Well as the title says...Does 4WD use more gas? I'v always been told it has.
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- scoobyrbac
4WD Does it use more gas?
Yes, because the drive train setup is less efficient than with a FWD or RWD layout.
Compare the comparable...a AWD Subaru Justy uses a damn sight less fuel than a RWD 4.2 lire Jag.... but TBH, never seen ANY direct comparisons...To clarify..the 4WD Escort Cosworth had a much bigger and sportier engine that that of the standard Escort.
I would assume that as there is more 'work' being done by an extended drive-train that it would, however, the ability to hold speed round bends might outweigh that... (not as much acceleration needed when coming out of the bend....)
Have heard that it is recommended in SUV's to switch to 2WD unless you NEED the 4WD...so I guess that might be something to consider.
I would assume that as there is more 'work' being done by an extended drive-train that it would, however, the ability to hold speed round bends might outweigh that... (not as much acceleration needed when coming out of the bend....)
Have heard that it is recommended in SUV's to switch to 2WD unless you NEED the 4WD...so I guess that might be something to consider.
yeah its actually a gas hog. I dont know if u drive a 4WD vehicle in 2WD if it saves it though, i would expect it does.
It still wont run as efficiently as a real 2WD though due to the additional weight you're carrying around.
Yes - more weight, and more friction in the drive train = Lower economy.
So why do I get 30 MPG combined city and highway in my WRX? 
Specifications:
1450 kilos.
2.5 litre engine.
230 horsepower.
Specifications:
1450 kilos.
2.5 litre engine.
230 horsepower.
Who says 4WD equals a gas-guzzling monstrosity? The point is that your MPG rating would be even better if it were a 2WD layout, even if somehow the weight would stay the same.
:smack:
Simple physics here guys... AWD's lose up to 35% of their power in the driveline, and they are heavier. That same engine will be more efficient in a RWD vehicle and be even more efficient in a FWD vehicle because of the weight savings in both the spinning mass in the drivelines and the mass to hold that spinning mass in place to get that power to the wheels. AWD's use more fuel per mile than any other vehicle if you used the same chassis/engine and simply made the car either RWD or AWD and removed the excess driveline. Because of the loss of driveline mass you have more power to push yourself forward and less power to counteract the willingness of the driveline to want to stay stationary.
If you have a 200HP engine with AWD it will consume up to 70HP in just the drivelines leaving you with 130 to propel forward. In a RWD 50HP is lost giving you 150 to play with and with FWD you lose 30HP giving you 170 to put to the ground whjich is 50HP MORE power to the ground than an AWD vehicle for the same engine. This is not static however and the faster you go the more power is needed to counteract the mass in the driveline which makes AWD's consume much more fuel at speed than a FWD vehicle.
Now couple this in with the weight savings you will need less power to maintain any given speed with a FWD because the car is now lighter with the same amount of HP. So you get more power to the ground AND better fuel economy no questions about it.
That being said there are things that improve gas millage to make the efficiency through ECU mapping and proper tuning, but this tuning can be done on other vehilces too and AWD's will always be on the bottom end of the spectrum to RWD or FWD cars for fuel economy, they will always eat more fuel than a RWD or FWD car with the same engine and even the same weight for the above stated reasons.
Simple physics here guys... AWD's lose up to 35% of their power in the driveline, and they are heavier. That same engine will be more efficient in a RWD vehicle and be even more efficient in a FWD vehicle because of the weight savings in both the spinning mass in the drivelines and the mass to hold that spinning mass in place to get that power to the wheels. AWD's use more fuel per mile than any other vehicle if you used the same chassis/engine and simply made the car either RWD or AWD and removed the excess driveline. Because of the loss of driveline mass you have more power to push yourself forward and less power to counteract the willingness of the driveline to want to stay stationary.
If you have a 200HP engine with AWD it will consume up to 70HP in just the drivelines leaving you with 130 to propel forward. In a RWD 50HP is lost giving you 150 to play with and with FWD you lose 30HP giving you 170 to put to the ground whjich is 50HP MORE power to the ground than an AWD vehicle for the same engine. This is not static however and the faster you go the more power is needed to counteract the mass in the driveline which makes AWD's consume much more fuel at speed than a FWD vehicle.
Now couple this in with the weight savings you will need less power to maintain any given speed with a FWD because the car is now lighter with the same amount of HP. So you get more power to the ground AND better fuel economy no questions about it.
