Or any other AWD/4WD systems out there like Subaru, etc.? Every time I bring up the TL's superior AWD to my friends there's always some ahole in the crowd saying "Well, Audi's Quattro has been around for years." I'm not familiar with Audi's system so I couldn't argue. It's very annoying to hear people diss the SH-AWD w/o even knowing a damn thing about it.

It is becuase the TL's is electronic versus, say, Subaru's mechanical system (I'm only assuming here)? Is it because TL cans do the 90/10 split between left/right and Audi can't?

Can someone give me some ammo or at least point me to a place where I can read about it????

 

Audi's Quattro system is near damn bullet proof.
I believe with my s4 its 60/40 split. Audi's AWD system is full time where as with SH the power is shifted when needed.
quattro ftw.

 

The standard Quattro is constant 4WD with a slight rear bias of 40/60 on some models and 50/50 on others.

SH-AWD is a variable AWD system with the minimal distribution of 90/10 on some newer models and 70/30 and on others. It then varies up to 30/70 on select models as needed variably and automatically. On top of that it actively vectors up to 100% of the rear torque to ethier outside wheel.

In the new S4 if you opt for the active rear differential option it serves almost the same function as SH but if I am not mistaken, I believe it only vectors what is available at the rear in the first place and who knows just what the percentages are? This doesn't necessarily mean that one is better in terms of handling but SH is capable of more rear bias and left/right vector when needed. When it's not needed the system drives in modes that allow for increased fuel effeciency.

Still to the day there are only a hand full of AWD sytems that function like SH. SH-AWD transfers power actively and variably through it's differential. Many times the term vectoring is used by brands even when it's done only by electronics and brakes. Most of these sytems are simply reaction based from slippage or loss, very few models have the true active differentials that act proactively first and reactively second, instead.

 

What my Audi friend above just cited as an advantage of Quattro is views as a disadvantage by Honda people.

Acura make a case for the Audi and Subaru systems being a full generation behind what is offered by Acura. It's hard to find a vectoring AWD system on anybody else's platforms unless you're looking at something like the Nissan GT-R, and spending that kind of money.

We can easily point to the fact that Audi are actively developing a competitor, a fully vectoring, controlled AWD system to replace the current production Quattro systems that you find in the A-type cars sold in the United States.

I truly believe that Acura SH-AWD is a full generation ahead of what you'll find on any other cheap production car in the North American market. I researched this, and it is how I ended up in an Acura.

Having said that, I also believe that the Subaru's AWD system is a clear second best and I would pick it over the Audi.

But...both Subaru and Audi are actively developing direct competition to SH-AWD and they'll probably have both their systems available in cheap cars before Acura ever allows Honda to use the SH-AWD to replace the current AWD systems on the cheaper Honda line.

 

Exactly!! :-)

 

The only system comparable to SH-AWD in regards to dry handling is Mitsubishi's Active Yaw Control. Sadly it's not available in the US (I believe its due to regs dealing with fuel tanks), but it can be fitted to a US car if you have the parts.

I don't believe a RWD biased system would benefit from SH-AWD or AYC much as a FWD biased system, and in regards to messy conditions (ie snow) I don't think either is a huge plus either.

 

This article will hopefully answer some of your questions.

http://www.popularmechanics.com/blog...s/4225886.html

As you can see while the SH-AWD system is well designed it isnt the best system out there.

Many AWD systems are great in many different applications though. IMO the best value on the market for a vehicle brand when AWD is a major decision factor, it would have to be Subaru.

AWD is a major factor in my next vehicle purchase and I have been researching this for some time. If you leave out the exotics like the GT-R etc. The best AWD system on a vehicle is probably on the BMW X6 but overall brand wise from what I have been seeing the Quattro system is still the best proven overall system....

I can only imagine what the next generation of Quattro will be like and will once again probably be the benchmark in the luxury industry like it has been for decades.

