Aspera's thoughts on AWD/RWD...
 

I've read some strange posts on this forum about AWD and RWD. It seems that quite a few of you have never looked under the hood of a Subaru. The engine overhangs the front axle by quite a lot. That's why it has to be short and lightweight. More still have never driven a Subaru. AWD really does work great in certain situations. Corner exit is one of them. Slalom is the other. There is no way my MR2 could turn a corner and accelerate up a wet on-ramp like my WRX.

My WRX can never corner as hard as my MR2 in perfectly dry, smooth conditions, though.

My first suggestion is to overlay pictures of the FT-86 with pictures of other cars and see if there is room in the nose for Subaru's AWD. While your at it; overlay a Celica, Scion, MR2, AE86, 370Z, all sorts of Imprezas, and the beastly heavy American ponycars.

Next, realize that many of you have made a false choice. If given a choice between RWD and AWD...choose BOTH! If we're lucky Subaru has taken the next evolutionary step with their AWD system. That would be a system somewhat like the R34 Skyline's GT-S/GT-R, where the GT-S is RWD and the GT-R is AWD but can bias almost all of the torque to the rear if need be.

The big difference between Subaru's AWD and the GT-R's AWD is a front driveshaft going to a front diff ahead of the engine. If Subaru did this, the engine could move back about a FOOT! All they need to do is run a front driveshaft through a special oilpan to a centered front diff that's ahead of the engine. (Subaru oil pans are deeeep).

My final thought is about the front frame rails on Subarus. They aren't parallel. So if Subaru was going to offer conventional AWD and RWD (with the engine set back to the firewall) they'd have to make two kinds of subframes or they'd have to make the frame rails parallel all they way back to the new RWD mounting points. I just don't think they're offering AWD in any way at this time. My gut feeling is that the car is RWD only.

Quick question, since I don't know too much about the technicals.
Isn't the technology controlling the GT-R's power shift to the rear wheels when it needs to be controlled by a computer? Wouldn't it require more parts to make the setup as a whole work and theoretically make the car heavier?

Again I'm only asking because I don't know.

Ummm.... No. The two extra differentials, driveshaft and two axles AWD requires comes at quite the weight penalty.

Why is the Lotus Elise/Exige such an awesome car? Not because it has AWD (which it doesn't). It is because it is so light. Like Colin Chapman said, "simplify and add lightness."

yea weight is the enemy

Ummmm...Yes.

Which car is faster? The Lotus Elise/Exige or the Lotus 56? I'll bet my money on the REAL Lotus with the front drive shafts and inboard brakes. (If you don't know what a Lotus 56 is...Google immediately. Look for a bright orange picture.) Ask yourself why Colin himself would change from a RWD car to an AWD car? He was looking for the AWD advantage. Sadly, he was dealing with brand new cutting edge technology and racing bodies that love to outlaw exactly that type of stuff.

Since you brought up the Lotus Elise/Exige...wouldn't it be better to have 100% over the driven wheels at all times than to have about 30%? (Lotus recommends an open rear diff for faster lap times.)

A few shafts, gears, and cases is a small penalty for what AWD gives. The weight isn't very much, and it is down low in the car. How many owners would love to ditch the *heavy* AWD hardware...and then load the car with subwoofer boxes, dynamat, and amps?:confused0068:

EDIT: AWD Lotus 56 was 1349lbs.

http://www.f1technical.net/forum/vie...php?f=3&t=7318

http://img442.imageshack.us/img442/4...63frontend.jpg

AWD is so superior that it was specifically outlawed decades ago because it was considered to be about the same as cheating.

You're comparing street legal cars to a lighter, much more powerful, open wheel race car with a turbine engine.


If you're going to bring up Lotus' racing history with AWD, it's only fair to point out that it's a mixed bag (and while it's true that AWD was banned, so was the turbine).


FWIW, I owned a 2002 WRX and drove other MYs, including the 265 hp 2009 (as well as the 2005 STI, which was a blast).

AWD has many inherent advantages (especially on wet and/or loose surfaces), but I find RWD to be more fun. To each his own.

i'm so agreeing with you

yeah, you really can't compare a turbine indy car to a mass-production sports coupe. i imagine AWD was something of a band-aid to try to get all that torque to the ground on the era's tires (on the lotus 56).

my view on AWD is that it's good for bad weather, and for point-and-shoot type cars. less driver skill is involved. not saying "none," but definitely less skill involved than with other setups. the GTR is a prime example of this. when reviewed by a driving instructor, he described it as "not a driver's car. no skill involved. any mistakes were covered up by the computers."

