Boyd Aluminum Fuel Tank Capacity

[Shoeless]

Hey guys,

Anyone done the exercise of finding the capacity in gallons of the Boyd Aluminum Fuel Tanks? I need this to plug into my MoTeC C127 as it can do some tricky things with fuel calculations that I'm barely scratching the surface attempting to learn.

I just haven't had the opportunity to run the GTM low and then go fill up.

Thanks,
Sean

[Nigel Allen]

Unsure of shape of the GTM tank, but can you measure the overall dimensions and calculate the volume?

[Shoeless]

It's got some funky angles on it to make it fit behind the seats. Not entirely impossible, just a little time consuming.

Just hoping someone has figured it out before I would have to try and go through an exercise.

[crash]

I would ask Boyd. Pretty good chance that these were designed in CAD and the calcs are easy if they have a sheet metal product design program. Otherwise I would suggest the fill and pump method as it should give you exactly how much fuel you can use as opposed to what you put in, which is not always the same.

[Shoeless]

I would ask Boyd. Pretty good chance that these were designed in CAD and the calcs are easy if they have a sheet metal product design program. Otherwise I would suggest the fill and pump method as it should give you exactly how much fuel you can use as opposed to what you put in, which is not always the same.

They were my first email unfortunately they didn't have a volume to share. I may have to just go top it off and pump out into fuel cans to get the usable volume, I like this idea.

[crash]

We generally do a pump to empty, add a specific amount of fuel and then pump out at end of a session to get fuel mileage on the race car at least once per race weekend. I understand you are not trying to get calculated fuel mileage from physical fuel used like we are, but I thought I would mention it as "pumping the tanks" is a pretty common thing we do, and explain why we do it.

Be careful not to run your high pressure fuel pump(s) dry. We have a low fuel light system where we know when the light comes on we only have about a half gallon or so of usable fuel in that tank, so we generally only go until this light comes on as we will be heading for the pits and refuel when it comes on anyway. Therefore that is our pumping out stop point.

Probably be okay with going just until the pump starts sputtering unless you come out with much less than you put in.

[Shoeless]

Makes perfect sense to me. The nice thing is I can output on the C127 the raw unitless value that the dash reads and uses for the fuel level calculation. The dash essentially takes the raw number off the CAN bus, uses a 2D table I create and outputs the fuel level. I can display that raw number on the dash and keep an eye on that as I'm pumping this out into fuel cans.

crash,

Do you just undo the fuel feed into the fuel rail and then attach it to another fitting that matches the fuel rail design? Or do you guys have something a bit more user friendly since you do it so often?

[crash]

We used to use an X fitting. It is a -6 four way male fitting on the return line. Our supply is -8. I put a cap on one of the X males and use that port for drain line attachment. Unfortunately with a change in system design I need an X fitting in -6 that now has a female on one end and three males. Difficult to find, so yes I am just removing the return fitting on the fuel rail and pumping it out there. I do worry about having sealing or thread issues and am very careful when I do the pumping. Wish I could find one of those one female and three males fittings, but until I do...it is a PITA. I would recommend the X setup if you think you are going to do this regularly.

Just so anyone reading understands...the X fitting attachments are:

One from fuel rail
One to fuel pressure sensor
One to return line
One capped to use for fuel sample/pumping out

Space, as you know, is very tight in the GTM and I want to have the fuel pressure sensor as close to the rail as possible so there are no false readings. This is why the X fitting is required. If you don't have the need for the X then running a much more common Tee fitting at the end of your rail will allow you an easy access capped port.

[Shoeless]

We used to use an X fitting. It is a -6 four way male fitting on the return line. Our supply is -8. I put a cap on one of the X males and use that port for drain line attachment. Unfortunately with a change in system design I need an X fitting in -6 that now has a female on one end and three males. Difficult to find, so yes I am just removing the return fitting on the fuel rail and pumping it out there. I do worry about having sealing or thread issues and am very careful when I do the pumping. Wish I could find one of those one female and three males fittings, but until I do...it is a PITA. I would recommend the X setup if you think you are going to do this regularly.

Just so anyone reading understands...the X fitting attachments are:

One from fuel rail
One to fuel pressure sensor
One to return line
One capped to use for fuel sample/pumping out

Space, as you know, is very tight in the GTM and I want to have the fuel pressure sensor as close to the rail as possible so there are no false readings. This is why the X fitting is required. If you don't have the need for the X then running a much more common Tee fitting at the end of your rail will allow you an easy access capped port.

Thanks for the insight, you have always been willing to share, and guys like us that are still active on the forums really appreciate it.

I'll think this over and figure out a game plan. I don't see the need for me to do this all the time, so may just rig something up temporarily to do what I want.

[VRaptor SpeedWorks, LLC]

Thanks for the insight, you have always been willing to share, and guys like us that are still active on the forums really appreciate it.

I'll think this over and figure out a game plan. I don't see the need for me to do this all the time, so may just rig something up temporarily to do what I want.

