So I understand the basics of the SHAWD system and love it. My question is....

When Im cruising around town and say make a sharp right turn, there is equal power to the front wheels and up to 100% of the rear wheel power goes to the back left wheel as I make the sharp turn. Makes sense, this is the point of the system.

However, at highway speeds, I noticed the exact opposite. If I am going say 70mph on a freeway bend to the right, still the front wheels have equal power but no longer does up to 100% of the rear wheel power go to the left wheel, now that power is on the right rear wheel when I am turning right. Is this because it acts to mimic the PAWS system and is trying to "push" out the rear end of the car to "trace the line" as Acura states?

Why is at low speeds the rear power goes to the opposite rear wheel but at high speeds it goes to the same side rear wheel as I am turning? Thanks

 

If I recall they made some adjustments to mimic what PAWS does for lane changes so it depends how much the bend was. Also understand if you are light in the pedal there is hardly any power going to the rear wheel. I think the AWD display is a little deceiving as to what each bar means. I like that at least 10% of the power is going to the rear wheels in this gen SH-AWD, but would still prefer to see them be even more aggressive and send maybe 25-35% to the rear all the time.

 

I think they have mechanical limitation of clutch pack (center differential) if they want to transfer constant 30% to rear.

 

KeithL is correct. The reason it is transferring power to the inside rear wheel at highway speeds is for added stability during a lane change. It "pulls" you over in a way. Feels fantastic if you ask me. If you are at high speed and you're going around a mountain winding road though with some slightly tighter turns, it'll go to the outside rear wheel again to help you around those.

 

I understand the lane change mimicking the PAWS system but when I am on the highway and there is a curve is it really helping?

And you mentioned at high speed going around a mountain it will push to the outer rear wheel, but from what I noticed is at lower speeds it goes to the outer rear wheel and higher speeds inner rear wheel. It doesnt know if Im on a twisty road or a slight bend on the highways thats just what I see happening. Just find it interesting when at high speeds and it does the inner rear wheel, still slightly confused on that matter.

 

Are you referring to the same corner at different speeds?

 

The SH-AWD system relies on a variety of variables to allocate torque - vehicle speed, steering wheel angle, yaw rate, and I believe relative traction (i.e., wheel speed of individual wheels versus the other three wheels). It's incredibly complex and ingenious. I find the result to be the most-confidence inspiring car I've driven. Confidence inspiring, but lots of fun too.

 

Might be hard to find. That said if you can find a large parking lot with very widely spaced light stations try this on a wet day.

Mark out a 200ft diameter circle. In full nanny mode floor the throttle & drive the circle. After a few laps keep the pedal to the metal & switch off the nannies on the fly & see how many loops you can make before recovering. Next try is to have the nannies off & just floor the throttle to start. Hold on for the ride & don't get to dizzy.

Most performance driving schools have this demo as part of the training to give you confidence in the onboard systems.

I know we are all the second coming of Ayrton Senna but the nannies can make us better drivers if used properly.

 

The one in the TLX also uses throttle input as a pre-calculator as well since it's electronic throttle. Before the engine makes the power, the SH-AWD already knows what it's going to do.

 

All Acuras since 2004 have been drive by wire so the ECU knows what's up.

The SH-AWD system over-drives the outside wheel during cornering to help the car act more like a RWD car and induce oversteer.

While in straight line with lane changes, minor power changes are done as the SH-AWD system detects slip and such.

 

When doing lane changes on the highway since I move the steering wheel so minimally I dont see any power change across the rear wheels. But around corners whether at low speeds or high speeds I can see the power distribution

And Bear avhistory: nanny mode???

 

^^ nanny mode = VSA and such turned on/off.