Controling the Z when $hit hits the fan. How?
#63
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Originally Posted by SteveZ
Now I see what you were referring to, I think. When I said VDC doesn't know lateral, that is not correct. What it picks up is Yaw, which to me is lateral movement of one end or the other of the car relative to the center. My observation is in relatively uniform 4 wheel drifts, VDC does not appear to kick in in the form of engine management, brakes, etc. unless there is a significant difference in the steering direction of travel and the 4 wheels. Also kicks in if there is a rotation around the center axis (over-simplified).
What I have never seen in print is the following situation:
1) Got into some deeper snow than expected (have Pirelli Snowsport 240 dedicated snows)
2) With VDC on, appears that as the rear spins the wheels and there is yaw to the driver's side, there is braking on the front - w/o my foot on the brake. The way I could tell is my limited forward progress showed the front wheel was not turning but pushing through snow, aggravating the impact of VDC because the front tire was meeting resistance.
I got out, very puzzled as have driven through much worse, and note the sliding of one or both front tires - not sideways but as if they were locking due to braking. Turned off the VDC, which to my understanding also cuts the TCS on the G Coupe at least, LSD is of course still working, instant forward progress. I was spinning both rears but the drivers' side a bit more which caused the yaw, slippage to the left. The difference was dramatic. I used the same approach anytime starting up in deeper snow and the tires would bite down, find traction, and I'd move. Turn on the VDC, and I felt like I was plowing the fronts even though pointed in the direction of travel.
My 350Z came with no TSC, no VDC, and an open diff (2003 Base, my understanding is today the Base comes with TCS). Life is much simpler in that case - you cannot back out of the driveway with frozen dew!
As I head into Winter #3, I know a little bit more than before, I refuse to park for the season. Even when I head out for overnight trips the threat of snow alone would cause me to forgo the Z or the G, then I'd see three days of dry pavement. The Pirellis make surprisingly capable studless tires and you definitely get a feel for throttle, brakes, and traction aids when there is a LOT less friction available
Again, thanks for the great info, happy driving. I am jealous of NoVa track above, nothing close here in Winter that isn't closed. Lime Rock is in the NW CT hills where I live, usually the area of heaviest and longest snow pack. No track for me in 200-300 miles
What I have never seen in print is the following situation:
1) Got into some deeper snow than expected (have Pirelli Snowsport 240 dedicated snows)
2) With VDC on, appears that as the rear spins the wheels and there is yaw to the driver's side, there is braking on the front - w/o my foot on the brake. The way I could tell is my limited forward progress showed the front wheel was not turning but pushing through snow, aggravating the impact of VDC because the front tire was meeting resistance.
I got out, very puzzled as have driven through much worse, and note the sliding of one or both front tires - not sideways but as if they were locking due to braking. Turned off the VDC, which to my understanding also cuts the TCS on the G Coupe at least, LSD is of course still working, instant forward progress. I was spinning both rears but the drivers' side a bit more which caused the yaw, slippage to the left. The difference was dramatic. I used the same approach anytime starting up in deeper snow and the tires would bite down, find traction, and I'd move. Turn on the VDC, and I felt like I was plowing the fronts even though pointed in the direction of travel.
My 350Z came with no TSC, no VDC, and an open diff (2003 Base, my understanding is today the Base comes with TCS). Life is much simpler in that case - you cannot back out of the driveway with frozen dew!
As I head into Winter #3, I know a little bit more than before, I refuse to park for the season. Even when I head out for overnight trips the threat of snow alone would cause me to forgo the Z or the G, then I'd see three days of dry pavement. The Pirellis make surprisingly capable studless tires and you definitely get a feel for throttle, brakes, and traction aids when there is a LOT less friction available
Again, thanks for the great info, happy driving. I am jealous of NoVa track above, nothing close here in Winter that isn't closed. Lime Rock is in the NW CT hills where I live, usually the area of heaviest and longest snow pack. No track for me in 200-300 miles
Very interesting reading Steve.
The only time I hit snow with the Z was at MidOhio in April of 2005. With the OEM re040, the car wasn’t going anywhere with 1 inch of snow. It would just go around in circle about the front tire. That was with the VDC off. When it was on, the car would just tremble, sorta like in an epileptic seizure, and wouldn't do anything. I appreciate your snow experience. I haven’t brought myself to get snow tires for the Z as I had a set of Toyo Garrit HT on the Suby last year and now I have a 4x4 Titan. I can’t justify the expense, although I’d really like to! I’m from Montreal, tons of icy roads there to test the Z in old school rally style during the holyday.
The Z’s electronics behave the same as with the G. VDC off will also cut TCS but maintain the ABLS, ABS and EBD. From my ice rally days and your description of the plowing Z with VDC, I’m pretty sure the VDC action on the inner front wheel (in an attempt to rotate the car that way) will effectively make the car plow straight. In slippery condition, the inside tire has to work more proportionally because we can’t get much weight transfer. Applying brake will not help traction.
There is also the fact that, most times, if the rear end stands out in slippery conditions, wheel spin quickly follows, forcing the intervention of the TCS.
Hey, can I rent your wheels this winter ?
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