How Fast 2 Rear Wheels Kick In

[thdoan]

I own an AWD 2004 RX330 in "TEXAS"!!! You may laugh, but AWD helps me a lot in wet condition. Several times, when the road is wet, and start from stop, other cars spin the wheel without moving but not mine.

Saleman told me that AWD is 50/50 all the time. But some forums state that it is FWD unless the wheel starts to slip. My question is if that is true, how fast the system will react and transfer torque to the rear wheels.

Thanks,

[wwest]

What Lexus said in an email to me in response to this question was that the RX330 is 50/50 when traveling at a constant speed and all four tires have roughly equal traction.

What I have determined for my own satisfaction is that under acceleration the torque split is more on the order of 90/10 F/R.

Now Since I have a 2001 AWD RX300 I cannot speak for the RX330 but with my RX300 if the front tires lose traction the engine is almost instantly dethrottled and the front brakes at applied to maintain a high level of engine torque once the VC does its job (if it ever actually does).

Remembering how potentially hazardous it can be to lose front traction (no directional control) due to engine torque application I think it is entirely appropriate to quickly dethrottle the engine while simultaneously using the brakes to maintain and apportion engine torque to the rear.

Your vehicle's Trac system also uses the brakes to simulate a rear diff'l LSD and maybe a front one too but I'm not so sure about the front.