AWD -> FWD question
 

I have heard that a few members have used the fuse to make thier AWD into a FWD. For these members, are you getting better MPG? How does the can handle compared to the AWD? Would it cause any problems to leave it in FWD for long peroids of time? I put a lot of miles on my SVX and am wondering if it was worth putting the fuse in to save a few bucks on gas. Thanks

well mine when i bought it had the FWD fuse in (dont know how long it was there) i dont know how it affects MPG yet cause i just took it out yesterday, the car handles better with AWD but it still sticks to the road in FWD.

Its not a good idea for an AWD car to be in FWD mode. Maybe for a few minutes but i would personally never do it.

Unless traveling a great distance on a surface affording lousy traction (giving an advantage to AWD), FWD/AWD has no effect on fuel economy. You're moving the same weight at the same velocity, regardless.

dcb

hmm thats interesting. Ppl have always told me having AWD drains a little more gas.

If anything, superior traction should improve fuel economy (ever so slightly).

dcb

i have played with the FWD fuse a bit
 

I experimented with mine a few times in the past. Each for a considerable amount of time.

When putting the fuse into an AWD SVX it does lower gas mileage slightly. On the highway I was getting about 25 mpg in AWD mode and that dropped to like 23.5 in FWD. Not that big a loss there. City was a little more. I get 21 city and it dropped to 18 in FWD.

THe biggest difference that i noticed was in the heat that the tranny produced. I have a temp guage on my tranny along with a B&M supercooler. In the summertime my temp ranges from 160-180. When i put it in FWD mode it went to 180-200!

Marisa's SVX had a temp gauge in hers as well before we put the aftermarket cooler in it. Her SVX ran with the stock cooler from 200-220 but in FWD mode it shot up to 220-235ish. WAAAAYYYYYYY too hot to maintain. She made me put it back into AWD immediately (once she found out i was experimenting with her SVX lol)

Anyway, thats what i noticed when playing with the FWD fuse. Its good for short amounts of time but i wouldn't use it long term because of the heat it generates. I don't know why it runs hotter but it does. Can anyone explain why that is?

~Ray

weird thing with my car is when the FWD fuse is in my rear tires stil spin, i noticed this in the rain when my rear end went out and i ended up facing the wrong way on a 4 lane street. also when i take out the FWD fuse and have it in AWD the car vibrates on and off at high speeds. someone suggested the diff mounts, but i dont know.

AWD verses FWD
 

Having the fuse in or out, won't affect the fuel consumption. When the fuse is in, the transfer clutch is disconnected, but the rear wheels are still driven by the front wheels, through the road.

As long as the front wheels are not spinning, both sides of the clutch still rotate at the same speed. It won't make any difference if the clutch is engaged or not.

Driving with the fuse in FWD, means that the TCU can't engage the rear wheels, to prevent front wheel from spining. If the front wheels spin, the open front diff will be subjected to jolting as the wheels grip or spin. Many front diffs have been destroyed because of this.

Harvey. ;)

Wouldn't there be some gain in fuel mileage in FWD, because in AWD more power is lost in the drivetrain and therefore it is less effiecent.

In AWD, power is transmitted to the rear wheels when the fronts lose grip. Having the front tires spinning is much less efficient, in terms of energy being used to propel the car forward, than having power shifted to the rears. Remember, too, that all the AWD driveline components are always turning, regardless of which wheels are doing the work.


dcb