this is a very noob question... but i'm gonna ask it anyways.

what is the major difference between RWD and FWD in term of power?

 

In terms of power?

FWD under most circumstances would be less complex, allowing more power to transfer from the engine to the wheels.

RWD involves heavier components.

If the engine is in the rear and its RWD, then I'd assume it would be roughly the same as a FWD car with a front mounted engine.

 

Typically the closer the drive wheels are to the engine, the less drivetrain loss... so the more power which is put to the ground.

As far as handling differences, there are tons of variables. The internet has tons of good reading on it: http://lmgtfy.com/?q=FWD+vs+RWD

 

I never realized that there is less powertrain loss with FWD vs RWD. I always assumed a transverse mounted FWD engine/tranny would have more powertrain loss than a longitude mounted RWD engine/tranny. Learn something new everyday I guess.

 

while the FWD may have less powertrain loss I think we can all agree that the RWD configuration is better suited to harnessing the same amount of power.

Torquesteer fer ze losse.

 

Yup, heavy driveshaft.

Carbon fiber for the win

 

El ez dee fer ze wynn!

 

I'm with ya there.... driving a high-powered FWD car with an open diff blows hard. Understeel for ze las!

 

What zee hellz are zeez guyz talkzing aboutz?

 

FWD cars with tons of power have a major problem with torque steer, that is you punch it and the power takes control of the steering..

the Caddy Northstar V8's and the Chevy Impala lineup with the V8 or even the S/C V6 were horrendous with torque steer..

put that same power in a RWD and the car launches straight and the Driver has more control..


lots of car companies have developed computers and various gearing systems to negate the FWD Torque Steer issues, but then you take a lot of the handling ability away from the driver and give it to a computer.

I have driven a lot of different cars from V12 MBZ's to custom drifting SRT4 Turbo Neon's plugging over 550hp to the front wheels..

IMO the best design I have come across is the transaxle (front or rear) AWD cars, like the Porsche Carrera AWD or the TL SH-AWD.

I have autocrossed a 2005 Porsche C AWD and the handling is superb.. putting it up against a big V12 Lambo and the Porsche will out drive the Lambo, no contest..

but of course, throw that big displacement V12 on a 1/4 mile track and it leaves the Porsche in the dust..


all depends on what you want and how you drive it..

you want to go fast in a straight line big displacement and RWD..


you want a autocrossing car, then transaxle AWD.. having a RWD based AWD car sucks.. Take the 300C or Charger, they offer the 5.7L HEMI in an AWD format, it's a front mount RWD setup with a big lope sided transaxle for the AWD.. had they designed it on a FWD base the car would handle 100 times better.. having that big HEMI in a RWD format and slapping in a transaxle does nothing for the handling..


FWD cars are more efficient and handle better than "most" RWD cars in the twisties.. but FWD cars are a bitch to control in a stright line 1/4 Race if they have too much power..

 

I have this "El Ez Dee" in my Clubman, and I still need to have both hands on the wheel...

 

I agree that AWD is where it's at, but Lambos are AWD, at least the Diablo, Gallardo, and Murcielago. I'm not saying a Porsche doesn't handle better, but it's not because of which wheels the power is being distributed to.

I personally have a harder time with FWD in the twisties. The portion where you typically accelerate out of the curve hard is all but eliminated. I think this is more driving style and personal preference than anything else though.

 

I'll agree for an autox track FWD and AWD fare very well, meanwhile RWD is a bit more of a handful, even in lesser powered cars. But slicks on all four corners are a great solution

The great thing about AWD is that corner exit is pretty simple.... assuming you have an AWD system worth a damn, you can even apply too much throttle and the AWD will take care of the work for you. Its not so simple with FWD and especially RWD. FWD cars can handle very well but they have their limitations. People think putting a big RSB on them will cure all understeer problems but that results in other problems, which manifest into things like 3-wheeling on the autox course under hard braking/cornering. It looks cool, but 4 tires will always have more grip than 3 tires.

