Toyota AWD Explained

"Driving Sports TV" (drivingsports)
04/23/2019 at 11:03 • Filed to: Driving Sports TV

We drove the new 2019 RAV4 through snow, rock and gravel to bring you this explainer on the Toyota systems — how they work and how they differ.

DISCUSSION (10)

HammerheadFistpunch > Driving Sports TV
04/23/2019 at 13:18

So a few things I noted, some not a big enough deal to care, and some as notes on your test.

1. In the torque vectoring system there isn’t a center coupling, it’ s all taken care of with the 2 rear clutches. Unless they also have a front propshaft decoupler, which they might, but all that does it turn on and off the propshaft, not apportion torque.

2. The reason the front tires are spinning is because, as you said, the rear axle can only get 50% of the torque which means at least 50% is in the front axle which, when you floor it, becomes light with weight transfer. The rear axle is engaging but because there is still quite of power going to the light fronts they are going to overpower their traction in spite of the rear getting the torque requested. On a hard launch this will happen to 90% of on-demand systems, even when/if they are getting rear axle torque. if you think about it there is no way the rear axle would ever break the tires loose since the bulk of the weight is over the rear axle on launch and only half the torque can go to the back axle. A good example would be a rwd with the same engine and half throttle wouldn’t spit gravel when launched, but a FWD car would, even with half throttle.

The Hyundai coupling (if it uses the same MAGNA Dynamax coupling as the KIA, which is a fair assumption) is actually quite a bit stronger at 1000 nm total torque limit, which allows it to move more torque to the rear axle than the toyota systems. It’ s a more robust system for sure. Still it’ s unfair to say that no torque is going to the rear axle, because it clearly is, just not enough to appear locked.

3. I t’ s probably important to note that the MGR on the rav4 is a 40KW model, not the 5kw model on the prius.

Driving Sports TV > HammerheadFistpunch
04/23/2019 at 13:24

I can always count on somebody over at Oppo. ;)

The new system does have a front decoupler .

I still need to get more info on the HTRAC in the 2019 Santa Fe - it behaved much different than the system on the Kia Sorrento

For the Hybrid, I do note the different MGR sizes in the video.

HammerheadFistpunch > Driving Sports TV
04/23/2019 at 13:52

Pretty sure MAGNA is still Hyundai’s tier I AWD supplier. I can’t imagine its anything other than a new generation DYNAMAX coupling. Probably just programed differently.

Driving Sports TV > HammerheadFistpunch
04/23/2019 at 14:54

Kia says the Awd system in the new Telluride was developed in-house. I haven’t researched it yet, but it’s possible the newest HTRAC dropped Magna as well.

HammerheadFistpunch > Driving Sports TV
04/23/2019 at 15:11

Interesting. It’ s hard to find any data on it but I do know the name HTRAC as its used in their Longitudinal setups is a MAGNA product.

Driving Sports TV > HammerheadFistpunch
04/23/2019 at 17:36

I have an email into Hyundai’s tech team. I needed to email them anyhow. Will let you know what I find out.

HammerheadFistpunch > Driving Sports TV
04/23/2019 at 17:42

Sweet thanks.

Driving Sports TV > HammerheadFistpunch
04/23/2019 at 21:19

They threw some emails around and finally decided it was still Magna on that one. (This is why it’s hard to report these things, even the manufacturer reps don’t always know.)

HammerheadFistpunch > Driving Sports TV
04/23/2019 at 21:37

my rul e of thumb is basically that if i didn't hear it from an engineer it's a guess. then i ask another engineer to be sure

Driving Sports TV > HammerheadFistpunch
04/23/2019 at 21:52

My Korean isn’t great. Lol.