Are the EPA mileage estimates for convertibles made with the top up or down?

And really, does it have that much of an effect?

It may be a moot point as it was 31 outside this morning...

Mike

On Sat, 4 Oct 2008 08:17:06 -0400, "Mike Y" <joe@user.com> wrote:

>Are the EPA mileage estimates for convertibles made with the top up or down?
>
>And really, does it have that much of an effect?
>
>It may be a moot point as it was 31 outside this morning...

Probably roof up - more aerodynamic that way. You get a lot of
turbulence from the wind flow swirling vortices over the back seat.

--<< Bruce >>--

in article ldJFk.35102$2J7.30145@newsfe02.iad, Mike Y at joe@user.com wrote
on 10/4/08 5:17 AM:

> And really, does it have that much of an effect?


yes .. slip streaming the conveyance ... with the top up for example, or the
tail gate down or removed ... helps mileage per se. However with a Boss 350
sucking 4 barrels ... not much room to play with there.

"Alan B. Mac Farlane" <alanb@sonic.net> wrote in message
news:C50E1502.1378%alanb@sonic.net...
> in article ldJFk.35102$2J7.30145@newsfe02.iad, Mike Y at joe@user.com
wrote
> on 10/4/08 5:17 AM:
>
> > And really, does it have that much of an effect?
>
>
> yes .. slip streaming the conveyance ... with the top up for example, or
the
> tail gate down or removed ... helps mileage per se. However with a Boss
350
> sucking 4 barrels ... not much room to play with there.
>

Hmm... 350?

But I agree with the sentiment. My Mustang is the 4.0L V6. Thing is, with
my Pontiac GP, I can't crack the drivers window more than an inch or so
(2 inches since I added the vent visors) before I can't use my phone for all
the noise. But with my Mustang, I can answer a call with the top and the
windows down. The only problem with the Mustang is the noise when I'm
going by concrete jersey dividers and I'm in the adjacent lane, or I'm
passing other vehicles.

Yeah, I'm sure the car is more 'slick' through the air with the top up at
65, but I really don't think it's the hit on efficiency it used to be in
older
models.

It would be interesting if someone had one of the 'information systems' in
one of the Mustang convertibles and see if it would report short term
mileage differences...

I wonder... Are there aftermarket message centers that report mileage
and such? I know they used to be available as add-on kits years ago before
vehicles started having on-board computers, but I assumed that market
dried up once it became a manufacturer's option. Still, I suppose if you
had the right software and a simple OBID II interface...

Mike

"I M" <nowizer@webtv.net> wrote in message
news:18670-48E7E564-1044@storefull-3253.bay.webtv.net...
>
>
> does the EPA actually road drive cars to establish mileage
> estimates....or is it it done in the lab on a dyno?

It is done in the lab on a dyno. I doubt they are not making any
allowance for top up / top down. I assume they do the testing using
the CD for top up. See http://www.fueleconomy.gov/feg/how_tested.shtml
.. For the Mustang there are not separate listings for convertibles and
coupes. Toyota does list the Solara convertible separately from the
coupe, and the convertible gets 1 mpg lower highway mileage. I assume
this is a result of the convertibles heavier weight and higher CD.
Another example would be BMW, they list convertible and sedan models
separately. The 135i sedan gets 1 mpg better city mileage. This is
almost certainly because it is lighter.

Ed

31? I have owned convertibles all my life and even I never put the top down
when it is below 55 degrees.


"Mike Y" <joe@user.com> wrote in message
news:ldJFk.35102$2J7.30145@newsfe02.iad...
> Are the EPA mileage estimates for convertibles made with the top up or
> down?
>
> And really, does it have that much of an effect?
>
> It may be a moot point as it was 31 outside this morning...
>
> Mike
>
>

My Mustang '09 GT convertible, my sixth one since '99, have all averaged
around 22/23 and I have the top down most of the time, except in winter


"Alan B. Mac Farlane" <alanb@sonic.net> wrote in message
news:C50E1502.1378%alanb@sonic.net...
> in article ldJFk.35102$2J7.30145@newsfe02.iad, Mike Y at joe@user.com
> wrote
> on 10/4/08 5:17 AM:
>
>> And really, does it have that much of an effect?
>
>
> yes .. slip streaming the conveyance ... with the top up for example, or
> the
> tail gate down or removed ... helps mileage per se. However with a Boss
> 350
> sucking 4 barrels ... not much room to play with there.
>

The EPA rating for the Mustang GT V8 convertible is one less than the V6
convertible, both city and highway. As to the V6 and V8 coupes they are one
less than the convertibles.

My one son has two '08 coupes, a V6 and a V8. In the real world, if you
live in a mountainous area like we do, his V6 coupe averages TWO miles LESS
than the his V8 coupe. Like it says on the label "Your mileage may vary."


"C. E. White" <cewhite3@removemindspring.com> wrote in message
news:48ea419a$1@kcnews01...
>
> "I M" <nowizer@webtv.net> wrote in message
> news:18670-48E7E564-1044@storefull-3253.bay.webtv.net...
>>
>>
>> does the EPA actually road drive cars to establish mileage
>> estimates....or is it it done in the lab on a dyno?
>
> It is done in the lab on a dyno. I doubt they are not making any allowance
> for top up / top down. I assume they do the testing using the CD for top
> up. See http://www.fueleconomy.gov/feg/how_tested.shtml . For the Mustang
> there are not separate listings for convertibles and coupes. Toyota does
> list the Solara convertible separately from the coupe, and the convertible
> gets 1 mpg lower highway mileage. I assume this is a result of the
> convertibles heavier weight and higher CD. Another example would be BMW,
> they list convertible and sedan models separately. The 135i sedan gets 1
> mpg better city mileage. This is almost certainly because it is lighter.
>
> Ed
>