Does FWD handle better than RWD?
11-01-2004, 06:03 PM
#16
Burning Brakes
FWD is generally easier and more intuitive, but RWD is generally quicker and more rewarding (when mastered).
A few years ago Touring cars in the Uk had 2.0litre na engines with an 8,500 rev limit (iirc around 300bhp). They were nearly all FWD. Ford tried RWD for the handling advantage but lost out as with a tranverse engine (orientation had to follow production cars) turning the drive through 90 degrees twice cost them too much power. So in this case FWD was quicker but only because of the way the rules were written.
Tony
A few years ago Touring cars in the Uk had 2.0litre na engines with an 8,500 rev limit (iirc around 300bhp). They were nearly all FWD. Ford tried RWD for the handling advantage but lost out as with a tranverse engine (orientation had to follow production cars) turning the drive through 90 degrees twice cost them too much power. So in this case FWD was quicker but only because of the way the rules were written.
Tony
11-01-2004, 07:11 PM
#17
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VW in general is probably the one FWD manufacturer (even more so than the Jap sports cars), that make a point in dialing out understeer on their front drivers; so that's what you're comparing your car to. In stock form the 951 is fairly neutral with a little understeer. If your alignment is a little off (towards understeer), then you could very easily have more understeer than the Corrado.
All else being equal, RWD handles better than FWD, like others have said.
However, a well setup FWD will definitely outhandle a RWD that's been setup wrongly or conservatively; vehicle weights being equal.
Make sure all your suspension is in good working order, and if you say you can handle more oversteer: a little more negative camber in the front, zero toe all the way around, heavier sway bar in the rear.
A nicely handling car in the tight stuff can turn into ugly oversteer when the speeds are higher!! Then you might wish you had a little more understeer.
All else being equal, RWD handles better than FWD, like others have said.
However, a well setup FWD will definitely outhandle a RWD that's been setup wrongly or conservatively; vehicle weights being equal.
Make sure all your suspension is in good working order, and if you say you can handle more oversteer: a little more negative camber in the front, zero toe all the way around, heavier sway bar in the rear.
A nicely handling car in the tight stuff can turn into ugly oversteer when the speeds are higher!! Then you might wish you had a little more understeer.
11-01-2004, 07:37 PM
#18
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Yeah thanks guys, I have an algnment issue. But my camber is sooo bad, its about neg 4. I am not kidding. Its really bad. I need to fix that. Little low on money right now cus I just bought a rennlist membership which I havent gotten!! Haha, just kidding. 30 bucks is nothing. Thanks again for the input. The corrado just got full suspension done, thats why it handled so well. I had no idea. He put H&R springs that dropped it 2 inch and bilstein struts. Its a sweet car, but no 951. lol
11-01-2004, 08:27 PM
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A few years ago Touring cars in the Uk had 2.0litre na engines with an 8,500 rev limit (iirc around 300bhp). They were nearly all FWD. Ford tried RWD for the handling advantage but lost out as with a tranverse engine (orientation had to follow production cars) turning the drive through 90 degrees twice cost them too much power. So in this case FWD was quicker but only because of the way the rules were written.
11-01-2004, 10:07 PM
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I have to be pushed, not pulled anyway just on principle. There's just something laughably stupid looking about a car with the big wide fat tires in front and the skinny ones in back. . . unless it's going in reverse of course.
11-02-2004, 03:38 AM
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Originally Posted by UK952
FWD is generally easier and more intuitive, but RWD is generally quicker and more rewarding (when mastered).
I've been daily driving a Peugeot 106 GTi hatchback for a year now (a fun little FWD car with enough built-in oversteer to be fast) and it's a blast, plus very easy to go fast in. It does suck in the wet though, not enough traction off the line and bad understeer on corner exit, spinning the front tires...
On the other hand, while the 951 is definately more difficult to drive very fast in (of course experts say it's an easy car to drive, but I'm not an expert), it's also much more fun. If it's a bit slippery out there, you don't get understeer - you get power oversteer!! Oh yeah! ... very, very satisfying to get a curve just right in the 951.
11-02-2004, 06:55 PM
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Tire grip is a vector sum, meaning in this case that the total grip a tire can provide in one or more directions (for acceleration/braking and turning) is limited. RWD splits up the traction load on the tires so that the back tires provide forward motion and lateral grip. At the same time, the front tires are providing steering plus lateral grip. If you think of this as 4 jobs to do (forward motion, lateral grip at the rear, steering and lateral grip at the front), RWD cars split this up evenly front and back. In a FWD car the front tires are asked to do 3 of the 4. I would guess that this translates in to being able to put the power down earlier coming out of a corner, but I'm sure there are other benefits as well.
First of all, when traveling around a corner where the front and rear tires have to travel nearly the same distance (a corner with a large radius), then the there is little grip used for steering and it doesn't matter which wheels are driven. In a tight auto-x corner on the other hand, the steering angle is large and you will use up some front tire grip for steering.
