Save gas. Drive slow.

[OUCaptain]

I drive a 99 Wranger 6cyl with 33" tires. I'm lucky to get 13mpg on the highway. I've slowed way down lately. I still drive quickly around town, I just start off a bit slower and avoid the highway if possible. I actually get better mileage in town.

 

[Auryg]

I also seem to remember the highway death rate dropping when Montana got rid of their highway speed limits.

 

[imported_Baloo]

Wind resistance becomess a factor at about 29 MPH. You will get your best mileage at or near 29MPH, much better mileage than you'd get at highway speeds. Some cars would get twice as many miles per gallaon at 29mph than they get at 70 MPH. But you won't see me going down the highway at 29MPH.

Driving slow improves mileage, so does keeping your RPM's low while accelerating.

 

[Demo24]

While it may be more efficient to go say 30mph, it sure isn't going to get you anywhere quickly. Thus round abouts 60mph is the compromise between reasonable speed and efficiency. Course if you car is lighter and has a lower drag coefficient then it makes it all the better.

 

[Linflas]

I ignored it the first time and I'll ignore it again if the Feds force that nonsense on the states.

 

[middlehead]

Interstate in this area is 75 limit, I usually go 65 if I'm in a relatively clear area but I'll speed up if I'm starting to impact traffic.

County and state highways are still 55 limit, but I don't use them often because they're not maintained sufficiently.

 

[EagleKeeper]

Originally posted by: Kelemvor
Once you get above the 50s or so the wind resistance has more affect so gas mileage goes down exponentially.

Faster you go the worse your gas mileage gets.

Try it for a week and don't go over 55 (or whatever the speed limit is). You'll see a difference.

Also, for manuals, shift into the higher gears as soon as possible.

Take foot of the fuel pedal when approaching an intersection early when you know you will have to stop.

For auto trannys - slow & steady from the start and back of a fraction when the car is ready to shift - it shifts sooner which puts you in the more efficient gear.

These are not hints for the show offs, but for the stingies.

 

[ViviTheMage]

Originally posted by: tenshodo13
Well, 60 mph IS the most gas efficient speed.

depends on the car ........

 

[Aikouka]

Originally posted by: mugs
:music: I can't drive... FIFTY FIVE! :music:

I have the sudden urge to watch BTTF2.

 

[skace]

I'll be sure to hit 90mph for your friend today, and pass a few fat girls to boot.

 

[IceBergSLiM]

Originally posted by: tenshodo13
Well, 60 mph IS the most gas efficient speed.

not in my car. If am going purely by the rpms......I can cruise at 85 mph at about 2500 rpms

60 mph is in the middle of a gear and the rpms are 3100

 

[Demon-Xanth]

Because of my car's gearing and the engine's tuning, my MPG is very flat from 55-75MPH. Below that I get worse, above that I get tickets.

 

[Demon-Xanth]

Originally posted by: Eeezee

Those government tips, are they city or freeway driving? That would make a big difference. 30mph on a closed track is not the same as 30mph in the city (lots of stopping + accelerating consumes much more fuel, thereby destroying your fuel economy)

If that graph was based on a closed track, that's pretty useful information!

The current record for the highest MPG on a production automobile was done at 50MPH.

 

[rivan]

As I understand it, tons of work has gone into gearing transmissions such that speeds near 55 (a common maximum speed) is the most efficient speeds.

If the national speed limits were made 65, I'm sure gearboxes and car aerodynamics would begin to conform to being more efficient at 65 instead of 55.

I have no sources to cite.

 

[Casawi]

I drive an SVU and realized this a few month ago. Yes I do save a lot of money driving slower on the high way, I am talking about a couple of days worth of fuel. I normally go thru 3 tanks a month, but when experimenting this 3 tanks lasted a few more days into the next month.
The problem was I couldn't always do that, you must be consistent to see the difference. A lot of time I feel in a hurry and I would speed, but I need to realized that the time I saved is not worth the gas it costs to save that time.

 

[funboy6942]

Its all about aerodynamics, gearing of the car, size of engine in such car, and how much you put your foot down and dont keep your foot still while driving.

My 88 Town car was rated at 16/25, thats with a v8 302, because in high gear its doing about 1300 rpm's. I get close to 30 because on level ground I get my car at 60, and I DONT move my foot unless I have to. Even if it means Im doing 50 going up hill. I may let off a bit going down it so not to get a ticket, but by doing it this way you get the most MPG no matter what you drive. This is even better then putting on the cruise, because in cruise it gives gas going up hill to keep you a constant 60, leaving your foot still and just letting speed drop a little going up hill means no extra gas given, means more MPG.

And now a days 55 will not save lives because NO ONE does 55, and then if you do you piss people off, making them mad, and drive like a ass hole even more, which increases the chance they will get into a wreck because you pissed them off to much to pay close attention to whats going on around them. So to do 55 now, you would actually kill more people.