 

The article is either incorrect or somehow missed the fact the SH-AWD system can surpass a 50/50 f/r split. The max f/r split is 30/70, and 100% of the rear torque can go to one wheel (not 50% as stated)

So either the article was poorly written or they missed how the system works. I cannot comment on the accuracy of their descriptions of the ZF or Ricardo systems since I'm not as well versed on them.

 

Isn't it interesting that Honda has three fully developed AWD systems in the marketplace at the same time? Realtime, VTM-4 and SH-AWD.

 

I think the author was talking about the MDX and I really wonder why, but he clearly doesn't have his stuff together. These newer systems probably won't make it into full production anytime soon and the ones that are already available are done so on a very limited basis.

At the time the article was written they were only in their pre-production phases and BMW has only released one in the X6 and Audi has simply added an optional rear differential to their Quattro system for the S4 and called it a day.

I wouldn't expect to see these sytems in the more mass produced entry segments, only exotic or expensive niche vehicles for now and the reason is that they are thrid party engineered. Acura has successfully developed its own system with cost and platform implemetation already in mind, now 5 years later.

Regardless of what is planned or third party produced the reality is not many readily available and luxury AWD systems make up to 70% rear torque and then can actively transfer up to 100% of that to either individual rear wheel and none other do so from a FWD bias.

 

I'd like to see SH-AWD used as a motorsport application to demonstrate just how effective it is under more rigourous conditions. Audi's Torsen differential awd systems have been proven over and over again as race-winning technology and until someone proves otherwise, it's still the best system out there. For now, SH-AWD, X-Drive, 4matic, et al, is mostly marketing hype.

 

It sure would be cool if SuperGT or ALMS allowed it. Sadly aside from rally racing (which doesn't really reflect the intent of SH-AWD), most forms of racing explicitly ban AWD. There have been 4WD F1 cars before the ban. Indy cars too.

 

^^I've often wondered about that, as I recall BAR Honda once had some form of torque vectoring across the front axle of its Formula One car. This was several years ago around the same time Renault had their mass dampener. Wasn't this system protested or banned?

I'm not sure what racing series Honda to campaign this technology in since they don't participate in world rally. I guess it would come down to finding a racing series that allows this type of differential. Maybe one day we'll see some version of this in the Speed World Challenge Touring Cars?

 

Good catch. The BAR had driveshafts and a diff, but no power (no connection to the engine), and I don't think it ever raced, but it was developed and tested (and banned).

http://www.racecar-engineering.com/a...-revealed.html

 

Interesting conversation. I do recall reading an article comparing the AWD systems at my time of purchase and this was what I took from it (feel free to correct me).
1. The SH-AWD was thought to be the most advanced for real world driving.
2. Some of the other systems added components to minimize understeer, but the SHAWD was the only one to improve handling.
3. In rally racing and snow, the Quattro has been the mark to beat, (I don't know if there is a SH-AWD rally race car)

It would be interesting to see head to head comparison of these systems in different road conditions. I'm on dry pavement most of the time, so I'd prefer the SH-AWD anywho.

 

That's a pretty good summation. Subaru and Mitsubishi can also hold their own (in terms of cars available for consumers--Citroen and Ford currently dominate the WRC) in rally racing, and BMW and Audi have similar tech to SH-AWD in their latest gen systems.

For those who want to see SH-AWD in racing, I doubt that will happen in the real world, but in Forza 2 (Xbox360 video game) you can race a Acura RL A-Spec against just about any car. With some further mods, it can become a 700hp 3000lb beast that can beat stock Ferraris.

 

Spoon Sports made a Honda Legend (Acura 2G RL) Track car.... pretty impressive stuff

http://www.hondatuningmagazine.com/e.../photo_05.html

 

Ichishima's daily driver is still a Legend converted to six speed.

