AWD vs RWD In Dry Track

[buterworth]

Why most race cars we can see today are RWD?Some say that RWD is best for dry track.Some say AWD is better but it's offen banned from racing,so that RWD is the only choice.


Which is faster? I'm confused.

[Adam43]

For many series the reason most cars are RWD is that AWD is illegal (for cost and equivelency reasons). AWD has a traction advantage on a dry track, but adds weight and complexity. So it could depend on the weight (and power) of the cars. Single seaters are probably unsuitable. It would effect aero and weight dristibution. However we have seen in touring car, where the minimum weight is higher and the packaging can be accomodated that AWD has been implimented (until banned!).

In the wet the traction element becomes more important and the comprimise balance shifts.

[buterworth]

The famous Audi Quattro Awd race cars were said to be unbeatable in DTM and IMSA in early 90s even under weight penalty ,then AWD was banned.But things happened almost 20 years ago,not everyone knows the truth and the details of those race cars and races.

The only AWD race car I can find today in formal,high-level and perfessional racing is the Cusco-Dunlop Subaru Impreza GT300(about 350 horsepower),which comes from Japanese Super GT.The Cusco-Dunlop team compaigned this unique AWD race in 2006, 2007 and 2008 season(withdraw from 2009 season).The Performance was not that impresse as expected.

But in popular time-attack event AWD cars are obviously more competitive.The time-attack race car in Unlimited Class have 500-700bhp(or even higher),and only semi-slick tires like Yokohama A050,Toyo R888,Dunlop 03G ,etc can be used.AWD provides more traction to handle those tons of horsepower when exiting tight corner.And i think this is the biggest advantage over RWD.So does it mean that those RWD supercars which produce 600+ hp need AWD to put down power?

How about changing wider rear wheels and tires to obtain more traction on an hi-horsepower car instand of using AWD?

[silente]

Audi, also in 90's won a lot of Touring cars championships with audi 80 quattro and with audi A4 quattro. They were really really fast, above all in small tracks, while they paid a lot on fast tracks because of the weight that rules imposed to them and because of the friction of all that differentials..

But somebody said that a Awd car is harder to set up because it is not simple to understand if it is understeering or oversteering and also where to make the weight going to keep the maximum from the tires. In my opinion a lot depends of the differential you use and on how you split torque not only between front and rear axle but also between left and right tires of the same axle...

[Al Weyman]

Err just look at Rob Birleys WRC Cossies Escort's domination in DMN series and you have your answer. The bottom line is and this may surprise some people who have never tried is that the race tracks even in the dry just do not have the grip that you get on the road and the reason is its all that oil and rubber chucked down. IMO I think 4WD would be an advantage at every track in every condition wet or dry and thats why we ban em as most of the field would be made obsolete. We had a guy want to run a Quattro recently in CTCRC Group One and we had to turn him down, can you imagine them old Capris standing up against a fully sorted one of those!

BTW how many dry races do you get in this country now, not many if last season was anything to go by!

[greenamex2]

In Classic Thunder we have a class for 4WD but restrict them to list 1b tyres and an intake restrictor. It's going to be interesting to see how they perform against the rest of the 2WD cars and whether we would have to tighten or relax these restrictions to maintain competitiveness.

[Al Weyman]

Also anyone remember the Nissan 4WD's ending the Cossie dominance in the Australian Touring cars leading to what we have today i.e. the RWD V8's? And you know my views on this in Classic Thunder Denis, if it had been up to me (it was'nt) I would not have let them in, time will tell!

[R59]

That's why Denis will only let them in with 1.b tyres, and not slicks, plus a restrictor. I suppose the next trick will be that they can only use a 1/4" SU and a No.9 knitting needle.

Aussie Touring Cars went the route of the V8's to make it more "Australian".

[greenamex2]

Originally Posted by R59

Aussie Touring Cars went the route of the V8's to make it more "Australian".

American is spelt "A M E R I C A N"!

