Ok, here's a topic I haven't seen discussed here yet. Trying to tune your MINI for better fuel economy.

I have a 2008 MCS Cabrio that's all stock right now. I have heard from time to time that some changes can improve fuel economy (for example, and CAI). I realize that 95% of fuel economy comes from the way you drive, but for this discussion, let's just assume that the way we're driving is the same regardless.

What items would (in theory) improve gas mileage?

Is it possible to have improved gas mileage at low RPMs and better performance at high RPMs? (i.e. if you always shift below 3500 RPM, you get better fuel economy after change the component, but if you consistently rev up above 3500 RPM before shifting, you get more power).

Thanks in advance.

 

Underside panels. front and rear splitters/diffusers. wheel well covers.
Keep the tire pressure up.
You could get smaller injectors and a tune.

 

justacooper FTW!!!

wheel choices can come into play as well. lightweight 15's would be a good choice.

 

I should probably add that I wouldn't want to lose power for the sake of better fuel economy. If I were willing to do that, I wouldn't have gotten the "S" model in the first place.

How much would you expect from aerodynamic adjustments, such as underside panels and wheel well covers? Are we talking about fractions of a percent difference or something more meaningful? Other than aesthetics, are there any downsides to either?

Thanks again.

 

iblack, you've got a convertible S - mechanically and aerodynamically the least amenable to fuel economy.

For relatively better mileage, shift up as early as possible, leave the top up, put on hard, skinny tires, and then go beat your head against a wall, because it won't really make a difference.

Panels and covers would not make a meaningful difference, IMO.

 

At relatively slow speeds aerodynamics don't make much of a difference in the required power. At 30-40 MPH a change in CD of .1 (Huge, that's like a Ford F150 vs a MINI) wouldn't mean a whole lot. Maybe good for 1-2 mpg. At speeds above 80 though, it's a big difference.

The easiest way to improve fuel economy is to drive more carefully. Tunes, CAI's and all the rest aren't going to do anything (Not to mention even if you could save 3-4 mpg, how long would it take you to realize any savings after the initial $500+ outlay).

 

Fair enough. I had a feeling it wasn't too likely to make a big difference either way, but figured it was worth checking.

I ran the numbers before and figured that even a big improvement in mileage (say, from 25 to 30 mpg) would only save me about $360 per year (assuming 15,000 miles and gas around $3.60 per gallon).

I guess I'll just enjoy the ride not worry about this stuff.

Thanks for the help.

 

Let's just say projects are in the works on this...

 

gearing on the S would make a big difference.

 

Rolling resistance is a major factor in fuel economy. At the cost of performance, you can keep your tire pressures higher and make sure your alignment, especially toe out/in, is correct. Also, driving style, and keeping speed down on highway is paramount.

This does not come from someone with high economy experience. Even driving conservatively with equal mix of freeway and around town, my car only gets 21 -22 mpg. Most of the blame is attributable to Jan and his 239 hp. tune on my car. That and 215-45x16 Azeni tires on my car which are a lot smaller in diameter than stock and beg to be tested all the time.