allqt

I have a question, just because a car is RWD, all things being equal, does it necessasrily mean that it is faster than a FWD car?

Please correct me if i am wrong, but my understanding is that the RWD should be faster because it is actually has the effect of "pushing" from the back to the front where the FWD (Acura) is more like pulling from the front.,. which in effect should be slower (ie like dragging?)

So in effect if the Lexus IS300 and Acura TSX which have comprobable HP ( i believe they are both 200HP)..please correct if i am wrong.. does that mean that in a race the IS 300 would win?

Can somebody please verify? or explain the difference? Is the fact that the acura is a FWD the main reason why people think it drives or feels slow?

thanks,

jpt

jpt

Also

that would be the fact that the engine makes less torque than the other car you mentioned (i.e. it's um, slower).

allqt

I just found an article on the net which summarizes the main differences btwn FWD vs RWD .

http://www.corollaperformance.com/TechInfo/RWD.html

Dan Martin

The benefits of RWD in straight line performance only appear at the launch, once you're moving, they'll be the same.

Beoshingus

The fastest cars are those that are LWD (Left Wheel Drive), meaning that only the front left and back left wheels are powered. This is because of the "right hand rule" which you may remember from your physics class when you were studying torque. Unfortunately, there are very few manufacturers that are pursuing LWD vehicles at this time due to the ignorance of the public and the difficulty of explaining the LWD concept to non-technical people.

ianS

And no Audi is RWD.

loulinjai

I remember quoting from someone...basically horsepower sells a car, but torque is what moves a car. you have to take into account of weight, aerodynamics, characteristics of a car and way horsepower is measured....
ie. the 400hp v8's in the 60's would not make 200hp in today's horsepower measuring standards

Beoshingus

My father and his 1968 428 Cobrajet Ford Torino would say that you are full of crap. And so will I for that matter. You're saying that those 400hp V8s from the 60's aren't as powerful as the 2.4L 4 in your TSX. Are you for real?

DaleC

Not a bad article, but keep in mind it was written by BMW, the high priests of RWD

During acceleration a car's weight distribution shifts rearward, so it is theoretically possible for a RWD car to transfer more power (torque) from the drive wheels to the road than a FWD car of comparable weight (mass). This equates to faster acceleration, not necessarily faster top speeds.

AWD provides the highest acceleration potential since all four wheels are available to "push" against the road.

Oh, and as ianS pointed out, Audis are all either FWD or AWD.

psteng19

The drive wheels are not really the defining factor in speed, but more so of handling.

RWD may launch better due to weight shift towards the rear but it will suffer from more drivetrain loss than FWD.

But FWD cars suffer from torque steer, more noticeable in cars with more torque and unequal length half shafts (Maxima, TL).

And since nobody has chimed in about this yet, Audi's are all FWD or AWD (Haldex with FWD bias, Torsen 50/50)

glott

yeah for the record audis are FWD or AWD (quattro)

DaleC

Nobody?

gsclifton

iTrader: (2)

Another great Car Talk thread rears its' ugly head in the TSX Forum . . . .


From the looks of your post, you seem really interested in racing perhaps. The TSX was not designed to be a fast off the line racing machine.

Beoshingus

I'd just like to point out that Audis are either FWD or AWD.

Dan Martin

So just so we're all clear, Audi doesn't make a RWD car.

Beoshingus

Right. Audis are either FWD or AWD. (Still no LWD from Audi.)

dom

Beoshingus

Is that smiley FWD or RWD?

dom

kyotousa

LWD is that foreal?.....i think that will make the car pretty dangerous to drive in the rain

and how is right hand rule going to explain this.....

IlliNorge

All this crazy RWD Audi talk, I feel I need to chime in. I OWN an Audi and that sumbitch is AWD.

IlliNorge

The dangerous part comes in when you try to make a right turn.....

Beoshingus

Two wrongs don't make a right, but three lefts do.

Beoshingus

Beoshingus

Page 2 by me; RWD NOT by Audi

dom

You sure? Better go and check, just so we're all certain.

dom

Sometimes I wish the TSX was AWD. This RWD is killing me in the winter.

Beoshingus

If you drive a FWD Audi backwards, does it become a RWD Audi?

Beoshingus

Drive backwards.

mrdeeno

For those that said Audi's are either fwd or awd...




Wonder what wheels are driving this tasty bee-yotch? Maybe the left wheels!!

Beoshingus

LWD, baby.

Newplay1

The ideal is real sporty cars are RWD but nowsday look what honda has done with double-wishbone suspension its sick if you ever actually take a look at your suspension...

Since we have wonderful DC2R,DC5R,CL9 euro-R you can't knock FWD cars.

mrdeeno

suspension technology can only take a FWD car so far.

it's still limited by weight distribution and amount of power that can be put to the wheels.

Which is where awd comes in...so more power can be put to the wheels, but AWD adds weight and the weight distribution still isnt' ideal.

the s2000 and NSX are rear-drivers...even honda knows that for a no-compromises sports car, rwd is the way to go.



You can make a FWD car handle as well as a rear-driver, but then why didn't you just start with a rear-driver in the first place????!!??

mrdeeno

Uh, I'm a mech-e, and i have no idea how this would work, with or without the right hand rule.

The center of the car will be assumed as the center of mass. If the car's a LWD, the left front wheel will apply a force foward and diagonal to the left, because it's offset from the center of mass. The left rear wheel will apply a force forward and diagonal to the right because it's also offset from the center of mass. Assuming the same amount of power is sent to each left wheel, the lateral directions of the diagonal forces will cancel and the only forces left will be the forward forces.

But the force is offset from the center of mass, which will cause a moment/torque to be produced around the centerpoint in a clockwise direction (hella torque steer, bee-yotch!). Applying the right hand rule, the torque direction would be down into the ground.

This is the same principle that gives front wheel drivers torque steer...and it also explains why the one-armed dude in a wheelchair just goes round and round.

mrdeeno

i hope you're kidding...i'm a mech-e and i'm sitting at work actually thinking about this.

Assuming the center of the car is the center of mass. The front left wheel would give a force diagonal to the left. The rear left wheel would give a force diagonal to the right.

Theoretically, the lateral components of the two forces (left-right direction) would cancel out and the forward component would sum up.

But the problem is that the forces AREN'T applied at the center of the mass, it's applied on the left side, offset from the center, which creates a torque around the center of mass with torque direction into the ground (applying the right hand rule).

This is the same principle that explains torque steer, and also the same principle that explains why that one-armed wheelchair bound dude goes round and round.

Beoshingus

Ah, but the one armed guy in the wheelchair is only applying force to one of the left wheels - not both.

Beoshingus

He hopes I'm kidding...

STL

http://www.vtec.net/news/news-item?news_item_id=429206

The 4-cylinder FWD Acura TSX won the 2005 SCCA SPEED World Challenge Touring Car Championship beating out RWD competitors like BMW (who was using 6-cylinder engines too). So FWD can be plenty sporty...

IlliNorge

Poor guy. Brings new meaning to the term "moment arm"