Hey gang,

Curious to know how accurate the OBC and the Idiot Light are. I've ran the Mini's tank to what I thought was empty before a refill.

For the last 2 refills, I've gotten over 13.2 gallons consecutively... 13.80 and 13.75 (OBC -4mi and 6mi). Has anyone run it to complete empty or pumped 14 or more gallons into the Mini's tank?

 

I have seen 13.6 pumped in... Just happy that there is still a little in there when it says empty.

 

I'm not worried about how much my tank holds as much as I am about how much gas I have left in the tank. Took the Clubman S into the dealer, and they had to clean the injectors and reset the computer. Just put 250 miles on a full tank of gas and the idiot light just show TWO BARS UNLIT! Can they re-calibrate the idiot light indicator to where it is half way accurate? I know that I am not getting that huge amount of mileage.

 

14.4 (but realize gas expands / contracts with temperature).

 

After a day at the track, my range said 0 miles, but I was able to nurse it to a gas station in town about 5 miles away and it took 13.5 gallons.

 

I've crammed 14 in one of my MINIs!

 

Once the range goes down to "- - -" you can still go another 30-40 miles or so if you are easy on it. That's how you get to over 14 gallons. I didn't run it dry, but felt that I was about to deplete the reserve so I filled up.

 

I thought gas stations regulate their fuel temperature?

If this were true, more people would be filling up early morning.

 

No, but the underground tanks don't change temperature between am and pm nearly as much
as the ambient air temp does.

 

The fuel pump is in the gas tank on just about all of the newer cars. When you run low on gas the fuel pump is not fully submerged and can cause a failure due to heat and lack of proper lubrication. A fuel pump problem is not really good at all.
"""That is what I was told about my Corvette"""""""
I never let my JCW get below 1/4 tank because of that advice. It is not worth taking a chance if the above proves to be true.
Ronnie948

 

Not sure how true that is. Many older fuel-injection cars have the pump outside the fuel tank. This is true on my '81 Audi 4000 and '87 Porsche 944S.

The pump is cooled more by fuel running through it.

 

Hm, yeah, that makes more sense.

 

Most owner's manuals caution against running too low on fuel due to possible damage to the fuel pump.

 

The MINI fuel pump is mounted at the top of the tank. It sucks in fuel from the bottom, and is cooled by the fuel moving through it. Any sediment at the bottom would be sucked up all the time.

I've run my range down to "- - -" nearly every tank for 7 years. Nothing is hurt by running low. My fuel filter was last changed 15,000 miles ago.

 

Including Mini !!!

 

[quote=Jonshungry;2845856]I thought gas stations regulate their fuel temperature?

If this were true, more people would be filling up early morning.

Many people do exactly that!

When gasoline is measured a standard temp of 60f is used, so if the temp in the tank is 60f at 6am and 85f at 3pm there is aprrox. 6% difference (I think that would be pretty accurate as we easily have 85f underground water temps at 3pm on a hot summer day like now).

Gasoline volume changes approximately 0.125% for every 1ºC change in temperature (0.058%/ºF) .

Good Reading on this subject:

http://www.gao.gov/products/GAO-08-1114

http://www.consumerwatchdog.org/reso...lUSAJune07.pdf

http://www.nh.gov/agric/news/documents/fuel.pdf

 

[quote=ron-s mini;2846440]85F - 60F = 25F
25 * 0.058% = 1.45%, not 6%

You'd have to have a 104 degree F increase in gasoline temp to change the
volume by 6%.

BTW, 1.45% of a full tank (say 13.2 gal) would be almost 0.2 gallons.

 

So I gather the tank's true volume is around 14.2 - 14.5 gallons. Cool.

 

I've run mine to 14.4 gallons as well.

 

Update...

On my last refill, it went to 14.458. I added 2 more clicks and got to 14.682.

 

same here, shamefully Ive drained it pretty damn low and put in well into the 14 gallons region (I know its bad for the fuel pump). But luckily never ran out.

 

Of course you can squeeze another gallon or so after the tank is full. The extra gas just goes up front into the evaporation system that is designed for not polluting the air with gas fumes. Do it to much and you will probably end up with some codes.

I'm sure it is not a good thing to do but people do it anyway & then complain about their car is a piece of crap because of fuel system problems.

I just fill until the pump stops, Then top to next dollar amount. I get gas at 1/4 tank. I do think it is in the owners manual about not over filling the fuel tank.

 

So the only way to really know how much gas the tank can hold is if someone ran it into the ground?

Anyone ever done such a thing?

 

I wouldn't run into the ground. Just bring a 1 gallon gas can with you. I used to do that with my '81 Audi while in college.

 

i know kind of old thread, but filling up after it stops even to the next dollar amount could cause a problem. at the top of the gas tank is a rollover check valve that stops liquid fuel entering the charcoal canister during a rollover accident. the charcoal canister collects fumes and filling up the tank more than its supposed to with fuel will cause it to get into the canister.