CRH Posted November 23, 2006 Share Posted November 23, 2006 I was at a demonstration of Detroit Lockers once and they had a Toyota Landcruiser with 40k on the clock. They had one rear wheel jacked up off the ground and the other had a brick in front of it. The LSD was worn to the point that it could not drive over the brick or get off the jack. As far as getting both wheels to spin on snow, how much torque would that require? Not much. The key is check the speed of each wheel, they may both spin, but one will be alot quicker than th other! And if one gets some grip it will stop. Link to comment Share on other sites More sharing options...
Jon in CT Posted November 23, 2006 Share Posted November 23, 2006 In case anyone is interested in detailed technical VTD info: http://210.101.116.115/fisita/pdf/G347.pdf Link to comment Share on other sites More sharing options...
NSFW Posted November 23, 2006 Share Posted November 23, 2006 Awesome link, Jon. It's kind of hard to read (technical Japanese translated into technical English), but it answers a lot of questions. The transfer torque according to the estimated μ is modified according to a deviation between actual yaw velocity and target yaw velocity. The target yaw velocity is calculated from steering angle and vehicle speed. When actual yaw velocity is smaller than the target yaw velocity (understeer behavior is excessive), the transfer torque is decreased to improve steering response. The other way, the transfer torque is increase when actual yaw velocity is large (oversteering behavior), so that stability of vehicle is improved. It insure a driver against unexpected spin motion of vehicle. And the whole business about using lateral acceleration and yaw to calculate friction addresses the concern I had about predicting wheel slip - they monitor lateral slip as well as regular (spin) slip, so they don't need to see wheelspin to know the road is slippery. And there's an interesting picture near the end of turning with the center diff locked, open or in between. Link to comment Share on other sites More sharing options...
Vimy101 Posted November 23, 2006 Share Posted November 23, 2006 I don't know if you've ever driven a RWD farm tractor but they have the brakes set up so that you can apply more pressure to one rear wheel or the other. It lets the driver to really tighten up turns. Seems that ESC systems use this concept. Link to comment Share on other sites More sharing options...
Guest Posted November 23, 2006 Share Posted November 23, 2006 There's some weird decisions being made at the Subaru-headquarters, I think. That's what makes Subaru, a Subaru! Link to comment Share on other sites More sharing options...
NSFW Posted November 23, 2006 Share Posted November 23, 2006 No Vimy, I haven't had the pleasure but the whole time I was reading that PDF on VDC I was expecting/hoping to find information on independent braking. Seems like that could be helpful in correcting oversteer and understeer (not that it would change the direction of travel much by itself, but getting pointed in the right direction is half the battle). Link to comment Share on other sites More sharing options...
SLegacy99 Posted November 24, 2006 Share Posted November 24, 2006 Sticky Link to comment Share on other sites More sharing options...
ilh Posted November 24, 2006 Share Posted November 24, 2006 I don't know if you've ever driven a RWD farm tractor but they have the brakes set up so that you can apply more pressure to one rear wheel or the other. It lets the driver to really tighten up turns. Seems that ESC systems use this concept....or aircraft brakes where you have a separate brake pedal for each side. Link to comment Share on other sites More sharing options...
SLegacy99 Posted November 24, 2006 Share Posted November 24, 2006 I learned to drive on my '96 LGT, at the same time we had AWD A6, Previa, and RX300. I learned to drive stick on a Corolla and I peeled out the front wheels a couple of times. However, I try and drive a rear wheel drive car, like a Jeep, and spin the rear wheels the first couple of accelerations. Just to use to being an AWD car and being able to floor it and go if I want. Makes me chuckle. Link to comment Share on other sites More sharing options...
itzed Posted November 25, 2006 Share Posted November 25, 2006 A little OT here, but I learned to drive on a 1978 Chevy Chevette. which I drove all through college. This POS was a rear wheel drive economy car, that got about 16 MPG. But man, it was so easy to spin those rear wheels on any wet road. That, combined with the understeer made it handle like a sled. It was a blast to do donuts with in the snow with that thing. Deep down inside, I still love RWD. Link to comment Share on other sites More sharing options...
Garandman Posted November 25, 2006 Share Posted November 25, 2006 I don't know if you've ever driven a RWD farm tractor but they have the brakes set up so that you can apply more pressure to one rear wheel or the other. It lets the driver to really tighten up turns. Seems that ESC systems use this concept. Most of the old "dune buggies" had split rear brake systems running to two pedals. The driver could brake one wheel or the other. Who Dares Wins スバル Link to comment Share on other sites More sharing options...
