My fuel mileage calculations disagree with you. I had a serious DROP in MPG after getting a 15% pulley reduction with the same "driving style". With more boost, the engine pushes in more fuel to ensure the proper A/F mixture, hence what creates more torque from the bigger explosion caused by the added fuel volumn(sp? or is is volume?). So with my foot at the same position (typically Wide-Open-Throttle), not only do I accellerate faster due to the added torque, but I also chew thru more fuel at the same time. So with my driving style the 15% pulley reduction did NOT drop my MPG, but LOWERED it by 2-8 MPG depending upon the type of trip!!

 

I agree. If you look at the fuel curves on dyno runs, you'll notice that the A/F ratio isn't that bad until over 4k rpm. Here's my take:

1. The ECU will notice that there's more air going into the engine so it will compensate to cover the fuel curve. An aftermarket ECU might change this, though. Another example would be running the same car in the summer and winter. If you don't use the A/C in the summer, you'll actually get better mileage because the ECU will notice that there's less air (since it's hotter) and reduce the fuel to the engine. You'll loose power but gain mileage. Trust me on this one, I also drive a Honda Insight : .

2. The 15% reduction will take more power from the engine to run since it has to be spun faster. It's like riding in a higher gear on a bike.

A regular 'ol air intake will bring more cold air to the engine but the reduced flow restriction more than compensates for the slightly colder (denser) air so mileage would go up.

 

This is a valid viewpoint and one that is probably shared by the majority of NAM members whose MINIs have power enhancements and even those that do not. The MINI is indeed an entertaining car to drive and must have introduced a lot of new owners to the joys of physics.

I wonder if this alternate viewpoint makes sense:

On the other hand the MINI is a tiny car, by USA standards, and may attract folks who sincerely believe, in concert with MINI's own promos, that SUVs in general consume too much space for what they usually contain and use too much fuel for what they usually accomplish. Part of the MINI's attraction to some folks might be that, for a new car, it helps them consume less of the world's resources so their might be more to go around.

I think the MINI has been designed to transcend divergent camps. Originally the Mini was an affordable, compact and economical car near the lower end of the automotive glamorarchy. The current MINI is compact, but has become a cultural icon near the top end of the image scale. To many who have bought it cost may have been secondary. In some well-heeled circles it outshines much grander cars. While a Bentley Azure may be deemed vulgar by some and the Honda Civic may be considered self-flagellation the MINI is too quirky to be easily categorized.

Because, obviously, people buy the MINI for different reasons (how many "classic" Mini's were sold in the USA per year or in total compared to MINI sales today--and consider the widespread demography) it seems justified that as many of them might be as interested in improving fuel economy as those who want to improve lap times. I am grateful NAM provides for a forum for everybody.

Happy motoring.

 

There is another thread that discusses it in more detail...

the OBC is extremely generous in its mpg averaging...around 24 to 26 in the city. I like the OBC, but when I did a gallons to miles hand calc I was woefully short! around 20 to 21

the other thread discusses how to alter the OBC factoring to get to read closer to actual mileage...

btw, I have the alta 15%, Scorpion and hai. I have been trying to drive like an old woman to maximize mpg using many methods described above...THIS IS SHEER TORTURE!!!! But another word for patience in the Bible is long-suffering

 

I know my MCS runs rich from the factory. Talking to a MINI owner who I respect mentioned that when he added the normal set of mods (intake, SC pulley, exhaust, and chip) he was able to run less richly and got better gas mileage as a result.

I'm quite happy with my average, which seems to be around 25.0 (right on where the obc says it is). Its a rough calculation but its in the ballpark.

I would agree with the "you don't buy a MINI for gas sentiment." Getting decent to above average mileage is a plus but certainly not the main purpose of a MINI. Especially an "S".

 

It increases VOLUMETRIC EFFICIECY, which is a measure of airflow, not a measure of efficient use of fuel. That's why tuned intakes, superchargers and turbos can have a VE greater than 100%! Also, more boost at constant A/F ratio will use more gas at the same RPM. That's why we increase boost, to burn more fuel and make more power.

The efficiency of the burn is goverend more by valve and ignition timing, and injector control.

Matt

 

Ok fine - but adding a pulley on a MINI and driving it the same way (which is very hard to do) still increases fuel economy. That's a fact. Why? I guess I don't know why but I do know it does. Everyone I've talked to about mpg that had the pulley mod done would agree. :smile:

 

With the pulley you have more torque allowing you to drive the same mph at a lower rpm (not across the board mind you, it all depends where your gains in torque are).

 

And I thought mph was all about gear ratios!

 

I just posted elsewhere, but I will add in here that I have an MCS with 19% and the HAI, on 16 inch stock runflats. Last Sunday, I ran about a 100 miles to a Solo2 event, ran the event, and returned the 100 miles, did some around town stop and go. Miles on the odo 328.1 / 11.419 gals = 28.73mpg. The highway was 2 lane not interstate, winding and hilly, speeds @ 60-65mph.
I was not trying for gas mileage, just my normal driving, plus an event.
I would agree that these cars improve mileage with age, and the pulley does not detract from the mileage.