 

I love the KB1 (Legend/2G RL) .... A JDM KB1 would be so bad-ass

 

I have had several Audi Quats, and their quattro system is the most reliable part of the car. I just traded one in on my new 10 TL AWD tech. I will soon see how good the system is in the TL, because it is an adventure just to get out of my driveway with out a 4wd...

 

If you look for previous posts from me, you'll see some of my observations... mostly dissatisfied with SH-AWD. I had three special-ordered Audis - all I'd driven - from 1996 on until November. And I was an officer in the Audi Quattro Club. And have toured the factory. You could call me a fan. But I wanted an AWD six-cylinder stick sedan... and wound up in a TL.

So here's the scoop.

• It's not Quattro to compare against. It's Torsen-based Quattro. The Audi TT uses Haldex, which is probably a bit inferior to the SH-AWD. The A/S 4/6/8 use Torsen, a mechanical system, that is really incredible.
• Similarly, Subaru has (or at least had) two systems - a great planetary gear system for their crappy automatics, and a crappy viscous-coupled system for their adequate sticks. (Love their engines though.)
• To determine the best, you have to agree upon metrics. This is where it gets sticky. Do you want:
  • Best handling in clean-and-dry?
  • Best wet/slippery acceleration?
  • Best dry/grippy acceleration?
  • Best mileage?
  • Most predictable?
• My take is:
  • Nothing beats Torsen-based Quattro on slippery-start conditions. Nothing. The SH-AWD is terrible, just hideous, at that. I mean, if you even think about debating this, it proves you're a mindless knee-jerking fan-boy; it's just that bad. SH-AWD slips as if open for the first half-second or so. It shouldn't.
    But the Subaru planetary gear system is close. The Haldex Quattro isn't so close.
  • The Torsen Quattro is very predictable. I think it's a bit more so than the SH-AWD. But I've only noticed a difference in high-speed hydroplaning type conditions.
  • I'm certain SH-AWD impacts mileage less than Torsen.
  • For carving dry roads and possibly for carving wet ones, Torsen Quattro is okay, but the SH-AWD system seems to extend the performance zone further. That's pretty impressive.

What would make me happier would be a software upgrade to force more equal distribution when not under slippary conditions. I would like the system to prevent, rather than responding to, slippage at start and when hitting a patch of ice. The fact that Torsen Quattro is really really full-time AWD is probably the only reason it's better in some conditions, compared to SH-AWD's essentially as-needed nature.

 

The 2008/2010 Mitsubishi Evolution X features S-AWC which includes the AYC, previously left off of USDM models.

 

Ya i realized that some of the percentages where a little off but it probably had something to do with whatever system they where referring to ie: RDX or MDX being it couldnt have been the RL as nothing was mentioned about the different acceleration device. Overall though the article is very accurate and credible in how the different devices work and I figured it was something the OP was probably interested in.

At the time of the article BMW was already using the ZF design in the production X6 and now has it in the X5, 7series etc. Audi has a version of the Ricardo design in the some of the "S" models like the S4, S5 etc. Im sure when the new 3 series comes out it will be in and the same for future Audi models as companies like ZF and Ricardo would probably be having trouble keeping up to volume demands considering these companies have large worldwide volumes compared to Acura's limited NA numbers.

If you go to Ricardo and ZF's websites you can see some limited info on their products. This whole Torque Vectoring thing is a nice improvement but has actually been around for some time. Ricardo starting working on it in the late 90's and Mitsubishi was basically the first to mass produce it around the same time Honda had a similar system on its limited production SH Prelude models in the late 90's.

I have often wondered this also why they have Realtime and VTM-4. SH-AWD is a very nice design by Honda but those other systems seem very poor in design and function IMO. The VTM-4 system reminds me of the GEN I or II Quattro systems from the early 80's

 

Nice write-up Techno and its very informative from someone who has experienced both systems.

Have you had a chance to drive a S4 or S5 with their new torque vectoring to see how it compares to the SH-AWD??

