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05 STI vs WS6 TA

9K views 86 replies 19 participants last post by  Wrinklechops 
#1 ·
Finally ran a TA today and got 2 good runs. 1st was a 20 roll and got him by 1 1/2. Second run was a dig and it was about 1 bus. Now I'm not sure what mods the TA had but it nice to flex a little 2.5 muscle. AWD FTW :cool:
 
#54 ·
Audi has one of the better AWD systems on hand. It's important to understand that "Quattro" is not a system but a term coined by Audi. In other words there are several different types of AWD systems deployed by Audi that fall under the "Quattro" banner.

As far as performance driven AWD systems Nissan/Infiniti's Atessa systems seems to be towards the top of several people's list as well as Subaru's. Audi is usually up towards the top as well.
 
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#55 ·
I want to settle an ongoing debate that has plagued some car forums I have been on for years.

Scenario:
- A Rear wheel drive car; 1996 M3 @210whp, against an AWD 60/40 transfer case ratio 2004 STi @220ish AWHP.
- 0-100mph race the STi wins (AWD duh)
- if started at 100-150mph the M3 wins (RWD duh)
- Drag coefficient of the STi is .29, M3 is .32 (advantage STi)
- Final Drive gearing is near the same

Basically those details above aren't really important; What I'm trying to prove to these guys is that an AWD car (with a set distribution of power [60rear/40front]) will encounter increased loss of wheel power as the speeds increase and the engine fights to put down power through all the gears and driveshafts. The RWD will suffer from the same losses, just not as much due to having less gears, less driveshafts, and less half shafts.

What I'm looking for is a theory, or equation that proves this. I know for a fact that a RWD car with less whp will be faster from this 100-150mph run than the AWD car with slightly more whp (how much more till the AWD car is the same speed [in time], I do not know).

For the record; I do my racing on the track (the 1996 M3 being my own). This is just to prove to some of the dyno whp brainwashed guys that think a whp number is the end all be all of real world performance figures.

Please don't include AWD super car examples that transfer upwards of 100% of the power to the rear wheels to take advantage of RWD superiority at speed. I already know this is why those manufactures do this and using this example to some of the simple minded folk on said forums doesn't go far.

Any help sorting these guys out will help a bunch, I already know I'm right, just lack the equations and terminology to prove such.



I'm trying to reason it out. Because you're talking about acceleration, I believe you have to take into consideration not just the horsepower available, but the torque being put on the wheels, and thus the actual force accelerating the car forward. This can also be complicated by different sizes in the front and rear tires when you consider the awd car.

For simplicity, let's consider the ideal case where both cars' engine output is (I will do this in metric for simplicity) 100kW (roughly 133 horsepower) and 100% of the power gets put to the wheels. I'm also going to assume that all driving wheels provide equal acceleration force with no slip. Each cars will also have an assumed mass of 1000kg (around 2200lb weight) I'm also going to admit that I don't know a whole lot other than the basics of how an AWD car works, so I'm going to calculate everything by the observable horsepower at each of the wheels. For simplicity's sake I'm also going to assume each wheel is equal in size and has a 1m diameter (large, but I don't think this will matter as long as it is uniform).

To start the calculations, I'll assume both cars are moving at a constant speed of 50m/s, or around 112 mph. Because v=r*w (v is velocity, r is wheel radius, w is angular speed), the angular speed of the wheels are v/r, or 50/(.5)=100 rad/s . Power, in watts, is equal to P = T*w or (power = torque * angular speed). Assuming equal torque spread between all driven wheels means that there are 2 driving wheels on the RWD and 4 on the AWD. So, the total power output of all the wheels on the RWD will be T*w*2, and for AWD will be T*w*4. However, because the transmission is 100% effecient and both cars produce 100kW power, the power in both cases has to be equal to 100kW. Therefore, each wheel on the idea AWD car only puts out half the torque of the wheels on a RWD car.

For numbers sake, for AWD:

P=T*w*4 or 100,000 W = T * 100 rad/s * 4, or T = 250 N-m.

For RWD:

100,000 W = T * 100 rad/s * 2, or T = 500 N-m.

What actually accelerates the car, however, will be the force, resulting from the torque of the wheels, on the ground. Torque is force*radius, so the force from the wheels will be the torque divided by the wheel radius.

Thus, for AWD:

F=T/r or 250/.5 = 500 N

For RWD:

F=500/.5 = 1000 N


The total force acting on the car will be the sum of each wheel's force on the road. In this simplified case it will simply be the individual wheel force multiplied by the number of wheels. In this example, this total for both cars is 2000 N. Both of these cars in the ideal case have the exact same force acting to accelerate them forward.

