It was mentioned above, but I have to concur with the hypothesis of rear brake lockup.

Do you live in a state where they salt the roads in the winter to melt snow?
My parking brake cable has locked up twice in the 8 years of ownership, due to salt-induced corrosion.

I'd release the parking brake, and assume it would release the pads' tension on the rotor, but not so. This obviously, (in hindsight) caused premature rear brake pad/rotor wear, and certainly negatively affects gas mileage. The thing is, I never noticed any squealing, bad smells or smoke; just an annoyingly short rear brake pad lifespan. Just something to consider.

Thankfully, I don't drive my car in the winters anymore, so that problem is behind me now.

 

I got to pile on here.

You're ranting about poor fuel mileage, but you can't seem to go to the trouble to accurately compute it from miles traveled and gallons at the pump, instead doing an extremely inaccurate estimate by looking at very non-linear fuel gage or interpolating "miles per tank". Start noting how much gas you're putting in, do the math, and average over several tanks to damp out the noise. Then report back.

And second, I think you need to reset your expectations of what typical mileage is for a 10-yo 1st gen MCS. For such a small car, MCSs were never stellar mileage champs - the supercharged engine was not very efficient, the aero of the car is relatively poor, and the emphasis Mini put on sportiness with things like very wide tires work against efficiency. Poor gas mileage was the main reason Mini abandoned the supercharged Tritec engine and went with a clean-sheet turborcharged design for the 2nd gen cars and the much higher mileage ratings for the same size car between Gen 1 and Gen 2 reflect how the 1st gen cars are relatively inefficient.

When the MCS first shipped, it was EPA rated at 25/34, but this was with a methodology that was way too optimistic; In about 2007, the EPA was forced to revise estimates for all cars lower to match what people were actually getting. Under this revised methodology, the estimates are 22/31. This means that if you're getting 22mpg in everyday urban driving, you're getting about what is expected. And if you're expecting 28 mpg in anything other than highway driving, you're likely going to be disappointed.

My 2004 MCS gets about 22 around town and 29 on the road, pretty close to the revised estimates. A number of folks on this forum are regularly getting sub-20 with their gen 1 MCSs. My car gets almost exactly the same mileage as a friend's 2006 VW GTI which is a considerably larger car with a larger and more powerful engine. The Gen 1 MCS is not a mileage champ for its size and if this comes as a surprise, you should have done your homework before buying the car.

Final point: Cars with 100K miles typically are down a bit on compression, their sensor systems are not running a full efficiency, the injectors don't work as well, etc. etc. etc. To be down a couple mpg for a 100K car seems completely normal to me.

All in all, I'd judge your "horrid" fuel mileage to probably be more/less normal.

- Mark

 

Double check and make sure you tires are at least 35-36 psi cold.

Check for clean air filter

Make sure source of gas is top tier and premium

Do the real mileage check with reading odometer and how many actual gallons to fill to click off. The fuel gauge is not very accurate and mine actually fails to move sometimes when I fill up.

Are you carrying anything that is heavy?- the total weight of you with your car affects mpg as does anything that increases drag external or wheel drag- wheel bearings? Nothing binding?

I assume tires and wheels are stock size?

The other thing is with 90K miles and an original MINI- you likely have suspension that is worn out- have a mechanic check the entire suspension (bushings and joints, engine mounts), My 2003 MCS has 84K miles and the suspension joints all over were worn out and needed replacement- way too much play all over the place. I get about 26-27 mpg in mixed driving and when new and stock I got up to 32 mpg on highway at best and usually about 28-29 in mixed driving.

Could you be burning more fuel than needed- yes, MINIs are known to run pig rich, see your tailpipe which is covered in black soot with each trip. It might be possible to replace fuel injectors or check the fuel line system for any leaks. Fuel filter OK?

Easy enough to check engine compression in each cylinder and check the codes for sure. Misfires happen.

Finally anyone else drive the MINI? Only one driver?

Are you shifting gears about 2000 rpm? Sooner or later? If you shift by about 2000 rpm you can get decent enough mpg but if you wait to shift at 4000 rpm you may burn more gas before getting into another gear.

 

Were not talking scientifically calculated mileage here, were talking about simple computation. And with that being said, you take the capacity of the tank when full, then take the miles traveled on the odometer and divide the miles by gallons in the tank? I dont see why I need to calculate it down to the precise pump, and gallons purchased down to the ounce to notice that the vehicle is getting subpar fuel mileage?

