You're a clever one. Maybe more AWD cars would win races if they weren't banned.
I really don't know what to debate with your traction circle argument. It is poorly explained, and I really can't argue it without making assumptions about what you meant. I'll go and do my own research since nobody seems to know, and report back eventually.

 

Rick,

Awesome video and way to go beating lots of GT3's! But of course according to some of these guys on this thread your tt is not a real sportscar!

 

You actually may want to review the whole traction circle theory...you do not have to reduce turning 10% to be able to do 10% acceleration or braking.

 

"My car is better"!

"No my car is better".

"No your both wrong my car is better".

Looks like we have another dick swinging contest on the play ground.

What ever happened to live and let live? Enjoy your ride!!

 

That is probably the first thing that people are taught in racing schools around the world. Have you ever seen skid marks going straight on the off-ramp into the guard rail? Do you know why that happens? It's because people go in a little hot, panic, and slam on the brakes. Now all of the available traction is used for braking leaving none for turning thus they go straight on. Try it in the rain sometimes in the parking lot, crank the wheel over at a certain speed and hit the brakes you will go straight in a non-ABS car - let off the brake and you'll be turning again. Woila, the theory holds . Have you ever tried pushing your car to the limit (on a closed course, obviously)? That will teach you more about the car's behaviour than any theory can, and the whole thing about finite amount of traction available will make a lot more sense.

here is a better write up than what I can explain in a short post without any pictures, etc. http://www.nyracer.com/friction.htm

the 90%/10% thing is true if you think of it in terms of the % of available fraction not in terms of reducing max turning by 10% and increasing max braking by 10% - see above link for more explanation.

 

I have raced cars frequently for the last 10 years and am quite familiar with this theory. I wasn't planning on argueing against the theory, so much as your belief that it proves AWD is inferior as a race platform.

 

I read the nyracer write up...and while it is short and absent very much detail, it does not in any way indicate that you have to reduce your braking from 100% to 90% to be able to turn at 10%. Because this simply is not the case. The reason why trail braking improves lap times (other than to correct for a misbalanced car handling wise) is that let's say your car can generate 1.0g in either braking or cornering. Friction circle theory shows that this car could also generate possibly .6g in braking while at the same time generating possibly .6g in cornering. It is not, as you say, that only so much grip is available and therefore if one uses .6g in braking in a 1.0g car then one can only at that time use .4g in turning.

 

so we're in agreement on one thing - that's a start. now let's also come to an agreement that the front of the car does the bulk of the braking. would you disagree? you should know that from 10 years of racing cars. it is also the front that is responsible for the car's turn in and overall position on the track to a great degree.

this means that the front tires have plenty to do already. additing another capability of having some acceleration would give a marginal advantage and only if there was not enough traction to be gained by using rear tires for acceleration.

rear tires do all the acceleration in a RWD application, less braking & turning then the fronts. This provides a nice balance in a dialed in car of tire wear front to rear - important element in racing.

so the benefit of AWD is small, what's the cost? it's is huge - the added weight and complexity of an AWD system makes it uncompetitive with a similarly set up RWD machine. this combined with the fact that there is not a readily available AWD system yet that would properly distribute acceleration between the front and rear of the car.

lastly why is R8 a mid-engine RWD platform if AWD is so great?

AWD is only beneficial in low traction application: rain, snow, mud, gravel, basically rally events - and that's what most rally cars run.

 

I really cannot understand how you can claim it is uncompetitive. It is competitive, it has been banned for having an unfair advantage in some racing series. It is not allowed in others, why not allow it? If it truly is uncompetitive nobody would use it.

AWD has proven itself against RWD many times. Just watch some Speed GT. While the Audi's do get a ridiculous start, they are also usually very near or at the fastest lap times, even with the added weight of success penalties and the AWD system.

As for the R8, well I don't know the rules of the series they run in, perhaps AWD is banned.

 

I guess what I am looking for, since they are clearly competitive, is when they are competitive in dry conditions.

 

Enough already!!! My one wheel drive BMW bike will beat all your cars around the track...period. So I guess that proves that the fewer number of drive wheels you have, the better track performance you will have????

Get on with your life and go drive your car.

 

^^^ If people wouldn't keep saying stupid ****, maybe would could have an actual discussion about the scientific merrits of each in varying track situations. Which is what I would like, because frankly, I don't care what people opinions about the various drivetrains are, just the facts.

I drive RWD only by the by, so don't go thinking I am some fanbois.

 

I tend to agree with Mafia. The limitations or challenges of a modern race car is in cornering, and not accelerating. In other words, take F1 for example... if we consistantly see F1 cars smoking their tires down the straights (other than coming out of low-speed turns), then we can argue that we need AWD to put the power down better. However, that is not the case.

Tire technology is such that it is able to put the power down during majority of straights of modern tracks for any given race cars (exceptions being among others drag racing, etc).

During turns, you may gain some stability via AWD in terms of pointing the vector of the car, however, that can also be achieved by the driver, suspension setup, aero, balance, etc for a RWD car.

HOWEVER, if the front wheels are driven, every bit of traction you use up in accelerating the front tires will be taken away from cornering, even if it isn't a linear correlation. Therefore, to maximize cornering forces, you want your front tires to do all the turning, and let your rear wheels do the accelerating.

 

i agree with StephenTi. as for the AWD being uncompetitive comment that is comparing apples to apples. you take a rwd car then *ADD* AWD hardware and you won't be competitive in the dry I guarantee it. Basically same car with 200lbs + of extra hardware will not be competitive - period.

The SPEED GT makes cars look so close because it's designed to by the rules. If car is too fast they get weight penalties, too slow they can actually remove some of it. Also keep in mind that SPEED GT was running on street tires. R compound recently, but even those are street tires still, so perhaps there is a bit of advantage gained when the tires go off and you can just plow through corners in the AWD. I've seen many times how Audi's are dropping a wheel or two and don't get upset like other cars. AWD is definitely more forgiving there is no question about that, but with a driver taken out of equation and other things being equal it is an inferior platform IMHO.

Obviously, AWD car that weights 2,500 lbs and has 400 hp will be faster than a RWD car that weights 3,000 lbs and has 300 hp. But that's not the comparison here. If you have AWD you have ADDED weight (remove it and RWD is lighter thus advantage RWD).

 

StephenTi said it!

Anything else is simply measuring the fruit from the b... branch.