Now that I've analyzed the obvious, it is important to emphasize what this all means: There is no inherent advantage for the theoretical AWD or RWD car. Even changing the power distribution between the front and rear serves no real fundamental purpose for better acceleration. You're simply multiplying and dividing by the same fixed constant and arrive to the same answer, that the force being put down ends up being the same when you assume 100% efficiency. Even shifting 100% of the power at high speed to the rear wheels on a supercar doesn't magically change anything about the physics of the situation. I just want to make sure that is clear, you probably already know this.

What DOES make a difference is the aerodynamic drag, the transmission, and the additional components in the AWD vehicle. You simply cannot beat the fact that an AWD vehicle simply has more power loss between the engine and the wheels. You can't beat entropy. A supercar most likely shifts power to the rear wheels, additionally, to provide better handling and to counteract the tendency of the front end of the car to lift while accelerating. By shutting down the drivetrain between the engine and the front wheels, additionally, the supercar will not lose the power it would while in AWD mode.

In addition to loss in the drivetrain, the transmission components for the AWD car are more numerous and thus will also need to be accelerated (I don't know how much this actually matters in the long run, but the engine is having to spin up additional shafts, gears, and other components. Even if the power is provided hydraulically, there will be friction loss in the hydraulic power system). All the rotational mass of these components can have the same effect as trying to run with ankle weights. Sure, you can do it, but you can't move your legs as fast because of the additional momentum.

For acceleration from 0 to an arbitrary speed, the AWD car will most likely win because it has a better traction availability (less traction demand on each wheel means that the power is spread more evenly, so slippage and loss of traction is less likely). As soon as you get out of a limited traction situation, the car with the least transmission loss will win.


I cannot come up with some equation that says, yes, in this situation the AWD or RWD car will win without going through some complicated assumptions and equation gymnastics. Even then, the driver of the car is probably going to mess the nice clean numbers up.

Now, if you were driving the cars with electric power, the losses might make the difference between AWD and RWD insignificant, but with mechanical and hydraulic drivetrain components, I'm pretty sure RWD is going to win the high speed race, every time.
 
#56 · (Edited)
nice copy and paste. could of at least sited where it came from.:thumbdown

and the above statement is wrong. completely. and spent 2 pages a worth a bs 2 state 2 obvious things. awd has more drive train lose. duh. and 2 cars given all things equal but 2wd vs 4wd ends up being exactly the same. duh.

lock it up plz
 
#58 ·
lundholm08, your starting to sound like Charlie Brown's teacher. I bet stock for stock I'd munch your M3 sense I don't think horsepower wise the 04 STI differs much from my 05, this is going off your comparison. But I want to go from a 95 roll instead of 100.That's all I have to reply cause I got half way threw your 2nd to last post and went into a trance of bordum and could not continue.
 
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#60 ·
That wasn't my post, it was from a physics forum regarding the efficiency of AWD vs RWD. But you're right, your '05 STi would munch a '96 or '97 M3. You certainly would not be munching on a comparable year M3, like the 2004 model. Certainly not my friend...
And I'm sorry you mistook your lack of understanding of complicated drag coefficients as a trance of boredom.
 
#59 ·
lundholm08;2431048 it's basic physics; the fastest way around a corner is to be [I said:
pushed[/I] or propelled from behind (like a RWD car). A front wheel drive car pulls you, and an AWD car based on a FWD design does much of the same.
pushed or pulled? hmmmmmm why not both? its much easier to overpower your drive wheels in a FWD or RWD setup, but cars like the STi, EVO, RS4, GTR, all have the ability to dynamically allocate power to the wheels with grip.

subie's AWD is symmetrical, and not based on FWD. example the 04 STi has a front/back torque split of 35%/65%

now as far as launching, AWD simply has more grip, however this becomes less true with more powerful cars. for instance AWD will not help a car launch if its powerful enough to do a wheely, but at that point its a dedicated straight line car and is useless on a curvy track, which moots the point. BTW 300 HP isn't enough to get the front wheels off the ground, so an AWD subie will still launch better than an equally power TA.

oh and someone was asking what the WS6 was, its a suspension package, no power mods.
a TA is like a camaro Z28 and a TA WS6 is like a camaro SS
all are powered by the same LS1
 
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#61 ·
pushed or pulled? hmmmmmm why not both? its much easier to overpower your drive wheels in a FWD or RWD setup, but cars like the STi, EVO, RS4, GTR, all have the ability to dynamically allocate power to the wheels with grip.
Your thinking is somewhat flawed my friend. While all those cars are indeed great cars and have AWD, you are actually LOSING power when you allocate it to all 4 wheels instead of just 2. You have more drivetrain power loss.