 

Makes me wish my Prelude had 4WS

 

i didn't really read all these posts...
but RWD i would have to say would be the one with the least power lost from engine to wheels.
FWD always has wheel hop. The power may be there more efficiently than being transferred the length of the vehicle, but every time i've ever really gotten on a FWD and roasted 'em, i thought i was breaking the damn thing cause of the wheel hop.
I own an 85 Mustang GT as well as my recently purchased 3.2TL, and it'll roast 'em no problem, and gets pretty damn good traction if i'm trying to. lol

 

Well for one thing, RWD has much better traction than FWD. And for that reason you can send quite a bit more HP and torque through a RWD platform. Then there's handling. A FWD is hard pressed to match a RWD in the twisties.. though don't tell the 2000 SVT Contour that.

 

Exactly. There's a lot of misconceptions about FWD vs. RWD but within its current power range, good FWD's driven by skilled drivers are faster everwhere except the first 60ft of the 1/4 mile strip.

I can manage the torque steer in my TL-S much better than the oversteer from my earlier RWD cars. The TL-S corners like its on rails and the tail can be flicked out (yes you can do this in a FWD car if you know how).

So enough BS from the lay-z-boy reclining poseurs: put a skilled driver in a great FWD car like the TL or TSX and it'll beat a lot of high HP RWD "sports" cars. Here's the truth:

At Willow Springs, the TL-S beats the BMW M3, Porsche 997 Carrera S, Lotus Exige, etc.
http://www.fastestlaps.com/track15.html

In the SPEED Touring Car series, the TSX and Mazda 6 dominate the BMW E90's. This is even after they changed the rules this year to make the BMW's more competitive:
http://www.world-challenge.com/events/points.php

 

FWD is hitting the wall with the front of your car

RWD is hitting the wall with the rear of your car

 

FWD is done to build a cheaper car. RWD is done to build a better handling car with more power.

 

not quite..

FWD started because of the gas shortage in the 1970s, the idea was to build a lighter more efficient and economical car.

it grew into the ability to have a lighter more economical car with more interior space because there was no center hump, no drive shaft, and the wind-shield could be pushed out further (enter the "cap forward" design) to give the car a bigger interior feel without actually making the exterior bigger.


in incumbent weather they handle tons better than RWD, but not as good as an AWD..

there are plenty of FWD cars that have as much power as a RWD in the same class, and they perform better sans the torque steer...

Take the TL vs a Lexus IS... pretty much the same class of car, and the TL performs just as well, if not better...

http://www.truedelta.com/comparisons...sion_code=&aff=

http://www.newcars.com/lexus/is350/r.../acura-tl.html

 

CAB forward. sorry for the typo

 

Sir, joo haz an E-Diff, ye do not haz a traditional mechanical "El Ez Dee"

 

Aren't traction and torque steer totally different issues? FWD should have better traction because the majority of a car's weight is distributed over the front wheels, enabling FWD cars to handle better than RWD cars during inclement weather.

 

For me...

RWD dead in the water when it snows.

FWD chances of getting to where you want when it snows....

 

Oh man, awesome!

Fishy you're the best.

 

Ah, and to the OP -

As mentioned above, FWD cars generally have a bit less drivetrain loss, so if you (theoretically) put the exact same engine into a FWD and a RWD car, the FWD car would put a bit more power to the ground, say around 5% to 8%

That being said...as power levels go up, the more difficult the problems with FWD cars become in putting down the power effectively and managing torque steer. RWD cars are far better at putting higher levels of power to the pavement without drama. This is why there are dozens of 400hp RWD cars available on the market today.....yet not one single FWD 400hp production vehicle.

That being said, FWD has some distinct advantages; it provides better traction than RWD in adverse conditions like heavy rain, mud, and snow. Its also cheaper to manufacture as noted above. Limited slip differentials and well-thought out suspension designs have made many FWD cars great handlers and even competitive on the racetrack.
Again though, these are the lighter weight, lower hp cars we're talking about.

