I am curious: Why is RWD considered better for racing than FWD and even AWD?

I mean, it is said that FWD can turn faster than RWD and can accelerate earlier out of the turn (or am I totally wrong)? Also, somebody told me that it is impossible to accelerate through a turn with RWD (which I really don't believe, but how comes somebody thinks that?)...

In addition, how comes AWD is considered better only on loose underground and drag? I know, this two really need all the traction you can possibly have, but I think the same rules apply to track racing, don't they? I always though an AWD not only accelerates faster because it has more traction, but it also corners faster of the same reason... So why are there almost no AWDs on the track?

fwd - light, uneven weight distribution, understeer at corner exit
4wd - heavy, even weight distribution, best acceleration, huge drivetrain losses
rwd - light, even weight distribution, oversteer at corner exit

basically fwd is the worst concept for acceleration especially out of corners
4wd is (by far - caution subjective opinion) the best concept but its weight penalty and drivetrain losses effectively ban it for any racing series with limits on power other than rallying where the road conditions pronounce the traction advantages of 4wd more
with an rwd concept you give up some traction making the car harder to control at the corner exit (not that much of a problem with wide slicks downforce and good tarmac) for a (huge) efficiency and weight advantage

It is known that FWD can not have more power than 200 - 220 bhp.
Second of all while accelerating cars weight center is being moved to the back of the car. You can see that clearly after pressing F in LFS. Rear wheels have more grip and therefore can handle more torge without wheelspin. This is also the reason why power distribution in 4WD is 60-40 / 70-30 (rear - front).

I dont know why AWD are not that popular maybe because steering wheels without propulsion give more information through the steering wheel about the car behaviour

I think that powerloss in AWD is still to high and the weight of 4WD chasis is bigger than RWD one. However electronic differential is making a terrific job on power distribution for example in Lancer EVO VIII or IX and this system is soon to be used in racing.

There is also driving technique of power-turning or whatever you call it.

Furthermore RWD cars are classic. Sport cars have always been RWD and its the way it will remain for long time.

RWD is more challanging and sport can not be too easy or it will be too boring.

Awd would be a good racing solution but it can only help you to put the power down better on corner exits for a short period of time. And that time period is the time there is the danger of wheel spin in a rwd vehicle. When not on that time period, awd cars lose to fwd and rwd cars because of the bigger losses between engine and tires in the drivetrain. Also the higher weight in awd versus rwd/fwd does not do enough to be justified. And fwd can't put the power down and steer efficiently at the same time.

In rallying awd can accelerate out of the corners better because the period of oversteer is longer for rwd. So awd can gain more there.

That's how I see it

EDIT: After reading my own post...maybe I should start posting in finnish

Most racing cars are mid engined. That's where the engine sits behind the driver but in front of the rear axle. This gives the car much better handling characturistics. Due to this the weight distribution of a racing car rests on the rear axle. Thus that is where you want the power to go. More weight = more traction. You will never see a rear engined front wheel drive race car, no weight on the axle means no drive. Also one axle one job. It simplifies the manufacturing of components and therefor the racing reliability if you simplify everything. Rear wheel drive enables this by keeping the steering and the drive seperate. Simple components mean lighter components. FWD/Front engined allows for a safer drive, which is why many raod cars use this lay out. The engine gives weight to the front axle allowing it have traction, but this is not actually the fastest method in racing as the engine will tend to lead a car into a corner producing understeer and torque steer on the exit when you are trying to apply maximum power. Rear engined cars being more balanced can produce a more nuetral handling whilst cornering. FWD cars are generally used for small twisty circuits where the need for quick manouvable attributes favour the FWD cars.

AWD cars obviously generate more traction, but the weight penalty induced by carrying a heavier drive train renders it wholy impractical in circuit racing. It has been tryed, Audi use it effectily in Touring Cars, but it is not the generally accepted pratice. In rallying the wieght is less of an issue, can can sometimes be an asset when traction is more important than overall speed.

It's not a simple matter.

Hmm... I knew some things you've said, but never put 1+1 together... :doh:

I see the reasons now, thanks @ll...

Also depending on the setup an AWD car can give very pronouced understeer on corner exit.

Dan,

yep... common prob with the fxr gtr and my sets... but a fun car to drive none the less....

mad

just load more torque onto the rear wheels and the understeer will be gone

FWD really need not be considered for racing purposes.

RWD cars make up the vast majority of racing cars and are the logical choice in mid engined cars, with the gearbox and diff all bolted onto the engine.

4WD cars tend to be heavier although they do give better traction, particuarly useful on slow courses.

A RWD car does not have to oversteer on corner exit, a lot of racing cars are setup to understeer slighty, especially in high power cars, something missing from LFS's setups.

4WD single seaters could be groundbreaking in hillclimbing, the Hepworth special (a 1970s 4WD chevy smallblock V8 hillclimbing single seater) still leaves the line faster than any of the Pillbeams or Goulds (big single seaters, built purely for short runs and as fast as F1 cars over them). Also Nick Mann's new car is an impressive Mallock style front engined clubmans style car, with 4WD and a 2 litre BDA, which uses a helicopter starter motor to give a constant boost turbo, is almost as fast as the big single seaters up Shelsley.

i remember BTCC a while back with the audi 4WD vs the others and in the wet the 4WD had a significant advantage.

