Quote:
Originally Posted by ZDan
The "as I expected" betrays bias. People tend to experience (or *think* they experience) what they *expect*. Blind A/B/A testing would be better, but of course not hugely practical!
"Precisely" implies you made *precise* measurements. Did you?
Weight over the drive wheels will help a bit, but even 100 lb. added only gives you 4% more drive grip, which you may or may not notice.
Weight distribution is nowhere near 50/50. http://media.caranddriver.com/files/...e-napoleon.pdf (55.2/44.8 full tank, no driver). They claimed 53/47 for the car with driver and passenger and a full tank, but as-tested weight distribution with fuel and driver is 54/46. That's not very good in snow... 100 lb. at the front of the trunk even with the rear wheels improves this to 52.2/47.8. Better, but not HUGELY so. 47.8/46 = 1.04x the grip. Might make the difference, might not.
May as well put the weight as far back in the trunk as possible. The car will still be more drive-traction limited than front grip limited. Might put another .5%-1% on the drive wheels.
I don't think so. The torsen is "torque-sensing", in low-torque situations, lockup should be light.
In a straight line, the torsen is ensuring that you don't get a 1-wheel spin and that both wheels are contributing as much as they can before they both start to spin. It is HELPING. Of course when you do break traction, you spin both wheels and lose all lateral stability instead of only spinning one wheel and keeping some lateral stability. But for sure the torsen is close to maximizing the available drive grip.
The PROBLEM is poor static weight distribution. The best solution is good winter tires, which you already have. Putting weight in the trunk in the form of sand or kitty litter or other material that can also be used as traction-compound will also help. I did that with my old 240SX with similar weight distribution and no limited slip.
In my S2000, with Torsen diff, 49F/51R distribution with driver and fuel, on Dunlop WinterSport tires, never a prob  |
Geez, and I thought you knew a thing or two.
This is all nonsense.
How much weight are we to add to improve traction? 200 lbs?
Anecdotal evidence isn't supposed to be scientific. Also, nobody can actually usefully measure traction in winter conditions because they vary so much. Even travelling twice over the "exact same road" doesn't work.
Torsen never locks up, ever. Low traction on one wheel means low traction times four at the other wheel, then you get wheelspin.
Torque bias remains EXACTLY the same regardless of available grip.
A simple and effective test is to find a steep snowy hill and see if weight makes any difference to whether you can get going from a standing start or not. All of my cars can on this particular hill, with snow tires and no weight. Except the BRZ. All of the cars brake equally well going down the same hill. Two are fwd with significant front weight bias but of course this is countered by the uphill. One is awd. I also drove a rwd version of the same awd car on the same hill in similar conditions. Weight distribution was similar to the BRZ. Performance was superior to the BRZ.
Another simple end effective test is to park and unpark in deep snow by the curb. Same results.
Another simple test is a parking lot skid pad. Same results.
Weight over the axle isn't the issue. I'm not sure exactly what the issue is but I suspect a 4:1 Torsen just isn't very effective in severe winter conditions.
I can't imagine suspension geometry is the issue.
It is a fact, easily demonstrated, that the BRZ is no good as a winter daily driver.