That is what I've done in the past to drain the tanks.....just rig up a piece of hose with the fuel rail fitting on one end......disconnect the feed to the fuel rail and attach to the drain hose and then pull the fuel pump relay and hotwire the port to run the fuel pump constant. The second I hear the fuel pump begin to suck air bubbles, pull the jumper wire to stop the pump.

[Shoeless]

I'll have to dig through my bin of parts, I may have a fuel rail fitting I tried to use somewhere, but just threw it in the bin as I never needed it. Until you need it

I should be able to turn the output on in the M1 software to activate the pump. I'll report back on this. I've got to shrink all the boots and get the harness back into the car permanently. I wish I could shrink the last large boot on the main harness on the car, but could be sketchy getting the heat gun all the way around. Maybe I'll do the patch harness boots tonight. I wanted to do the C127 boot, but the last item to test is the GPS Antenna. Its powered up, but I need to back the car out of the garage a bit so it can see the sky and hopefully look on the satellites, then I can shrink that boot.

[Shoeless]

Got the GTM out for a little road tuning and flexing its muscles this afternoon. First couple trips around the neighborhood were a little sluggish, but simply pausing the time graph in the M1 software and running the cursor back to that area and pressing "Q" on the keyboard, tuned that cell to the target lambda. Before you know it the VE table was looking a little better and the car was running smooth. Enough to run to the gas station and top off to check the usable capacity of fuel.

I found a fitting in my bin that would work with the end of the hose coming out of the ID-F750 Fuel Filter and used that to run to the gas cans. Within the M1 software there is a Calibrate All tab, that lists everything and is searchable. A quick search for Fuel Pump and I as able to turn on and off the pump between filling the gas cans.

In the end right as the fuel pump started sputtering, I ended up with a total of 15 usable gallons.

[crash]

Just a couple of observations. Not trying to be critical and of course you can look at my cars and always find something that could be done better, but for whatever reason are the way they are. Just offering suggestions here.

1) I would be careful about the way Shane suggests connecting the fuel pump and especially disconnecting the fuel pump to drain the fuel. His method could lead to sparking which could be dangerous when having containers of fuel in close proximity. Sounds like you went a different route anyway, but just a general warning to try and avoid sources of ignition when doing a fuel drain.

2) I see you have mounted that breather to the main rollover hoop. It is a bit of a pet peeve of mine, but I try and avoid drilling holes into frame members. It is convenient to mount things in this way, but, for me, it leads to the potential to weaken the tube that is being drilled into. Therefore I try and weld tabs onto the frame where I need to mount something and then attach whatever to the tabs instead of directly to the tube by drilling and riveting. Again, plenty of places on my GTM race car where this was not done and I have probably gone and welded in hundreds of rivet holes and replaced with tabs, so I am working on my execution on this as well, but I REALLY try and avoid drilling into what I consider critical tubes for the safety of the driver which includes the main roll hoop, door bars, and really any tube that's purpose is to protect the driver/passenger.

3) While your fuel pump placement looks convenient, I tend to place my fuel pumps down low and, if possible, at or below the lowest point of the fuel tank. While the pickups do route through the top of the tanks, the theory is that once over that hump, the low fuel pump location will promote the pumps staying primed. This reduces wear on the pumps, and also, hopefully, helps me get as much fuel out of the tanks as possible. I understand space is a premium in the GTM, but that is how and why I do the low fuel pumps.

EDIT: On second look I see that what you have there is just a filter? Probably running in tank pumps? Never mind my observation, but thought I would leave it anyway for others and future reference.

Again, not trying to be critical, just offering some suggestions as to how and why I have done things.

[Shoeless]

Hey crash,

I don't take it as critical at all, this is all great feedback especially for someone like me who is building a GTM as a first build project type car. I worked for my dad who owned his own shop his whole life and started working on cars very young, but nothing even close to the caliber or cost of this build. There's really not many ways to learn how to do something like this other than to dive in head first, make some mistakes, and learn from them or learn from others. I try to learn from others before I make the mistakes, and have with much of your input over the last 5 years of me building this thing. Some lessons are expensive, like going with a hobby type ECU thinking it was a great choice because I didn't know any better, and now knowing I should have gone full MoTeC from the beginning with the desires that I wanted from the beginning. It's all good.

Good points on not drilling frame rails. I wish I would have bought my TIG machine well before I even ordered the kit to learn how to weld. That way I would have done exactly as you noted, but at the time, I just drilled and riveted. Live and learn some.

Yep, the item you are looking at is the Injector Dynamics ID-F750 Fuel Filter. I came across this filter some time ago and looking at the numbers and what they were advertising it looked like a great item for me to add to my build. Plus has a build in block on the side for the Fuel Temp and Fuel Pressure sensor. Running an in tank Lingenfelter High Flow fuel pump in the passenger side tank.

[icoulabeenav8]

I welded bungs in the bottom center of each tank and closed them off with a threaded plug. I cut a circular hole 6" or 8" (I forget which) in the panels centered beneath each tank's bung to be finished off with an appropriately sized cover attached to the panel beneath the fuel tanks..

To drain gas, I elevate vehicle, put on my rubber gloves, place my super wide funnel in the gas can centered under the fuel tank, unscrew the bung, and voila!, drainage.