Quote from himself :

It is known that FWD can not have more power than 200 - 220 bhp.

for a ROAD car the limit is 250 with proper suspension...

says who? how heavy is the car? how hard does the power come on?

Quote from Blowtus :

says who? how heavy is the car? how hard does the power come on?

That's just a figure TopGear and other motoring press are using at the moment. Not too long ago they were all saying 200bhp so I wouldn't take what they say as fact and I fully expect Clarkson to say at some point in the future: "so you thought the most power a fwd car could manage without ripping itself to pieces was 250bhp.......well.......you were wrong" :cue tyre smoking hot hatch being punished, background rock music, and nice filters on the camera.

Quote from Jakg :

for a ROAD car the limit is 250 with proper suspension...

What are you talking about, you can have a 500 bhp FWD road or race car it will just be horrible to drive, there's no limit to how powerful you can make a FWD car

Quote from ajp71 :

A RWD car does not have to oversteer on corner exit, a lot of racing cars are setup to understeer slighty, especially in high power cars, something missing from LFS's setups.

a lot of cars in lfs have massive understeer at the exit ... especially the fz5 and the fzr

Quote from Shotglass :

a lot of cars in lfs have massive understeer at the exit ... especially the fz5 and the fzr

Yes but the LXs and FOX tend to be setup towards oversteer.

Quote from ajp71 :

Yes but the LXs and FOX tend to be setup towards oversteer.

yes because its faster at the expense of less driveability

Quote from Shotglass :

yes because its faster at the expense of less driveability

Thats bollocks a small single seater should be faster set towards a slight understeer. Don't use the arguement that these cars should be setup like historic single seaters, these are modern cars with modern materials and construction.

every tyre has a finite amount of grip to be shared between any actions its asked to do, slowing the car, accelerating the car, holding the car round corners or turning the car.

traditionally rwd was used because it spread this load, then, ignoring ferdinand porsche's rather strange effort for racing in argentina after ww2, when f1 went from 1.5 to 3 lt in 1967 people started worrying that 2 tryes couldnt cope, hence all the top teams , and cosworth for some reason, decided to try 4wd. all discovered that it didnt really work as either the fronts couldnt cope with power or the car was very unwieldy on a track, the result being that the lotus ended up with as little as 10% power to the front wheels which didnt really justify the added weight / complexity.

at the same time tyres improved by a huge amount and someone had the idea of tying an upside down plane to a car and so the problem was gone till the era of qualifying 1.5 turbo grenade engines but by then 4wd was banned in f1.

4wd has been competative in saloon racing but in most of the catagories the raced the power could be coped with by 2wd in the dry so no real advantage and weight penalties, both from running gear and rules, rendered then popintless.

fwd currently dominates uk saloon racing due to rules requiring cars to follow road versions and also the power / tyre grip figure being too low, in germany were power in the dtm is higher a fwd would be a major challenge to drive.

when you factor weight distribution in, both static and actuall, fwd has no chance at high power. assuming you can build a fwd and rwd with same weight dist then when you acelerate weight is being taken off a fwds driving wheels just when it needs it the most. of course when its slippy and acceleration is less, the extra front weight a fwd has in real life stays more over front and so in such conditions they can have an advantage. of course if youve a 911 then the weight is ove real wheels and they just stick and go till the corner.

could go on more but just realised im supposed to be in work in 20 mins

Quote from sinbad :

That's just a figure TopGear and other motoring press are using at the moment. Not too long ago they were all saying 200bhp so I wouldn't take what they say as fact and I fully expect Clarkson to say at some point in the future: "so you thought the most power a fwd car could manage without ripping itself to pieces was 250bhp.......well.......you were wrong" :cue tyre smoking hot hatch being punished, background rock music, and nice filters on the camera.

The Nissan Maxima has 265hp if I recall. My friend's dad has one with a 6-speed and it's a blast to drive. Sure it can cook the front tires if you want, but if you're easy on the throttle on corner exits, man does it go! Driving the Maxima, I can pretty easily keep up with his AWD Audi S4 on twisty backroads.

I don't believe RWD is considered superior for racing than AWD. Who says that?

If F1 was allowed AWD don't you think they'd use it? Ofcourse they would but they can't because its banned.

An F1 team, perhaps Brabham under the ownership of Bernard Eccelstone, tried AWD on their cars, and the added weight and complexity at the time made it absolutely awful. The drivers hated the way it drove. In fact, if I remember correctly, it was only better out of very slow corners. RWD was quicker off the line (controlled wheel slip), faster through corners, better at braking and lighter.

I think the same would be true today, even with 'clever' 4WD.

awd would wipe the floor if it was allowed, with no 'penalties', is the impression I got from reading a few bits and pieces. If it were a disadvantage, would there be a need to ban it?
awd is a little more advanced now than 30 (more?) years ago...

RWD > AWD or FWD? Why?

I dont think it is in LFS, the RWD cars aren't as realistic as the FWD cars imo. Physics are just too wrong, mainly because of the low speed buy, RWD is a pain in the ass on the slow stuff in LFS.

my 2c