I have had my 2008 convertible for a week now and have a couple of questions.

1. The manual says gas tank is 13.2 gals. plus 2.1 gals. reserve. Is that a total tank size of 15.3? When I got gas for the 1st time the gage showed 1/4 of tank remaining & the red light in the gage came on, which would indicate appx. 2 gals. left. But when I fillied up I put in 12.3 gallons. Which means I only had .9 gals left or 3 gals left. My trip computer said I had 60 miles range left. That would indicate it's realy closed to a 15 gal tank???

2. I got my MINI with the Chrono package which gives me the tach & speedo next to each other. It also comes with the on-board computer. The manual says I am able to scroll through the functions for avg. speed avg. mpg etc. it also says and current speed. I dont get the current spped just average speed. The dealer says it's an option you have to order, someone else said it's a programable feature???

I thank all those in advance for any comments or thoughts regarding these issues. THANKS.....Mike in Fl.

 

I don't think the fuel capacity is 13.2 gallons PLUS a 2.1 gallon reserve. It's closer to 13.2 gallons *total*, although I've been able to put a little more than that in a near-empty tank, which is probably from the extra volume of the filler neck. I do know that one time when the "miles remaining" readout on the OBC got down to 3 miles left, I still wasn't able to put anywhere near 15.3 gallons in it.

I have a cabrio with the Chrono Pack as well, and if you have the Chrono Pack, you lose the ability to display current speed in the OBC display. I think this is the case with NAV-equipped cars as well. I believe the reasoning is that since the Chrono/Nav packages relocate the speedometer to the steering column, there's no need for a digital speed readout in the OBC.

 

Yeah... what he ^ said.

 

Yeah... what Blimey said.

 

By the way:

1) the fuel gauge isn't even CLOSE to being "symmetric" - the last 1/4 goes a WHOLE LOT faster than the first 1/4.
2) My red light comes on at (I think) closer to 1/8 tank vs. 1/4
3) The "miles remaining" estimate on the computer is notoriously inaccurate ... I've seen it drop from 20ish to 0 in as little as 4 miles. I've also driven at least 5 miles on "0" range remaining - so who knows...

 

Yeah... what he ^ said.


okay, okay...I'll stop now.

 

You are very wise, CPJ.

 

Thank you, BC.

 

This statement holds true for every car I have ever owned !

 

I used to own an 1985 325e which had an onboard computer that did the exact same thing. It was so inconsistant that we would never use it. Though it would always register 0 if you ran out of gas.

 

I think the "miles remaining" is an estimate that takes into account (a) the amt of fuel left in the tank; multiplied by (b) the current average miles per gallon referenced by the on-board computer.
So I suspect if ya generally drive aggresive, then drive like granny - you'll stretch that last gallon out...but drive like granny, then burn up the last bit & it'll go faster than you expect?

 

Whoa... now I am confused. What the other guy said. huh?

 

I once got stranded with the OBC saying i had 25 miles left before empty! The car wouldn't start, but it still said 25! After getting some gas, it started right up. how impolite!

 

Yeah, what he ^ said that he ^^ said that he ^^^ said that he ^^^^ said
that he ^^^^^ said.

 

+1

 

Item #1 is intentionally programmed into every car. The reason is to make you feel like you are getting good mileage. While (mostly) full, the gauge reflects less fuel used than actual. Later, it has to "catch up" so it drops more rapidly.

The distance to empty isn't really inaccurate; it's just not very useful. It takes real-time readings, so if you are sitting at a light, based on consumption at that time it may say you have 30 miles to go. Then you take off from the light and suddenly you have 6 miles left. Of course, the less fuel in your tank at the moment, the more dramatic the moment to moment differences are.

 

Partly correct - the computer calculates your remaining range based on your driving over the last 20 miles. . . otherwise, while getting 0 mpg at a light, your computer would expect your range to be 0.

Can't really comment on that, 'cause I like to think car designers give us more credit than that. I prefer to think that it's psychological (you notice the quicker drop in gas when you're down to 1/4 tank) or because fluctuations in fuel available due to the ptich of the car are more pronounced with less fuel in the tank than more (which really does happen).

 

I've always thought that it had more to do with tank geometry and the fuel level sensor - sensor measures the "height" of fuel in the tank, but the volume per unit height is much smaller at the bottom of most tanks where they kinda taper down. But this is of course (a) an assumption (though a pretty rational one) and (b) a gross generalization.

 

I s'pose my last post might have been tough to follow but I still think it calculates based on (a) how much gas is left in the tank multiplied by (b) your Avg Miles per Gallon counter? (I got nothing to back that theory up though?)

I s'pose we could try this test: (I would except mine's garaged till the snow melts!)

1. Take a look and see what the computer calculates your Miles Remaining is (make a note). (lets say its currently 20 MPG x the 5 gallons left = 100 Miles Remaining)
2. Reset your Avg Miles per Gallon counter.
3. Drive 5 or 10 miles...nice and easy, which should inflate your new Avg Miles per Gallon. (lets say now it reads 30 MPG x the 5 gallons left = 150 Miles Remaining?)
4. Look again and see what the computer calculates your Miles Remaining to be (make another note).
5. Finally, reset the Avg Miles per Gallon counter again.
6. Drive 5 or 10 more miles, but this time really hammer it; which should drastically DEflate your new Avg Miles per Gallon. (lets say now it reads 10 MPG x the 5 gallons left = 50 Miles Remaining?)
7. Look again and see what the computer calculates your Miles Remaining?
8. Is there a change? (more than the 10-20 miles you drove for the test?) Is the change drastic? If there is a drastic change in Miles Remaining (my example was 50 Miles vs 150 Miles Remaining), then it would support the idea that it is calc'd using the Avg Miles per Gallon multiplied by amt of fuel in the tank?

Who wants to try it for us?

 

^ Or we could look in that dreaded owner's manual -- 20 miles / 30 km

 

LOL - Brilliant Idea!

 

I regularly put more than 14 gallons in my tank, and I have driven more than 10 miles with the OBC range saying zero (I like to live on the wild side).

 

LOL, very funny.

 

the other day my wife said the mini needed gas. I got in and sure enough it said 0 miles left. I live about 10 miles from the gas station and drove there and put 15 gal in the tank. since then i have asked my wife to stop and put her own gas in and not make me live on the wild side.

 

That's pretty much it. Because of the way the fuel-level senders work (linearly-variable resistor attached to a float), the gauge needle won't drop at a constant rate unless the tank is a uniform shape, such that each inch of fuel level equates to a constant volume of fuel.

I had a 1972 Mercedes that got around the problem by not spacing the fuel "ticks" evenly on the gauge face. There wasn't even a needle's-width of space between the "Full" and "3/4" marks, and there was only a little over a needle's-width between "1/4" and "Empty". The space between "3/4" and "1/4" probably accounted for 75-85% of the needle travel.