Can you get 30+ MPG going 70-75mph?

[Vracer111]

I was able to get 31mpg going ~80mph through the Panhandle of Texas and mountainous regions of New Mexico, and going through the Grand Canyon North Rim area/mountains of northern Arizona...mountains don't decrease your fuel mileage if you do it right. Use the contour of the land to your advantage and navigate traffic correctly to not get stuck behind slower vehicles turtle racing for an extended time. 70-75 mph seems worse on fuel mileage than 80-85mph...

Oh yes, I run 5-W30 and was on my track tires (Kumho Ecsta XS in stock size, aired to 40psi) as well...

[dnieves]

I saw that once on a long continuous drive (constant speed) but I thought the MPG counter was malfunctioning. Then again regular stop and go traffic/city driving displays pathetic mpg (as expected).

[reeves]

29-30 mpg, with ~70% hwy commute daily.
31-33 mpg, with 95% hwy traveling out of state (cruising alot at 75-80mph).

[Dake]

Originally Posted by rice_classic

I don't know what it is about this car but the MPG hit I take when changing from 70 to 75mph is like 4mpg. At 70mph without cruise on I can get 34mpg. At 75 I get 30 or 31.

Drag increases exponentially with speed.

That being said, I still get 34 mpg at 74 mph.

[chrisl]

Originally Posted by Dake

Drag increases exponentially with speed.

That being said, I still get 34 mpg at 74 mph.

Technically, drag increases quadratically with speed, which is quite a bit better than if it were to increase exponentially.

(Sorry - my inner engineer is picky about that sort of thing)

[carbonBLUE]

i get over 30mpgs at 60mph-80mph

my celica gts got 34mpgs at 100mph cruising cross country, would be perfect for gumball 3000 lol

but my celica gts would get 34 mpgs at 70mph aswell lol pretty much no change in fuel economy

[Ozzman]

I can get 30mpg on the highway at 75mph with a mountain bike on the back adding more drag.

[humfrz]

Originally Posted by carbonBLUE

i get over 30mpgs at 60mph-80mph

my celica gts got 34mpgs at 100mph cruising cross country, would be perfect for gumball 3000 lol

but my celica gts would get 34 mpgs at 70mph aswell lol pretty much no change in fuel economy

......and what country was that ...... (Nevada is not a country .... ) .......

[carbonBLUE]

Originally Posted by humfrz

......and what country was that ...... (Nevada is not a country .... ) .......

when did i mention nevada? i took a road trip for 1200 miles and set my cruise at 100 mph. I didnt see a soul for like 2 hours here and there. :/

[humfrz]

Originally Posted by carbonBLUE

when did i mention nevada? i took a road trip for 1200 miles and set my cruise at 100 mph. I didnt see a soul for like 2 hours here and there. :/

Well, the only place in the the US that I've been able to cruise at over 100 mph for any extended period of time was Nevada ...

Allow me to re phrase the question. What country were you in that enabled you to cruise at 100 MPH ..??

[strat61caster]

Originally Posted by chrisl

Technically, drag increases quadratically with speed, which is quite a bit better than if it were to increase exponentially.

(Sorry - my inner engineer is picky about that sort of thing)

Uh X^2 is exponential as well as quadratic.

A square is a rectangle but not all rectangles are squares.

He isn't wrong, you're just being pedantic. And not in a useful way, you could have at least linked some literature:

[ame="http://en.wikipedia.org/wiki/Drag_equation"]Drag equation - Wikipedia, the free encyclopedia[/ame]

[carbonBLUE]

Originally Posted by humfrz

Well, the only place in the the US that I've been able to cruise at over 100 mph for any extended period of time was Nevada ...

Allow me to re phrase the question. What country were you in that enabled you to cruise at 100 MPH ..??

i was in the USA Its a straight road the follows the freeway in texas (like 6 hours of nothing till you hit el paso)

I got stopped twice on the way

1st cop stopped me to warn me of the sand that had blown over the road about 10 miles up

2nd stopped me for a warning from going a bit too fast (no ticket)

They stop people mostly just so they don't go insane from the immense boredom, every year I ask them how many people they have seen in the last hour and the answer is always less than 15 lol.

90 mph -100 mph isn't really that fast in modern day cars because they are aerodynamically sound and the suspension can easily handle it.

