Can someone please explain the difference between these and one or more of them is more economic on petrol? Thankyou
vtecintegra,
May 17, 1:29am
Depends on the mplementation - there isn't any standard definition of what gets labelled 4WD and what gets labelled AWD it is manufacturer dependent.
toyboy3,
May 17, 1:32am
4wd and awd use more petrol and tyres
tamarillo,
May 17, 2:07am
4wd and all wheel drive are same thing just different names by different people. But not all 4wd vehicles are made the same. Some use two wheel drive mostly and only engage other axle when slip is detected. These are usually front wheel drive under normal driving. Penalty is extra weight of the extra drive chain. Hence if all else is equal the 4wd version uses slightly more gas than a 2wd version.
2wd simply means only one axle is powered, either front or rear. For most driving conditions this is ample, indeed many softroaders are available with 2wd only as owners don't really intend to go off reading.
Unless you need it stick to 2wd.
budgel,
May 17, 2:39am
My understanding is that 4WD vehicles are selectable whether they are using 4WD or not, and it is not recommended 4WD is used on a dry sealed road because the transmission can bind up between front and back. AWD is full time 4WD, and the binding up is avoided by having a third differential between front and back, meaning they can be driven on sealed roads without a problem.
bwg11,
May 17, 2:46am
4WD and AWD are not the same thing. All AWD's are 4WD, but not all 4WD's are AWD. To me proper AWD implies a centre diff, which may just be a simple lockable centre diff, or best a torque sensing diff (which in an over simplification, sends power where it is needed). This is "full-time" AWD. A Prado or an Imprezza would be good examples of full-time AWD.
Recently some soft off-roaders claiming to be AWD are FWD with a light duty drive train to the rear which is only engaged, manually or when a predetermined amount of slippage occurs. Don't confuse these with full-time AWD.
4WD may be "full-time" as in the case of "full time" AWD or "part-time" where the drive to the usually front axle can be disengaged.
For the OP, 2WD will always be the most economical than any of the AWD, 4WD alternatives.
tamarillo,
May 17, 6:44am
InTHINK poster is simply trying to decipher the acronyms used by car makers, so whilst I'm sure your technically correct, car makers don't follow the rule and AWD and 4WD get used according to the whim of marketing, or indeed sometimes the media. Agreed there are different types but I don't think there is a clear rule everyone follows as to how to describe them, hence I felt it simpler just to say that the terms are used for broadly the same thing. I don't agree with you that something can be 4WD but not AWD though. Even if it's just an electric motor driving the rears on demand it is still AWD. some are selectable, sometimes part time, but end of day all wheels can be driven. Still think that in plain simple English the two terms are synonymous.
Thanks everyone, i think i got the difference now. ????
bwg11,
May 17, 8:46am
Thanks for the link, I had chosen not to further complicate the issue with the distinction between systems with and without a low range transfer case.
slarty45,
May 17, 9:49am
low ratio is handy when backing trailer with my 3 diff Vitara. not great on gas being permanent 4 wheel drive but traction is real good in mud & snow
mack77,
May 17, 10:08am
Just to confuse the "picture'' further, my old Honda Odyssey AWD car has a transfer box instead of a center differential but to enable it to be driven on a sealed road it has a viscous coupling in front of the rear differential that only transmits torque (a small percentage) when it senses that the front wheels are rotating faster than the rear wheels. There are no controls for the driver and it actually performs better than my previous Toyota Carib with its center differential that had a control to make it limited slip. There are so many different types of 4WD/AWD vehicles that I think it is best to describe them by the type of transmission system that they have.
brapbrap8,
May 17, 10:26am
Even more confusingly, Mitsubishi utes and SUVs can be switched between 2wd, Awd (4x4 with centre diff for use on road), and 4x4 high or low range with the centre diff locked for off road only. It is actually a really good system, modern diesel utes and SUVs have enough power that All wheel drive is not a silly idea.
mrfxit,
May 17, 9:24pm
Yep the lines have been well & truly blurred these days as they fight for Market dominance.
WHEN you realise what you can & can't DO to a specific vehicle, thats when you start to realise which true type you have.
Originally it was this .
RWD = rear wheel drive, (manual/auto gearbox's) FWD = front wheel drive, (manual/ auto gearbox's) 4x4 = selectable 2wd or 4wd (4wd + Hi/Low ratio off road only) manual gearbox only AWD = permanent 4wd (fixed ratio). (Manual/auto gearbox's)
Now we apparently have a small selection of models with selectable 2wd/4wd/Awd on & off road with hi/low ratio, (Which I suspect to be an auto gearbox in disguise.
mrfxit,
Jan 26, 1:00am
Good link
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