In addition to loss in the drivetrain, the transmission components for an AWD car are more numerous and thus will also need to be accelerated (I don't know how much this actually matters in the long run, but the engine is having to spin up additional shafts, gears, and other components. Even if the power is provided hydraulically, there will be friction loss in the hydraulic power system). All the rotational mass of these components can have the same effect as trying to run with ankle weights. Sure, you can do it, but you can't move your legs as fast because of the additional momentum.
 
#67 ·
In all seriousness lundholm08 the videos prove nothing and me claiming I beat one proves nothing. I'm just stating what happened in my encounters and would not come on this site trying throw around false information. If I win great for me and if I loose I admit defeat. There is no shame in that, it's happened before and I know it will happen again.
 
#72 ·
LS3 vette (My bro's car) just havin fun.
S/C 04 cobra ,replaced my doors shortly after as this car was highly modded.
LS1 camaro ,don't know mods but held my own against him.
I'll run anything just for kick's, like I said you win some you loose some. In all honesty the only reason I posted originally was because I was supprised to have outrun the WS6 TA from a roll, I really thought the outcome would be different. That just goes to prove on the street's alot of elements come into play wich affect the outcome.
 
#70 ·
Your copy and paste was a good attempt...but it doesnt prove anything.

Equal cars (335's per se) the AWD will put down slighltly less power due to drivetrain loss if the entire engine, turbo, and ECU is the same between them....no one will or could argue that.


That still doesnt prove your point through.
 
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#73 ·
That's a good point about the equal cars like 335i vs 335xi, the xi having more drivetrain loss. But hell, I live in Colorado so you know I'd take the 335xi. Hence the reason I have my WRX :)

My point has only gotten to this point because someone said that the Trans Am would lose because it's heavier (144lbs more) and RWD. I only said that having RWD was not basis for a complete disqualification of being a powerful and capable car.

So, all I'm saying is a 300hp STi puts what, 250 to wheels? And a 335hp Trans Am probably puts, what, 300hp to the wheels? Maybe a little less? Still more than the STi...
 
#71 ·
agreed your logic is flawed as is the horrible 12th grade physic lesson
 
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#74 ·
For acceleration from 0 to an arbitrary speed, the AWD car will most likely win because it has a better traction availability (less traction demand on each wheel means that the power is spread more evenly, so slippage and loss of traction is less likely). As soon as you get out of a limited traction situation, the car with the least transmission loss will win.
 
#76 ·
bolded for false.
 
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#75 ·
I agree. One time I beat a Dodge Charger Daytona. I thought I was doomed for trying, but the trick of it was that we were in a little twisty canyon kinda, and I could whip around the corners better.
Another story, kinda funny...I was on the highway when all of a sudden I saw two cars come flying up behind me, so I started to gun it. As they got closer I could hear the blow off valve on the STi...but as they flew past me, it was a Mustang Cobra that was well in front of the STi. I only know it was a Cobra because he took the same exit I did, and then he started ****ing with me lol. Must've been one of those "kill ricer" types, I don't know... But man that Mustang could fly... what do they have like 360hp+?
 
#78 ·
But man that Mustang could fly... what do they have like 360hp+?
Depends on the year... the Termi's were rated at 390 at the shaft, but they take light mods very very well and can turn into beasts on the stock block.

The previous few years were NA 4V and made something like 315 to the shaft...

The GT 500 is suppsedly 500 (duh?) to the shaft...

HP is subjective anyway...
 
#80 ·
The logic is as follows:

Premise: Same weight, same HP, equal drivers, rwd vs awd. Which will win?

Real world solution:
Track with less than a half-mile straight--AWD (Subaru, Nissan, Audi...pick your poison).
Track with longer than a half mile straight--RWD may pull past AWD in straight.

End Result: Depends on where the finish line is.

If it is anywhere near a corner exit, AWD.
If it is near the end of a long straight, RWD has a good chance.

A comparison of an E45 M3 against an STi is a good case example. Similar weight, but the M3 does entertain a 30 or so HP advantage, plus a higher top end, so not sure how well this will go over.

If the driver of the AWD vehicle is a defensive driver, AWD will win every time, as once they pull ahead out of a corner (where their higher exit speeds alwasy dominate) he/she will block the RWD.

Multiply this scenario by a factor of xxx if the race begins from a standing stop.

FYI...I've raced E46 M3s a few times, with more than 4 events being driven by an instructor who owned the M3. Times were nearly equal, but in heads up competition, I took him everytime as I was able to out accelerate him out of the first corner, and he never had the oomph to get past me after that. Rolling start did nothing to change this (from around 10 mph).

Now...add in the Mother Nature factor...and multiply the advantage of AWD by another xxxx.

ps...I never did see any refutation of the banning of AWD from various high level tarmac motorsports. This is fact. I wonder why???

