fortunately I run a 24" diameter wheel/tire package

so axle torque = thrust

a couple of weeks ago i was reading a thread on mpg, and got curious...

i watch mpg carefully, as an indicator of overall drive train health, so i knew i was getting a consistant 26.5-27.0 mpg mixed back roads and highways

at the time my driving habits were usually about a 75-80mpg highway cruise (> 3k rpm) and changing up around 3,500-4,000 rpm. not aggressive really, but not that gentle either...

so i tried featherfooting it! i change the highway cruise speed to no more than 75 ( < 3k ) and started changing up at 2,500 rpm where i knew i did not need acceleration. my back road cruise at 40-45 mph became a 5th gear cruise, and i started driving at 2,000 rpm.

bang -- 32.0 to 33.1 mpg - consistantly

that was such a jump that i've kept the new habits!

when i now go out and run a piece of twisties hard, with the use of the full powerband, i feel almost guilty at the fuel consumed. overall i've gone from almost two tanks per week to about one and a little.

and honestly i'm enjoying the handling as much as ever - i didn't slow down on the back roads, i just run them one gear higher...

 

A good short paper on this subject appears here ... helps make the concepts laid out in this thread a bit more understandable.

 

So, about 98% of stock O.D.

You've changed three parameters, making it hard to tell whether your increased mpg is from reduced speed, reduced rpm, or a change in driving style. With the boxy shape of the MINI, reducing speed speed from 80 to 75 will give you improved mpg. Changing how much you put your foot in it can also affect mpg.

Try maintaining the same speeds and acceleration rates, and only change the typical rpm you are running. See how that affects mpg.

 

lol ... funny you quoted me with that link? (I guess I come across confused) What's funny is I read that very same article a good many years ago, a few times. It was the single most useful paper I'd ever read on the subject and finally made me understand the significance of torque, RPM, redline, and gearing ... and how mistaken I had been in not appreciating cars that made their torque peak near redline, i.e. low torque, high HP screamers. Reading it along with some others finally provided me with the 'epiphany moment' I needed to understand HP vs. Torque. It explained to me why an M3 with so much less torque then my C43 could spank it.

It's also behind my confusion as to why the R56 S has such a relatively 'low' redline by todays standards. Being able to deliver the torque for just 500 let alone 1000 more RPM would do worlds of good for the performance of the R56S. I'd figure the moment of inertia of a 1.6L and air-flow needs would easily lend itself to a 7K or bit higher redline. (Aren't the Audi and BMW direct injection engines higher redline engines?)

 

[quote]
__________________

Quote:

karlInSanDiego

Sorry for getting off subject, but Karl, It looks like an old MGA in your sig. Do you have any finished pics or is it still a work in progress?