Log in / Register

 

 

8 months ago

RWD vs. AWD vs. FWD

Everyone has their own preference when it comes to drive-train layout. There are those who want the organic feel of a RWD car, those who prefer the every day grip of AWD, and even a few misguided souls that scream “FWD FTW!” at the top of their lungs. I only kid about the misguided souls bit, but you get the point.

When you boil them down to their basics though, you find that they all have their inherent advantages and disadvantages and they all serve their purpose, just by different means.

We're going to stick to front engine for these scenarios as it gets murky when you consider mid and rear engine.

Let's get FWD out of the way, as it's the easiest to dissect. FWD was originally designed as a means to reduce cost, improve fuel economy, and increase the space available in the cabin of the car. But most of us don't care about all that. In a racing application, it has some advantages. They typically have slightly less drive-train loss, as there is no drive shaft needed from the transmission to a rear differential. It is also slightly lighter as a result of this same fact. As a disadvantage, you're using the same wheels to propel the car as you are to turn. This means that it's difficult to feed more power and increase speed during a turn without resulting in understeer.

AWD. It's made some major advancements in the last 10 years, but lets cover the basics. AWD has a couple disadvantages. It weighs the most of the three layouts and has the most drive-train loss. It can also negatively impact the balance of the car in regard to front vs. rear weight distribution. On the track, a basic AWD system can apply power earlier out of a turn then the other formats, but because the front wheels are still supplying power and trying to turn, understeer can result. Car makers have combated this lately with trick and techy differentials and electronics that modulate power to the right wheels as the car goes through and accelerates out of a corner. So much so that the car is sometimes virtually RWD for a few moments (sometimes 3wd too).

RWD. Okay, I'll say it, my personal favorite. I've owned all three from 150hp, up to 400+hp. It has a certain feel to it the others can't replicate, idk. But ok ok ok, facts! Rwd has more drive-train loss than FWD, but less than AWD. It's also in-between, in regard to weight. With RWD, it's also much easier to create a car with neutral balance, where weight distribution is an even 50%. RWD can also apply power around a turn without much trouble, but can get tail happy towards the end if the car's power outweighs its grip limits. With the right tires and enough aero, this issue is virtually non existant except on a very tight course.

So let's play out a scenario. Sorry FWD, but you're going to sit out on this one.

We have in our possession, two identical cars. Same strong down-force, same engine, and same weight without its drivetrain (tranny, axles, diffs, half shafts, etc). But one is AWD and the other RWD. The result? One car will weigh a little more and make a little less at the wheels, the AWD car. This means, on a straight, the RWD will slowly edge out the AWD. But the AWD car has great grip, which gives it the advantage around tight corners. One would imagine that on a well rounded course that the two cars would be even. The AWD completely taking the hairpins, the RWD even or quicker around wide sweeping turns, and the RWD edging ahead on long straights. In the end, they would likely be dead even, or at least extremely entertaining to watch.

So there's my extremely abridged and abbreviated take on the three. I'd go on rambling, but I figure I've already either bored or knotted the panties of anyone who's bothered to read all this.

I'd be interested in seeing what others think of the three layouts. What's YOUR favorite?

Community comments (89)

3 months ago
I'm not feeling confortable with RWD. from my opinion, AWD should not be considered if the engine have under 190HP 400NM.
For an audi A4/A5, because the car is heavy and AWD is adding weight also, 2.0tdi with 177HP&380Nm is to less power for fitting an AWD. at least 190HP is mandatory for AWD
4 months ago
Hmmm...
At the last 24h of Nürburgring there were AWD and FWD Audi TT where the FWD had faster lap times because of the wheight deficit.
4 months ago
Surely there's no point arguing about who is right or wrong when everyone builds cars for a different purpose or taste. I'm sure someone who builds a 7 sec drag car doesn't feel dissapointed that it won't handle as well as a Ferrari. I'm sure he doesn't cry at night knowing it doesn't have power steering or predictable handling. He built it to be crazy fast in a straight line and make him feel like he just poked a black bear with a big stick. Just got off the phone with Nasa. They are saying there's no point in building any more rockets they can only get 0.02 mpg and a really poor turning circle. Parking is a an issue as well.
5 months ago
@Anon.

You're still missing a lot.

First of all, I was saying that the most recent camaro has an IRS, and most people don't swap out the irs for a solid axle, as the stock irs is strong.

Also, even the camaro with an sra has pretty good handling. It can even be made better. The 4th gen camaro dominated many classes in scca racing, despite its solid axle. It's main competitor in its class that repeatedly lost to it? BMWs.

