Fuel tank filling ( Boyd)

[Stickshift84]

Anybody know of a foolproof method?

I tried doing a standard fill this weekend and the pressure backed up and sprayed down the side if the car. For those that do not know plastidip us stained by gas so before I fix it I need s method that will work every time. Needless to say the stained plastidip bummed me out. But I can fix it.

[Quiny]

I had asked the same question some time ago. The stock tank has multiple vents, one that closes when the tank is half full. I think we just have to fill it slow. I was concerned about raw fuel coming out of the vent if we overfill it.

[AZPete]

Stickshift, how is the vent on your Boyd tank plumbed? I've got my Boyd vented to a charcoal canister and I wonder about this backflow also.

[D Clary]

Where did you vent the tank?

[wleehendrick]

That's a bummer! I have a Boyd tank and am interested in seeing solutions.

[Goldwing]

I've been wondering about this for a bit too. I, too, have plumbed in a charcoal canister (stock unit) with the tank vent line rising as high as the filler neck before going down to the canister. The evap purge line goes to the intake manifold (need to look into that as well), then the open vent line sitting also as high or a little higher than the fill tube with a filter on the end. I put the tank line and vent line as high as the fill tube to prevent fuel getting in there, as I don't have any of the stock valves or lines that control venting. That's where I stopped and moved onto something else.

The gas pump nozzle has a tiny hole near the tip that normally draws air though a Venturi action. When that hole gets covered with gasoline (or when spiders plug the canister vent line in Mazdas and Suzukis and air pressure builds up), the change in suction pressure trips a mechanism in the fuel nozzle to shut the fuel off. So, we need to come up with a way to trip the pump by covering the nozzle with gas, but not flow out and down the side of our hard work. Most cars have a splash plate with a spring loaded door the fuel nozzle fits through. I assume, but haven't verified, this trap door provides the needed splash of fuel to trip the fuel nozzle before it splashes out. But, on the wrx there are a couple small lines going to the filler neck with a valve of sorts on the fuel diagrams. I haven't tracked down its purpose yet. That issue aside, perhaps all we need is a restrictor piece just behind our fuel cap for the nozzle to just barely fit through? My open vent could be an issue there, I think the Rex has a valve at the end if the vent system that may have 2 purposes. 1, to test the integrity of the tank at the ECU's will, and 2, to help with filling operations. I've read as much, but not enough to nail it all down in my head yet.

That's as far as I got, before setting it aside. Finding a restrictor for the nozzle to squeeze through and maybe a way to shutoff the fuel vent when the tank is full were where my head was going next.

[wallace18]

I have built 2 FFR cars. A 33 and a 818S. Both you have to fill slowly. The vent is small even with the FFR tank. You cannot fill it like an OEM car.

[D Clary]

Again, where did you vent the tank.

[Goldwing]

Anybody know of a foolproof method?

I tried doing a standard fill this weekend and the pressure backed up and sprayed down the side if the car. For those that do not know plastidip us stained by gas so before I fix it I need s method that will work every time. Needless to say the stained plastidip bummed me out. But I can fix it.

Backing up a bit. Did the pressure back up during the fill or when full surprising you with an overflow? I had read the latter earlier, but now wonder if you meant the former? If the Boyd vent isn't fast enough for filling ops, could we add a vent to the top of the filler neck? Many oem cars have a line there. I'm not sure how to connect that, just thinking here. The extra line would add venting capacity strictly during filling, wouldn't do anything at other times. Just a burp tube. Thoughts?

[wallace18]

Again, where did you vent the tank.

I bought the roll over valve from Boyd and attached it with a hose to a carbon canister and that to a hose that vents out back of the car.

[longislandwrx]

This should be a blast for everyone in Oregon or like me Suffolk county that doesn't let you fill your own tank :|

[Hindsight]

That is one thing I really, REALLY don't miss about Oregon.......

[Stickshift84]

Update

My tank vent is run up to and attached to the strut brace with a small k&n filter. I know it is working as the filter element is discolored and you can smell gas through it. No charcoal canister.

My tank did not completely fill. Excess pressure in the rank caused the gas to back up. No chance for the nozzle to shut itself off like in a normal car.

One option could be to add a secondary vent in the fill tube.

Otherwise careful filling similar to how you would fill a portable gas tank should work.

[wleehendrick]

My tank vent is run up to and attached to the strut brace with a small k&n filter. I know it is working as the filter element is discolored and you can smell gas through it. No charcoal canister.

