[CanAutM3]

Originally Posted by Vic55

Dont discount what you dont know (where I have lived) and I wont disrespect your knowledge about where you currently are at.

So I ask this as you seem to be an expert on the value of RWD vs AWD in all conditions and with high performance cars. I do know a thing or two about a thing or two having had 13 M's with a blend of both RWD and AWD along with countless other cars that have over 500hp in the RWD and AWD variations. I also have had both G80's in the RWD and X drive (still have the X):

What about the tq transfer from the rear axle to the front- does that not help via grip and handling entering and exiting turns? Also where do you come up with this higher rated hp comment(s). Im just trying to understand your comments in a more educated manner.

Again asking for your education here and not trying to create a non SME debate. And dont forget I mentioned that I tuned my car too which is also a factor.

jmg
CanAutM3

Even as a long term advocate of RWD for performance application, I don't believe it is a black or white answer anymore.

In general terms, it is true, AWD only helps with acceleration and does not help cornering and braking.

Traditionally, RWD cars have been faster than AWD around a dry track, where older AWD system imposed a rather important weight penalty and the torque distribution induced important understeer. Further, the power of these "older" cars was not sufficient to significantly overwhelm the grip of the rear tires.

However, with modern cars, with ever increasing horsepower levels and smart AWD systems that have become much lighter and can infinitely and dynamically vary the front-to-rear torque split, the disadvantages of AWD have reduced while the advantages have increased. The high power of modern cars can easily overwhelm the grip of the rear tires even in the dry. On a dry track with super grippy track tires, RWD might still have an advantage, but in most other scenarios, modern AWD have the edge. Further, it takes some serious skill to take full advantage of RWD performance, not something the vast majority of drivers can leverage on day-to-day basis. AWD will bring much more confidence to the majority of drivers which will make them quicker.

After 20 years of owning RWD cars for the track, I changed to an AWD last year and was a bit wary. I have to say I am quite impressed with how it handles. My wife has always owned AWD cars, and when put on track they would just understeer under power, there was no way around this. But with my current car, it essentially behaves as a RWD car unless the systems feels front traction is needed. So I can still get beautiful on power rotation when coming out of corners and can even get it to drift nicely if I press a little more, which was just impossible with older gen AWD systems. The AWD does not help under braking, nor turning-in nor at the apex, but if there is insufficient grip exiting, it sure helps powering out of of the corner. I recently had the opportunity to drive a 991 GT2RS (RWD only) around my local track and was pleasantly surprised to how similarly it drove to my AWD turbo. For sure, it was much more direct and "pure", but it was very similar to how it responded to driving inputs. Which means the AWD on the turbo is very transparent, you don't really realize it is there.

My 911 is my all season daily driver, so even if I plowed winters in RWD cars for the last 20 years, it sure is fun to have the traction advantage of AWD in those conditions.

[Sp2pilot]

Reason to get AWD = traction
Reason to get AWD in CA = smog(at least it used to be)

I haven't lived in Cali in a minute, but they used to not have AWD rollers at smog stations, so a sniffer would have to do in addition to a visual inspection. I dunno if that's the case still.

[TT_mand]

Originally Posted by Sp2pilot

Reason to get AWD = traction
Reason to get AWD in CA = smog(at least it used to be)

I haven't lived in Cali in a minute, but they used to not have AWD rollers at smog stations, so a sniffer would have to do in addition to a visual inspection. I dunno if that's the case still.

Now on newer cars they don't even put them on the roller anymore in Cali. Just a visual and plug into the obd port to make sure everything's good

[RockinPA]

The answer is simple.

X-drive gives you both awd AND rwd. The weight increase is negligible. I don't understand why anyone wouldn't check the box for x-drive…

I love warming up the car in 4WD sport and then flipping the car into rwd at the touch of a button. Winning.

Shameless photo attached because every post should include a photo. 😅

[Fugly M3]

I drove one in the snow at BMW Ice Driving in Sweden back in February...that was enough for me. I take my car up to Mammoth and traditionally could only take the BMW when there wasn't much, if any, snow on the ground. Now, with high perf. all seasons, I'll be able to take it up there in up to moderate snow and only have to take the big Land Rover for the heavy events. That basically flips the BMW/Land Rover trip ratio on its head. As comfortable as the big Rover is, it's no BMW on the open road.

[PatientM]

Originally Posted by RockinPA

The answer is simple.

