Effect of temperature on fuel bladder.

Only empirical. It seems to vary by car. Obviously the bladder is more flexible in warm weather.

Tom

 

While I don't have an equation for max fill at different temperatures, my experience with my 2005 shows that every degree Fahrenheit allows about 0.03 more US gallons per fill. (Not that there's any real reason to suspect that the effect is linear...) In your case, every 20°F increase should allow you to pump in an extra 0.6 USgal.

 

Hi Jay,

The change is most dramatic around freezing. My experience is that between 25 F and 50 F was a gallon. I filled up at 25 F just after the tank went from 3 to 2 pips, and then again at 50 F again just after the the change from 3 to 2. The car filled up exactly one gallon more, at the same pump.

 

I just filled up at noon today when temp is 90+F in Northern California.
I always filled up at 2 pips. The total gallon is 6.48.
No difference to when temp was 70F.
I wonder here?

 

Hi PT...,

Hmm. That seems an awful low amount. I would guestimate my car would fill up about 9 1/2 gallons at 90 F, just when the third pip goes off.

You might have had a pump with a low trip pressure.

 

It's not exactly scientific, but click either of the banners in my sig to see my fill-ups with their seasonal variations. I almost always wait until the last pip starts flashing, so that should provide a reasonably consistent reference point. For this purpose, ignore the tanks in mid-July last year; they were in the midst of a 2000 mile round-trip drive where I refilled at one or two non-flashing pips.

 

In the tech training literature available here, they make this statement:

 

This is a great plot, but I'm scratching my head about some of the points. Some of the higher temperature points seem a bit extreme - several are above the boiling point of water, waaaay above the initial boiling point of gasoline.

 

That's because I'm stupid. I thought I used Celsius, but of course those are in Fahrenheit. Ooops.

I wasn't exactly at 100% the last two days, lots of travel and not much sleep. Thanks for double-checking!