Basic MPG info

[Vwbeamer]

Originally Posted by Charlie Cheap

We sometimes get too involved with "magic" answers to better MPG, but the basics can be improved. I am a retired ASE mechanic who ran a city fleet for over a decade, I built cars ground-up for over 50 years, and studies the internal combustion engine for half a century. The minimum fuel necessary to achieve the speed desired, the best spark available to fire the mixture, and matching the transmission, rear gears, and tire size with minimum weight plus keeping aerodynamics in mind, will give excellent MPG. Driving habits...using proper grade gasoline, building the engine for Torque rather than Horsepower, and driving for best economy by not pushing your right foot to the floor, and MPG will improve. No MAGIC just common sense.

is your post aimed at car makers, or ecomodders?

Most late model cars have the basics covered, and if not it's impractical for the average person to change the cam, exhaust, heads, etc to change the torque curve of his/her engine, or to change the gearing of his/her car( on most FWD cars different gearing is not even available.) On older cars the timing is adjustable, not so much on newer cars.

I agree, there are few magic answers. Increase tire pressure, learn to drive more efficently, remove uneeded weight from the car.

Most other things will never have an economic payoff, or will take a very long time.

[cRiPpLe_rOoStEr]

Originally Posted by Vwbeamer

on most FWD cars different gearing is not even available

I've been looking for spur-gear sets for some econoboxes, and mostly they're either unavailable or more race-oriented and therefore not suitable for normal driving.

[Ecky]

Regarding gearing, I've noticed most manual transmissions (available in the US) are not geared "properly" for economy - but manuals are only something like 1-3% of vehicles sold. I'd wager most of those opting for manuals are not opting for them for economy.

Take the 2020 Civic as an example: The 6 speed has a top ratio of 2.82 (6th gear * final drive). The CVT has a top ratio of 1.61. Or, in other words, at a speed where the CVT is cruising at 2000RPM, the manual is turning just over 3500RPM.

[cRiPpLe_rOoStEr]

Originally Posted by Ecky

Regarding gearing, I've noticed most manual transmissions (available in the US) are not geared "properly" for economy - but manuals are only something like 1-3% of vehicles sold. I'd wager most of those opting for manuals are not opting for them for economy.

I remember comparing specs of cars available in the United States and in Brazil around 15 years ago, and noticing most automakers highlighted close-ratio manuals there, while wide-ratio ones were prefered here.