But there is just no way for one to go 55 is the best all around because all cars are made, geared, and powered differently. If we all drove the exact same car, then yeah, maybe, but to get the best you need to keep the rpm's under 1500, and do not move your foot, and you will get the best gas that car/truck will ever get. Even if it means in your car, and the way it is geared 1500 rpm's mean 45 mph

 

[WaTaGuMp]

Originally posted by: IcebergSlim

Originally posted by: tenshodo13
Well, 60 mph IS the most gas efficient speed.

not in my car. If am going purely by the rpms......I can cruise at 85 mph at about 2500 rpms

60 mph is in the middle of a gear and the rpms are 3100

But at 85 you are taking in more air and fuel simply because the throttle is open more, so my money would be on the 60 mph.

 

[FoBoT]

no
i am sure most of the people posting in the thread were not drivers when the national 55 mph limit was introduced. it sucked, it'll suck again

 

[Canun]

Originally posted by: FoBoT
no
i am sure most of the people posting in the thread were not drivers when the national 55 mph limit was introduced. it sucked, it'll suck again

Yeah, it sucked. Especially when you get busted going 85mph in a 55mph. Got a reckless endangerment ticket for that because it was 25mph over the posted limit. Now that road is 75mph as the limit.

 

[jagec]

Originally posted by: Eeezee

Originally posted by: ADDAvenger
Drive a motorcycle, get 3x mileage

My car (98 Towncar) gets about 20, while my 150 scooter/cycle/whatever you wanna call it gets ~65. I thought larger engines would get worse mileage, but I have a friend that has a 650 that also gets about 60mpg, but then again he didn't say if that was all-around or just highway. So what if he gets 40 around town, that's still 2x what most people have, and a bit better than most hybrids at a small fraction of the cost. Granted, cargo space is limited, and it won't work for a family, but for just yourself or a couple it's great.

Yes, dropping a few thousand pounds and significantly reducing surface area probably helps fuel economy a lot

Although the Cd is usually much higher for bikes.

Still, it's kind of nice to have something as fast as a Corvette that gets 55MPG.

Originally posted by: Baloo
Wind resistance becomess a factor at about 29 MPH. You will get your best mileage at or near 29MPH, much better mileage than you'd get at highway speeds. Some cars would get twice as many miles per gallaon at 29mph than they get at 70 MPH. But you won't see me going down the highway at 29MPH.

Driving slow improves mileage, so does keeping your RPM's low while accelerating.

Nope, REALLY depends on engine and gearing. Very few cars are at their peak efficiency at ~30MPH.

 

[Sentinel]

I may as well drive slower, my steering wheel vibrates at anything above 65mph. Ha.

 

[Vic]

Originally posted by: Sentinel
I may as well drive slower, my steering wheel vibrates at anything above 65mph. Ha.

Get your tires balanced?

And if that doesn't work or the shimmy doesn't go away above ~75 mph (unbalanced tires/out of round wheels will usually harmonically balance out above that speed), then you need new ball joints/tie rod ends.


edit: to the OP and the other 55-ers...

Point blank, my objection to the "save gas, drive slow" and 55 mph limits arguments to conserve fuel is that you are essentially forcing me to drive slow because you drive an inefficient vehicle. That is BS. And as I noted in the recent helmet thread, is representative of the typical American mindset where you won't do the right thing unless everyone else has to do it too.
Here's the thing, my car doesn't go into top gear until about 60 mph. I get about 26-27 mpg at 80 mph. I drop down to about 21-22 in (even frequently spirited) city driving. Your SUV doesn't get better than 20 mpg no matter how you drive. Oh, and my car has 350 hp. What's your excuse?

 

[E equals MC2]

Originally posted by: Sentinel
I may as well drive slower, my steering wheel vibrates at anything above 65mph. Ha.

um, your tires are misalinged.

 

[BoomerD]

With our 2005 Expedition 4X4, driving between 55 and 60 yields about 18 mpg, where driving 70 yields about 15 mpg.
Pretty good savings IF I'm not in a hurry or going LONG distances.

The quality of gasoline makes quite a difference in mileage too. (no, not talking about the difference between "top-tier" and "normal" gasoline, but the difference in octane levels in different states and the quality of the product pumped out of the tanks.

When we were on vacation 3 years ago with the truck...(brand new, less than 1000 miles on it when we left) we encountered a LOT of difference in gas purchased in different states, (85 octane in many parts of the Rockies) and some terrible gas from various stations. The WOSRT gas we got came from a Shell Station outside Grand Island, Nebraska...mileage in both vehicles dropped by over 10%) (we were delivering our 1990 BMW 735i to our son in Wisconsin) Over the entire 6200 mile trip, we got 18.6 as a high and 14.7 as the lowest MPG's, with speeds remaining constant. (posted limits +5)

We love the Expedition, but it sure doesn't like to pass a gas station...

 

[nakedfrog]

Money versus time...