He said he pulled a fuse to disable the AWD, and run FWD in the summer netting him an extra seven MPG.
that's not possible. Most importantly, others and myself have done it quantitatively and it makes no difference.
Technically speaking it could make a minor difference, but it would be nearly negligible in real world situations, though i'll concede some minor increase if someone was very perceptive and anal about driving habits - like maybe 1mpg. 7 is impossible with the FWD fuse alone.
2nd - it doesn't make sense.
a 4WD Subaru still has hundreds of additional pounds of 4WD components - rear bearings, hubs, axles, rear differential, rear driveshaft, carrier bearing, rear extension housing, 4WD clutches/center differential.
A FWD "car" does not have all that additional weight. Putting in a fuse does not make that hundreds of pounds of components disappear.
Not only the weight - but the amount of additional rotational components induce drag and moments of inertia associated with every additional rotating part - let's work our way from the wheel to the transmission to see the increase of rotational mass, inertia, and resistance:
1. beefier rear bearings
2. rear outer CV joint
3. inner rear CV joint
4. rear differential stub shaft bearing
5. rear differential ring and pinion
6. rear differential front piniion bearing
7. rear driveshat ujoint
8. center carrier bearing
9. joint at center carrier bearing
10. front driveshaft ujoint
11. bearings, clutches, driven gears or center differential (manual trans).
running a 4WD vehicle in FWD does not magically make those things disappear unless he bought his car from Peter Pan.
More compelling information: Average gas mileage for a 2000 Outback is 24mpg (http://www.fuelly.co...ru/outback/2000)
If he increased 7mpg - then he's getting 31mpg. that's not possible without severe modifications to driving style or components.
Or alternately if he didn't get 31mpg - then his car probably wasn't running properly and getting less than average and some maintenance, repair, other issue was resolved.
and finally - i would highly suggest not putting much stake in "what some guy said" - i can't begin to tell you how many incorrect notions i hear about cars almost weekly. people make improper conclusions, correlation doesn't mean causation, people change their oil and think they know everything mechanical, people drive one Subaru and think they know them all....
I could keep going - but the bottom line is this is completely off base and he's either whimsical in information or was honestly misled in some way.
my sister has a '10 Forrester that she says she's disappointed in the fuel economy with.
not a good car for gas mileage conscious people. if gas milegae is a concern i would not recommend buying a high ground clearance, 4WD, automatic, about the largest 4 cylinder engine you can get, with roof rails. that car has many items that detract from gas mileage, not a very efficiency friendly car for those interested in that.
it could also be:
driving: letting the car warm up in the morning, short trips, heavy on the go pedal and break pedal.
location: mountain driving, city driving, stop and go, frigid so the car is idling a lot while warming up or de-icing windshields.
what kind of vehicle did she have previously?
people coming from small FWD/RWD cars with good mileage are sometimes unimpressed with Subaru mileage.
people coming from big SUV/truck world will appreaciate the Subaru mileage and still having 4WD/automatic.
My in laws were entertaining Subaru and coming from american FWD cars and i told them not to get it, he would hate the gas mileage. He bought it anyway but he was at least prepared and love the thing so much for it's snow prowess and other aspects he ended up buying another new Subaru Outback as well. He values it for what it is.
if she had a dinky FWD american econobox then that may explain it. they have good gas mileage and are cheap...but they're weak in about a dozen other ways. can't have it all, gotta pick what's best for you. if gas mileage is more important than safety, 4WD, ground clearance, aesthetics, etc - then gotta choose accordingly.
Edited by grossgary, 11 April 2014 - 09:32 AM.