TOP UP VS DOWN MPG

[xnuyokr]

I took a 150 mile road trip from Pa to Upstate NY in my 1LT Vert. Averaged 21 mpg going there with the top down, 24 mph coming home in the rain with the top up! This while averaging 75 and 80mph with cruise control on the highway! It wasn't all highway driving, maybe 2/3rds. Anyone else in a drop top getting much better? I average 19 around town!

[marsmann]

I'm in PA too. And recently took a trip to upstate NY to Manlius. I averaged about the same, top up both ways. 22-24mpg.

I normally average 17-19mpg mixed with 50/50 highway/local. Now, on certain days my right foot gets heavier, and that affects it too.... negatively!

I've never really tested it with top down.

[pgustavson]

On my last trip to the Outer Banks (340mi one-way) I averaged 25.5mpg with the top down the whole way and (gasp!) a bike rack holding two bicycles strapped to the trunk. It was mostly interstate and rural highway - not much stop-and-go at all. I've made that trip before w/o the bikes and got 27-28mpg both with top up or down. I think I might lose some mpg with the top down, but not much. Was your trip north more uphill than the trip home???

[theragtopguy]

28 MPG from Philly area to Outer Banks with the top down this past June.

[95birdible]

I never drive with the top up but since I have had my 2012 1SS since April of 12, I average 18 mpg city/highway and 22 mpg on road trips. Not bad for a 400hp V8. My 2006 3.3L V6 Caravan only gets 17 city and 21 highway

[xnuyokr]

I was suprised that I only got 21mpg on the way up, however there was some slow going before I eventually got on a highway. I'm pretty happy with the 19mpg that I get around town, especially with my "spirited" driving! (Lovin the sound I get from the CAI, resonated X pipe and Muffler delete)!

Great numbers for V8 Birdible!

[95birdible]

I think so since my old 68 RS Z/28 back in high school had dual quads, 373 Posi and I got about 12 on the highway and 8 in the city. Motor dyno's at around 380 and the tires. That car was a beast but I could barely crack the 13 second 1/4 time. My current car hands down is better all around. Although my 68 after I redid the suspension actually handled better IMO

[SS PANTHER]

I tried this out last weekend with my 2013 SS A6 vert. Made a 65 mile trip one way with the top down. Average was 75 degrees outside at 10pm. I reset all my trips and mpg, etc. at my house, which, is at 2200' ASL.
The first part of my destination takes me down to 900' ASL in the first 10 miles than pretty much levels out after that. Cruise set at 70mph, no traffic. Right before getting off the freeway my mileage was 26.2mpg. By the time I reached my destination 3 miles later on the street it was 25.8mpg.
Driving home with the top up was almost the same for most of the trip at 25.6mpg and degraded to 24.7mpg by the time I reached home after the the last 10 miles of the trip with a steady incline. I was impressed. I have full bolt ons, shorties not LT's, and most suspension upgrades. Now I'm not sure if I want to dyno and trans tune and change my 3.27's to 3.70 gear's.

[hworth18]

22.9 mpg average with about 50%/50% hwy and city, I get about 29 just hwy miles on long trips. I can't tell you what the difference is with the top up or down since it's a mix.

[SS PANTHER]

Originally Posted by SS PANTHER

I tried this out last weekend with my 2013 SS A6 vert. Made a 65 mile trip one way with the top down. Average was 75 degrees outside at 10pm. I reset all my trips and mpg, etc. at my house, which, is at 2200' ASL.
The first part of my destination takes me down to 900' ASL in the first 10 miles than pretty much levels out after that. Cruise set at 70mph, no traffic. Right before getting off the freeway my mileage was 26.2mpg. By the time I reached my destination 3 miles later on the street it was 25.8mpg.
Driving home with the top up was almost the same for most of the trip at 25.6mpg and degraded to 24.7mpg by the time I reached home after the the last 10 miles of the trip with a steady incline. I was impressed. I have full bolt ons, shorties not LT's, and most suspension upgrades. Now I'm not sure if I want to dyno and trans tune and change my 3.27's to 3.70 gear's.

Oh, and BTW I did not have the tonneau cover on. I was not using my Range AFM device either. I am going to redo the test at about the same time this week with the Range unit plugged in.

[pgustavson]

I ran the test as well. I had to make another trip to Hatteras Island on Wednesday morning. Did the first 120mi with the top up - 28.7mpg, all but 9mi on highway. I reset and then did the next 120mi with the top down - 28.8mpg, all highway. No difference at all for me this trip. I didn't reset anymore, and when I made it back home Thursday night my overall average mpg was 28.5 for 721mi of mostly highway with the top down. Not too shabby. Oh, and I have never used the convertible top boot (that's what I call it) - not sure I even know where it is though it's likely in close proximity to the equally useless engine cover...

[SS PANTHER]

Pgustavson, Interesting that you had very little change in mileage top up and down also. Do you have a windscreen and did you drive with your windows up? Also, what were temps and humidity like?

[pgustavson]

Windscreen? No.
Windows up? Never with the top down. Too BMW-driverish. I don't recall whether I had them up when the top was up, though I think so.

Temps were in the mid 70s and humidity was somewhat high. It was muggy enough that when I left home, the top was too damp to lower even after I tried to towel it dry. When I made a pit-stop at 120mi, the top was dry so I lowered it.

I was actually expecting a difference, but it didn't happen. I am not a huge speeder either, so I set the cruise control a few over the posted limits (55-70). Maybe that helps consistency. However, a "spirited" blast down an on-ramp momentarily rewarded me with a few tenths off the mpg...

[SS PANTHER]

Originally Posted by pgustavson

Windscreen? No.
Windows up? Never with the top down. Too BMW-driverish. I don't recall whether I had them up when the top was up, though I think so.

Temps were in the mid 70s and humidity was somewhat high. It was muggy enough that when I left home, the top was too damp to lower even after I tried to towel it dry. When I made a pit-stop at 120mi, the top was dry so I lowered it.

I was actually expecting a difference, but it didn't happen. I am not a huge speeder either, so I set the cruise control a few over the posted limits (55-70). Maybe that helps consistency. However, a "spirited" blast down an on-ramp momentarily rewarded me with a few tenths off the mpg...

Great top down mileage. I figured you had much higher humidity back there then here. I am surprised you weren't able to top 30mpg with top up with a LT, but my mileage was actually less with my top up although there is a gradual incline part way home.