 

This is a great topic and there is a lot of good info here but I wanted to clear up somethings as even Popular Mechanics and as usual the internet and even Wikipedia are misinformed.

Audi and BMW are now both utilizing the ZF differential in the rear of their standard AWD systems but only on select applications at this time. The first to include this was the BMW X6 and has since made it into the X6M and X5M. The new 5 series redesign is up next and there are talks about it possibly being offered as an option like Audi does in the Audi S4/5 but then others suggest that they may retain it for the high end models to further distinquish the M line. Unforunately, the Ricardo differential never caught on and they are still waiting for it to reach production in a brand vehicle at some point.

The new 7 series with xDrive does not have this "vector drive" but it does have a new electronic vectoring sytem that is very similar to Mercedes' Torque Vector Brake but no vectoring is actually done in it's mechanics alone. These sytems use new, improved electronics with throttle and brake application to emulate the active nature of these other differentials.

They only notable differences in the ZF and even the Ricardo differential compared to SH-AWD rear differential is mostly how it is implemented within the AWD system. Obviously SH is front based and others are rear. All three transfer power actively side to side at the rear and up to all the available torque at the rear can go to just one wheel.

What makes the SH-AWD system different and maybe just because it is front based, is that it also actively tranfers power to the rear as well as side to side. There is not much of a need for this when an AWD sytem is already rear biased but it still makes the SH sytem unique and still fairly advanced. On the plus side it acts as a fuel and power saving measure but in icy or slippery start ups it will not behave like a 4WD as many of the other sytems do.

I am not commenting or implying anything is better than the other, that still depends largely on how the vehicle is engineered around the system and on how one defines better in this situation and just what ones needs are in an AWD sytem and vehicle. What I will say is that despite what many say, read or think, SH-AWD is still a very advanced sytem and its easy to see the competition is just begining to only catch up to it.

 

Thanks for the write-ups everyone, very informative stuff!

Just you wait... some lurker from the TSX forum will be here soon to tell us how the AWD sys is inefficient, slow, heavy...blah blah... compared to FWD TSX

 

This is a good discussion!


I could be wrong, but isn't improving dry road handling the primary goal behind SH-AWD? Admittedly, I know very little about AWD systems but it seems difficult to determine the "best" system when comparing SH-AWD to systems that weren't too designed around improving dry road handling.

 

Does anyone here know what is the default torque split (front/rear) for the TL-SH AWD? The salesperson I spoke with today at the dealership said it's 50/50 with a maximum of 70% going to the front axle when called upon.

Can someone shed some light on this?

 

False answer. It's 90/10 Front/Rear and can go up to 30/70.

 

In other words, the sales rep doesn't have a clue?

 

This thread is amazing and I have got tons of stuff from it. After the Dynamic Performance Control from X6 was launched, I just realized that the current trend is toward to this torque vectoring all wheel drive systems, and started to understand what Honda means about "...that provides cornering performance that responds faithfully to driver input, and outstanding vehicle stability...". For sure, more subsequent moves from other carmakers are coming soon.

 

One hopes. There is a MPG penalty and SH-AWD takes quite a bit of power (4wd dynos show around 200hp at the wheels on a RL that makes 290hp at the crank), but the performance (and safety) benefits are quite impressive. My RL with SH-AWD is like a suction cup holding me down on spiral on ramps. I honestly feel safer hitting the gas through turns than I do on even throttle, lifting off, or applying brakes.

 

How's about the performance over the snow days this winter? If you don't mind. Thanks.

 

I agree with everything this guy has to say about Quattro. I had a 2005 Audi A4 1.8t 6 speed and I have never driven any car more secure in any type of driving conditions. Still by far the best handling car I have ever driven. Only reason I got rid of it was because all the engine problems I was having up to 74K miles which is when she was laid to rest in my book. Would I buy another one? Absolutely but when I get one that's CPO or care less about putting money into mods and more about upkeep which is expensive on that car past warranty.