-Mike

I agree on the awd everyone i know who has it says it makes them a way better driver but i still find it fun to drive but as already said to each his own everyone will love what they love me personally im going ft86 i love boxer engines and rwd both tigether is a dream come true

:) Spoken so true ^_^ When I heard it had a Boxer engine I was SOLD.

I can't wait. I mean a RWD with a CG pushed so far back would be a wet dream LOL.
I was going to swap a CA18Det into my 240sx just because I loved how it set so far back in the engine bay. I can only imagine how a RWD platform engineered around the boxer engine will handle like.

I like Toyota is trying to revitalize their brand but I'm also loving how they are treading into new territory and production sport car design concepts.

honda ...very diappointing...

LOL I was expecting somebody to use the phrase "apples and oranges", but nobody did.

In fact FWD, RWD, and AWD can occasionally be compared to each other in the same car. The Impreza was made in FWD, and AWD, and has been known to be converted to RWD. AWD is the best for that car.

The Celica was made in all three drivetrains (different models). The most sought after is the AWD Celica GT-Four.

The Lancer is a little more spread out, but it has been made in all three variations. The AWD EVO is the top choice.

Skylines (as I mentioned earlier) were offered in RWD and AWD. Which one was faster? That'd be the GT-R.

The list goes on and on. Porsche, Lamborghini, Veyron, most Audis, Focus RS, etc. The fastest cars OR the fastest versions of a particular car are AWD. The limit isn't so much the weight, but the cost and packaging. Otherwise most cars would have AWD. That may change in the future with electric cars.

An AWD car may be designed to "TURN OFF" torque to the front wheels, rendering it RWD. But a RWD car may never "TURN ON" torque to the front wheels.

I've been saying for a long time on NASIOC that Subaru needs to develop a new AWD system with the front diff in front of the engine instead of behind it. My engineering suggestion is a driveshaft through the oil pan.

EDIT: "The IS250 AWD 0-60 7.0 seconds flat (RWD is 7.6)..."
I have no idea where these numbers came from, but...if true, I think that relates to the FT-86 directly.

AWD is like training wheels. :drinking:

the Porsche GT2 is faster than a Turbo, and it's RWD only. i don't know where you're coming up with the IS250 0-60 times, but i'd like to see that. as far as the Skylines, there are other factors other than which wheels are driven that make a GT-R faster than say a GT-S or GT-T.

a few of the cars you mentioned were made AWD for rally purposes. i sincerely doubt anyone will be rallying their FT86. ;)

-Mike

That's because of the weight reduction in removing the AWD system, amongst other things.

AWD = quicker off the line than a similarly weighted RWD car. And it can also be a lot of fun (4 wheel drifts).

okay, and as we're all well aware, weight is the enemy. i don't need this car to be capable in inclement weather or dirt, so i have no need for AWD. give me something lighter.

quicker off the line doesn't (to me, i'm not a drag racing fan) make a car "faster." briefly in a straight line, yes, the car will be moving faster. after that, there's increased drivetrain loss resulting in a lower top speed, and generally more understeer around a corner. to me, that says slower. ;)

i've had my MR2 in a 4 wheel drift, sliding slightly sideways with zero countersteer coming out of a couple corners at Streets of Willow Springs. that was plenty of fun.

sorry guys, no one here will convince me that AWD is better for anything in dry conditions. :)

-Mike

Never said it was better. Just said it could also be fun. I don't see the need for drivetrain snobbery. Whatever gets you through the 1/4 mile, track, drift course, etc. etc. faster than the other guy, then more power to you.

As for the 0-60mph. You can't compare an AWD to a FWD or RWD.. You can launch an AWD car at about 6000rpm and you'll get just a little wheel spin if you have anought power. What that mean? better 0-60mph.

But I can assure you that on a longer race on a ¼ mile for exemple, AWD vs FWD/RWD with same power? the AWD will be behind.

Similar power, perhaps, but what about similar weight (and therefore, similar power-to-weight)?

Why? Don't you think it would be competitive in Group 2 rally? From the way you're talking about RWD being superior, I'd expect you to say that it would not only win Group 2, but blow the doors off of all the AWD cars and take the overall win. LOL

Most guys will admit that AWD has an advantage just off the line in a drag race (given the same tires, torque, and vehicle mass). But they don't go the next step. Every corner is just the starting line to the drag race down the straightaway. A race track is essential a set of drag strips of different length connected by curves. In that case, AWD has the advantage on every slow speed corner exit. As the car approaches the limits of adhesion (due to increased torque, higher speeds, or slippery road conditions)...the AWD advantage claws its way towards medium and high speed corners.

