Slowing Down To Conserve Fuel

[Mark in NY]

quote:

---

Originally posted by Razl:
Me too. But the primary force to slow down is the wife and son. She reminds me constantly that I'm not a kid anymore.

Somewhat

How close do you have to be behind an 18-wheeler to notice any MPH savings due to the reduced air drag?

---

At a nominal 70-80 MPH, with a Corolla sized car: if you slowly pull up behind the big guy you will feel a good amount of buffeting when you are about6-8 feet away. Thats the signal that you are just entering the zone.
About 2-3 feet away you will suddenly pull forward as the front of your car enters the evacuated area immediately behind the truck. You quickly ease off the gas or its bumper car time.
Stabilize around 18 inches away and on level ground you can just about take your foot off the gas completely and still maintain steady speed. After just a few minutes of this you will see a substantial rise in coolant temp due to lack of airflow through your engine compartment. It is a substantial effect when you are dealing with a semi and a small light car in tandem. On the track with 2 similar, light, areodynamic cars, the speed needs to be about double to get the same amount of effect.

As they say- Don't try this at home.
Unless (maybe) its smokeys day off and the truck driver is your friend..........

 

[DockHoliday]

It has been my experience that coasting to stops, and anticipating lights, are the best ways to improve city MPG. As an example, as soon as I realize that I am going to get hit by a red light, I get off the gas. If I can do this with enough advance, I can turn a stop and wait into a slow and go. However, this does not always make me popular with the commuters behind me as so many people are on the gas right to the end.

 

[JohnnyO]

I slowed down a little on the highway after I noticed that I got better-than-usual mpg towing my jetski with the OD off at 65-70 than emtpy with the OD on going 80.

 

[Bret Chase]

quote:

---

Originally posted by oilyriser:
I also tested a 1991 Dodge Grand Caravan:
71 mph -- 21 mpg
50 mph -- 29 mpg

using the same calculations as earlier:
$6.70/hr savings rate (lower due to the extreme reduced speed)

---

I got my wife to set the cruise at 65 in our '91 Grand Voyager AWD and we got 27mpg on a 35 mile trip. doing the same at 75 it gets 21mpg.. needless to say She's a believer now.

 

[Bret Chase]

quote:

---

Originally posted by oilyriser:
Subcompacts used to come with 75 hp motors, and people survived.

---

I used to drive a 55hp 3 cyl Geo Metro, yes I survived it and all in all it wasn't that bad of a car, but Man, merging onto the interstate could be terrifying.

 

[Al]

I have seeen a definite pattern of people slowing down and driving less..about time

 

[Starbreaker666]

I have slowed down as well. My '04 Monte Ss/SC gets 34-36 MPG on the Highway at 60 instead of the 65 in my area. drops to 31-32ish at 70..

 

[JHZR2]

quote:

---

Originally posted by Bret Chase:

quote:

---

Originally posted by oilyriser:
Subcompacts used to come with 75 hp motors, and people survived.

---

I used to drive a 55hp 3 cyl Geo Metro, yes I survived it and all in all it wasn't that bad of a car, but Man, merging onto the interstate could be terrifying.

---

Yep, my MB turbodiesel had 120 hp at full boost, and an auto trans...

Never met a merge that scared me, and this was even with traffic in one of the most densely populated areaqs of the world... Im not talking middle of nowhere.

You just need to know how to drive a car with less power. So many people are so dumb, they cant grasp the concept, just like they cant use a manual trans.

JMH

 

[kingrob]

My cousin used to have a 53 hp Datsun, back in the age of muscle and pony cars. It was a wonder he survived. Plus, it had an air conditioner in it- you could only turn it on if the car was idling because if you tried to drive while it was on we're talking 0-60 in 50 seconds. I mean, there really were steep hills that car simply could not climb, hills that we take for granted now could have got him killed. I pray to God we never have junk cars like that make a comeback.

When we talk about under powered cars I think of cars like that; anything over 100hp should be adequate for everyday driving (but not for me).

 

[NovaMan]

I used to have an '81 VW Rabbit with a 1.7L and a 5-speed. It only had 75HP, but it was small (light) enough and geared well enough that it felt peppy around town even in 2004. Then it got wrecked.

Unfortunately, I could never calculate the gas mileage because the odometer was broken when I bought it.

I could make 10 gallons last forever in that car.

 

[Forkman]

Yes, the "jack rabbit" starts from a dead stop are definitely a fuel economy killer.

I listen to people whine around here about the price of gas (just dropped back down to $2.88 for 90/10 ethanol blend from $2.98 as I predicted to a few coworkers once the OMG fill up fill up now panic stopped and the immediate increase in demand tapered).

Yet despite the whining, I still see everyone (from little economical 4 bangers to full size SUVs and trucks) stomping on the gas pedal when leaving a stoplight.

I've adjusted my driving habbits slightly over the last week, and taken a slow down and slower take off approach. I've noticed a huge difference. From 20mpg city to 24mpg city. Highway driving isn't really effected and I'm still pulling about 31mpg hwy.