Major points taken from a 1974 book called
Economy Driving by Doug Roe.
1.) Cornering Speed vs. Tire Wear
Driving through a turn at high speed to maintain momentum is generally not a good idea. Second to gas, tires are often the most expensive consumable a car owner faces (oil arguably being neck and neck).
Tires wear most rapidly during turns. This can be seen in track racing, where tires often only last 100 miles due to high cornering speeds. Generally, for every 10% increase in cornering speed, tire wear increases 50%.
2.) How to deal with stop signs.
I'm not sure of the reason behind Roe's method, but I suspect it is to aid in timing. In any case, this method will depend on your car's gliding distance. Roe chose a 1/4 mile for the example.
At 1/2 mile from a red light, ease off the throttle so 2-5mph are bled off by the 1/4 mile mark. At the 1/4 mile mark, completely let off the gas.
3.) How to Pass on a Two-Lane Road
Maintain a healthy following distance (~5-6 seconds) behind the car being passed.
Visual Following Distance
Occasionally, ride on the leftmost portion of the lane to observe opposing traffic. When an opening appears, accelerate swiftly to passing speed while staying in the same lane. Right before the following distance is gone, swerve into the opposing lane and overtake the car. The idea is to minimize exposure in the opposing lane while maintaining momentum. Supposedly, this is a trick heavily used by truckers.
An interesting "what if" was posed: What if an opposing car should appear during the overtake maneuver? Speed up (leadfoot) or use the brakes?
Roe suggested speeding up and taking the fuel economy hit of wide open throttle simply because that car was being overtaken for a reason. By flooring it, you save youself the potential of being stuck behind the guy during a crucial maneuver (e.g. climbing a hill). If you are in front, you get to set your own pace.
4.) How to Climb a Hill
This was before the days of FE instrumentation, so this may be most applicable to "blind" drivers. Also, for legal reasons, Roe doesn't suggest engine off cruising even though he mentions it was (illegaly) used during the national competitions
Long, shallow hills (1-5 miles) are best dealt with by maintaining cruising speed. If you cannot accelerate quickly on the following long, shallow, downhill grade, you are better suited to stick it out.
The idea is that if you want to maintain a trip speed of 40mph, you have two options. Option 1 is to deccelerate (let's say, to 20mph) on the uphill, forcing you to accelerate to 60mph on the downhill. Option 2 is to deccelerate to 38mph on the uphill and let gravity pull you down at 42mph. Option 1 will require you to use gas to accelerate up to speed while Option 2 uses a pure gravity assist.
Stopped at the Bottom of a Hill is best dealt with by accelerating swiftly (just under enrichment) to gain as much speed as possible before the hill really steepens. Accelerating and climbing are two evils, so it is best to minimize the first before the second begins in earnest.
Tricks, Suggestions, Information- Headwinds and crosswinds are almost equally detrimental to fuel economy. Headwinds are detrimental for the obvious reason, they increase aerodynamic drag. Crosswinds are detrimental due to aerodynamic drag and increased tire deflection. Crosswinds load cars heavily laterally, causing the tires to deform in another direction. Increased deformation means increased rolling resistance.
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- Calling an aviation weather service before a commute can hint of changing wind conditions. Storm fronts are often characterized by changing wind conditions (one direction in the morning and another during the afternoon). If you know the wind is going to change, you can drive slow during a headwind and make up the time during a tailwind.
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- The time spent in the wake of an opposing truck can be minimized through a dangerous maneuver. While the truck is in the distance, merge over to the right hand portion of the lane. As the truck begins to pass, quickly merge left exactly to the centerline. The book includes a diagram showing the wake (which I'm too lazy to recreate), but it shows how most of the wake is avoided.
History- Pulse and Gliding was first demonstrated during a 1940 economy run, but was labelled "momentum driving" by its progenitors. This is according to Roe, though...
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- 1968 world championship mileage car was a Fiat 500, whose only major modification seemed to be a freewheel clutch on it's transaxle. It achieve around 367mpg.
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- At the time of writing, the world championship car was a 1959 Opel that had a modified rear axle that placed both wheels next to each other in the trunk. Using smooth aviation tires at 200psi, it achieved 376mpg.
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Opelmobile
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- A contestant with a 1924 Chevy Model A achieved ~160mpg. One of his methods was a modified carburetor de-icer "warm air intake."
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- Advanced fuel efficiency instrumentation existed for carbureted cars during the 1970's. Using a speed sensor and a fuel flow meter, instant MPG was shown. One model was called the "Spacekom" and another was manufactured by a British firm called Aviatric Ltd.
- LostCause
"Economy Driving" by Doug Roe
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, we could have acronyms of HH and/or LCH ( ... or HHM and/or LCHM).
Needless to say, I don't take that route anymore.