If you read the Texas driving laws, speed limits are only "suggested" speed limits and gives you a guideline for the road( whether or not you get a ticket for it is completely up to the cop and deeming you unsafe dependent on road condition, how thick the traffic is, and time of day) . People control the speed limit here, if traffic is flowing at 85 mph in a 60 mph its completely legal for you to be doing 85 mph as well. A few places in Dallas, cops will stop you if you are bottle necking the freeway aka going too slow

So way out in BFE where you don't see anyone for long periods of time, you can cruise at higher speeds than indicated and get away with it.

Yeah you can google it if you want and flame me.

I was in a circumstance where i got a ticket for doing 87 in a 70
I fought and won against that tick.
My defense was that: I was on a 4 lane highway and every single lane was doing 85 mph, the cop contested that I was the only one speeding in the left lane. The video tape was reviewed showing that he was cruising at 83 mph- 85 mph with traffic before and after he cited me the ticket WITH the traffic ticket. I simply accelerated a margin faster than the flowing traffic so I could get out of the left most lane so I could make an exit a couple miles up the road without obstructing traffic in the PASSING lane by braking and slowing down two lanes so I could fit in (In texas the left lane is considered a passing lane)

He simply singled me out for having a brand new sports car and being young.

To add onto that, some of the mid night rallys I attend consist of about 50+ cars going down deserted freeways getting across the dallas-ft worth metroplex at cursing at speeds close 100mph. We go by cops and they just sit there, we had one of them follow us to our destination and told us to just watch out for other motorists (mind that during the 5 miles he followed us we didn't pass a soul that wasn't with us. And mind that there is a difference between racing, trying to top your car out, and cruising at 80mph - 100mph.

btw the FR-S AT gets about 26-28mpg cruising at 90mph

Also there is a road in texas that's 85mph, I've traveled on it a few times and have seen traffic cruising at 100mph and the cops don't do anything to to those people either.

Faster is safer when outside of large cities, the autobahn has proven this year after year. The most deadly accidents usually involve 2 or more cars, and when you don't impose a speed limit, people tend to spread them selves out and put larger distances between each other. If i ever drive faster than the posted speed limit, it's because I can visibly see a break in traffic and I can get away from the other people on the road that are on their cell phones not paying attention.

What's more dangerous, a person traveling 15mph faster than you in the left lane with clear road ahead of him. Or someone traveling 10mph slower than you merging into your lane?

Im sorry i drug this post out but i realized that what i posted could have easily derailed this thread. Any response to this post not relating to the OP, I will not acknowledge. EDIT: I'm not directing this specifically towards @humfrz I'm just saying that I don't want anyone trying to internet police me. 99% of the time I just flow with traffic getting from A to B.

So to get back on track

I drive an auto FR-S

55 mph 45 mpgs
60 mph 43 mpgs
70 mph 39 mpgs
75 mph 37 mpgs
80 mph 36 mpgs

These are rounded amounts, amount can be higher because the numbers i have seen are not on flat roads and do see some slowing and acceleration and very light elevation changes

Number that I have posted are long distance numbers, If you are diving within the city's limits on the freeway you probably won't get these numbers due to the constantly fluctuating flow of traffic.

I haven't done much long distance traveling at 85 mph+ from full to empty without stops because it hurts gas mileage too much where in the celica it didn't affect gas mileage. I can tell you it is less than 30 mpgs above 85mph in the FR-S, the money saved by going slower than 85 mph on long trips is enough to buy me a nice steak dinner when I reach my destination. I would much rather have my steak dinner, than to get there 15% faster after a 10 hour drive.

As a side note, I get pulled over every time I go down that back road highway and never get a ticket. Simply put, they average speed that people drive down that is the better half of 80 mph. Just don't get caught trying to chase your car's top speed. The only people they pull over and ticket are the people who have headlight(s) or taillight(s) out, the people doing well over 100 mph, or people passing recklessly and not giving common curtsy to other motorists while over the speed limit.

[Eurasianman]

Originally Posted by 1086

Also note that the entire tank is 13.2 gallons - I am not sure if the reserve tank is 3 gallons or 2, but from what I have experienced it must be about 3 gallons, which means that the tank size before the 'E' light turns on would be roughly 10.2 gallons.

According to the owner's manual (Section 5.2, Page 365):

Low fuel level warning light
Remaining fuel
(Approximately 1.8 gal. [7.0 L, 1.5 Imp. gal.] or less)

[HunterGreene]

Yes, given "summer blend" gas and favorable winds. Headwinds will chop your MPG impressively.

Summer/Winter blend of gasses can affect MPG as well. My driving habits in winter are different than in summer anyways. I'm seeing 27-30 MPG during winter and 29-32 mpg during the warmer months.