That being said there are things that improve gas millage to make the efficiency through ECU mapping and proper tuning, but this tuning can be done on other vehilces too and AWD's will always be on the bottom end of the spectrum to RWD or FWD cars for fuel economy, they will always eat more fuel than a RWD or FWD car with the same engine and even the same weight for the above stated reasons.
That 30mpg drops VERY quickly when you use the loud pedal though
Even a BWM Mini Cooper I had a while back dropped to high 10s/low 20s mpg when I played in it
Hehe, same here, I get 30 down the highway, but if I really start getting on it it drops in the low 20's. If I am on a racetrack..meh... I went through 3/4 of a tank with 15 laps at silverstone...granted it's like 5 miles a lap, but still.
goign back a bit but...thats a bad clarification! The only diffrence between the cosworth and the standard escort was 8 more valves and a turbo, engine size was the same! Just bolted a twin cam 16v on top instead of the standard 8 ohv head. then added the turbo.
ahem
A physical body will remain at rest, or continue to move at a constant velocity along a straight path, unless an external net force acts upon it.
But less weight = less rolling resistance, no?
not sure... isnt rolling resistance mostly a matter of tyre deformation which can be reduced as much as you like thanks to the co2 that comes out the back of your car (why has no one ever thought of combating global warming by filling tyres with co2?)
I think he meant under acceleration, not contant velocity.
PS - w00t! I can join in easy Physics discussions thanks to Mechanics!
Dude that's an even worse clarification :P The Escort never came with a 2L engine (CVH or Zetec) as standard. The Cosworth YB engine was developed from the orginal Pinto, which never appeared in Escorts - always being used for RWD setups.
But yer AWD is less effecient then 2WD.
which bit of the english language in the sentence "you will need less power to _maintain_ any given speed with a FWD" is unclear?
Oh god this is why I keep out of Physics discussions.
1996 Nissan Altima, 2853 pounds, 150 hp 2.4L 4 cyl, 4 sp auto trans, FWD - 20-22 mpg
2006 Mazda Tribute, 3487 pounds, 200 hp 3.0L V6, 4 sp auto trans, AWD - 22-24 mpg
Go figure.....
The difference? I live in very hilly territory. Where the Altima spends its commuting at 65 mph with the throttle at halfway to make the hills, the Mazda's throttle is barely touched. Low end V6 torque overrules the 4 cyl in fuel mileage around me.
You have to take into account, where and how you are driving a vehicle when talking fuel mileage....
2006 Mazda Tribute, 3487 pounds, 200 hp 3.0L V6, 4 sp auto trans, AWD - 22-24 mpg
Go figure.....
The difference? I live in very hilly territory. Where the Altima spends its commuting at 65 mph with the throttle at halfway to make the hills, the Mazda's throttle is barely touched. Low end V6 torque overrules the 4 cyl in fuel mileage around me.
You have to take into account, where and how you are driving a vehicle when talking fuel mileage....
~22mpg isnt anything id consider acceptable in a less than 5 year old car
In an ideal world you are correct. But with diffs and gear lube there is resistance which slows the driveline down, maybe saying driveline mass will slow it down alone was not accurate =P There is resistance in a driveline so it takes more power to overcome this loss
A FWD or RWD has 1 diff, an AWD system will have 3 so will have 3x the resistance of a FWD.
The mass itself is not the problem, it's the resistance, how much I am not sure, but it will slow the driveline down quicker =) 3x quicker =P thus you need more power to compensate.
Very true, but then an AWD system will still have a lower gas milage than the same engine in the same weight vehicle with a FWD or RWD system. How much I don't know, but it will be less which is what we are talking about, not the actual fact of high/low gas milage so if you put that engine in the AWD vehicle, and placed it in a FWD or RWD config, you will have more power and better fuel milage.
Depending on the car, I agree. Lucky my car isn't less than 5 years old, it is 12 years old
. (2008-1996=12)All I know is I get 25 mpg highway with my AWD '98 Outback w/ a 2.5 L H-4, whereas my dad gets 33 mpg COMBINED in his Quattro '05 A6 with the 3.2 L V-6.
Obviously there's a lot more to mileage than JUST the drivetrain. I wouldn't worry about mileage loss in an AWD car. Usually it's only 1 or 2 mpg anyway - not THAT much of a penalty for all the benefits you get.
Obviously there's a lot more to mileage than JUST the drivetrain. I wouldn't worry about mileage loss in an AWD car. Usually it's only 1 or 2 mpg anyway - not THAT much of a penalty for all the benefits you get.
So I guess you're living very offroad or in a snowy area, because better handling in these environments are pretty much the only benefits you have from a 4WD car. 
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4WD Does it use more gas?
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