Hi Stickshift,

Can you comment on how bad the gas smell is in a garage with your set-up? I have the WAF (wife acceptance factor) to deal with. I eliminated my evap system, but am contemplating adding a simple small charcoal canister if needed to reduce the odor. I'd prefer just to put a little filter on the end of the vent tube like you did (if I can get away with it).

Otherwise careful filling similar to how you would fill a portable gas tank should work.

Yeah, you also have to deal with careful fueling on a motorcycle. Fill slowly and keep an eye on it; just don't pull a Ewan McGregor and splash gas in your eye (like he did in Long Way Round)!

[Goldwing]

I'm liking the idea of adding a secondary vent to the fill tube. On the tank side, adding a tee where the rollover valve screws in, putting the rollover valve on top of the tee, and run the new secondary filler neck vent line off the side of the tee. How to attach the vent line on top at the fill is where I'm struggling. Perhaps drilling and tapping the steel fill tube like many did when following Wayne's coolant burp line to add a hose barb? Then connect the two with hose? You might even be able to hear when gas hits the vent from below cueing you to stop the fuel pump. Any ideas on a secure fitting at the top of the filler neck?

[Stickshift84]

While I have noticed the smell it was not frequent. Right now I get a lot of lingering gas smell in my garage as my engine is running very rich. I will take note of it as time goes on.

[tmoretta]

The Miata canister is small, cheap and easy to mount in the 818 engine compartment.

[Goldwing]

image.jpg

I mounted the wrx canister on the left side of the transmission with the two end mounts bolted to the top of the frame rail with a spacer. The other end has bar stock in a triangular brace. So far, with the body test fitted, it seems to work fine in that spot, with minor trimming along the lower lip. It sits higher than the outside rear corner pieces, but slightly lower than the diffuser area. It could be made to be higher without too much fuss.

I can't say it doesn't interfere with splash guard aluminum yet, but impedes on that space less than the FFR exhaust setup on the other side, so it should be fine.

[longislandwrx]

Looks like the boyd tanks vent screws into a 1/2 npt hole, but the check valve itself is pretty small and goes to a 5/16 barb

http://www.fueltankparts.com/fuel-ta...ies/vents.html

could you run a 1/2npt to 10 an, a foot or two of 10am line and a 10an rollover? I think that 1/2 diameter would bleed a lot me air than the 5/16
http://www.summitracing.com/parts/ru...FSMV7Aodz3UALQ
http://www.jegs.com/i/JAZ-Products/5...rentProductId=

That is one thing I really, REALLY don't miss about Oregon.......

I pull the I'm from out of state card. They look at me like I have two heads when I start pumping my own.

That or I say "it's ok, I work at another gas station so I'm well qualified"

[wleehendrick]

The Miata canister is small, cheap and easy to mount in the 818 engine compartment.

Yeah, that's my backup plan if I find just a filter on the vent line stinks it up too much.

While I have noticed the smell it was not frequent. Right now I get a lot of lingering gas smell in my garage as my engine is running very rich. I will take note of it as time goes on.

My wife backs her 135i in our garage, so when she starts it up, the cold-start enrichment/high idle fills the garage up with fumes, so she shouldn't complain if the 818 emits some. Anyway... You smell that? Do you smell that? Gasoline , son. Nothing else in the world smells like that. I love the smell of gasoline in the morning. The smell, you know that gasoline smell. Smells like . . . victory.

I pull the I'm from out of state card. They look at me like I have two heads when I start pumping my own.

That or I say "it's ok, I work at another gas station so I'm well qualified"

I go to OR for business pretty often, and don't mind the attendants filling up a rental, but I'd be real careful with the 818! A couple years ago I was up with my wife on vacation. We were down south in Willamette Valley and needed gas on Labor Day... what a RPITA! Most stations were closed and one we found had one guy working and a lots of cars waiting. I just swiped my card and filled it up; I think he was thankful for the help. What a totally silly, make-work law.

[Evan78]

...perhaps all we need is a restrictor piece just behind our fuel cap for the nozzle to just barely fit through?

Seems like a good idea to me.

[D Clary]

I took apart the Boyd rollover valve as it is identical to the ffr supplied valve. The valve is closed by a square piece of plastic with a ball bearing weight. Because of the length of the plastic and the size of the ball it barely opens when right side up. I shortened the piece of plastic and drilled out the fitting a little bit. I don't know how much difference it made but the valve opens way further.