Gas tank size….

[Yawyeet]

I ran my powerboost a little closer to E than I normally do yesterday. I had 20 miles to empty when I stopped to fill up, I managed to put 31.2 gallons in a 30.6 gallon tank. Did the pump lie or has anyone had a similar experience?

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[JIMFOUNTAIN]

I put in 29.002 gallons a few weeks ago when I wanted to transition from 87-88 octane to 93. DTE was about 30 miles at that point. So about what I expected.

But 31.2 gallons does seem high.

 

[12Lariat21]

The 'fuel tank size' is not the physical size of the tank, it accounts for 10-15% expansion volume (dead air space). So depending on the grade your sitting on, level of the truck, you can squeeze extra fuel into them. **Don't try to as you'll likely just spill the excess fuel at the pump, or driving down the road, but there is physically more than 30.6 gallons of volume there.

Plus your DTE is an average of the last X amount of driving, and that gauge isn't super accurate anyway, so take it with a grain of salt. Seems like the only way you were getting an extra 30 miles out of that tank is if you were 75% all electric driving...

 

[Yawyeet]

Just found this post, I searched for something along these lines yesterday but never saw it

https://www.f150gen14.com/forum/threads/gas-tank-size.15072/

 

[Tomatoboy]

To add to what’s been said, the fuel filler neck isn’t part of the rated capacity of the tank, yet in many vehicle designs it can hold as much as a gallon-ish of fuel if you’ve squeezed extra fuel in at the pump…it’s a bad idea, as it can spill out, but it’s physically possible.

 

[Yawyeet]

@12Lariat21 I drove roughly 30 miles after the 50 mile DTE warning leaving the range at 20 (I mentioned this to note the tank was quite close to E)

I was on level ground and did not “top off” I let the pump shut off automatically.

Also the ambient temperature was around 90* F I’ll bet the tanks are closer to 65-70 F underground. It seems intuitive that a gas tank designed to be pressurized does not change volume a great amount for an ambient temperature change

 

[12Lariat21]

@12Lariat21 I drove roughly 30 miles after the 50 mile DTE warning leaving the range at 20 (I mentioned this to note the tank was quite close to E)

I was on level ground and did not “top off” I let the pump shut off automatically.

Also the ambient temperature was around 90* F I’ll bet the tanks are closer to 65-70 F underground. It seems intuitive that a gas tank designed to be pressurized does not change volume a great amount for an ambient temperature change

Yeah who knows. There could be inconsistencies with the molding process too, maybe your tank is actually closer to 32 gallons.

The gas pumps are regulated, but only checked annually, so it is always possible for something to go out of calibration. You could take an empty container to the same pump, collect a 1 gallon sample, and then check that with a known measurement container to see how accurate it is. Then if there is a discrepancy you can bring it to Costco's attention. All depends on how deep you want to go with the investigation.

 

[BLoflin]

To add to the confusion, every car/truck/brand/model I've owned always had a "buffer" of at least 20 miles after the DTE went to 0. So even when DTE=0 I've had a least a gallon in the tank.

This makes the OP at 31.2g put in when DTE=20 (which would imply about 2 gallons still in the tank), even more confusing.

 

[mdn14]

I've put in close to 31 gallons with about 20 miles DTE before as well. Also not topping off the tank. I think we just dipped into the reserve a little bit too much.

Most tanks read E and then you still put in less than the design tank capacity. Ie. 28 gallons at E in a 30.6 gallon tank.

 

[discothan]

adding to the oddity, I've got the 36gal extend range tank on an ecoboost engine and I have yet to be able to fill more than 32 gals at the various pumps. I've consistently drive down to 0 DTE or even sometimes past 0 DTE by 3-4 miles, coasting most of the way. LOL.

There are some engineering drawings that on here that show the different tank designs in each of the eco/powerboosts and it does seem like a lower "reservoir area" that the fuel line feeds from. This might help assist in an inclined parked truck to always have gas to start and run.

 

[My 2ND Ford]

adding to the oddity, I've got the 36gal extend range tank on an ecoboost engine and I have yet to be able to fill more than 32 gals at the various pumps. I've consistently drive down to 0 DTE or even sometimes past 0 DTE by 3-4 miles, coasting most of the way. LOL.

There are some engineering drawings that on here that show the different tank designs in each of the eco/powerboosts and it does seem like a lower "reservoir area" that the fuel line feeds from. This might help assist in an inclined parked truck to always have gas to start and run.

Not odd, lots of posts about tank capacity and how much you can put it when the gauge reads empty. I ran my 26 gal tank down to about 40 DTE and the most I squeezed it was about 22 gals. My brother in law has had 36 gal tanks for as long as I can remember and he says the same thing. Best he has ever put in was about 32 gal. However, having been in automotive for a long time and seeing what repeated low fuel quantity can do to a pump, I rarely run mine down past 1/4 tank.

 

[afsnco]

Depending upon whether you have the Max Tow Package, 31.2 is reasonable since that tank size is 36 gallons. I have that package and it's great to know it can go long-haul without needing continual fill-ups.

 

[mdn14]

The powerboost, regardless of options, has a 30.6 gallon gas tank

 

[m_bt54]

I’m showing 86 miles to empty on my Powerboost. I’ll get it down to as close to zero as I can and report back.

 

[hitekguruaz]

I have had similar experiences. And I agree with 12Lariat21. The tank volume is rated at a certain temperature and does not account for the fill next. Gas has a substantial change in volume depending on the temperature. Filling somewhere like Costco that has well made and buried tanks and high volume of customers probably have cooler denser gas coming out of the tank in the ground and this is the result.

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