GTS Jeff Posted November 27, 2006 Share Posted November 27, 2006 Nice review, went through the same thing when I was buying my car trying to figure what to get. I almost got the Outback because of the LSD but the chrome pipes and the ride height swayed me. You have real guts putting the MT at the bottom of the list on this forum LOL I was like "Oh oh" But I agree. The Active AWD is so much more sophisticated, from 90/10 to 50/50 and everything in between based on several sensors not just the two on the axles. Its lightning quick thats what they mean by it anticipates the slip, its so fast its not perceptible. I can't even get the fronts to chirp in dry or even slip in the wet, And it doesn't engage harshly in corners just smooth like butter,I can only imagine how good it is with the couple of extra sensors for the VDC. Its just ridiculous to have this much sophistication for $20k, I love it. You're not driving hard enough if you can't feel the AWD working. When I take cloverleafs fast, I can feel the car understeering a bit before suddenly neutralizing itself as the car feeds power to the rear wheels. Link to comment Share on other sites More sharing options...
b4wantab Posted November 28, 2006 Share Posted November 28, 2006 There are a few large clover-leafs where you can get on it and feel the balance shift as you work the gas without ever changing the stearing angle. (standard disclaimer to follow) Highly recommended, when you are alone and no one else is around. Still haven't found the 50K reference. All the tractors I have driven also have a lever by your heal to mechanically lock the diff. Very nice when you need it. Anyone able to verify if the STi system has three mechanical LSDs, three torsen based units? Peace, Greg Link to comment Share on other sites More sharing options...
SLegacy99 Posted November 29, 2006 Share Posted November 29, 2006 Did we ever find out about this fluid based differential wearout..erage....cause I still dont quite get it. Link to comment Share on other sites More sharing options...
Vimy101 Posted November 29, 2006 Share Posted November 29, 2006 Did we ever find out about this fluid based differential wearout..erage....cause I still dont quite get it. The viscous LSD will last the life of your vehicle. The key is to stir the fluid properly to get it to do what you want to do. Smooth throttle operation is paramount for performance and longevity. I have never seen anything about VLSD failing under nominal service applications. The VLSD system has been used for decades in one form or another. Link to comment Share on other sites More sharing options...
tonizdravkov Posted November 30, 2006 Share Posted November 30, 2006 i just buy slick50 manual transmission formula.can somebody tell me if i can use this aditive because is not recomended to use in cars who have cvt and antilocking diferentials. my car is legacy 2.5gx awd 156hp sedan year 2002 Link to comment Share on other sites More sharing options...
b4wantab Posted November 30, 2006 Share Posted November 30, 2006 The LSD is a sealed unit that is in the carrier. It's operation will not be effected by the gear oil/fluid you put in the differential. It is not serviceable, it if breaks it needs to be replaced. I am unsure as to what is required in your diff, I would think it would be at least GL4. I use Mutol gear 300 in both trans, manual trans, and rear diff. Very happy with the results. I have not found my reference to 50K yet, but I also have been very busy and haven't looked much. Peace, Greg Link to comment Share on other sites More sharing options...
BlueDevil Posted November 30, 2006 Share Posted November 30, 2006 It should be added that the LSD is an option on the Forester, or at least the XT. Mine had it, some do not. Link to comment Share on other sites More sharing options...
erito Posted February 20, 2007 Share Posted February 20, 2007 90-10 split have never existed here in Sweden. We get the japan built cars and they all have 60-40 default split and VDC on 4EAT cars with Active AWD. That's a great AWD setup! The 5EAT cars have VTD and VDC and default split 45-55. Link to comment Share on other sites More sharing options...
SLegacy99 Posted February 20, 2007 Share Posted February 20, 2007 Alls I know is that I love my 50/50 split. Link to comment Share on other sites More sharing options...
erito Posted June 18, 2007 Share Posted June 18, 2007 Does any model beside WRX STi have front LSD? JDM models maby? Link to comment Share on other sites More sharing options...
paul_tracyposer Posted November 23, 2007 Share Posted November 23, 2007 You're not driving hard enough if you can't feel the AWD working. When I take cloverleafs fast, I can feel the car understeering a bit before suddenly neutralizing itself as the car feeds power to the rear wheels. after reading this thread....and trying to fully comprehend and appreciate my 4eat Legacy...i must mention the first few times i felt this transition on cornering.....i remember distinctly having a slight Oh SH!T moment as i felt the car go from slight understeer to neutral/oversteer....disconcerting and fabulous all at the same time....barely perceptable but it works. i would doubt the average driver would be able to compensate in a MT as well.....JMHO. I do wish that traction control and stability control were included....i have both on my Beemer and they really are a huge safety net.....should be mandatory for mall cars. off topic. thanks....C Link to comment Share on other sites More sharing options...
stevo101 Posted July 19, 2009 Share Posted July 19, 2009 i wanted to bring this thread back from the dead because im just a confused noob here! i have an 09 legacy i limited auto. i read a bunch of things about the awd systems i just have some questions for people who have the same type of awd i have! 1.does it blow when it comes to performance sence we only get 90/10?!? i know its not a turbo i know its not fast but i would have like the 50/50. 2. is it just as good in the snow and rain and all that stuff like the 50/50 split cars?!? Link to comment Share on other sites More sharing options...
RJS5689 Posted February 26, 2010 Share Posted February 26, 2010 Really, the active AWD on the 4EAT does a better job than the continuous AWD? Its power split is 90:10 and can send up to 30% to the rear. How does that beat a default 50:50 split with LSDs? Link to comment Share on other sites More sharing options...
Lojasmo Posted February 10, 2011 Share Posted February 10, 2011 Frankly, my previous ride (03 a4) had a much more sophisticated system. My 95 lego handles like a unimog. I am pleased. 5mt Link to comment Share on other sites More sharing options...
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