X-drive gives you both awd AND rwd. The weight increase is negligible. I don't understand why anyone wouldn't check the box for x-drive…

I love warming up the car in 4WD sport and then flipping the car into rwd at the touch of a button. Winning.

Shameless photo attached because every post should include a photo. 😅

MY GOD that car is gorgeous... my 4 yr old loves that color... how much is that color option if you don't mind me asking?

[RockinPA]

Originally Posted by PatientM

MY GOD that car is gorgeous... my 4 yr old loves that color... how much is that color option if you don't mind me asking?

Thank you dude! You have one smart little kid! Haha.
$4500. Mexico blue. It isn't made under that name any more - apparently the color is unchanged but lives under a different name now. This is (I believe) the last one made. New name for supposedly the same color is Daytona Beach Blue. No clue why they changed it, though. Maybe for the same reasons other similarly innocent things have been banned /changed etc for fear of offending someone. Ridiculous. I don't want to hijack this thread but here are a few more….different lighting and unedited.

[Limegrntaln]

BMW is telling you, straight to your face that xDrive has nothing to do with snow, or inclement weather, when they fit every G8X from the factory with Summer Only tires. Tyre Reviews explains it the best. The BMW Star PS4S G8X specific OE tire, gives up wet handling, over the off the shelf, tire store PS4S.

[KANdaddy]

Originally Posted by jmg

Its true that AWD does not improve braking or increase grip in the dry or wet when there is no grip to begin with (ie al tires are hydroplaning)

It does, however offer more "grip" in the sense that the system will send power to the wheel with grip. So in a RWD LSD equipped vehicle compared to a AWD vehicle, the RWD has 2 available options for grip, while the AWD has 4. For instance, if both rear wheels on a RWD have lost grip, the RWD car is out of options for power delivery. An AWD car that has no traction in the rear wheels, still has 2 front wheels it can deliver power to.

So wet, dry, or icy, grip is dynamic and changing, based on the road conditions, and weight distribution of the car over all 4 wheels. In a corner, for example, the weight goes to the front of the car during braking, as the car apexes and the brakes are gradually released, the throttle is applied, the weight starts to transfer to the rear. Too much power, and the rear wheels brake traction and you have a potential oversteer situation. Too little power and the exit speed isn't as fast as it could be.

When tracking a RWD vehicle, I try to get the car pointing down the road as much as possible to accelerate as fast as possible without losing control of the vehicle. When I feel the rears losing grip and start to step out, I dial in some counter-steer, and feather the throttle to reel in the rear. This costs fractions of a second, which is what we are fighting for on the track.

With AWD, we can get on the throttle a little bit sooner because the system is making dozens if not hundreds of decisions a second to send power to the wheels with the most grip, so when the rear tires start to loose grip from too much power, some of that power is sent to the front to both tame the car, and still maintain forward acceleration. This saves fractions of a second, which, again, is what we are fighting for on the track. Also, it is confidence inspiring, which also could lead to faster times.

So you gain traction from the apex to corner-exit, but not necessarily corner entry nor pre-apex.

This should be the standard answer to those "AWD" haters that think its only good for bad weather driving.

[Vic55]

Originally Posted by Limegrntaln

BMW is telling you, straight to your face that xDrive has nothing to do with snow, or inclement weather, when they fit every G8X from the factory with Summer Only tires. Tyre Reviews explains it the best. The BMW Star PS4S G8X specific OE tire, gives up wet handling, over the off the shelf, tire store PS4S.

Originally Posted by KANdaddy

This should be the standard answer to those "AWD" haters that think its only good for bad weather driving.

Along with the factual and expert experience of our track posters.

CanAutM3 jmg

I feel the street and real world takes rather kindly to the AWD system with a negligible cost in weight/steering. I guess that was what I was trying to elude to all along but sadly my articulation skills under the influence left something to be desired.

I know that in almost any situation, the grip of the X drive has my car under control with the excess hp these cars have. And then once one tunes it, its even moreso a must especially from a dig.

[Hit_Apex]

Second page already and hasn't morphed into a Porsche GT3 thread. Good job crew!

[amuk]

Originally Posted by PatientM

Morning! To all my Cali brothers and sisters, why get an M3 AWD in California? Was talking to a buddy who said he just wanted the fastest M3... aside from that I don't see any upside? I put in for 6mt ... but it had me thinking... why else?

Honestly, imo the only reason to not get the AWD is if you want the manual.

