unknown technical terms

[mandh2010]

i am looking into a pickup and i thinki want a car that can switch between 2 and 4 wheel drive. what is this system called? what are good search terms to use to find a car with this. many suggestions please. also,what affect does this have on mpg? i hear conflicting things from time to time. i'm pretty new and help would be very appreciated.

Thanks much,

MandH2010

[Airjer_]

If you can switch between 2 wheel and four wheel it would be called four wheel drive or 4x4. Most real trucks fall into this category. there is usually a 2 hi, 4 hi, and 4 low option.

4x4's can also have an automatic four wheel drive option that automatically engages four high if it senses rear wheel slip.

All wheel drive would be all four wheels turning at the same time with no option for two wheel drive. I can't think of any trucks that have this but there are many SUV's that use this.

[akboss]

Originally Posted by mandh2010

i am looking into a pickup and i thinki want a car that can switch between 2 and 4 wheel drive. what is this system called? what are good search terms to use to find a car with this. many suggestions please. also,what affect does this have on mpg? i hear conflicting things from time to time. i'm pretty new and help would be very appreciated.

Thanks much,

MandH2010

Airjer did a good job of explaining the basics of a four-wheel-drive (4x4) system. As far as MPG, chances are you aren't buying a truck to get good MPG's - they are all relatively poor if you are used to filling up a sedan. That being said, using good driving technique and keeping the vehicle in '2WD' mode will help.

There are several reasons AWD or 4WD vehicles get poorer fuel economy, the simplest of which is added weight - all the driveline components can add as much as 200lbs to a vehicle, which is like carrying a trunk full of crap all the time. The rest is to do with the friction caused by the added drive wheels when engaged and the associated gear ratios, known as drag.

[MagicRat]

There are two basic systems:

Part-time 4wd (four wheel drive). This system is designed for 4 wheel drive use only on loose or slippery surfaces, like snow, gravel, dirt, etc.
Paved surfaces require the use of 2 wheel drive only, to prevent damage to the driveline.
These systems have been around for decades, and are relatively simple and inexpensive. But these days, they are found only on inexpensive light trucks.

Full-time All-wheel-drive. Unlike the part-time systems, this system has a center differential in the transfer case, and allows the front and rear wheels to both be powered, but turn at different speeds. They can be used on four wheel drive mode on paved surfaces.

Some full time systems allow the driver to shift into two-wheel drive to save fuel.
Other systems do this automatically, and use two-wheel drive normally, and engage four wheel drive by themselves when things get slippery.

[mandh2010]

your comments are very helpful, i wonder about hemis as well. ive heard a variety of different functions and am not sure which to believe. cani have one installed on any V6 or V8? how much would it cost? what are the advantages or disadvantages? fuel milage? etc... any and all responses would really be appreciated

thanks,

MandH2010

[mandh2010]

here is another unknown technical question. what is the very technical difference between these?
-Part Time 4WD
-4x4
-full time 4WD
-A4WD
-Shift on the fly
how are they all different? when is the best scenario for each? is installation possible without throwing obscene amounts of money at the car? how expensive is upkeep? recommendations? is there a good resource for more inforation on these? any information about the different systems would be great!
thanks,

Mandh2010