Seriously, it's no big deal. I like RWD for aspects that AWD can't provide without major speed and a huge error multiplication factor, such as major tail hanging and the ability to finese the car with the throttle (better at least).

If I was asked which would I prefer in a race, it would be AWD no question. If I knew of no other factors about the race, and that was my only choice (AWD or RWD), AWD would be the answer.
 
G
#83 ·
You're right about many things. Just thought I'd chime in about the F1 ban thing...

Porsche tried racing the 959 in Le Mans, aka the 961. It was never competitive and so was abandoned.

F1 tried AWD like back in the 60's I believe. It was the Ferguson P99, and it crashed on the 2nd lap. They tried again and again, but it sucked.

Take this and extend to the 70s. Notably, Jackie Stewart tried but could not find it in his heart to stick with his AWD car and chose to drive his RWD car instead. Shortly after realizing that Stewart was owning them, Chapman (Lotus) abandoned their AWD car.

Also the ban had nothing to do with AWD, but with the 6 wheel cars.

March and Williams each built cars with an identical 6-wheeled layout, but neither car was ever raced in F1. In both cases it was found that the cars were about the same as normal cars in terms of speed since the extra traction was negated by the added rolling resistance, although the March 2-4-0 was later to have some success in hillclimbs.

AWD cars got owned in F1 over and over (until Nissan and Audi showed up).

From Wikipedia:

Bugatti created a total of three four-wheel drive racers, the Type 53, in 1932, but the cars were notorious for having poor handling.

Ferguson Research Ltd. built the front-engine P99 Formula One car that actually won a non-WC race with Stirling Moss in 1961. In 1969, Team Lotus raced cars in F1, and the Indy 500, that had both turbine engines and 4WD, as well as the 4WD-Lotus 63 that had the standard Cosworth engine. Matra also raced a similar MS84, and McLaren entered their M9A in the British Grand Prix, while engine manufacturers Cosworth produced their own version which was tested but never raced. All these F1 cars were considered inferior to their RWD counterparts, as the advent of aerodynamic downforce meant that adequate traction could be obtained in a lighter and more mechanically efficient manner, and the idea was discontinued, even though Lotus tried repeatedly.
But, obviously technology improved and AWD got better and Wiki had this to say about the F1 ban that Audi caused:

Audi's dominance in the Trans-Am Series in 1988 was equally controversial as it led to a weight penalty mid season and to a rule revision banning all-AWD cars, its dominance in supertouring eventually led to a FIA ban on AWD system in 1998.
All that said, I guess I have learned a lot about AWD and RWD through our discussion, and I thank you all for your input. I guess I've come to this conclusion sort of:

AWD can make a mediocre driver good, while RWD, if utilized properly by race-drivers can be powerful and have a slight edge.

So, I'll take AWD cuz it gives me more confidence and control, and I live in CO where nasty weather happens, and I need my AWD for a daily driver. If I was rich, I'd probably have both. AWD for daily use, and a good RWD power car for fun at the track, yea?
 
#81 ·
in real world case i would see the short 6spd gearing of a sti hurting it's self over a e46 m3 which is geared better for plus 100 speeds. i do agree there. but ever saying the awd drive train hinders it's performance more as the speeds get higher is silly. parasitic drive train it lose is the same any speed. the only thing changing is gear ratios and increased aerodynamic drag. and a drop if hp is the engine/turbo setup is getting hot, causing heat soak.
 
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#85 ·
You're right I'm sure it would. But I don't necessarily credit all that to AWD. Ideally I'd actually like to become proficient with RWD, and then AWD. That way, if AWD is better then I will appreciate it much more. To me, it's like...your first car when you're 16 being an STi or something, where do you go from there? If you set the standard so high, sometimes it's hard to exceed it. Hell, I'd have loved an STi for my first car, but I had to go through about 5 cars before I could afford my WRX on my own. I appreciate it much more now.
 
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#87 ·
You obviously didn't see what I said about how "technology has advanced" and how Audi and Nissan kicked major ass with their AWD?

I'm getting so sick of this. I'm not against AWD, I think it's great. That's why I have a WRX for crying out loud. But I think a skilled driver can do very well in a RWD car, and I think a lot of us amateur-race drivers (no offense to any hardcore guys in here) think we're better drivers in AWD cars...

I was talking about the 60's and 70's cars with AWD because I was giving a brief history of what led up to the ban on AWD in the F1 series (which a moderator asked me about). You said this argument is about going around corners... need I again refer to the top 4 spots on the Top Gear track (just as an example) that are held by RWD cars? And until recently (Nissan GT-R, Bugatti Veyron, Lambo) the top of the list was dominated by RWD vehicles.

The large font was to illustrate a point. I'm sorry you still don't understand. I think we can all agree both AWD and RWD have their advantages.
 
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