paul_philly

All,

I have been in the Edmund's, clublexus and Infiniti forums talking about the RL vs. the GS and M. There are some obvious misconceptions out there like "SH-AWD doesn't activate until 6000 rpm's" and others. However, consensus is that SH-AWD has no advantage over AWD in snow and rain; they all agree that it has avantages on dry surfaces, but not winter conditions. Hmmm...I may agree with that.

What's everyone else think?

Oh, on a different topic, anyone watching the Eagles dominate the second half against the Bronco's? AWESOME! Go Birds!

vp911

What if one wheel is slipping on snow and the other three are fine - the one that is slipping will not rcv power. It has its advantages in all conditions.

paul_philly

But the SH-AWD only accelerates the outside rear wheel in cornering...

vp911

Yes - for a reason. The point is to accelerate the outside rear wheel when cornering -but you asked about the other conditions. Say it there is ice on the road and say your front two wheels are fine and the rear left wheel is fine - if the rear right wheel is slipping, the power will go to the other three wheels, not the rear right wheel. acura.com has a good interactive demo of how it works in such conditions.

paul_philly

VP -

Thanks for the input. I just viewed the video on Acura's website, and it specifically states that "SH-AWD accelerates the outside rear wheel for better handling in dry conditions."

So, I must respectfully disagree with your assessment. I'm sure the RL will handle very well in the snow this winter, especially with a full time, fwd biased AWD system. But the SH part seems to have no advantage in snow.

This, of course, won't pursuade me to trade the RL for a GS or M, but I like to be informed about what the system can and can't do.

vp911

I was always under the impression that it would have better handling in the snow. I may very well be wrong - perhaps others here can chime in - especially those who have had the car in the winter.

vp911

"the only all-wheel drive system capable of accelerating the outside rear wheel in a turn for enhanced handling and additional turning force. The system optimizes acceleration traction by sending power to the wheels with the most traction for increased control. The result is class-leading cornering performance and stability, as well as superior traction on dry or wet surfaces."

ASP

read this and post this where needed . . .

https://acurazine.com/forums/showthr...ghlight=sh-awd

vp911

I hadn't seen that before ASP. Great scan!

bluemule

Looking at the RL SH-AWD brochure, which is of course a brochure, but which describes what the system is supposed to do:

The brochure discusses SH-AWD traction and control vs. a conventional awd system. The overall impression I get when looking at the brochure is that torque is variable front to rear and side to side depending on how the car is being driven and the road conditions encountered.

SH-AWD varies distribution of engine torque between front/rear wheels, and side to side; sends power to wheels losing traction, sends torque to the outside rear wheel and mechanically accelerates an outside rear wheel when cornering.

So, it's not just a dry road feature and only limited to operation of torqueing the rear wheels through corners. It's a system which proactively directs torque to enhance stability when accelerating, decelerating, cornering...promoting neutral steering, decreasing oversteer.

ALSO, from the brochure, the following characteristics generate neutral steering:

70% torque to front wheels, side to side balanced when straight line cruising;

up to 70% to outside rear wheel when accelerating through a corner (100% of rear wheel torque to outside wheel and 5% faster rotation speed);

when crusing through a moderate corner, up to 70% engine torque to rear wheels with the outside one getting a bit more;

up to 40% torque to rear wheels and side to side balanced during straight line acceleration;

in all weather conditions.

The brochure describes a complete system for all conditions which helps with neutral steering.

I note that Consumers Reports doesn't seem to be too impressed with the RL's SH-AWD handling. I don't know the criteria they used to reach this conclusion. Regarding some of the current years autos, I'm still a little bit wary of their uncharacteristic gushing enthusiasm for another brand's current offering, especially when that vehicle had rather uninspiring reviews in previous years and no proven track record with the new model. I haven't kept up with CR's site regarding these issues, even though I'm a life member.

So, who knows. One reason I bought the RL is because of the promised stability of the SW-AWD system. I sometimes drive in muddy conditions and having hydroplaned a non ABS/non VSA/non AWD vehicle into a creek, I opted for the RL. I figure that if Honda says it works, it works. That's been my experience with Honda.

Fred

Jbro

Given two AWD vehicles with one being the RL, the RL with SH-AWD should still out corner the other vehicle in the snow. The advantages that SH-AWD has on dry surfaces should apply to wet or snowy conditions. Of course in wet or snowy conditions, maximum cornering speeds will be less than it is for dry conditions.

paul_philly

Great information from all.

vtecracer

SH-AWD helps in ALL conditions. I saw a video of an RL being tested in the snow and the speed and control the driver had through the corners shocked me. I had never seen a stock car take a turn so fast on a snow covered road. Ice on the other hand is a different story. I dont think even the RL with the most advanced AWD system in the world can combat the effects of ice.

DCRL

Don't put too much stock in Consumer Reports. The magazine's test of the Acura RL concluded with these words: "A full-sized spare rests under the trunk floor". They got a few other things wrong as well. But, maybe they had a special model.

NJRonbo

Guys,

Have a simple question...

Is the SH-AWD always active when you turn
on the ignition?

Or, is there a button/switch that you need to
press to turn it on or off?

After 4 months of owning my RL there are still
some buttons I haven't really taken the time to
learn what they do.

Thanks for the help, as always.

vp911

SH-AWD is always active. There are no switches/buttons for it.

paul_philly

NJRonbo -

It's always on. Remember, the "SH" part is the ability to accelerate the rear outside wheel faster than the average speed of the two front wheels when cornering. You can actually see the power distribution on the Driver Information display - if you go into turns wuickly, you'll notice the "power bar" moving in the direction of the wheel receiving the additional power.

bluemule

The last time I checked their forum, that was pointed out to them and they were going to correct the ratings online. When I get a chance, I think I'll look at their forums again to see what the test drivers said about SH-AWD and handling issues in general. I do recall one of the drivers saying that the RL's ride was harsh...to put it mildly. That language didn't find it's way into the ratings, btw.

