How does a vehicle with a standard transmission use less gas than an automatic transmission?

Answer 1

It takes extra horsepower to turn the inner workings of an automatic compared to a manual. The new automatics are more efficient than they used to be, so the difference would be smaller.

Answer 2

They don't always. Driving habits can greatly affect mileage.
Essentially in a manual trans. the engine is coupled through the gears to drive the wheels. In an automatic instead of a solid clutch the engine is coupled to the gears through the torque converter. It is somewhat like two turbines facing each other and very close. The engine turns one which moves transmission fluid. The fluid pushes against the other making it turn which turns the gears. Since there is no solid connection from the engine to the gears there is some loss of power. But many if not most automatics nowadays have a lock up torque converter acts like a regular clutch once the engine and trans are turning at the same speed. This is somewhat simplified but I hope it helped.

Answer 3

Everytime you push in the clutch, the motor goes to neutral. Think of how often you have the clutch in! Quite a bit in city driving.

Even sitting at a stop light in idle with an automatic transmission is using about 4% more fuel than truly having the car in neutral--which it would be in at the stop light. And, if you are driving a standard transmission, you push your clutch in (putting yourself in neutral) long before you get to the stop--because you have to to hit the brake. With an automatic transmission, you are always pushing around some transmission fluid even when idling--and that is taking power.

So all the time braking, all the time being stopped, and all the time between gear shifts, you're not using as much gasoline.

(And, the car weighs about 75 pounds less--but that is real minor.)

Answer 4

The auto transmission uses a pump to pressurize the oil. the pump uses power (consumes gas). the auto trans uses a torque converter which is a fluid coupling that slips in the lower gears and allows you to stop in gear. the slippage of the converter creates heat in the oil which is lost. most all (modern) auto trans now have a converter lock up which locks when you are in top gear cruising down the highway. this gives good economy - but you still have to power the hydraulic pump. the manual trans is a solid hook up through the clutch and there is no pump to run. the gears are lubed by splash oil which uses a little power (friction) - but not much.

Answer 5

because autos are in "gear" at all times when driving, and the gears are set by the driving....where a manual the gears are changed by the driver for conditions they decide ...
for varying conditions...

Answer 6

only if you know how to drive it. shift before shift point help a little
auto can't do that.