High Speed Fuel Economy

I'm interested to know if anyone has measured their fuel economy on high speed long distance trips. More specifically, 80+ MPH cruising speed.

Edit: I'm only interested in data for GT's.

Not a lot of people have access to the ability to drive 80+MPH for extended periods (few hours) without getting ticketed.

Why do you ask?

NoVaGT said:

Not a lot of people have access to the ability to drive 80+MPH for extended periods (few hours) without getting ticketed.

Why do you ask?

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In the midwest it's not that difficult, particularly with a good detector and Waze.

I'm just curious how efficient this body style and powertrain is as speed increases.

Last weekend I rented an '18 Eco Premium and ran I-75 from Miami to Bradenton. Cruising speeds of 75- 105mph and, according to the gauge, got around 22 mph. (and no tickets!)

My daily commute is about 9 miles at avg 45 mph on suburban road with lights, and about 9 miles at avg 70-75 mph on hwy. I am getting 20.5 mpg overall. When I am on highway at that speed the average creeps up. Don’t know if that helps.

I measured about 25-26 mpg according to the computer with cruise set at 80-82 over about 50 miles. Rumor is the computer is about 1mpg off.

You can definitely drive 80+ in socal without getting a ticket.

Vicr said:

Last weekend I rented an '18 Eco Premium and ran I-75 from Miami to Bradenton. Cruising speeds of 75- 105mph and, according to the gauge, got around 22 mph. (and no tickets!)

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:shocked:

I have checked my car @ 70mph cruise control on for 31 miles and it averaged 29 mpg by the computer but actual calculated for that tank of gas was 1.3 mpg less than the final indicated value of 23.2 mpg. I also think I had a 10-15 mph tail wind that day.

I've seen between 22 - 26 cruising at 80 (morning cruise to work)

draconis123 said:

I've seen between 22 - 26 cruising at 80 (morning cruise to work)

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Is that in your current state of tune? Trip computer or hand calculated?

My 16 gt stick did 31 mpg Imperial at 85 mph all the way across Montana on the Interstate. only 2 less than at 60 on small roads. Its happy there..
(take 20% off for US mpg)

l'Ingegnere said:

Is that in your current state of tune? Trip computer or hand calculated?

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Yes. Current tune. That's with the trip computer so between 1-2 mpg less.

HeavyMetalMonk said:

You can definitely drive 80+ in socal without getting a ticket.

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Wish VA was like that, here it's considered reckless driving.

MustangDaily said:

Wish VA was like that, here it's considered reckless driving.

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CHP's stated goals are safe and efficient flow of traffic, not $$ generation. That being said it ends up being highly arbitrary. You can cruise at 80 with everyone else one day and get a ticket for 72 in a 65 the next (personal experience talking).

I know a guy who just got back from a 100 mile drive from Los Alamos to Albuquerque averaging about 90... 23.9 mph. Of course it is more downhill than up.

I'm lucky to get 18-20 cruising at 80-85 everyday. My best has been 22 mpg when driving in bad weather (keeping it easy on the gas and going slower).

Now that I'm back to e85, I get 13.5 mpg.