[R59]

No, they went AUSTRALIAN!
IE: Holden vs Ford. And the engines are the Australian versions of the American designs - like the Rover V8 was a British engine, even though Buick designed it, and sold the Airfix kit to Rover.

Just to keep things really local, they have the V8Utes series.

[Al Weyman]

And you don't think the fact that the 4WD Nissans and previously the Cossies kicking the crap out the home grown Holden and Ford V8 entries had nothing to do with it?

[R59]

That's what I was saying, wasn't it? Change the rules to outlaw Johnny Foreigner's cars!

I must say, I still prefer the old Gp.A Touring Car rules, with multiple classes, from minnows to monsters, it was much better, giving a broader feel to the series. But that's OT.

[Al Weyman]

It was good racing I remember watching it on satilite years ago, much better than the current BTTC IMO.

[greenamex2]

Corolla GT's stuffing it up the inside of cossies round the twisty bits, only to be totally destroyed on the straights. 180-190BHP on a 'standard' intake system was never really going to match over 400BHP from a dodgy homologation special.

[Al Weyman]

Thats why GM pulled out the Camaro from IMSA racing as Ford bought in the Merkur (XR4ti) and totally stuffed everyone first time out, they were reputed to have in excess of 500bhp from the turbo charged American Pinto. I started to build one once for ModProds you may be interested to know as we were not allowed to run Cossies. Roland Hayes was going to do the engine and reconned a 'lazy' one would be good for 350bhp and if that was'nt good enough we could always turn the wick up. It was a still born project even though I had bought a beautiful fully prepared new Cossie 2 door body shell but the committee wanted me to run that silly third rear window which I thought was a bit petty so I pulled out and built the IROC, wish I had'nt now as I think the Merkur would have been very competitive.

[buterworth]

Active torue vectoring AWD systems have been well developped these years,while RWD still use traditional mechanical LSDs.

How about putting an active torque vectoring LSD on a RWD car?Would it be competititive agaist those active AWD?

[Al Weyman]

How can it? It will still have only half the traction as 4WD however effiecient it is and I am sure RWD Ferraris and late model powerful RWD stuff like Monaro's already exploit the best traction technology available.

[buterworth]

Originally Posted by Al Weyman

How can it? It will still have only half the traction as 4WD however effiecient it is and I am sure RWD Ferraris and late model powerful RWD stuff like Monaro's already exploit the best traction technology available.

Ferrari has already use e-diff,but it never works better than mechanical one in porsche,or corvette.
And what is traction?Does traction mean max power(or torque) on the wheel without any wheel spin?(Maybe I'm not quite understand the concept of traction)
AWD is said to be the quickest in exiting tight and twisty corners.Is AWD still be quickest in turn-in and mid-corner?

[Al Weyman]

I would describe traction as both wheels transmitting power equally, if you see some footage someone shot at Mallory of my black car exiting the hairpin you would see what I mean by lack of traction as the inside wheel lit up and smoked rubber for 50 yards. To me that was down to a poor lsd and was costing me seconds a lap especially at Donington where I had to get out the throttle entering the main straight and lost time against a Toyota Supra with independant suspension that simply hooked up and went.

[buterworth]

Will in-cockpit adjustable sway bar give much help to rwd?

[aa/fd]

Here is a Lotus 56 FWD approach from the 1960's nice restoration photos
http://www.avonaero.com/STP%20CAR.htm

[Zico]

I was looking at the Dp1 site again for the 1st time in a while since coming across this thread..

Its like a mini GT car with 4wd and 1300hp/ton!! powered by a 500bhp 3 litre Hartly V8 iirc.. http://www.dpcars.net/

He has recently embarked on building a similar concept but in Rwd called the DP4.. just to be able to compete in a series... and even an electric version of the DP1 !


Very interesting site, loads of info, from design concept to the finished product.. Fantastic reading with lots of pics & videos, must be great to be rich.. lol