If we focus on "real"
race track racing where the corners are not to tight then the advantage of RWD is mainly in weight distribution (or to be more accurate, the possibility to optimize weight distribution).If we separate cornering in three parts.
Braking and turn in: To evenly load all tires and get the best braking you want 50-50 weight distribution when under full braking. To compensate for the weight transfer you will need a static distribution of maybe 25%-75% front-rear to get best braking.
Mid corner: Here we want even weight distribution to evenly load all tires. Maybe a little more weight on the driving wheels as they probably will have wider tires.
Corner exit: Here we want to transfer power to the ground to get maximum acceleration out of the corner. For this we need as much weight as possible on the driving wheels. The more power we have, the more important it will be to get the driving wheels loaded.
If you sum all this up, the conclusion is the following.
A FWD car needs to be heavy at the rear to get good breaking and heavy at the front to get acceleration out of the corners. This is obviously a conflict which is hard to solve.
Even more, when accelerating out of a corner, weight transfer will increase loading on the driving wheels on a RWD car but decrease it on a FWD car.
For low powered cars a 50-50 weight distribution will work well for both FWD and RWD and the difference between them will be small.
For higher powered cars an RWD need more weight on the rear wheels to get good breaking and to get good acceleration out of corners. A Formula one car has probably 65-70% on the rear wheels.
A high powered FWD car will need more weight on the front wheels as there is more to loose if corner exit acceleration is impaired. It will still never get as good grip as a well balanced RWD car and it will brake worse.
Of course a well designed FWD car can be faster than a poorly designed RWD car and this does not take ease of driving in account.
Tomas
11-02-2004, 08:35 PM
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FWD and RWD cannot be expressly compared. That is one aspect of "handling" which is a subjective term. The higher end sports cars tend to be RWD, but everybody has their preferences.
I would suggest picking up a couple of books ("how to make your car handle" is a descent one), and doing some auto-xes if you're interested in better controlling your 944 turbo, or learning about the merits of weight distribution, drive wheels, etc.
I would suggest picking up a couple of books ("how to make your car handle" is a descent one), and doing some auto-xes if you're interested in better controlling your 944 turbo, or learning about the merits of weight distribution, drive wheels, etc.
"How to make your car handle" is a very basic-knowledge book and unfortunately looks mostly on FWD cars. Sorry, but factory FWD cars NEED to handle better, as the manufacturers have a nice saftey blanket dialed in called understeer. If you want to get your mind blown away by handling knowledge, "Engineer to Win" and more so "Tune to Win" by Carrol Smith are considered the top in the field. See Chris Moon's earlier post.
Also, FWD and RWD are only preferential if the driver does not want to be competitive with his/her car. FWD has a severe disadvantage in many track situations.
One personal pet peeve of FWD that I have, and one that is pointed out by motorsports engineers, is related to both Chris's post and Thomas L's post. Let's say for argument, you are going through the apex of a turn and want to tack out under throttle. Accelerating out of a turn will transfer weight to the rear tires, giving a FWD car a loss of traction and a RWD car a gain in traction. Granted many skilled FWD drivers can enter the corner differently to compensate partially, the RWD car simply has an advantage. Furthermore, when the RWD car loses traction in a turn, throttle steer will correct it. When the FWD car loses traction, it understeers and you have to lift and/or brake to correct it.
Circumstance, car setup, and driver skill are the main factors at deciding what will win, but all things constant, the RWD car has an advantage more often than not.... and damnit, it's just more fun too
By the way... to add to what Thomas was saying about weioght distribution, Ferrari conducted tests to determine what was the "ideal" weight distribution in terms of handling. Their conclusion was that 45/55 provided the best braking, acceleration and handling combo for a street/track car.
11-02-2004, 11:00 PM
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a pretty easy to read book that discusses this topic is "bob bondurant on high performance driving".
for the serious driver, another great book, which many professionals consider to be 'the bible' of driving books, is 'the technique of motor racing' by piero taruffi, which has long been out of print but seems to have been recently resurrected;
http://www.amazon.com/exec/obidos/tg...07846?v=glance
for the serious driver, another great book, which many professionals consider to be 'the bible' of driving books, is 'the technique of motor racing' by piero taruffi, which has long been out of print but seems to have been recently resurrected;
http://www.amazon.com/exec/obidos/tg...07846?v=glance
11-02-2004, 11:06 PM
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Originally Posted by nize
a pretty easy to read book that discusses this topic is "bob bondurant on high performance driving".
for the serious driver, another great book, which many professionals consider to be 'the bible' of driving books, is 'the technique of motor racing' by piero taruffi, which has long been out of print but seems to have been recently resurrected;
http://www.amazon.com/exec/obidos/tg...07846?v=glance
for the serious driver, another great book, which many professionals consider to be 'the bible' of driving books, is 'the technique of motor racing' by piero taruffi, which has long been out of print but seems to have been recently resurrected;
http://www.amazon.com/exec/obidos/tg...07846?v=glance
