I Think These AWD Systems Are Bullshit

"Wobbles the Mind" (wobblesthemind) 11/28/2016 at 19:00 • Filed to: Rants

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Just this crap coming out where it puts down 90%-100% of torque to the front or rear wheels until it detects slip then sends “as much as needed” to the opposite wheels. I’m sorry, but I think this is some bullshit. We are being sold AWTT (All Wheel Traction Control). I’m not just pointing out Jaguar and its Torque-on-Demand AWD or AWD w/ Intelligent Driveline Dynamics. Many other brands (especially with their cars) do the same crap.

Now companies are trying to save face by creating “predictive” systems rather than the old “reactive” systems which everyone complained about because it was like the cars didn’t have AWD. It’s because they don’t. I don’t care what Jaguar, BMW, or even Mazda says, we have very complex traction control systems on most cars.

Maybe I’m just being sensitive, but with everyone trying to call their AWD system the best thing ever because it not only limits/cuts torque like traction control systems, it also throws that torque wherever the hell it can.

I’m just saying, drift modes are a thing now? Really?! Because I want my AWD vehicle to do all the things it would do with 2WD but with an extra couple hundred pounds in the mix.

Torque vectoring. I just feel like it is more traction control than drivetrain in function. That’s just my feelings, I don’t give a flip about differentials being present if they are only a part time worker.

Sam > Wobbles the Mind 11/28/2016 at 19:09

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Let’s you drive like Chris Harris, when you have the driving skills of Justin Bieber. Lets them experience their $100,000 car without mowing down a crowd. And you don’t have the AWD push at low speed.

Logansteno: Bought a VW? > Wobbles the Mind 11/28/2016 at 19:11

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Manufacturers would probably LOVE to make them constant, especially on sportier offerings. The only problem is it takes more effort to spin all that stuff all the time which means more fuel used. And the government won’t like that.

cluelessk > Wobbles the Mind 11/28/2016 at 19:11

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Relax. Don’t buy a car with a fwd bias if you don’t want one.

99% of people don’t care. They work perfectly fine for the conditions they were designed for.

There’s no reason to send power to all the wheels all the time.

Tekamul > Wobbles the Mind 11/28/2016 at 19:17

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All these systems are there to keep the car moving forward in wintery conditions, and to round out the ‘feature set’ without hurting MPG too much.

It’s not like somebody is going to take their cx5 to the track and be disappointed by their corner exit speed.

Moves-Like-Senna > Logansteno: Bought a VW? 11/28/2016 at 19:24

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Are you a GM Mechanic?

Logansteno: Bought a VW? > Moves-Like-Senna 11/28/2016 at 19:28

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Yeeep

JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t > Wobbles the Mind 11/28/2016 at 19:38

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Properly done, Torque Vectoring is brilliant. The Alfa Romeo Viscomatic system being a notable early example. It was built in partnership with Styer-Puch and built on some of the concepts developed by Styer-Puch during their collaboration on the 959 AWD system with Porsche. Except instead of the use of differential-diameter tires and neutral-load-differing drive-shaft rates the Viscomatic system featured a single epicyclic (planetary) gear set in conjunction with an electronically lockable viscous-couple. Instead of the complex arrangement of clutches, as on the Porsche, Viscomatic’s single gear-set and brake band allowed real-time variability of the front to rear drive-shaft ratios. Unlike the Porsche’s active clutches, the viscous-couple is a reactive torque-transfer mechanism, but the computer’s ability to modify the effective final-drive ratio between the front and rear wheels at will means the viscous-couple can be called on to provide torque re-distribution at any time, regardless of wheel slip (additionally the electronic-locking mechanism can be called upon for 50-50 forced split in low-traction situations). The rear mechanical helical-Torsen diff combined with ABS-linked brake traction control (like the FiST and FoST and Mclaren) e-diff provided rear-wheel vectoring, the front diff was open, but also featured a “lighter” e-diff effect, as it was feared the system could interfere with steering feel and cause over-heating of the front brakes. By monitoring steering position, throttle position, engine load, wheel and suspension velocities and a 3-axis gyro-sensor the torque split could be compared to tables of traction-force and idealized acceleration vectors to predict most requirements before the vehicle actually encountered them.

of course this all required that half the trunk space of the car be occupied by computer hardware and that any service tech that worked on it had to have a special set of calibration and management tools, it being the early ‘90s and all.

It is also *RUMORED* (absolutely NO hard facts exist in the public space about the *ACTUAL* cost of the system) that Alfa Romeo **LOST** nearly $50,000 on every 164-Q4 sold with Viscomatic.

dogisbadob > Wobbles the Mind 11/28/2016 at 19:47

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It is real AWD because you need the extra shit to send power to the rear wheels in the first place. regular traction control on FWD cars can’t send power the rear wheels at all. You need an extra diff and other shit. The Prelude SH had torque vectoring but no AWD. There is no differential of any kind connected to the rear wheels; they’re just along for the ride. The cars you mentioned are able to power all 4 wheels.

Don’t older Jeeps and trucks and SUV’s have a part-time 4WD? (I think the JK still has it) And you really *are* only supposed to use it part of the time! In fact, running them in 4-Hi all the time will tear apart the transmission! In regular road driving, it’s supposed to be in 2-Hi.

The GTR has had such an AWD setup for a long time, that only powers the rear wheels until it needs to power the front.

Phatboyphil > dogisbadob 11/28/2016 at 20:18

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AWD and 4x4 are different. AWD (like subaru) sends 50% of engine torque to each axle. 4x4 sends 100% of torque to both axles, and on some locks the front diff which is why its offroad only.

Moves-Like-Senna > Logansteno: Bought a VW? 11/28/2016 at 20:50

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You sir are my new best friend <3 I have a list of GM vehicles I’m looking to purchase soon.

sn4cktimes > Wobbles the Mind 11/29/2016 at 04:42

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Just need to step back a few decades and go with 4WD, which yes you can drive on the road before someone chirps that 4WD = no pavement nonsense.

4WD LO and/or lockers engaged = no pavement.

BiTurbo228 - Dr Frankenstein of Spitfires > Phatboyphil 11/29/2016 at 06:09

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Might want to go check up on that. In the Subaru you’ll have 50% of the engine’s torque going to each axle, giving 100% overall.

In the 4WD example you’ve given, you’d end up with 200% of engine torque...

Usually the distinction between an AWD system and a 4WD system is the presence of a lockable diff, although tbh the distinction isn’t clear in a lot of cars (for instance, the difference between an unlocked Landy Defender and a Subaru WRX is negligible in mechanical setup and function).

If you really want to draw a distinction between the two, an AWD system has a centre diff whereas a 4WD system doesn’t. For AWD, the front and rear diffs can spin at different rates, whereas in 4WD they’re forced to turn at the same rate (which is why 4WD isn’t suitable for the road as you’d scrub your tyres if you turn). If the diff ratios are the same on the AWD system, both send 50% of their torque to each axle.

Party-vi > BiTurbo228 - Dr Frankenstein of Spitfires 11/29/2016 at 08:10

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I would say the biggest factor in 4WD vs AWD is a two-speed transfercase/center differential, and the fact that most (albeit older) 4WD systems did not have any form of torque splitting other than a default 50:50 F:R

BiTurbo228 - Dr Frankenstein of Spitfires > Party-vi 11/29/2016 at 08:52

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Ah there we go :) I knew I was forgetting something ;) thanks

Nauraushaun > Wobbles the Mind 11/30/2016 at 15:45

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So they only go AWD when you need it. So what? Who needs AWD when they don’t need it anyway? The answer is nobody.