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**Fair!** · 05-03-2005, 11:25 AM

Re: May 3, 2005

Torque-vectoring All-Wheel Drive

From the start, though, Audi insisted AWD had another advantage: improved handling - even on dry tarmac. The auto maker made its point over the years by dominating several forms of racing, sometimes thrashing 2-wheel-drive competition so emphatically that AWD was banned.

ARG! So... tired... of hearing this marketing ploy/engineering myth reiterated for going on two decades!

Here's the real story: in the mid 1980s, Audi was pushing turbos and AWD into several racing series that had never seen either technology. WRC and IMSA, then Trans Am racing, all had Audi money thrown at them and world class racing efforts were brought to "gentleman's racing" in many venues.

The Trans Am story is interesting. SCCA Pro Racing Trans Am series race cars were ~2550 pounds, ~500 hp 5.0L carb NA pushrod V8s, and tube frame chassis with similar body shapes as 2-door American pony cars (Mustang, Camaro, etc).

Audi wanted to compete in SCCA Trans Am racing, but wanted to throw a LOT of money at the class and utterly dominate the domestic pony cars - to try to boost the image of Frumpy Audi. They had an IMSA spec car making 600+ hp that they brought into line with Trans Am rules... with several exceptions. They somehow managed to convince the SCCA Pro Racing rules makers to give them a MASSIVE weight break AND snuck in hundreds more hp because they had the DIS-advantage of a heavy, AWD car that was (loosely) based on a uni-body street car (it was a serious tube frame chassis disguised in remnants of a unibody shell) with a "just a 2.2 liter engine!"... with a turbo.

They came in hundreds of pounds light (thanks to a favorable, if obtuse SCCA ruling), had ATMOSPHERES of boost on a race motor that had F1 like boost/strength, and made upwards of 800 hp. They claimed to be underpowered with a stated "450" and then later revised that to "only 510 hp". The straight line speeds the factory Audi T/A cars were posting were 10-20 mph greater than the nearest competitor. "This is from our All Wheel Drive advantage!" ... aaaaand the 300-400 hp that they lied about not having. Cue the marketing drivel and lots of ridiculous and misleading TV spots and magazine ads...

They managed to keep up this charade for 2 seasons, dominating every race... due to being the lightest cars with hundreds more hp, simply from asinine rules exemptions and loopholes they exploited to the fullest. Remember, this was in the Turbo F1 Era (or right thereafter) and turbo hp was still somewhat Voodoo and wholly unknown in Trans Am racing. Competitors had enough, and armed with common sense and some good data, they stormed the SCCA and demanded that not only the Audi weight exemptions and brought back to up to the same minimum as all other competitors, but that the unlimited boost have a restrictor to limit their obvious massive power advantage.

The SCCA did update the rules, and then Audi suddenly got slow. Then Audi went away squealing, calling this rules change "obvious proof of AWD's superiority!" when in fact all wheel drive had jack and squat to do with ANYTHING in this class. The SCCA then banned turbos in Trans Am altogether, because nobody else ran them or wanted them in this fairly low dollar class (a prepped Trans Am car could be built for $50-100K back then; who knows how much Audi invested, but it was probably millions).

more history here... but with a lot of the Audi spin intact http://www.theracesite.com/index.cfm...m_article=4575

In the real world, engineers and enthusiasts agree AWD usually is superior to either front-wheel drive or rear-wheel-drive in wet, ice and snow, but they debate AWD's ability to "improve" handling or cornering behavior on dry roads.

Formula 1 engineers don't want or need AWD, and these are ~1500 pound cars with 900 hp...???

AWD adds little more than weight and complexity (3X as many diffs are needed + lots of controlling software) and only comes into play when traction is radically reduced (rain, snow, mud, ice) and/or power is increased exponentially on dry pavement. It is obviously the only way to make WRC cars usable on slippery bits with 300+ hp, esp. since the class is limited to subcompact cars that are normally FWD (a FWD layout would be disastrous in these WRC race cars).

When we start having more and more 1000+ hp street cars (and this day may come), sure, we might NEED to have more AWD systems in sports cars. Until then, they are a gimmick, a weight/cost/complexity penalty, and really only useful in slippery conditions (north of the Mason-Dixon line).

Don't make the common mistake of confusing TURBOCHARGED POWER with AWD. Most AWD cars that are "fast" are also turbocharged, making them much higher powered versions of otherwise frumpy, slow, front heavy FWD cars. 120 hp FWD Subaru 4-door vs. 300 hp AWD STi. Even with RWD only, the STi would be as fast... or faster. With FWD only... it would be ugly.

edited for spelling with google toolbar!

**beavis** · 05-03-2005, 03:27 PM

May 3, 2005

Not saying that AWD is tha bomb, BUT F1 cars use huge sticky gubmall race tires for gobs of grip and equally huge spoilers for downforce. It's not that they don't want AWD, they don't NEED AWD. Any normal street car (weak-nut, riced-out, uber-wing-sporting wannabe rides don't count as "normal") has neither of these advantages. And the more idiots, that don't have a clue how to drive (not race, but just drive), get on the roadways, the more people will want (need?) AWD, ABS, EBD, (toss in your acronym here), traction control, and all that jazz.

**hancheyb** · 05-03-2005, 03:34 PM

May 3, 2005

Fair,
You missed the important article. Yeah yeah yeah.

-2005 Ford Freestyle vs. 2005 Honda Odyssey

They barely give the nudge to the Odyssey. I'm not sure about that. I haven't looked at the Freestyle, but the interior quality (if it follows Fords of the past) would be enough for me to pick the Honda.

B

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