Gas mileage



# Thread: Gas mileage

1. ## Gas mileage

Ok i have been thinking.
If you drive 2 hours at 75 miles per hour,
If you drive 2 hours at 60 miles per hour what will get you better gas milage.

With 75 miles per hour you are drive 20 or more minutes less. Can someone help me out with this.
thanks
matt

2.

3. Originally Posted by hoyt bowhunting
Ok i have been thinking.
If you drive 2 hours at 75 miles per hour,
If you drive 2 hours at 60 miles per hour what will get you better gas milage.

With 75 miles per hour you are drive 20 or more minutes less. Can someone help me out with this.
thanks
matt
Depends on the vehicle I'd say, but the increase in consumption to get the vehicle to 75 mph, and maintain it there will probably more than offset the extra distance covered in those two hours. You would have to give it a try and calculate how much gas is needed for each, and repeat the experiment to get an accurate average...

4.

5. Join Date
Dec 2007
Location
Pasco County, Fl
Posts
4,039
rule of thum, higher rpm's more fuel.

there is a certain point that the vehichle will burn a steady rate of fuel and thats supposedly where it is best to maintain it at.. ut theres no telling if its 40 mph, or 70 mph.. there are computers on the market that will tell you though like hybrid cars..

6. When gas got up to \$4 a gallon last year, I actually started doing something similar to this and here were my results. These are all based on highway mileage though.

Car is an 02 Pontiac Grand Prix with a supercharged 3.8 V-6.

Driving 80 mph before gas went up, I averaged around 26-27.5 mpg.

Slowing down to 70 after the prices spiked, I averaged 29-31 mpg.

This is from several trips, so it's almost a 10% increase for those numbers. I've heard that 60 mph is usually the magic number for most vehicles for ideal mileage.

7. Ok I will tell you from experiance..60 MPH at 2 hours definitly takes LESS.
I commute 45min - 1 hr to college nad the same back 5 days a week and can definitly tell a difference in a week when i run 70-75 than when i stay at the speed limit of 65. hope this helps.
Last semester I made the trip with a chrysler LeBaron GTC and this semester I am using a 2009 Toyota Prius....its nice for a gas tank to last a whole week! compared to 2.5-3 days

8. Join Date
Jun 2004
Location
Eau Claire, Wisconsin
Posts
5,466
It's Miles Per Gallon not Time Per Gallon. The amount of time has nothing to do with it. You will get better MPG at 60 than 75 for sure and save gas, it will just take longer to get there.

9. 10%+ increase sounds about right. I used to drive from Phoenix to Los Angeles monthly.
2002 sentra 1.8l
Before gas spike:
85mph @ 3500ish RPM - 5hr drive and would have to fill halfway at half tank or make it within LA county and gas light would be on.
After:
65mph @ 2500ish RPM - 6hr drive and would make it to downtown LA with enough gas to drive to the hotel and goto a couple bars.

10. Funny thing about all the MPG's on todays cars is they are almost the same ratio as they were in the 60's and 70's. My father was a enginer in the field back than. He has talked about this ratio for years, finaly I had to have him explain it to me. Long story short it comes down to displacement to weight ratio within a given gear ratio. Years ago it was 300-400+ HP with a frame and body weight of a mac truck(10-12 mpg highway). Now it is 250-350+ HP and the weight of hang glider(28-30 mpg highway). That is the reason the corvette ranks every year as one of the most economical MPG performance cars. If driven with a light foot on the highway they can and will hit the low 30's.

11. Join Date
Apr 2006
Location
Near the old Tustin MCAS
Posts
288
I use the scanguage II on my Escape Hybrid. It's setup to display the water temp, mpg, and hybrid battery State of Charge. I mainly driver around 60-65 at 15-2k rpms and been averaging 36 mpg.

12. Join Date
Sep 2006
Location
Missouri
Posts
180
If you want to figure time as cost... wouldnt depend on how much value you place on your time? If going faster means getting to work on time, thus not getting docked pay for being late..... then the extra fuel cost would be offset by the income not being lost. There are the intangibles of NOT having the boss breath down your neck, NOT having the boss standing in the parking lot looking at his watch each day for the next week...... etc. Driving at less speed does use less fuel though.

13. I drive 100 miles round trip/day, to work. I usually drive about 80, and get 30mpg(averaged per tank)in my VW jetta. If i back it down to 68mph, i get 33 to 34mpg (averaged per tank). You will save 3 to 4 mpg , by slowing down, as long as you're staying in high gear.

14. Thanks all. Im going to slow down now.
matt

15. cmherman and coachmac have it right.

No elaboration.

16. Just don't slow down to much. Just got a new company car. A Dodge Journey. It has the slap-stick option on the automatic transmission, pulling the shifter down to that option lets me see what gear the auto chose. If I am under 40mph and in auto it will only go up to 5 (6speed trans). Under 30 and it will stay in 4. Let's just say that around town milage is very poor. If I can get out on the highway and stay above 45 it does much better.

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•