Nothing really funny about an older camaro with a live axle. It works on the street, at the strip, and at the roadcourse. It's not the best on the street, but it works very well and is lightweight.

You're right, it would be funny to see a corvette with a live axle. Primarily because very few have them. Only the most hardcore drag racers have them, but their cars are very far from a stock corvette. Many of them are basically tube frame cars with a fiberglass shape of a corvette.

Your original comment is derisive and derogatory.
5 months ago
@Anon
Had to laugh at that. Clarkson? Sharp? I've seen chicken eggs more pointed than him. He's an opinionated tool who happens to get lucky and say the right things every now and then. The guy doesn't even know how forced induction works; that alone is enough for me to disregard pretty much anything he says about cars.

No, you don't get it. If the owner isn't going to use that "ultimate" performance car on the track or what have you, then there's no point in it. But if he IS going to use it for drag racing, and drag racing only, then there's certainly merit in "ruining" a formula that doesn't apply to drag racing. That is why your initial comment is not at all funny and doesn't make much sense. Yes, that setup would help someone achieve faster times on a prepped strip. And if that's where they plan on using it, speed is all that matters. The "ultimate" performance car formula doesn't apply to drag racing, so you bringing it up was utterly pointless. If it was your attempt at humor, even Dane Cook wouldn't steal your jokes. Also, it should be "MadCoolShirtGuy", "CoolShirtMadGuy" looks stupid. Seriously, don't quit your day job.
5 months ago
@CoolShirtMadGuy
what Clarkson is doing here? If you find my comments to the Clarkson's sharp remarks about automotive world, then I am pleased :)

You are still not getting it, aren't you? Of course, live axle has some advantages on the dragstrip. That was the whole point in the beggining. Let me ask for help from Admiral Apparent here. Matt told us a story on how to build the ultimate performance car. The recipe was simple, put enough power to almost overcome the traction with the most stickiest widest tyres possible. Even with the car like that there will be a guy in a shirt who will put a blown big-block in that car and make SRA conversion to put even more power at the wheels. Maybe It would help him achieve faster trap time on a prepped strip, but Matt's recipe for the ultimate performance is already ruined.

Don't get me wrong, I love drag racing, especially top fuel classes. I like classical muscle car era drag cars. But I find the destiny of those fastest corvettes mentioned in prev post is somewhat miserable. ZR1 is already at the point where Matt's way won't help you. But yet we have below 7 second drag prepped street corvettes that can't turn for shit. Thanks God ferraris, porsches and other exotics are too expensive to ruin with drag-strip performance packages
5 months ago
@Apathy
Thanks for the input, but you sound like a Captain Obvious here to me
1) of course I was talking about recent gen comaros
2) sentence doesn't make sense, but I agree :)
3) I even know the history of the fastest quater IRS Corvette
And who was talking about IRS vs SRA in handling aspect
6 months ago
@Anon
And I sense a huge pocket of empty air between your ears.

The only people who would find your comment funny are idiots who know little about cars beyond what they've heard from Jeremy Clarkson and the rest of the Top Gear crew.

See, when it comes to drag racing, a live rear axle is better than an IRS setup 9 times out of 10. It doesn't genius to figure out that *maybe* you should use the setup best suited for what you plan to do with the car. Yeah, it may be "archaic" technology, but what does it matter when that LRA humiliates your IRS? What are you going to say? "My suspension's more advanced"? Fat lot of good it did you.
6 months ago, last edited 6 months ago
@Anon:

There are several issues with your joke in regard to the camaro and corvette:

1) Most Camaros come stock with a solid rear axle

2) The new ones that don't have a very strong rear axle so they keep the IRS.

3) Most corvettes keep the IRS in drag racing. It's one of the strongest IRS' in the industry AND a Corvette holds the record for the quickest drag car with an IRS.

Also, I'm a bit tired of derogatory comments related to SRAs and handling. An SRA car can handle as well as an IRS car, it's just going to be more finicky and less stable on uneven and rough surfaces.

Though, there are actually tracks where solid rear axle cars are at an advantage. Sebring for example, its choppy sections around turns actually lends to an SRA car being more stable for some reason. IRS cars begin to pitch around the turn due to the sections.

IRS has a real advantage when only one wheel is disrupted, causing a change in camber in the other wheel in an SRA application.
6 months ago
@Coolshirtguy
I sense a huge pain below you back.

Anyways, a lot of people find it funny to see, lets say, a highly prepped Camaro or Corvette for a dragstrip to have a live axel.
6 months ago
Quote: 'In the end if you have a truly powerful car, there will be americans that will add even more power, cut front drive and put live rear axel.'
Yes that's true. As yet there is no FWD or AWD solution when the front wheels are off the ground. I did email GM about using the front suspension design from 'Big Foot', but they aren't returing my calls.
6 months ago
@Anon
No, there is no addition. Matt's comment was funny and full of win; yours makes no sense and is full of fail.

