An outsiders view on the SVX

[dcarrb]

The engine is doing the same amount of work, moving the same mass, regardless of which wheels are driving the car.

dcb

well thats correct, however with FWD only, your motor is moving, lets say, 22lbs of rotating mass, and with it enabled, its moving 70lbs of rotating mass, the weight of the vehicle dosent change, but the rotating mass of the increased driveline does... does that make sense?

[mbtoloczko]

The SVX tranny is essentially a FWD tranny that connects the rear driveline to the front driveline with a variable pressure clutch. When you are cruising along in AWD mode the clutch is lightly engaged. During hard acceleration, its full engaged. When you put it in FWD mode, the clutch never engages, but since the rear driveline is still connected to the rear wheels, the rear driveline still spins along as usual. No change in rotating mass. However, you might see some small increase in gas mileage in FWD mode because the front and rear drivelines are not fighting each other during cornering. If you put it back in AWD mode, make sure the front wheels have at least 4 psi more than the rear. This minimizes the difference in rolling circumference between the more heavily loaded front wheels and the less heavily loaded rear wheels.

good information! It uses a viscous clutch I assume then. Similar to the skyline and AWD olds bravadas. That makes sense to me.

[benebob]

Others have tried it on the Ultimate Subaru board and actually found that their mileage is worse slightly (which would probably be to driving conditions my guess). You need to remember that only 10% of the power is going back there and the loss will occur regardless of if the fuse is in or not. Even if you get 10% better economy. The wear on the system that is not meant to be fwd except for emergencies far outweight any benefit you might see. Slow down or turn the ac off and you'll get better mileage.

[mbtoloczko]

Originally Posted by 5.0_CJ

good information! It uses a viscous clutch I assume then. Similar to the skyline and AWD olds bravadas. That makes sense to me.

Actually, its a multiplate clutch that is electronically controlled. Sorta like a Skyline, but with the Skyline, the rear wheels are always driven.

right. This is native FWD whereas teh bravada and skyline are native RWD.

ill pull the fuse out!

[oab_au]

Originally Posted by 5.0_CJ

well, wouldn't it cause a higher load on the motor driving 2 other wheels? right now its not driving the rear wheels, I understand the halfshafts and driveshaft are turning, of course, since the car is going down the road, but you have that same amount of drag when the rear wheels are under a load as well, but now your loading up the motor further at high rpm's, correct?

When the FWD fuse is in, the engine still drives the rear wheels, through the road. the front wheels pull the car along, causing the back wheels and rear drive line to turn. Still uses the same power.
Now if you could drive it with the fuse in and the back wheels off the ground,,,,,,,,,,Oh never mind.

Harvey.

[dcarrb]

Seems the added traction of AWD would actually improve fuel economy, if only to a virtually immeasurable degree. As I recall it was pretty easy to unintentionally break traction with my old 90 horsepower GL in FWD (I used to shift it to 4WD in the rain); with a FWD SVX, I'd think that a common occurrence.

dcb

[HighwayUFO]

Originally Posted by Chiketkd

Thanks for helping your friend keep his SVX on the road! The sound of the 3.3L flat six at full throttle is second-to-none!

-Chike

Sounds even better with side pipes. I encourage all of you to call me up and take a listen for your self. Such a unique sound and rasp to the tone. Every time I start my car up it melts my butter.

Keith