My guess is that the sticker MPG on a Mini Convertible is calculated in a top-up configuration. That is if they actually differentiate the MPG from the non-convertible model at all.

Question: what is the real-world reduction in fuel economy in driving with the top down? I would think it would be a BIGGER difference on highway than in the city. Is it just a mile or two? Five? Ten?

I almost exclusively drive with the top down, but I also don't drive that often or that far. Was curious what other people have experienced.

 

They definitely do differentiate the MPG between Convertible and non-Convertible. I don't know the numbers off-hand but the Convertible is worse because it is a heavier vehicle and even when the top is up, it will have more drag than the solid roof Coupe.

The issue you have of top up vs top down, you have more drag when the top is down, but let's say the weather is warm and I have the top up, I will be running air conditioning. When the top is down I'll pretty much turn the AC off unless it's really hot and I am in slow traffic, so it's a trade-off.

It's hard to verify because while I do a lot of highway driving, traffic conditions and my mood will vary my MPG quite a bit. Some days I don't mind 65mph, some days I enjoy 75mph, and some days I can't do more than 55mph. I would estimate 2-3mpg drop when the top is down but again, I could just be talking out of my ***.

 

If I wanted gas mileage I would have purchased a Prius. I wanted that "top-down" feeling you get in a great handling car on a road like the Blue Bridge Parkway.

 

Hiya Rich,

I'll get back to you. That said, I'm not for sure sold that there's a difference, or a reduction, between the two.

I have a couple of engineer buddies (yeah yeah, I know, engineers right? =) ), and this reminds me of an interesting conversation I'd had with them years ago. Basically, I think the premise revolved around gas mileage and drag reduction on pickup trucks. I would often see tailgates hanging down, and they told me it was because the drivers (erroneously) dropped it to reduce drag and increase mileage. Whoaahkay, made sense to me!

But (grasping my memory straws a little here, might have been referencing a Mythbusters episode or something) they essentially explained that the way aerodynamics worked out, leaving the tailgate in the up position created a sort of stagnant air "bubble" in the back of the truck. There was, as a result, less drag against the air bubble than against the entire bed of the truck.

In theoretical summation, then: maybe, when I'm driving down the highway with the top down, I'm living in my own bubble... Yup! Lol.

- Ald

 

My response is much shorter. When asked about mileage I put on the biggest grin I can and say: "I don't care." The top is down at all times unless conditions 1, 2, 3 or 4 are in affect.

 

Top down= more fun and better mileage

 

This thread really interests me, so I'll play =)

Alright, using my commute as a baseline (mixed, about half highway and half street, ~25 miles each way), I drove almost exclusively top down and came out with just shy of 39mpg. I could probably have probably stretched it to 40, but we'll call it 39 on average.

So, for the sake of science, I decided to fill up today and begrudgingly drive through the next few days top-up. It's too soon to make any judgments here, because naturally I hit every green light on my way in, but for fun's sake I'm at about 41 for my ride in. Let's see how it averages out over the next few days.

For Science!

- Ald

 

So I'm just back from vacation, and about halfway through a tank of gas on the top-up half of the adventure, with an average of ~38mpg. So, that puts the difference in gas mileage at <3%, leaning towards top-down performance.

So yep - what ECS said! More fun, (possibly) better mileage. Now I can go back to putting the top down =D

 

You have my condolences for the time you had the top up...for the sake of science. Henceforth, leave the science to the scientists and get back to topless motoring - motoring at it's best.