RWD is nice for underpowered cars without racing tires, tho. LOL

UNFAIR ADVANTAGE
 

Drivetrain loss: How much? 0.5hp? 100hp? I remember seeing an Audi study on frictional drivetrain loss and the results are not what you'd expect. There are more gears, but less torque going through those gears on average.

Understeer: Do rear mid-engined cars understeer? What kinds of differentials are you talking about? The Impreza would still understeer if it was RWD because the engine is in the nose and the factory rear swaybars are tiny. You might also be dealing with driver error. I wonder if the drivers were trail braking when they complained that the cars were understeering pigs.

AWD better in dry: Audi raced against RWD cars on pavement back in the 1980's in IMSA and Trans Am. They won so much that they were banned for having an unfair advantage. When Audi Quattros get to race on paved tracks, they usually are forced to take heavy weight penalties or even tire penalties.

"Audi came into the series in '88 and surprised many with their Quattro scoring eight wins out of 13. To top it off, one of their three drivers walked away with the drivers' title. Hurley Haywood took the good while teammates Walter Rohrl and Hans Stuck gave aid for the 4-wheel drive cause. Audi left for IMSA and SCCA made rule changes: two wheel drive only cars and to the shock of many, they placed a ban on non-American manufacturer cars.":eyebulge:

http://www.youtube.com/watch?v=_hskT...layer_embedded

Watch the end of the video and hear it from the drivers' own mouths. AWD has a 'hidden' advantage in dry conditions. During a road race, all cars start on cold tires and a fresh track. The RWD works the rear tires very hard. The AWD works them more evenly. The RWD car is more likely to have the rear tires "go off". The track itself becomes covered in tire rubber and debris (marbles). That's then the AWD cars attack.

not sure where i stand, but...
http://www.youtube.com/watch?v=eH9wvKyZa34

Sexy Beam!
 

...at 14:00 "Four wheel drives are fast at the corner exits."

Hrmmm, now where did I see that?:thumbup:

The contest compares 4 door cars that are nose heavy, high Cg, with AWD traction to 2 door coupes that are only 2WD, but are lower and lighter due to packaging. The best car would be AWD but with better packaging. That's why I'm in favor of a FM AWD car.

i wonder what kind of chassis stiffening is required for an AWD system vs a RWD

http://octanereport.com/uploads/imag..._legacy_03.jpg
Look to the Cusco/Advan Super GT cars for a comparison of RWD and advanced AWD. Early Cusco Imprezas were RWD. Then they got clever and built a new AWD system. This is NOT like a production Subaru AT ALL.

now that makes sense for road use, the engine is WAY down on the bottom. i couldn't possibly see this for rally use tho. how much weight did their system add?

feel free to try and bring me some more convincing arguments, but until then... :happy0180: don't misunderstand, i quite like AWD for certain things, just not in the FT86. i'm enjoying the discussion though, and i hope you are too. :)

-Mike

Of course AWD offers greater performance than rwd, but is performance what we're after? No! We seek driving enjoyment in a road car. RWD requires more skill to drive and teaches you to interact more and understand your car better. Anyone can drive an awd car with about 250 hp. Just slam on the loud pedal when you want to go. RWD takes more skill, reduces weight, and imporves steering feedback. RWD is the choice for a driving enthusiast.

Be sure to tell Evo and STI drivers that they aren't true enthusiasts.

Just because you think it so, does not make it so.

RWD does have its own set of challenges that can improve a driver's skills. But so does AWD driving. Particularly AWD tracking. Don't dismiss it as not for true enthusiasts just because you can't see yourself in one.

And for the record, I want the FT to be RWD, not AWD.

:barf:

I never said Subie/Evo drivers aren't real enthusiasts. I could see myself driving wither one of those great cars, but rwd is a more pure form of driving skill and enjoyment, and yes it does require more skill than awd.

Both got advantage and disadvantage, we can discuss AWD vs RWD vs FWD all week the truth is each car or racing enthusiast have different preferences point is we have have same passion on cars. same goes to drifting, drag racing, time attack, auto cross, rally and road racing.

Oh Axel, you bastard!

Sorry, but that's not going to cut it. You are again confusing your own preferences for "facts."

Are you trying to say that driving a rwd car does not require more skill than driving an awd car?

Damn, we need some new info badly so we can argue about new stuff instead of rehashing the same old arguments. :thumbdown:

+1 million

!!

The Subaru version will be awd with a NA 2.0 motor making about 250 hp
http://www.insideline.com/subaru/toy...ota-ft-86.html

I'm going to say that's bogus