If electing for the Comp models, regardless of where you live and the weather conditions, to me it doesn't make sense to not get the AWD unless:
1) You really need to save a couple grand even though you're already buying a vehicle well over 70k
Or
2) You need the car now and a dealer/seller has a RWD available. You can't wait for an AWD

[Limegrntaln]

Originally Posted by amuk

Honestly, imo the only reason to not get the AWD is if you want the manual.

If electing for the Comp models, regardless of where you live and the weather conditions, to me it doesn't make sense to not get the AWD unless:
1) You really need to save a couple grand even though you're already buying a vehicle well over 70k
Or
2) You need the car now and a dealer/seller has a RWD available. You can't wait for an AWD

If that's the case, it's worth it to hold out for an xDrive just for the resale value alone.

[BLKSAPPE92]

Originally Posted by Vic55

Dont discount what you dont know (where I have lived) and I wont disrespect your knowledge about where you currently are at.

So I ask this as you seem to be an expert on the value of RWD vs AWD in all conditions and with high performance cars. I do know a thing or two about a thing or two having had 13 M's with a blend of both RWD and AWD along with countless other cars that have over 500hp in the RWD and AWD variations. I also have had both G80's in the RWD and X drive (still have the X):

What about the tq transfer from the rear axle to the front- does that not help via grip and handling entering and exiting turns? Also where do you come up with this higher rated hp comment(s). Im just trying to understand your comments in a more educated manner.

Again asking for your education here and not trying to create a non SME debate. And dont forget I mentioned that I tuned my car too which is also a factor.

jmg
CanAutM3

My experience if you're trying to accelerate while in a corner and you put more strain/power to your front turning tires that are also driving now you can get understeer and the car will stops turning and just start sliding/plowing forward sooner than tires that just steer but you may not have ever experienced that

[BLKSAPPE92]

Originally Posted by MunkyTool

I don't think you understand how 4WD works beyond accelerating

I absolutely understand the system and 4wd isn't awd but anyway every car I owned growing up was either awd or 4wd. I stopped choosing to own them after my Audi. I don't have a use for them anymore and id never buy a second hand awd car because most people don't even understand the maintenance and care behind them

[BLKSAPPE92]

Originally Posted by jmg

Its true that AWD does not improve braking or increase grip in the dry or wet when there is no grip to begin with (ie al tires are hydroplaning)

It does, however offer more "grip" in the sense that the system will send power to the wheel with grip. So in a RWD LSD equipped vehicle compared to a AWD vehicle, the RWD has 2 available options for grip, while the AWD has 4. For instance, if both rear wheels on a RWD have lost grip, the RWD car is out of options for power delivery. An AWD car that has no traction in the rear wheels, still has 2 front wheels it can deliver power to.

So wet, dry, or icy, grip is dynamic and changing, based on the road conditions, and weight distribution of the car over all 4 wheels. In a corner, for example, the weight goes to the front of the car during braking, as the car apexes and the brakes are gradually released, the throttle is applied, the weight starts to transfer to the rear. Too much power, and the rear wheels brake traction and you have a potential oversteer situation. Too little power and the exit speed isn't as fast as it could be.

When tracking a RWD vehicle, I try to get the car pointing down the road as much as possible to accelerate as fast as possible without losing control of the vehicle. When I feel the rears losing grip and start to step out, I dial in some counter-steer, and feather the throttle to reel in the rear. This costs fractions of a second, which is what we are fighting for on the track.

With AWD, we can get on the throttle a little bit sooner because the system is making dozens if not hundreds of decisions a second to send power to the wheels with the most grip, so when the rear tires start to loose grip from too much power, some of that power is sent to the front to both tame the car, and still maintain forward acceleration. This saves fractions of a second, which, again, is what we are fighting for on the track. Also, it is confidence inspiring, which also could lead to faster times.

So you gain traction from the apex to corner-exit, but not necessarily corner entry nor pre-apex.

I never said awd doesn't accelerate quicker because it does. The message I replied to was about someone saying it's safer and I said it doesn't brake faster or corner any better and honestly a car hydroplaning it don't matter how many wheels drive the car because they aren't touchy the ground.

[jmg]

Originally Posted by BLKSAPPE92

My experience if you're trying to accelerate while in a corner and you put more strain/power to your front turning tires that are also driving now you can get understeer and the car will stops turning and just start sliding/plowing forward sooner than tires that just steer but you may not have ever experienced that

That is true on front biased AWD systems. Here is why:
Your tires can only do 1 thing 100%. So if you brake, and your tires are using 100% of it's grip to stop the car, it cannot change directions. That's why, if you don't have ABS, and you lock up the wheels, your steering inputs will not change the car's directions.

