FFR provided metal pipe and hose. I bought the roll-over vent valve and ran a hose to a little charcoal canister to eliminate fuel vapor smell. It's a nice unit in my opinion.

[idf]

Hi all,

Got 3 autocrosses on my car and absolutely loving the car and having a blast, but I'm starting to get pretty frustrated with my fuel tank. I have the "old" style tank that was before they made the firewall cut for more driver room. The connections for the fuel pump and level sender are the style that use a 1/4 turn ring, not using the Subaru tank top mount. I had to hack together the Subaru pump to the supplied top bracket. I think this is the tank that shipped with the earliest kits, with the older front-end.

I cannot seem to get the 1/4 turn flanges to consistently seal. I've had them both on and off many times. The O-ring (not really an O-ring, looks more like a rectangle section) doesn't really index well into the hole, and the diameters of the mating flange vs the O-ring are such that it is very easy for the o-ring to slip out on one side. I have had this happen over time too, so even if I pressure/smoke test and verify it's all sealed up, there's no guarantee it will be tomorrow.

Second but more minor issue, the fuel level sender is either getting its float stuck or just has intermittent shorts/opens. My fuel gauge is pretty much a random number generator between totally full and totally empty. At one point it sorta worked, but lately I've had it on and off like 5 times and I can't seem to get it to stay consistent. It'll be reading ok, then I'll go around a corner and then it'll jump to some random position (usually 100% or 0%, but sometimes somewhere in-between) and just stick there until I take it out and back in again. I've tried a ton of different orientations.


Has anyone gotten to a point where they're happy with this tank? I'm wanting to get it reliable before my next autocross mid-May so I don't have the lingering fear of fuel spilling onto the hot headers constantly in the back of my head. I was going to start with pulling the fuel pump and level sender both out, measuring the O-ring groove, and ordering a better set of O-rings from McMaster. For the sender, I guess I'm just going to keep iterating with orientation of the float and maybe try bending the wire and try to find a spot where it doesn't bind up. But this kinda seems like something that could be a never-ending battle, I'm wondering if I should just consider either the Boyd tank or a fuel cell and know I have a solid solution.

I had the same issues with original tank and leaks around the fuel pump and sender. I replaced the o-rings with Model B90229 from The O-Ring Store LLC with good results.

[lpmagruder]

Thanks for the tip, I got and installed those o-rings and smoke tested the tank. There still seems to be a pinhole leak, bit it looks like it's near the connector and not the seal itself. My smoke tester is building pressure in the tank which it never did before, so I'm hoping that's enough to keep slosh from coming out.

As for the level sender, the tony little copper contacts in it were all mangled, I was able to take it apart and bend them back but I have a feeling that's a very temporary solution.

[lpmagruder]

If anyone else has the same problem, I ordered 10 of these o-rings to get the minimum order, so I have 8 left.

Yours for free.50 plus shipping from Kansas.