Fred

Rob L

Yep, I would agree with the above. It is mainly for dry road conditions but logically it can do the same on snow covered roads.


Fact is the system appears to be the ultimate AWD system out there so nobody should really criticize it and act like it is useless because the car they like doesnt have it.

Oh and whoever said the system doesnt kick in until 6000rpm is a fuggin idiot.

I also dont know what car CR was driving to imply the cars cornering isnt good. I mean even with the crap OEM tires it has good cornering. Can't imagine what it must be like with some good summer performance tires.

One more thing...I did watch the Eagles start to come back but go back to complete crap in the last half of the 4th qtr.

Nocturnal

The only poor thing about SHAWD is that indicator in the MID. You can't see it when you turn the wheel!

I've experienced SHAWD a couple of times on dry roads and it was a wonderous feel. It definately turned in tighter than my S4 used to. True point-and-go technology.

vp911

Yes! I hate how I can't see it when I turn the wheel - although I guess its safer that way.

Nocturnal

Indeed. You can imagine someone suing Acura because they were looking at the fancy bars dancing back/forth and slamming into a tree.

db22

Doesn't the '06 miss the tree!

Bitium

The Rl is not FWD biased. If you did 200 laps on a perfect round track at max speed, the RL will keep most of the power on the outer rear wheel, but that does not make it RWD biased, does it. Neither driving straight on the highway at 60 mph makes the car FWD biased. The system is not biased at all, it just uses the front and the rear wheels at the most significant time.

The SH does have advantage in the snow, is not better then 4-matic in that aspect, but better than any other AWD.

The car still has a 30:70 70:30 ratio, meaning it will use the front or the back wheels as necessary (like stuck in the snow), but then it can apply the power to just one of the outer wheels in case you hit a patch of ice to push up if possible to the right direction. Picture your self inside a box going down hill in the snow with a paddle. If the box starts to go to the right what would you do?? Used the paddle on the right side (applying power) to steer the car left, just like the RL does, of course this is more effective in a dry surface, but just like tires alone are more effective in dry surface, but the system works just as good on any situation.

vp911

Bitium - great explanation. I am curious - I don't know much about the 4matic system - what makes it better in the snow?

Bitium

Unlike the SH-AWD, were each front wheel can have 15 to 35 % of the power, the 4-matic can leave any of the 4 wheels at 0% and applying the rest of the power to the wheels with most traction. 4-matic is dependent on traction, it will not adjust the power distribution because you take a corner, is a reactive system. It reacts to traction circumstances. I lot of cars like MB and BMW use their VSA like system to do what the RL SH-AWD does on corners, but is not as good because they apply the brakes to the inner wheel unlike SH-AWD were it sends the power and speeds up the outer wheel. Same theories apply in different ways. You have to remember the VSA will probably be more effective in a snow situation to control the car than SH-AWD, unless you need more traction.

Go back to the box. On the same situation above.

SH-AWD will push to steer the box to the left while incresing or maintaning the speed

VSA will do the same but putting the paddle sort of in the right front to slow the car down while steering it to the left.

So is all up to the drivers intentions and actions. To me you will take more advantage of VSA on the Snow than SH-AWD, unless like I said you just need more traction on a specific side or wheel on the car.

GaddAMIT

my dad has a E350 4matic and it is incredible in the snow. I really do have a tough time getting scared in that car to loose traction. Obviously it is possible, but it is also pretty difficult. As most drivers are more cautious in the snow as it is, the car seems VERY safe. I have also driven the RL in the snow, and it seems just as good in the snow. Im not sure if an average driver would be able to tell much difference in the snow. Then again I pushed my dad's MB a lot harder then I did with my friends RL, just for the fact I would feel horrible if I messed up my friends car.

Nocturnal

If you don't look at where you're going no amount of technology will keep you on the road.

vp911

Thanks bitium

paul_philly

Very insightful and intelligent responses from all. However, couple of things. Firstly, Bitium, the RL is FWD Bias. The manual states that if the planetary gears breakdown, the car can still be driven from the front wheels; that, plus under normal driving conditions 70% of the power is in the front constitute a FWD biased AWD system.

Secondly, all the points made are valid and correct. However, the "SH" part of the system, where the outside rear wheel gets accelerated faster than the average speed of the front wheels, is "activated" through yaw sensors monitoring wheel spin, degree of wheels, car's center of gravity (and more) to provide added stability through turns and cornering. None of us will be driving hard or cornering in the snow, therefore I must still respectfully disagree with the statements indicating SH helps in snow (regardless of what's on Acura's site). Although I do like Bitium's box down a hill theory.

Thirdly, to say that one AWD system (4Matic) is better than another system is pure opinion. I've read articles over and over again that say Subaru's symmetrical AWD is the best out there. I've read, even on the Lexus forum, that SH-AWD is the best out there. There are so many factors involved such as tires, ground clearance, weight of the vehicle, driver's characteristics, and more that you just can't say one is better than the other. For example, in 7 inches of snow, the Subaru Outback will have better manuverability than our RL's since we have 5.8 inches of clearance and they have 8 inches of clearance; better than 4matic too.

What everyone agrees on is a full time split (like the RL and the Subaru) is better than the normal RWD platform that sends power to the front wheels only when slippage is detected.

It's been a good thread though...