car question: "Automatic (4 speed)"

[Eric J in MN]

How is that different from just "Automatic"?

http://www.fueleconomy.gov/feg/bymodel/1998_Chevrolet_Camaro.shtml

[itsmesgd]

1. not 100% sure but I think that it means that it only has 3 forward gears and reverse with no

overdrive. I've had sticks and autos with 4 and 5 gears.

[wildhorses]

2. reverse is considered a speed?

:shrug:

[montanto]

4. no

[flvegan]

3. It's just more specific.

Automatic transmissions also have "speeds" or gears. The transmission just does it for the driver. A 4 speed automatic is just that. When it's in gear, it will shift 3 times as you accelerate. The 4th gear might be an overdrive.

I think.

[wildhorses]

6. that's what i was thinking

i don't think reverse is considered a 'speed'

[montanto]

5. has to do with horsepower and fuel economy

you notice the car accelerates better in lower gears, 1st, 2nd, because the engine is turning faster than the output of the transmission 3:1 2:1, etc. putting more "speeds" in a transmission allows the engine to stay in its peak efficient power range longer: More power, better acceleration, better economy.

[jobycom]

7. Many older care had three speeds.

Older cars (before 1980s) had three speed, sometimes even two speed. Four speed is more common now, with the fourth being an overdrive, but some people still specify that it has four gears, the way some people still advertise air conditioning as an option. Some more expensive models have five or six speeds, and the newest development is the Constant Variable Transmission, like the Prius and several new cars.

Generally, an automatic is less fuel efficient than a standard, but the more gears, the better the efficiency (except on some high end performance cars). The CVT is supposed to be more fuel efficient than a standard, though I think that depends on the person driving the standard.