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Old 12th February 2006, 11:15   #1
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Question 4WD Vs 2WD - The Difference !!!

Please Increse My IQ !!!!!

Situation: I'm travellin across state say from Mumbai - Goa

Problem: Should I drive my SUV in 2WD or 4WD???? What difference would it make both performance wise as well as fuel economy wise???

Answer://thanx in advance :P
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Old 12th February 2006, 11:35   #2
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I dont think there should be any problem drivig ur suv in 2WD. Putting it in 4WD consumes more fuel as there is an increase in friction when supplying the power to the extra 2 wheels. Most of the latest SUVs automatically shift to 4WD if there is a loss of traction detected
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Old 12th February 2006, 15:41   #3
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4WD is particularly useful on loose soil, gravel, wet tarmac, snow, etc. no particular advantage on dry tarmac, even under high speed cornering conditions. the procedure of 4WD functioning is long. the short version is, 4WD's are great for mountaneering or other off-road situations, but of no particular use on tarmac. you need AWD on tarmac.

bombay to goa highways do not have any stretches where you require 4WD. (i speak from experience- have taken my 4wd). if you drive in 4WD through tarmac, you'll chew through the tyres quicker, and the powertrain will go through undue stress.

if you engage 4WD, you'll find that the initial pick-up is slightly slower than in 2WD mode. but the roll-ons and top-speed will be better. engaging 4WD reduces your F.E, by a small margin. if you do so on tarmac, your F.E will decrease by around 10-15%. i.e, if you get, say, 10 kmpl in 2WD mode, you'll get about 8.5-9 in tarmac, under normal driving conditions.

@tsreekaranrao- you are talking about FWD based SUVs like the CR-V or the tucson or the x-trail. they are soft-roaders. not the same case with true 4x4's, which have full-time 4x4 or part-time 4x4 that's RWD biased...
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Old 12th February 2006, 17:29   #4
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whats the difference between AWD and 4WD
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Old 12th February 2006, 19:21   #5
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an AWD has a lot of electrical aids along with a number of solenoids to transfer the power to all four wheels. also, the power transmission to all the wheels is permanent, that is the differentials transmit the power to wheels all the time (like the impreza, or the chevrolet forrester). a 4WD is usually referred to as in a part time system; that is, the 4WD is usually switchable between RWD and 4WD (like in gypsy, safari, etc.) . under normal driving conditions, the car is RWD, or FWD (like in CR-V or tucson).

in short, 4WD is the general term; AWD is a type of 4WD.
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Old 12th February 2006, 19:29   #6
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the explanation of 4WD is RangeRover and Prado..

When a 4WD is traveling in a straight line all four wheels rotate at the same speed, but during cornering each wheel travels at a different speed due to the radius of the turn. All vehicles have a differential on the front and rear axles to allow the wheels on the same axle to rotate at a different speed. Constant 4WD’s have a central differential fitted to allow for different speeds between front and back wheels, but most part-time four wheel drives do not When a 4WD is traveling in a straight line all four wheels rotate at the same speed, but during cornering each wheel travels at a different speed due to the radius of the turn. All vehicles have a differential on the front and rear axles to allow the wheels on the same axle to rotate at a different speed. Constant 4WD’s have a central differential fitted to allow for different speeds between front and back wheels, but most part-time four wheel drives do ...so 4WD when driving on rough murky terrian and 2WD on slopes..
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Old 12th February 2006, 19:30   #7
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I haven't been on this road so i cannot comment much. But just in case it rains, 4WD would give u a lot more traction and will be more sure footed.
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Old 14th February 2006, 09:55   #8
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veyron1 awesome man looks like ur a car tech freak ......... or are u a mechanic "tech engg." ???

newayz thanx a alot for the info will put dat knowledge to use on my trip this vacca
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Old 16th February 2006, 02:15   #9
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Quote:
Originally Posted by veyron1
if you engage 4WD ... the roll-ons and top-speed will be better.
Top speed and acceleration will be quicker with 4WD

How do you say that?
Especially since most 4WDs dont ecourage you to go anywhere near top speed when 4WD is engaged!

Ambylimo, i seem to share the same thought as you about the center diff, but havent actually seen it in print anywhere! Do you have any links?

cya
R
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Old 16th February 2006, 02:30   #10
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@rehaan: well, i did try attempting a top speed run, just once, for the sake of it, on the expressway, with my safari. the speedo clocked 160, max limit allowed. without 4wd, on the same stretch, it managed about 150+...

like i said- after engaging 4wd, your acceleration will go to the dogs, uptil about 80 kmph, thereafter, the enhanced traction and torque distribution helps gather speed. but the results vary in actual real-world conditions, depending upon road, winds, fuel, air, etc.....

@frozenbhp: i ain't both, my friend...just an enthusiast, much like yourself...
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