I like it! And not just because it validates my choice of automobile. :-p

What they didn't show was the chain holding the Toyota and Honda back Honestly, not too shocked there. Real-time 4wd means front wheel drive with the fuel efficiency of a 4wd.

 

Where are the domestic truck based systems? I've had the front wheels on Ice and had the auto 4WD system in my Chevy Trailblazer kick the rear right in after a rev or two of the front tires. Traction is even better when the center diff is locked.

 

I'd like to see older model Subaru's on there with simply the viscous center diff, not the latest and greatest with VDC on them.

That was a cool video. I like this one though. http://www.youtube.com/watch?v=cB71qL33q3k&NR=1

 

I wish there was that much sand near me.

Well there are a few issues. First this is not a lab test, but was done in a dealership.

 

the "torque steer" was from the tire tred pattern, and not from torque steer. Even the subaru did it to some extent. aggressive tire pattern will make the tires walk.

 

Subaru doesnt decide when to send power to the front wheels (forester part) as they are by default front wheel drive.

 

AWd systems being secret

 

http://corporate.honda.com/press/article.aspx?id=3653

 

(complete with a drawing)

 

The AWD systme on the toyota comes from a sienna seems to have a center diff with some sort of torque control .

 

VW

http://media.vw.com/article_display.cfm?article_id=9754

 

Its a shame, otherwise its an interesting video. Alos VW has a halidex system,

 

http://www.haldex-xwd.com/

 

that doesnt seem to secretive to me.

 

I wonder why they didnt test more cars.....

 

 

nipper

The test seems perfectly valid, the narrator is just a little short on knowledge (and/or is grandstanding).

 

Too bad the cars that failed couldn't lock their front-rear differentials, they'd have done fine. Or maybe even if they had traction control that could sense the spinning wheels and just plain lock 'em like the VDC system obviously can.

 

Shows the value of VDC!

 

The full-time 4wd cars are full-time 4wd, just so long as all 4 wheels have traction.

 

Dave

I guess the only used automatics because manuals in general have a 50/50 split. Dont they?

 

It would be nice to see these videos from the German ADAC with 50 cars or something. A real test. Ok it shows that subaru is fine but still bit tricky video

Anyone know where there's info (posted or otherwise) explaining in more detail how the power distribution works with the Sube particularly in the '98 vintage?

 

To be honest, my knowledge doesn't go beyond what's in the sales pamphlets.

 

Thanks.

http://www.endwrench.com

 

archives 4eat

 

nipper

I'm wondering how Acura's (Honda) SH-AWD would do in that test? It's supposed to be able to send full torque to one wheel.

I'm wondering how Acura's (Honda) SH-AWD would do in that test? It's supposed to be able to send full torque to one wheel.

There are quite a few cars missing from this test.

 

 

nipper

SH-AWD can only favour single rear wheels.

 

It would still do very well in that test.

SH-AWD is an acronym for Super Handling All Wheel Drive. It is an all-wheel drive platform designed and engineered by Honda Motor Company who describes it as "A world’s first, the SH-AWD system combines front-rear torque distribution control with independently regulated torque distribution to the left and right rear wheels to freely distribute the optimum amount of torque to all four wheels in accordance with driving conditions".

 

It was first developed for the 1997 Honda Prelude Type SH. A variant of the system is also being featured on the 2007 Acura RDX and Acura MDX SUVs.

 

Components of the SH-AWD system were developed by BorgWarner. It essentially is a set of clutch-packs in a T-shaped differential at the rear of the vehicle. There is no center differential. Rather the vehicle's have transverse mounted engine's with power take off units going to the T shaped rear differential/clutch packs. The three clutch packs can engage for the right rear wheel, the left rear wheel, or near the base of the T. With the Acura RL sedan, the system sends 70% of power to the front wheels and 30% to the rear under normal conditions but these ratios can reverse according if needed. The system can work because the clutches can slip under circumstances where the vehicle is turning, thus allowing the rear and front wheels to turn at different rates around a curve. SH-AWD in the Acura RL also features an "acceleration device" just ahead of the rear differential which, through the use of a planetary gear set, can overdrive the rear axles by as much as five percent. This is done only when cornering.

 

SH-AWD in the Acura RDX and Acura MDX use a default power split of 90% to the front and 10% to the rear. Like the unit in the RL, both can power the rear wheels with up to 70% of the engine torque. With this variant of SH-AWD, there is no acceleration device. Instead, the rear differential is constantly overdriven by 1.7 percent. During straight line performance, that difference is scrubbed off by the clutch packs. When cornering, the difference is used to overdrive the outside rear wheel.

 

The power split under straight-line, high-speed acceleration varies from vehicle to vehicle. It approximates the weight distribution for each

 

The rears are OVERDRIVEN by 1.7%? What kind of unobtanium are those clutches made of?

The rears are OVERDRIVEN by 1.7%? What kind of unobtanium are those clutches made of?

 

That means that your rear tires wear out 1.7% quicker or you use at least 1.7% more gas than needed. Still prefer the subaru AWD though, symetric.

The rears are OVERDRIVEN by 1.7%? What kind of unobtanium are those clutches made of?

 

very very very expensive unobatanium. That can not be a cheap "differential"

 

There are cheaper ways to do what honda is doing. Honda is good, but they do tend to go just a weee bit overboard at times in the "gee wow" area.

 

I wonder how well it scrubs off that added speed taking I80 across nebraska.

 

 

nipper

The rears are OVERDRIVEN by 1.7%? What kind of unobtanium are those clutches made of?

 

I'd warrant that the clutches are supplying no power to the rear tires under normal conditions, not the claimed 10%.

 

Either that, or maybe the clutch-pack is filled with goo, so when its 100% 'released' the goo acts like a viscous coupling, giving the 10% to the rear.

 

Damn, gotto go see if that's patented!

 

 

Dave

I'd warrant that the clutches are supplying no power to the rear tires under normal conditions, not the claimed 10%.

 

Either that, or maybe the clutch-pack is filled with goo, so when its 100% 'released' the goo acts like a viscous coupling, giving the 10% to the rear.

 

Damn, gotto go see if that's patented!

 

 

Dave

 

5330038

5330038

 

There is nothing that honda doesnt patent

 

nipper