I've just noticed that the OBC is running a touch under 25 mpg recently, which is about 2 mpg less than it was a couple months ago. I'm guessing it's due to having swapped out the runflats for non, but still.... I'm wondering. Is anyone else getting LESS mpg as time goes on? I've got about 7000 miles on it. My driving habits haven't changed, and I drive it pretty hard in L.A. city traffic, for the most part.
Your thoughts?
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when i first got my car i was getting about 26mpg in the city (tons of stop go all day long), and that's about 5mpg less than most people claim to get. Now i get about 22mpg and I'm at 4000 miles. i thought it might be my driving habits, so i asked for tips on NAM and i took people's advice and i can't get it higher than 22mpg in the conditions i drive. I took it to the other side of the city a couple weeks back (lots of long straight roads) and I got about 26mpg. this sucks.

 

How does the O.D. of your new tires compare to the runflats? Many of the non-runflats have a slightly different O.D. which would throw your mileage off and change your effective gearing.

I seem to be getting worse mileage at 3000 miles, but I haven't been watching carefully. I just put larger O.D. tires on. I'll have to see how that effects things.

 

No difference in my (stock) setup, with over 8600 miles on the clock. Still calculating a steady 33.5, plus or minus a few 10ths.

 

Did you go from stock 205/45-17 runflats to

215/45-17 non runflats?

If so the non runflats are both wider for more rolling resistance and
taller than stock by 0.4". To correct for the tire diameter you should add 1.7% more miles but that really isn't enough to account for the difference.

2 mpg out of 27 is about 7.4%. Some might come from how you drive with the non runflats- do you drive any faster on corners or from stops? Average speed any different with non runflats?

 

Do you ever re-set the OBC?

 

I went from the stock Goodyear 195/55R16 runflats to Fuzion 205/55R16 non-runflats. It's possible that I'm driving a touch faster from stops and on corners, mostly due to the car not feeling as responsive as it did at first. I'm not sure if it's because I'm more used to it now or because the new tires have less bite, which they certainly do.

I haven't reset the OBC. I'll do that today.
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Why even use the OBC numbers? You really need to calculate the mileage to be accurate.

 

I do calculate the mileage. I guess I stated the OCB numbers because I don't want to feel even worse about the results! The OCB consistently shows about 1 mpg more, and this includes the recent drop since the tire change.
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The OD means that your car is off by about 1.8%. Not the about 10% mpg difference that you are saying. Possible messing with the diameter screwed up how the gears were most efficient. You are way under the 33 mpg ive been getting with a decent amount of driving in traffic, seems odd that it would be so much. Are you using an auto, i havent heard too many autos matching their numbers?

 

I went from 205's to 215's and lost a few MPG. I'm also spending more time >4,500 RPM after breakin. My average has gone down from 28-30 to 24-26. Another thing to consider is how much gas goes into your tank when you fill it up. Fill up in cold weather and you'll get better mileage than filling up in hot weather.

But since I'm getting about 25% better mileage than I did in my TT, and having twice as much fun, I'm way ahead in the total scheme of things. How many cars can you drive like a bandit and get such good mileage? I can't think of one...

 

After the break in my mpg dropped also. That's because I just can't stay below 4500 rpm all the time anymore. If you shift at 3000 rpm or below at every gear, you will get an awesome mpg.

 

Interesting thought on RPM and shifting - I am a newbie here and still waiting for my Cooper (nonS) - at what RPM are most people shifting ??

 

I've been using the air conditioning more lately -- summer being over it is finally getting warm here. That may be why mine seems to have dropped.

 

I have found that, ironically, when I try to improve my mileage it gets worse. I seem to get better mileage with somewhat more spirited driving. I blame that incredibly wide torque curve.

 

I really don't understand the tremendous gap in mileage. I run pretty fast in the twisties, love to put my foot in it (yee haw!!!), and have A/C on all the time--it's still in the 90's here in Texas. And I do get caught in city traffic.

The Prince engine was designed to be 20% more efficient in fuel consumption than the Tritec, and I certainly have been very happy!

Now if they could only drop the hood scoop temps...

 

There's fun driving, and there's economy driving.

For economy, shift up as soon as the engine won't lug, coast to stop lights and maybe not even need to stop, keep engine revs low, keep the speed at or below the legal limit. The lowest speed in your highest gear will generally get you the best economy.

My question: why did I get much better fuel mileage tearing around in Colorado mountains (40 mpg) than commuting here in the Iowa plains (33 mpg)? The only reason that makes any sense to me is the gasoline. I use MINI-recommended Top Tier premium gasoline. Around here Conoco-Phillips is all that's available. In Colorado it was Shell.

Molly is a 2007 MCS 6-speed manual, now almost 11,000 miles.

 

In my fairly conservative driving in my manual MC, I've been getting consistent mpg of around 37-38 in mixed driving and even had the OBC register 45 mpg for a 200 mile interstate trip (cruise at 65 no ac). I follow oldsbear's advice and use lowest speed in highest gear possible. To answer the question on shift points I generally shift in the 2500-3000 range, but on occasion when the situation calls for it will run it up to 4000. The new engine is a flatter torque curve and I haven't really found the need on a MC to run it up much past that. My mileage has been pretty consistent since the day I bought the car. Maybe a little better after the first tank or two.

 

mines been that low too dont know why i drive pretty conservative 99% of the time. but i cant get it above 25 mpg ever since i had it. at first i figured break out now i just cant gett any higher

 

Well, I don't know how you got 40 or 33 mpg at all, unless your mileage in the mountains was calculated going downhill. I do disagree with your first statement.

The MINI yields max torque anywhere from 1700-4000+ rpm. If you're at low rpm and go to accelerate, you have to press harder on the gas to acclerate than if your engine is spinning more. When you step on the gas ALL cars will deliver more gas (richer mixture) to help you get going (in the old days the carb would just squirt more gas directly in the intake without regard to how much air was moving through).

I think with the MINI, if you are going at say 4000 rpm and want to accelerate you don't have to press the gas padel as much to get moving faster, thus alleviating the need for a richer mix to get there.

That's my unscientific explanation of why the MINI seems to get better mileage with more spirited driving sometimes.

 

I don't do any of those things--makes me wonder what I'd get in my MCS if I did. Hubby always complains about my lead foot, but I got this car for serious fun!

I do use top-tier gas, though.

 

17's and 18's will give you poorer mpg than 16" wheels. (Of course, unless you have lighter racing wheels that are similar to or even lighter than 16" wheels.)

 

I have stock 16" wheels. How much is the difference? Maybe that's it.

 

My computer is telling me I'm getting 33.3 mpg I try to shift around 2500-3000 rpm and I do mostly highway driving to work. I have 4000 miles on it

 

I am getting 28.9 MPG in LA traffic with my MCS auto. Actually I am getting better than that, because my tires are a little bigger than stock's at over 25". OP, have you checked your tire pressure? Maybe your tires are under inflate. Even a few PSI can kill the mpg. I kept my 18" at 38 PSI.