 

All 100k services were completed soon as I bought the car, brakes have been changed, no caliper/parking brake issues what so ever. I am the only driver, use Shell 93 octane. No current misfires noticed nor logged by ECU. All bone stock car. Suspension maintenance was also performed within the 2 days of buying the vehicle, I was previously aware of the control arm bushing issues and such of the car from previously doing service on them (I am an ASE technician).

 

Id have to disagree with this, considering the fact I run into driveability issues and performance issues all day at work every day, I would have to disagree with the statement that 100k mile cars are down on compression, efficiency, injectors not working properly. Modern piston ring designs (early 90s) and on have VASTLY improved sustained efficiency of piston ring to piston wall sealing. Poorly maintained cars even see sustained/healthy compression with higher mileage 200k+. 100k mile mark is becoming the new "broken in" mileage, hence why you dont do any services to cars nowadays until that mark. Sensors operate off voltage, magnetism, and so forth depending on what sensors we talk about. If it were the case where they are not full efficient at the mere 100k mile mark, then you would be recommended to replace MAF sensors, MAP sensors, CKP/CMP sensors and even ABS/TCS sensors at 100k miles just like spark plugs, assuming that a cars essential "brain and feedback" system are just inefficient by that mileage is blind, simple minded and severely uneducated about modern EFI systems. How often do you replace injectors on a vehicle as part of maintenance? Or ever?

Not arguing with you, just stating that there is a lot more then just "assuming age" to poor fuel mileage.

 

The car is getting poor fuel mileage, based on what its rated for and for its design and driving style, therefore I posted here to see if anybody else is suffering from it even with well upkeep of maintenance and service to see if there is a common problem such as maybe a leaky bypass, or whatever else? Maybe an OE design flaw that someone has noticed and corrected. Thats all, not trying to ruffle feathers here lol

 

Yes, and there is not necessarily anything wrong with your car. The 1st gen MCS simply has poor mileage. That's how Cadillac was able to run an ad saying that the Escalade gets better mileage than a MINI Cooper: http://www.caranddriver.com/reviews/...take-road-test

 

No one is getting their feathers ruffled. But the statements you are making as fact simply aren't true. Your car is rated - brand new and in perfect condition - to get 22 mpg in urban driving. From the poor data you've supplied, it appears it is getting about this. You may be personally disappointed or feel a car like this should do better but it is what it is. There is no magic bullet to correct an "OE design flaw" - the mileage it gets is baked into the compromises of its overall design. Hunting for faults that don't exist won't improve the mileage.

If you really want to calibrate whether your car is getting the mileage it should, I'd take a trip where the variables are cut down and you can get a true handle on mileage. And keep careful notes on the odometer mileage and the fuel used. On a trip cruising at steady freeway speeds (65-75), you should be getting around 27-31 mpg and be able to go around 300 miles on a tank before the low-fuel light comes on and you need to fill up with a couple gallons in reserve. If you're not getting this, you may have an issue with your particular car.

- Mark

 

It makes me laugh everytime somebody ******* about mpg in their MINI. I for one did not by this car for the fuel economy. I bought this car because I LOVE the car, the culture and everything that goes along with driving a MINI. If all your worried about is fuel economy drive a bloody Prius!!!

 

I bought my MINI for fun and mileage (my Jeep get 15mpg on the highways). I don't drive like an old lady so my hwy mileage is usually around 28mpg in my 08 MCSc but the other day I took a trip from my home in Queens NY to Scranton PA. I drove as like my dad did and used the cruise to keep my speed steady and slower than I'm used to driving (lead foot here). I managed to get 31mpg during this trip. I was actually impressed how well I did.
I know this post doesn't really address the issue of the OP but I felt the need to chime in.

 

Right on dude - case in point:

400,000 MILE MINI

 

I do about 80% around town driving in my '03 R53, and average about 21 MPG calculated (EPA city MPG is 25). My trip computer is about 2 MPG higher. In my area we have 10% ethanol all year round and that has a significant effect. Yes, I'm disappointed it isn't higher.

 

If you are filling up when "the red light comes on" you have used ABOUT 11 gal. I watch mine very closely (03 MCS). So you are getting about 20 to 22 MPG. I was getting the same before I got mine re programed (JCW tune) and now I get about 24 with mixed driving.

It never really mattered how I drove I still usually got the same mileage.

 

I'd say this is more or less average, perhaps even a little low.... but for the 2nd gen cars, not the 1st. The 2nd gen turbocharged cars are a good 5 mpg (20% more or less) higher than the 1st gen supercharged cars. BMW has stated that one of the main reasons they abandoned the supercharged cars was because of poor fuel efficiency.

