expanding the bladder

<div class='quotetop'>QUOTE(efusco @ Aug 1 2007, 08:40 AM) [snapback]488605[/snapback]</div>

But the Prius has an 11.9 gallon tank according to Toyota's US web site.
I've been able to put close to 11 gallons into the tank without forcing it, and there were still two pip left on the gauge. There was a fillup at about 5000 miles (when the weather had finally warmed up) that the bladder clearly expanded on it's own. The gas pump clicked off, and when I gave it the usual one or two extra clicks it suddenly decided to take an extra gallon and a half without clicking off. It also didn't overfill or make the gurgling sounds that it would if fuel was filling the evap hoses or filler nozzle.

 

<div class='quotetop'>QUOTE(narf @ Aug 1 2007, 11:09 AM) [snapback]488626[/snapback]</div>

11.9 gallons gross, not net. The usable capacity of the U.S. Prius' gas tank is less, and varies by temperature and vehicle. I've never put more than 10.5 in mine, and that was only when I couldn't find a place to refuel and drove until it scared me silly.

Tom

 

<div class='quotetop'>QUOTE(douglas001001 @ Aug 1 2007, 07:30 AM) [snapback]488601[/snapback]</div>

What would be the point of expanding the bladder? Just fill the tank, and stop when the pump clicks off. Is that few more drops of fuel that important? Did you ever have another car, and remove the gas tank, and try to pound out a few more gallons out of the regular steel tank? I don't see your problem.

 

I never understood the bladder myself. I know it's there to prevent gas from evaporating, but why can't they just stick the bladder to the edge of the tank so that it doesn't just magically lose 2 gallons out of it's tank size?

 

<div class='quotetop'>QUOTE(douglas001001 @ Aug 1 2007, 04:07 PM) [snapback]488796[/snapback]</div>

It doesn't sound that way to me based on what you've posted, and what I've seen others post, plus my own experience. My maximum refill has been 9.03 gallons.

The bladder isn't really something you can modify, and it seems to me that since it's possible to get a range of 400-500 miles from a tank of fuel without problem, squeezing a bit extra in doesn't make any sense even if it were possible. Fill it until it clicks off, and drive it until it needs filling. Simple and reliable!

 

<div class='quotetop'>QUOTE(douglas001001 @ Aug 1 2007, 04:32 PM) [snapback]488824[/snapback]</div>

There is an ambient temperature component. I imagine that the bladder material is less elastic in sub zero temps than at 80 F. I have put in 10.5 gallons on numerous occasions without 'filling the pipe', no gurgling, no spit-up. When my '04 gets to 1 pip, I can put in about 9.5. It gets to 1 flashing about 1/2 gallon after hitting 1 pip. I KNOW that I have a lot more left in the tank at 1 pip than my wife's '06 which will take 10.5 at 1 pip. I wouldn't push her car after the flash like I can mine.

 

Well, if you really want to stretch the bladder, fill up on a cool morning that you are going to drive for a while. I've calculated that a full tank at underground temps will expand around two litres max. If you fill up to the top of the filler tube you will need to burn off that two litres of fuel before the tank warms up to 40C. Otherwise the expanding fuel will force its' way past the carbon canister into the tank space.

I don't think you will ruin the tank if you overfill once or twice, especially if you burn off the fuel before it expands too much. I've overfilled twice so far (nossle didn't shut off). What I learned is there is about 2.5 litres in the filler tube, allowing me to go an extra 60 km or so.

All that being said, what makes you think the bladder will stay stretched? I suspect it will return to its' previous size. Perhaps a better way to proceed is to carry a few gallons of extra fuel (safely) and see how far you can go when the fuel gauge indicates empty. You are probably not using the last gallon or so that you could. From what I've read, there is at least two litres of fuel in the tank you can't pump out, and if you run out, you need at least two gallons before the car can pump the fuel reliably.

Or better yet, just fill normally and live with what you've got.

 

<div class='quotetop'>QUOTE(David Beale @ Aug 1 2007, 02:50 PM) [snapback]488881[/snapback]</div>

Or fuel up after dark to both maximize the fuel volume and minimize the fuel evaporation from the pump.