One last thing, about drag cars. There are some FWD drag cars out there now putting out 500+ hp, and cutting some very fast times....into the 8's and even 7's. Yet, that doesn't mean they're easy to keep pointed straight down the track, believe me. Ultra high-hp FWD drag cars are a serious handful if you don't know what you're doing. The RWD cars are much easier to launch and keep straight.

 

The general context of this thread was that of performance and that is how I addressed my response. RWD cars are always going to have significantly better traction capabilities than front drivers for one simple fact of physics: weight transfer. There are other factors which favor a RWD platform over a FWD one.

Strength. RWD's can be made stronger because of their larger comonents and lack of some major weak points. This enables a RWD platform to handle more power and torque.

Less complexity. A FWD platform is rather tight and complex compared to a RWD.

Maintenance. Goes without saying.

Lower costs in certain mishaps. Say you loose control in the snow and slide kinda hard into a curb hitting a front wheel on its side. The potential of costly damage is greater in a FWD vehicle than a RWD.

Of the world's finish machines, not one is a FWD. Corvette, Porsche, Rolls Royce, BMW, Mercedes, and so on.


The reasons given for companies going to FWD have already been pointed out. After the gas shortage of 1974, we saw this turn occur. FWD cars could be made smaller and lighter with acceptable interior space and lower fuel use due to smaller engines. The public was sold on the idea of better traction in the snow and to a fair degree, all of this is true. But the early versions were poor handles with terrible road feel and sloppy steering - almost a gyroscopic feel (some still have this).

However for the last decade or more, some really fine handling FWD cars have been produced. So it has grown up and now is an excellent platform for many models.

 

I beg to differ about 1/4 performance between FWD and RWD cars. I will grant you that there are some great FWD handlers out there and I would put the TL series, particularly the manual, in that mix, although my 2000 SVT Contour would leave a TL on a twistie road (try a .92 200 skid pad for a stock SVT).

But on a drag strip, RWD rules. And especially in the top classes. You are never likely to see a FWD AA/FD, Funny Car, or Pro-stocker. And the door slammers - same thing.

 

I'm not disagreeing with the rest of your post, but I still don't understand how RWD has better traction. Maybe we are thinking of traction differently, leading to some confusion. If the dictionary definition of traction is used, which defines traction as "the adhesive friction of a body on some surface, such as a wheel on a rail or a tire on a road," FWD will have better traction because the majority of a car's weight is distributed over the front wheels. The higher weight results in a larger normal force acting upon the tires, and therefore, more friction. With the same amount of power, it's normally easier to burn out with a RWD car because there is less traction in the back than in the front.

 

^ Now I'm a little confused. You're saying if a car has a perfect 50/50 weight distribution a FWD config would still have better traction then a RWD?

 

No, I'm assuming that a FWD vehicle will be front heavy and have something like a 60:40 weight distribution, which is normally the case. There may be some FWD cars with close to 50:50, but I don't know of any. In general, RWD cars are slightly front heavy or have a 50:50 weight distribution, so there will be less weight above the wheels for RWD than for FWD. Obviously, this entire analysis is null for mid-engine or rear-engine vehicles.

 

The reason your traction theory doesn't hold water is because your scenario applies to a car at standstill and right at the initial movement, but no further. Yes, there is more weight over the front wheels, and therefore more traction to get the car to start moving (hence good to start moving in snow/slick conditions). But in a straight-line performance situation such as a drag race, where there is significant acceleration, the mass of the car (center of which is above the tires) shifts to the rear, negating any extra weight over the front wheels and increasing downforce at the rear wheels thereby giving the rear wheels more traction.

An example of where this is a problem with performance cars in a drag race is this...you WANT some wheelspin for maximum acceleration. since there is less weight over the rear wheels, a RWD car will have some wheelspin, allowing the engine to wind up to where it can generate any usable torque and as the car starts to move and weight shifts to the rear, the rear tires "hook up", ie gain traction and get the car moving without bogging down the engine.

