I've noticed in my Mini on trips around 75-80 mph, it's not very hard to near 30 mpg. I recently took a trip over the i5 with the Mini for the first time, where the speed limit is 70, but the flow of traffic is 85-90 mph. Keeping with the flow of traffic, my fuel economy dropped significantly, and I could only manage 25 mpg. I don't recall if I was driving against wind that day, but for a speed increase of only 5-10 mph that seems like a big drop. What kind of gas mileage do you guys get at those speeds? Is this the norm?

 

It's not the speed or even rpm increase that comes with a simple additional 5-10 mph, it's the increase in that specific rpm range, and the other factors that come with it, involving air and fuel flow for that rpm range.

And yes, that seems normal, maybe even better than normal.

 

Wow, mine has mods and doing 85mph and like 3500rpm and I still seen 33hwy and city I get 25 and I'm far from a light footed driver.

 

My screen name may have a lot to add to the conversation. Air density obviously creates resistance and at some point on the speed scale the equation steepens rapidly requiring increased energy to overcome. Aircraft demonstrate that as the higher the altitude, the better the fuel economy. Those contrails in the sky are at or near 35K feet.
Besides, when people ask me what kind of mileage I get I just grin and say "I don't care, it's too much fun fuss over that.".

 

Top up or down?

My long-term average on my R52 S is about 27 MPG. I definitely see low 20s at 75+ MPH, especially with the top down, but around 30 MPG around 50-55 MPH, unfortunately not for long enough to bring the average up.

 

Air drag force goes up with the square of speed. And as someone else pointed out, I'm surprised the stated fuel economy was that good at the speeds cited.

 

I've got the same sort of mileage on my R53. Averaging between 75-80 gives about 25mpg. Between 65-70 gives ~32mpg.

I also noticed that my car's average MPG readout on the OBC is about 2 higher than the actual consumption so I would keep that in mind as well.

 

t

 

That's impressive, I can't get close to that at 85 mph and I only get 23 in the city :( I'm light footed for the most part but I like running through the gears every so often

 

I seem to pull much better than that but as you mentioned who knows how accurate it is. Although a tank can last me 3 weeks easily but I don't drive it that much . Only on nice days . I was driving today just to test some things out and I swear to God I reset it just to see and it was all city driving and I was at 30.1 when I got home..BUUUUT I was short shifting grandma accelerating and neutral coasting to every stop light .. I could see it honestly getting 25mpg driving as I was but 30 seems like a stretch

 

This is with the top up, I'm haven't driven long distances with the top down so I'm not sure what I get, haha

 

That's my attitude too, although I do feel a little guilty when I get such poor fuel economy with a small car, but the supercharger whine is worth it.

 

I'm pretty sure your real fuel economy is a little lower, the computer is optimistic, but regardless if you're heavy footed 25 mpg still seems pretty good.

 

I just completed my first highway trip last weekend in my 2006 R53. It was roundtrip, 3 hrs out and 3 hrs back, on the same day, same route to take my daughter back to college. I was shocked at how low the MPG was. I took the MINI over my mini-van (2008 Toyota Sienna) for fun and hopefully some fuel savings. The MINI average about 26 MPG per the computer, not much better than what my van would have been.

I definitely think speed comes into play. As I rounded a large city and kept the speed to ~60 MPH in a 55 zone, instant consumption was in the 30's. However, as was traveling ~75 in 70 MPH zones on rural interstate instant consumption was more or less in the mid 20's or so.

 

WHAT??? It goes up??

 

The cold weather has effected my gas mileage negatively more than anything

 

Wow, maybe you were going against some wind? Seems like my car is doing better than expected then.

 

It was raining / snowing most of the trip, but I'm guessing my supercharger may have given me a little bit of a mpg penalty over yours also.

 

Here's what I usually get on the freeway driving speed limits ..
the lower number I have only reset once after doing the ECU reset a.I reset a few weeks ago and I've driven it pretty hard and mostly city,so that would be amazing imo if it's getting that mileage .I reset my speed and the top mpg before I left today to go to the dealership about a 40mile round trip.
i was doing 70 on the freeway and there wasn't much stop n go traffic .
.I feel like there's no way it can get the mileage it does but as long as a tank of gas lasts me I kinda do .I guess I need to write down my mileage before fill up and then fill back up and do the math and see how much it differs from the computer .