Just curious about this one - have any of you 500C owners noticed a difference in mpg when running with the top down?
Technical 500C Fuel Consumption
- Thread starter jrkitching
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Technical 500C Fuel Consumption
I never noticed a difference, but I've never run a whole tank with the roof down.
Today though, I did a 30 mile run to the airport and back. On the way there with the roof up and the fan on cool so as not to mess up my Mum's hair, and the way back with the roof fully down and no fan on.
The average consumption stayed the same on the way there and went up on the way back. My usual trips are round town so I would have expected it to go up on a longer run anyway. It certainly didn't drop with the roof down.
Today though, I did a 30 mile run to the airport and back. On the way there with the roof up and the fan on cool so as not to mess up my Mum's hair, and the way back with the roof fully down and no fan on.
The average consumption stayed the same on the way there and went up on the way back. My usual trips are round town so I would have expected it to go up on a longer run anyway. It certainly didn't drop with the roof down.
To me that would actually suggest that there is a drop in consumption when you put the roof down. Lets say the car does 50mpg on the way there, then when you're going back home and the engine is warm and more efficient it does the same mpg that would suggest that the car is less efficient with the roof down. If the car was the same with the roof up as down then your mpg would have gone up as you've switched the air con off.
There are too many things influencing fuel economy for it to be obvious whether the roof's position has an effect. In my humble opinion. 
Ok - I had a 20 minute drive to Mum's to pick her up so car nice and warm before I started my journey to airport.
The drive is a bit hilly, more undulating, but it's the same there and back.
On the way there the average mpg was 43.3 and stuck there. On the way back it went up to 44.5, Not a huge difference, but I only meant it show that the mpg doesn't necessarily go down with the roof down.
But probably far too short a drive for a proper test.
The drive is a bit hilly, more undulating, but it's the same there and back.
On the way there the average mpg was 43.3 and stuck there. On the way back it went up to 44.5, Not a huge difference, but I only meant it show that the mpg doesn't necessarily go down with the roof down.
But probably far too short a drive for a proper test.
As I mentioned before, the engine will be warmed on the way back it will perform better.
:chin: Wonder how much her mum weighs. :devil:
Keithjecks
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I am sure the drag is higher with the roof down, but i have never noticed any difference in fuel consumption
There are too many things influencing fuel economy for it to be obvious whether the roof's position has an effect. In my humble opinion.
Spot on, on the way there more fuel in the car, extra person, luggage, on the way back roof down, one person, no luggage, less fuel. The return mileage must be much better but slightly let down by roof open..
It's an open and shut case Watson.
I'll be picking her up tomorrow, so could test the journey again the other way, except she doesn't get in until 10pm and it's due to rain so I won't be putting the roof down! I'm such a wimp but there is the frizzy hair issue!