As for handling in non-straight situations, RWD is optimal for the fact that the front wheels handle the steering while rear wheels propel the car. The front tire patches only have so much traction available based on the contact patch, and if it requires double duty of moving the car forward as well as steering, the overall traction available for either is lowered. this is compensated for by both wider tires and suspension tweaks to keep the front contact patches as large as possible to maximize available traction...and this is why FWD cars that handle well are described as "on rails"...because the less body sway there is while cornering, the larger the contact patch is on the front inside tire to maintain more traction. My M45 sport handles better than my CL-S w/ sways ever did, yet my CL-S handled like it was "on rails" while the M45 doesn't have that "rails" feeling at all.

Another thing to consider is weight distribution. FWD cars are generally transversely mounted engines that are mounted more or less over the front drive wheels. Audi has started using longitudinally mounted engines in its FWD cars which help move some of the weight to the rear, but are still in general more front heavy than a RWD car. In a RWD car, the engine can be moved rearward since there is no connection to the front wheels, allowing for closer to neutral weight distribution (near 50%/50% front/rear). If you have the center of mass closer to the center, it is easier to rotate than if the mass is forward of that center (ie hold a 35lb dumbbell out in front of you, when you rotate your body to the right with that dumbbell out in front of you the dumbbell must be "moved" to the new position to the right and therefore offers some resistance to move to its new position. If you are to hold that dumbbell closer to your chest, when you rotate your body, the dumbbell rotates with you...the latter is much more "neutral"). This is what causes understeer...the front-heavy mass (e.g. the dumbbell) is resisting the rotation of the car and wants to go straight = understeer. If the weight was closer to the center, there is much less resistance to the rotation of the car which reduces/eliminates understeer. Again, this is mitigated by suspension tweaks. Since understeer is easier to "feel" and easier to fix (ie slow down), a lot of rwd performance cars are tweaked FOR understeer at lower handling limits so people don't push their rwd cars too hard and end up with out of control oversteer.

 

Thanks for the detailed explanation. I should have clarified that my analysis was only for situations near standstill. I wasn't arguing that FWD is better for performance or handling in general, so I have no disagreement with your explanation.

 

Yeah, you're not looking at this as I am. Traction, in the performance context here, refers to the ability of a car to "hook up" at launch on a drag strip. Perhaps I should have been more specific.

 

Hey man, I try real hard to be misinterpreted. Its more fun that way.

Yes, I actually agree with you. Like I said, its the first 60ft that kills FWD cars at the 1/4 mile.

And similarly, I qualified my statement within the current power limits of FWD cars, i.e. around 300HP. Of course there are much faster RWD cars, but they need significant more HP to start beating the best FWD cars.

I am amused by all the theoretical physics mentioned in some of these posts, but let's see some facts where in the same HP class, RWD cars beat the best FWD cars on the track (longer than 1/4 mile ) or on road courses.

 

Very nice job. Another benefit that the American supercars had during the mid-60's (they were never called muscle cars back then - that term came later) was easy use of traction bars. The GM supercars (Pontiac GTO, Chevelle SS396, Oldsmobile 442, and Buick Skylark Gran Sport) came stock with traction bars, only they were called "trailing arms". But they served the same purpose which was increase the effect of weight transfer over the rear tires.

 

Right, because theoretical physics are all theory...that's why there's such an abundance of high HP and high performance FWD cars. I guess Porsche/Ferarri/Lambo/BMW got it wrong all these years. Hell, even when Honda wanted to design vehicles with maximum performance (i.e. s2000 and NSX), they went with RWD.

You discount theory yet you yourself don't provide any evidence to discount it. Why make something complex (ie all the expensive tricks and such) on a FWD car to get it to handle well, when you can just do it the easy way and make it RWD...oh, because you want to base it on the same platform as a family sedan in order to save money...gotcha!

 

Its all preference... personally I enjoy throttle steering a lot. Torque steer, while usually not as bad as its said to be, is never fun nor beneficial in handling.

 

:ibsomeonestatesnascarsstockerswoulddobetterw/fwd:

 

what the hell are you talking about? None of what you said in any way applies to the post you quoted. Did you even read what he wrote or did you just feel like ranting about how you don't like FWD?