delirium

On a 2000 RX300 4WD. What is the distribution of the power to the front & rear wheels?

Front: 30%?
Rear: 70%?

Thanks!

smalcom

On the RX330, it is 50%/50% for normal driving. Lexus eliminated the viscous coupling, and uses the VSC and brake system to direct power to the proper wheels.

delirium

Very nice! How about the 2000 RX300 4WD?

mooretorque

Well, it's about 80/20 front/rear under normal driving conditions. Viscous coupling means rear can't ever be more than 50% at max.

paul8801

This says 50/50 under normal driving conditions (all wheels have traction):

http://www.edmunds.com/reviews/roadt...2/article.html

But if a wheel slips.........

Where did Willard go?

On second thoughts, let's not ask.

delirium

Hmmm.. is it 50/50? I thought the front had more power because my front wheels wear faster than the rear.

ederny

If you read the article... One must really question where Liz Kim is coming from? ....does she know the difference between premium fuel and regular? ...and for that much, I thought it was an anti-sway bar, not an anti-roll bar. What the hey - guess it's all the same anyway.

On my '99, I'm confident the split is more 50/50, but no doubt changes with speed and temperature due to fluid dynamics. Considering, I look for performance in snow (read as "getting home in a storm"), the '99 AWD has performed excellently for me this winter.

mooretorque

ederny, I initially thought it was 50-50 also, but I found Willard's arguments from his garage testing to be pretty persuasive and Lexus's replies to his emails to be evasive. (I know his posts tended to be detailed and tedious, but sometimes that's just the way things are; gotta admire a guy in his 60s who's still testing things others assume as well as doing most of his own maintainence........guess it's the engineer in him.)

That said, wifey's 99 AWD with rear LSD has tracked like a train in every situation it's been in, failing to negotiate only some insanely steep streets that were ice and snow covered (which I'd only tried, Willard-like, to see just how much the RX could do!!). So, regardless of torque distribution, I've been totally satisfied with it's performance.

RX300SS

The fronts will generally wear faster due to wear caused by steering/cornoring and remember about %60 of the car weight is on the front ...

paul8801

Mooretorque, Lexus always claimed torque bias was 50-50 with all wheels having traction, and I believe Willard always acknowledged that was correct. If there is no torque bias built-in to the mechanical gearing at the differentials, then that would be the case.

The issue is what happens to the torque bias when a wheel slips, i.e. to what extent the viscous coupling then acts as a limited slip device at the center differential. This depends on the design of the viscous coupling and it would be variable depending on a number of factors including the different rates that the front and rear axles are spinning - i.e. complicated, which is probably why Lexus' email answer to Willard was so vague (although I agree they could have been more informative).

The results of Willard's experiment indicated that with the front wheels slipping, most of the torque stayed at the front and the viscous coupling did not limit the slip enough to get enough (in his opinion) torque transferred to the rear. However, at least for his garage experiment, he didn't want to go over 1500rpm at the engine (I wouldn't either) which is not that much above idle, so who knows if he reached the full potential for the viscous coupling to transfer power.

In any case, this winter was a good opportunity to try my 2000 with rear LSD on steep hills after 2ft of snow, and I thought it performed just fine.

ederny

So, if you know the link to the garage experiiments off hand, I would like to review them.

Glad you're happy with RX performance in snow. Just for grins, I did an ad hoc experiment this winter. In my driveway, 150' of snow, on ice, on frozen stone with Bridgestones, I decided to floor-it from a standstill to see where the power was going. Cripes! the thing took off... all four dug in and sent snow and mud airborne - just like in the movies. I was satisfied I could handle most anything in the RX. And so the winter went, I drove and it snowed. I ignored the snow, which we had plenty of all winter - didn't think twice about it after that, just went anywhere, anytime I wanted.

Many thanks for your comments.

RX300TC

I answered this question in "Suspension and Handling Section".

Unlike Wild *****, I took the time to sit down with a Lexus Service Mananger and went over all the schematics and diagrams.

Make no mistake, ***** just liked to hear the sound of his own voice, and prove to the world that he saw things others didn't. A very sad man.