Ok - I'm new to this forum and I've searched to see if anyone has mentioned this before, so be nice! I've got an 06 Mini w/ a five speed manual transmission. At 80 MPH I'm running around 4000 RPM's or just under which sounds and feels high. If anyone has a 6 speed manual what RPM's are you running at 80 MPH? I'm averaging around 34 MPG at those speeds, but I think I'd get better gas mileage if I were running at lower RPM's with a 6 speed. I've got 15 inch wheels and going to a 16 or 17 inch wheel may give me a 4% reduction in RPM's to 3850, but it sounds like the engines sweet spot is somewhere between 2800, and 32 RPM's. Any thought? Thanks!

 

That doesn't sound high to me. My two 1.8T Audi's were about the same RPM at 80

 

with the 6-speed, I'm not too much lower, prolly around 3500 or so, but I forget right now. anyways, sometimes its better to be at a higher rpm because then your engine is right in its power band which means that even though its at a higher rpm, its working less to keep the car going at that speed. if you were at 2800 you'd be below where the engine is making most if its power which means that its going to be working harder to keep the car going at w/e the speed is, therefor using more gas.

This has always been my understanding, but if I'm wrong please correct me

 

Thanks - Your're right about the power band RPM's. Sustaining 4000 RPM's just seems like a lot. The What kind of gas mileage ae you getting w/ your 6 speed?

 

I have an '02 MCS with the 6 speed. At 80 MPH I am right around 3300 rpms. I get about 34-35 mpg at that speed, according to the computer. Doesn't seem to make that much difference from yours. I find that to be kind of weird, because I can increase my fuel mileage up around 38 mph if I am tooling around at 60 mph at 2300 rpms. Considering that you are getting 34 mpg at 4,000 rpms, which is a difference of 700 between the 5 speed and 6 speed, then I should get better mileage than that...and I am running 17" wheels also. AGHHH, math is starting to make my brain hurt. Too........many.........numbers.........

 

I wouldn't be surprised if the six speed manual transmissions have changed from the 02 to 07 models. I know the 07's have the Getrag transmissions in them. I don't know what the final drive ratios are. You're right too much math. I can get close to 40 MPG at 55-60 MPH. Did you notice any difference in performance, handling or gas mileage with your 17" inch wheels? Thanks!

 

Holy crap...40MPG, and not have to do it in a Geo Metro? Bonus.
I have always had the 17" wheels on my car. The only thing I can tell you is that there is a difference between the runflats and standard tires. The runflats I believe are a harder rubber which translates to not quite as much sticky-to-the-road feel, they will also jar the fillings out of your teeth when paired with the Sport Suspension. I like the standard tires I have on now better. The tires themselves also went from a 205/45R17 to a 215/45R17, which probably helped a little in the way they feel on the road, slightly wider, and a tad taller. I think performance wise I like the non-runflats more. Oh, and my speedo is slightly off now, but that is probably from the size.
I personally like the looks of 18" wheels, but I think the ride would just be that much more choppy with that much less rubber between you and the road.
Other than that, I really haven't noticed anything different in the gas mileage between the two.
I did have a kind-of-neighbor that had a MC with the 5 speed who was consistantly getting 38mpg on her 15" wheels...go figure. Maybe she was just a granny driver or something.