 

Huh?

 

Last summer I took my '03 MCS from LA to Tucson at 70-80 mph, used the cruise control for the most part, kept the windows and sunroof closed, avoided the AC (tough, but possible), and managed 35.1 mpg average. I was happy with that.

At the time, the car had an alta intake with silicone hose. 17" S-lites with stock Pirelli run-flats.

I was happy with that.

KFD

 

OK folks,

I'll give you my system, bunch of mods (pully/CAI/catback/light wheel SSR Comps/unichip/etc.) drive the heck out of it.

Fill it with gas when it gets low and Don't Worry About It.!!!!!!!!!!!!!

I'd rather get 10 MPG on a twisty road than 40 MPG anywhere else.

Earl

 

THIS IS NOT TRUE!!!!!!

At the same RPM, you are pumping more air into the motor. It takes more gas to get the right mixture! LESS efficient in gas per mile, MORE effiecent an air pump. Please, please, please stop saying that a pully makes a motor more efficient!

Those that claim better gas milage claim it based on running in the next gear because they have more torque and CAN run a lower gear.

Real world things for improved gas milage:

Thinner, harder tires.
Increase tire pressure. (both of these lower rolling resisitance).
Get a good oil, like Royal Purple or Red Line. Use the thinnest grade for your driving style.

and the best of all, keep your foot from pressing down hard.

If you want to go into your car, I found that my SC bypass valve wasn't set too good, but I don't know if fixing it helped or hindered.

MTH software (or other ECU mods) that lean the really, really rich mixture should be good for an MPG or two.

some have claimed better gas milage with exhaust and intakes, some not. I guess it depends on driving styles....

Matt

 

Trade it in for a GEO metro 5 speed 2 door 52 MPG hwy

 

I made the above post to demonstrate that a 19% pulley does not necessarily prohibit acceptable milage, not as a claim of maximum efficency. My early experience was 24-25 mpg, that was before the pulley. I now have more miles on the car, and even though I have the 19%, there has been an improvement in milage. Perhaps it would be even better if it were as delivered, but then I would miss the improved drivability from the 19% pulley. I consider it a very worthwhile trade-off.

 

Thought I would share that I did the same thing as I posted above, ran the 100 miles back and forth to the event, autocrossed, plus another 60 or so highway miles, tanked at 307.7, and was rewarded with 30.05 mpg. Talked to a gal with a cvt cooper who is getting @ 33 and she drives @ 90 miles rt commute, so I am pretty happy with 30 not trying!

 

Okay, finally a new idea. How about the TURBONATOR! that will give you some added mileage and also a little HP and torque to boot-$70. good luck!

-Paul

 

I typically feel that anything to increase power should increase fuel efficiency if tuned correctly.

Spinning a supercharger faster is the exception to this rule though. Given the increased parasitic losses I think the best you can hope for is to break even.

The best mod for fuel-efficiency (and power) is something to let you tune your fuel maps. The VAFC is a start, though not a very good solution. All of the other options are unfortunately proprietary and have to be dealer-tuned.

 

Sounds too good to be true... but I can attest that two weekends ago I changed to Mobil1 5W-30, added a K&N cone, inserted a "Tornado Fuel Saver" venturi thingamabob and turned in a hot-lap of 125MPH (on Interstate 495).

Then last weekend I drove ~55 miles down to Budds Creek MD and back (twice) for the NOPI event... and continued driving this week commuting 33 miles to work. Filled up last night @ 430 miles driven with Range:20 remaining miles; she took 12.85 gallons.

NO OTHER VEHICLE IN THE WORLD CAN COMPETE WITH <<MINI>>

 

Wow! You were cutting it pretty close, the Mini only has about 13.2 gallons to the tank! That would mean you were down to about a third of a gallon. You must have been in the low fuel warning zone for awhile.

 

Actually it's a butthair shy of 15 gallons... I know from experience.

 

2 gallon reserve right?

 

Must be a Cooper not an S...I cannot for the life of me get 300 miles out of tank (fill up of 12.5+ gallons) which equates to about 25 mpg granted most of that is city with 1.5 mile short bursts of highway. I stay around 20 to 23 when I drive like an old lady ( apologies to all the old ladies out there )

 

If you are at autocross or the track and your MINI enters the "empty" zone with the light on. Be very careful about running the reserve down.

In performance driving you are likely burning fuel in idling and at the rate of about 11-15 mpg or worse at wide open throttle. A few laps around the track and that would mean you might not be able to get to a gas station in time.

I once ran OUT of gas that way for the first time in 30 years!
Fortunately I have AAA and the nice tow truck man gave me a few gallons to get me going. I had a very long steep uphill to climb coming home from the track on empty. I only needed to go 2 more miles to get to the fuel pumps.
Didn't make it.
Experiment in risk taking is over.
Called my wife and she said "forget it (getting her help), call AAA"
Thank you very much.
And I found out there are some "nice people" that did stop to render assistance or a cell phone.

Another solution- bring a little extra fuel to the track in a small gas container if you like to run on vapor.