So, in a front biased AWD system, or most FWD cars, if you are using 100% of the tire's grip to turn the car, then apply throttle too soon, your tires will have to take some of that grip that it's using to turn, to use it to accelerate. That leaves less grip to turn and coupled with weight distribution to start shifting to the rear, leads to understeer.

However, in a rear biased AWD system, like the one in the G8X, the throttle is applied to the rear wheels first during cornering, since the weight is on the front and the turning forces are working the front tires and the rear tires have more grip left over. Mind you, this is an oversimplification, in reality grip is dynamic, and so is where the system is sending the power. But, in the simplest terms, power goes to the rear first/most because there is more grip available. When that happens, the weight distribution starts to shift to the rear, giving the rear even more grip.

Here's where the dance of AWD and all those LSDs happens that I described in my other post. Car starts to oversteer, then the front tires get some power to "pull" it out, then it starts to understeer, and it reduces power to the fronts and lets the front tires use more of it's grip capabilities to change directions instead of both change directions and accelerate. This dance stabilizes the car on corner exit and results in faster exist speeds due to utilizing all 4 tires for optimal grip, and the ability to apply throttle sooner than in a RWD vehicle. More time to accelerate, results in a faster exit speed.

Originally Posted by BLKSAPPE92

I never said awd doesn't accelerate quicker because it does. The message I replied to was about someone saying it's safer and I said it doesn't brake faster or corner any better and honestly a car hydroplaning it don't matter how many wheels drive the car because they aren't touchy the ground.

You said it doesn't "corner any better", but I consider judging how a car corners to include corner exit speed, which AWD certainly helps. This is all backed up by lap times.

[CanAutM3]

Originally Posted by BLKSAPPE92

My experience if you're trying to accelerate while in a corner and you put more strain/power to your front turning tires that are also driving now you can get understeer and the car will stops turning and just start sliding/plowing forward sooner than tires that just steer but you may not have ever experienced that

As I posted previously, this is not the case with all AWD systems. All prior AWD cars I had driven on track exhibited the behaviour you describe, adding power just resulted in understeer. However, systems that can infinitely control the amount of torque that is sent to the front axle and that are well tuned can work around this. Such systems are found on the G8X and on my 992. The only Audi that has such an AWD system is the R8.

You are correct when you state than sending power to the front axle reduces the ability of the front axle to change the direction of the car. However the same applies to when power is sent to the rear axle. Getting power-on rotation at corner exit is key to fast laps. Applying power to the rear axle when cornering reduces the lateral grip and increases the slip angle; which in turn induces more rotation. There is however a limit to how much power can be applied, at some point too much power yields over rotation. That is where a good AWD system can help. Once it senses too much rotation, it sends some torque to the front axle to balance the front and rear slip angles, so you still get the right amount of rotation but with the ability to put more power down.

[BLKSAPPE92]

Originally Posted by jmg

That is true on front biased AWD systems. Here is why:
Your tires can only do 1 thing 100%. So if you brake, and your tires are using 100% of it's grip to stop the car, it cannot change directions. That's why, if you don't have ABS, and you lock up the wheels, your steering inputs will not change the car's directions.

So, in a front biased AWD system, or most FWD cars, if you are using 100% of the tire's grip to turn the car, then apply throttle too soon, your tires will have to take some of that grip that it's using to turn, to use it to accelerate. That leaves less grip to turn and coupled with weight distribution to start shifting to the rear, leads to understeer.

However, in a rear biased AWD system, like the one in the G8X, the throttle is applied to the rear wheels first during cornering, since the weight is on the front and the turning forces are working the front tires and the rear tires have more grip left over. Mind you, this is an oversimplification, in reality grip is dynamic, and so is where the system is sending the power. But, in the simplest terms, power goes to the rear first/most because there is more grip available. When that happens, the weight distribution starts to shift to the rear, giving the rear even more grip.

Here's where the dance of AWD and all those LSDs happens that I described in my other post. Car starts to oversteer, then the front tires get some power to "pull" it out, then it starts to understeer, and it reduces power to the fronts and lets the front tires use more of it's grip capabilities to change directions instead of both change directions and accelerate. This dance stabilizes the car on corner exit and results in faster exist speeds due to utilizing all 4 tires for optimal grip, and the ability to apply throttle sooner than in a RWD vehicle. More time to accelerate, results in a faster exit speed.