I know you probably think you were being clever or something, but that was just pathetic. I've seen 5 year-olds do better.
6 months ago
In addition to Matt's. In the end if you have a truly powerful car, there will be americans that will add even more power, cut front drive and put live rear axel.
6 months ago, last edited 6 months ago
@ Matt : So cool .
6 months ago
@Matt LOL. So true.
6 months ago
Do you have excessive wheelspin?
No? Then you need more power!
Yes? Then use an LSD.
Do you have excessive understeer or oversteer now?
No? Then you need more power!
Yes? Then use wider tyres.
Did this solve the problem?
Yes? Then you need more power!
No? Then you need AWD or have more weight over the driven wheels.
Did this solve the problem?
Yes? Congratulations! You have enough power.
No? Congratulations! You have balls the size of felix baumgartners.
6 months ago
It also depends on your driving style, like BR2 said.
6 months ago
Front and rear wheel drive vehicles are usually faster, quicker and more nimble than all wheel drive vehicles, all wheel drive is better on loose surfaces like dirt and gravel and wet or slippery surfaces like a rain-soaked road because AWDs have better traction. Rear wheel drive vehicles usually have the best handling. It all depends on the environment, terrain, and climate you live in when it comes to which layout is better for you. My truck is rear wheel drive.
7 months ago
FWD is better for low power engines. Underpower RWD, can't oversteer by power and is frustrating. Renault Clio RS with 200 hp, is more effective, is cheaper and provides geat driving performance than GT86 or BRZ. The feeling whith this car is espectacular too, and more effective with a lower price. And if we expend the same money that the Toyota we can buy a Megane RS, this car is very funny to drive, with a very responsive rear and fantastic handling.... but the performance is far away than GT86 with a weak engine. I prefer RWD in very light cars or with 300hp or more.
7 months ago
Pretty obviously if you ask me RWD is the most FUN & REWARDING on the street and or track.

AWD does of course have advantages but overall RWD is just more fun.

FWD is without question not optimal for performance driving. The only real advantage I can think of for FWD is less power loss via the drive train. If all you care about is doing races "from a roll" then sure FWD would be king.
7 months ago

There is no better choice.. it depends by the use of the car and by our driving style..



^The Truth
7 months ago
@Piorun

it's correct.. 4wd has more grip then 2wd so it's better when surfaces have low grip (for example gravel.. snow.. mud..)
on tarmac 4wd could be very fast but 4wd bring more weight and weight is handicap in racing.. that's why on track you'll see more 2wd then 4wd..

but also i've already said.. there is no better choice.. it depends by the use of the car and by our driving style..

P.s.
in group b world rally championship lancia delta 037 (2wd) won 1983 team championship.. beating audi quattro.. in 1982 audi ascona 400 (2wd) won driver championship beating 4wd audi..
and to close the low capabilities of FWD i remember that in 1972 lancia fulvia won world rally championship and todays is still winning competition in rally and track race..
so don't think so much about the better.. sometimes is just enough change our driving style
7 months ago
@AS

sure Audi Rs5 won driver championship and the second RS5 closed this championship in 4th position ( .superstars.it/Superstars-Series/Standings-and-Results/International-SST-Series.aspx ) and audi rs5 lost team championghip (.superstars.it/Superstars-Series/Standings-and-Results/Team.aspx ).

in last 6 season (you could see at en.wikipedia.org/wiki/Superstars_Series#Champions ) 4WD won 3 times and others 3 times by bmw m3 so it's tie.

a last thing...
if you see all the qualify results of last season you have another tie!! 4 pole position to 2wd and other 4 pole position to 4wd.
In conclusion 4wd isn't better and remember, in this competition audi is official team, others not.. in racing world this means more budget to audi to improve their cars.
7 months ago
Now as i think:

AWD is necessary option for Off road cars and SUV's.

It laso may help on track for pure track time for extreme machines, but it dont help as much as we maybe should expect, RWD cars are as fast, or even faster. Good track controll is enough, no need for AWD today.

And its obivious choice for winter or wet weather.


RWD comes to shine when we talking about driving ejoyment. It still ok on typical road for most of the time.
Pages:    1234Next

Quick Vote

Does the new Porsche 911 Turbo has enough power?

Yes
No

6080 fastest lap times for 3571 cars from 264 manufacturers.
© Fastestlaps.com 2006-2013