- Mark

 

Just a clarification.... EPA revised all the MPG figures for the Gen 1 cars in 2007 because the previously published figures were unrealistic. The car shipped with a window sticker that said 25 city, but if you go up to the EPA site today, an R53 manual is EPA rated at 22 city.

- Mark

 

I'm typically seeing 26 - 27 combined in my '05. Highway only I may get to 30 but that's pushing it. City is probably 25ish.

Mind you, it's down a good 3mpg since 10% ethanol became the norm. With real gas it used to be much better, quicker, more responsive, happier - but that's another debate.

 

42 posts and no real quantification of what the actual mpg numbers are!?!
Just write down the miles on the trip odometer and the number of gallons at each
fillup and divide one by the other. It's not rocket science (but it is pocket rocket science).
I have been doing this every fillup for 9 years. I keep an index card and a pen in the glove compartment.
(I have a 2003 MC, not an MCS, and my average mpg is about 26-27 mpg, - mostly non-highway driving).

 

At least the OP made it obvious it's a seat-of-the-pants calc. I frequent a GM diesel truck forum and typically they are quoting the dash read-out - which is notoriously not accurate. And often resetting it on the freeway then marveling at 25 MPG in a 8,000 pound truck, or 99 MPG down an off ramp. Yea that's real world iin a rig with 397 HP... 765 ft lbs of torque and 20,000+ pounds GVWR from the factory.

 

It may have been said but the fuel filter is not part of the maintenance plan as they have this strange belief it's a "lifetime" part. After changing mine at 126k miles the trip computer showed an improvement of 3/4 of a mile per gallon. Not a huge difference but every bit helps.

 

I got about 25-27 mpg in town calculated when I first got mine and it was 100% stock.

When I did the one-ball, it bumped up about 1 mpg and ran a little better.

When I did the airbox mod, it stayed about the same mpg, and ran a little better.

When I ditched the one-ball for a hand-me-down free-flow exhaust, I picked up about 2-3 mpg around town, and if I drove it like a granny, I could get almost 31 mpg.

When I added the 16% pulley and cooler plugs, I gave back all the mpg increases to get the extra power. That said, I can *still* coax almost 28 mpg out of it if I drive like a granny--it's just harder to do so when it's so much fun to go ZOOM....

HTH!

C ya,
Dutch

 

My '05 MCS (Pure Silver, Boost) gets about 22-23 city and 28-29 highway, both according to the in-dash computer. I'll follow up with calculations according to Act_04's methodology.
Per Act_04's earlier comment, I wasn't aware of such a large discrepency between actual mileage and the computer readout mileage. Is this a common problem? And if so, should the computer mileage estimate basically be ignored?

 

I have found that the computer is consistently about 10% "optimistic". So, if it says 28.3, it really means 28.3 - 2.8, which ends up yielding 25.8 or thereabouts when you calculate using the miles/gallons method.

HTH!

C ya,
Dutch

 

The computer readout is an estimate. Does anyone know how the computer gets its numbers? I ask because it might give false numbers based on size of fuel injectors, if the car has been tuned, and the outer diameter of your tires.

Think about it this way, your car's computer can only detect the number of rotations on a wheel. There is an average tire size (bigger diameter = larger circumference = more distance traveled per rotation) that it will then use to calculate a distance based on the number of rotations. So there will be error (however minimal) as you wear your tires down by driving. This is just one example of how error is introduced into the computer readout. There could definitely be other sources and it is impractical to design a system that could measure perfect mileage unless you want to pay a lot more money for your vehicle.

 

As an ase tech, you know to ONLY TRUST A FUEL GUAGE on full or empty.
just calculate your mpg. Simple get a real number.
Low to mid 20's mpg on a gen1 car is common...especially with widert tires rims...and if they are not the stock diameter, your speedo is off...both for distance and speed...
just a hunch...pull off the intercooler....look down at the fuel injectors...and let us know what color the striping is...i'm thinking you might be running jcw injectors or bigger no tune....
But a tech would plug into the odb and look at the longterm fuel trims and could determine the same info....
A bupass vanve stuck or ziptied CLOSED (opposite how it normally fails) would get you worse mpg...always on boost, never on bypass as desgined below 2500 rpm or so.....
Also mid 20's with driving style is kinda normal....so calculate your mpg....kinda the most important number!!