You said it doesn't "corner any better", but I consider judging how a car corners to include corner exit speed, which AWD certainly helps. This is all backed up by lap times.

I understand how awd and fwd works and how much grip a front steer tire can handle between steering and driving. As I said already I know an awd car can accelerate faster after exiting a corner then a rwd car. Someone on here said safety for family is why they bought an xdrive and all I said was braking and cornering have nothing to do with awd safety and neither does hydroplaning.

Also a Porsche gt2 rs has a better track time than a 911 turbo s but the 911 turbo s has a better 0-60

Same with a gt3 rs and a 911 turbo the gt3 Beats the 911 on the track but not in a straight line

[BLKSAPPE92]

Originally Posted by CanAutM3

As I posted previously, this is not the case with all AWD systems. All prior AWD cars I had driven on track exhibited the behaviour you describe, adding power just resulted in understeer. However, systems that can infinitely control the amount of torque that is sent to the front axle and that are well tuned can work around this. Such systems are found on the G8X and on my 992. The only Audi that has such an AWD system is the R8.

You are correct when you state than sending power to the front axle reduces the ability of the front axle to change the direction of the car. However the same applies to when power is sent to the rear axle. Getting power-on rotation at corner exit is key to fast laps. Applying power to the rear axle when cornering reduces the lateral grip and increases the slip angle; which in turn induces more rotation. There is however a limit to how much power can be applied, at some point too much power yields over rotation. That is where a good AWD system can help. Once it senses too much rotation, it sends some torque to the front axle to balance the front and rear slip angles, so you still get the right amount of rotation but with the ability to put more power down.

I just commented to someone on Porsche the gt3 rs out performs a 911 turbo s on the track in every aspect same with the gt2 rs and the 911 turbo s but the 911 turbo straight line acceleration beats both that's awd against rwd

[jmg]

Originally Posted by BLKSAPPE92

I understand how awd and fwd works and how much grip a front steer tire can handle between steering and driving. As I said already I know an awd car can accelerate faster after exiting a corner then a rwd car.

You specifically said:

Originally Posted by BLKSAPPE92

My experience if you're trying to accelerate while in a corner and you put more strain/power to your front turning tires that are also driving now you can get understeer and the car will stops turning and just start sliding/plowing forward sooner than tires that just steer but you may not have ever experienced that

I merely pointed out that what you noticed was from front biased AWD systems. A rear biased AWD system acts very differently and does not understeer in the same way that a FWD or front biased AWD system does.

Originally Posted by BLKSAPPE92

Someone on here said safety for family is why they bought an xdrive and all I said was braking and cornering have nothing to do with awd safety and neither does hydroplaning.

You can hydroplane or lose grip in any combination of wheels out of 4:
1/4
2/4
3/4 or
4/4 wheels can lose grip.

In an AWD vehicle, you can potentially lose grip in 3 wheels and maintain mobility. On a RWD you can only manage to lose grip in 2 before you lose mobility. So the AWD vehicle is potentially safer than a RWD vehicle in those particular cases.

Originally Posted by BLKSAPPE92

Also a Porsche gt2 rs has a better track time than a 911 turbo s but the 911 turbo s has a better 0-60

Same with a gt3 rs and a 911 turbo the gt3 Beats the 911 on the track but not in a straight line

I'm not sure what you are implying here. Is it that that a AWD Turbo is slower on the track than a GT3RS and GT2 because its AWD? That's simply not the case. The Turbo is close to 500 lbs heavier than both those other cars for one. That's not the only difference.

[CanAutM3]

Originally Posted by jmg

That is true on front biased AWD systems. Here is why:
Your tires can only do 1 thing 100%. So if you brake, and your tires are using 100% of it's grip to stop the car, it cannot change directions. That's why, if you don't have ABS, and you lock up the wheels, your steering inputs will not change the car's directions.

So, in a front biased AWD system, or most FWD cars, if you are using 100% of the tire's grip to turn the car, then apply throttle too soon, your tires will have to take some of that grip that it's using to turn, to use it to accelerate. That leaves less grip to turn and coupled with weight distribution to start shifting to the rear, leads to understeer.

Sorry to nitpick, but that is not quite correct. Even rear biased AWD will induce on-power understeer. My wife's previous S4 had a fixed 40-60 front-rear torque split and still plowed under power. To be able to alleviate that trait, an AWD system needs to be able to completely decouple the front axle, which the G8X and 992 can do.