[Jamesons Viggen]

Originally Posted by verbs

It's not an it could be, it wont. There's no way a 335i with just a PPK is going to have traction issues it 100mph from a roll. Not even 80 mph. Not even 60 mph. I say this from not just a common sense standpoint, but as someone who has owned more heavily tuned 335i cars in the past.



It may or may not take a silly amount of power to have traction issues from a roll in RWD.....but a huge component of that is the speed you start at. The 335i is also at a traction disadvantage due to it's 1-wheel drive action in the back, and even more so if it's equipped with skinny 225mm all-season tires on the rear which some people have. Other considerations include road conditions (flat/dry vs. bumpy/wet) and tire conditions (bald?)


We are saying the same thing, only neither of us have specifics, so why go on and on when it's all conjecture.

0-120 is a different race than a 60 mph roll. If one car is Xdrive, the other RWD, Xdrive has an advantage in 0-120, although the advantage/pendulum swings-the point where it reverses is 100% GUESS.

Now a 60mph roll, Xdrive simply has no advantage as I said, these cars do not have the power to overcome traction at such a speed. So Xdrive is left with a weight penalty and slightly higher drivetrain loss and no traction advantage left.

Your car is an apples to oranges comparison. Your E36 Z3M weighs about what 500lbs less than a 335i? Weight helps prevent wheel spin...and with "roughly" a 50/50 weight distribution, the 335i has about 250lbs more sitting over the back wheels than your Z3M. Obviously there are a number of other car specific considerations, including tires, suspension, gearing, power curve/delivery, limited slip differential, etc.

Originally Posted by verbs

Keep in mind that tunes on 335i cars tend to give substantial power gains in the low-mid range compared to peak power levels, which can lead to better gains than one would expect (traction permitting).

Look at the 335is cars and their overboost feature in the low/mid range.

Aftermarket tuners (JB4, Dinan, etc) are the same way.


Looking at peak power gains with the PPK doesn't paint accurate enough of a picture when discussing gains in 0-60 or 1/4 mile times.

We are saying the same thing, only neither of us have specifics, so why go on and on when it's all conjecture.

0-120 is a different race than a 60 mph roll. If one car is Xdrive, the other RWD, Xdrive has an advantage in 0-120, although the advantage/pendulum swings-the point where it reverses is 100% GUESS.

Now a 60mph roll, Xdrive simply has no advantage as I said, these cars do not have the power to overcome traction at such a speed. So Xdrive is left with a weight penalty and slightly higher drivetrain loss and no traction advantage left.

My car is not so much a comparison, but an example of when RWD traction is an issue and stock 275whp or as your brought up, tuned 350whp cars are not going to contend with traction issues at 60mph rolls. My car for example will require 700 or so hp to find traction issues at such a speed. If I had AWD and 700hp(say like a tuned GTR, but without the damn weight of a GTR lol), being able to plant 700hp from a roll would be a neat trick.

Pretty much at a certain power level, or more accurately as you brought up-power to weight ratio, traction becomes an issue even from a roll.

You could have a 750whp CTS-V that weights 4000lbs and have similar traction issues to a 2000lb Elise with half the power(other factors such as tires etc not withstanding).

[verbs]

Originally Posted by Jamesons Viggen

We are saying the same thing, only neither of us have specifics, so why go on and on when it's all conjecture.

How is someone like myself who has owned more heavily tuned 335i cars in the past and not been close to experiencing spin at the speeds you mentioned "conjecture?"

It also doesn't take more than common sense from those with experience driving high hp cars to know that a PPK tuned f30 335i isn't going to spin the wheels at a 100, 80, or even 60 mph roll.

My F30 335i will be tuned this week and I'll be able to verify the obvious.

[Jamesons Viggen]

Originally Posted by verbs

How is someone like myself who has owned more heavily tuned 335i cars in the past and not been close to experiencing spin at the speeds you mentioned "conjecture?"

It also doesn't take more than common sense from those with experience driving high hp cars to know that a PPK tuned f30 335i isn't going to spin the wheels at a 100, 80, or even 60 mph roll.

My F30 335i will be tuned this week and I'll be able to verify the obvious.

Because, until you have an F30 Xdrive next to a F30 RWD, knowing the EXACT speed in which one will pass the other is conjecture. You are saying the same thing I am that they do not have enough power to cause wheel spin at rolling speeds. The conjecture part was about at what EXACT speed does one pass the other. Neither of us know-that is all I am saying. It could be 50-it could be 80-I dunno until I see it happen.

[verbs]

Originally Posted by Jamesons Viggen

Because, until you have an F30 Xdrive next to a F30 RWD, knowing the EXACT speed in which one will pass the other is conjecture. You are saying the same thing I am that they do not have enough power to cause wheel spin at rolling speeds. The conjecture part was about at what EXACT speed does one pass the other. Neither of us know-that is all I am saying. It could be 50-it could be 80-I dunno until I see it happen.

It's not going to be 80. At whatever speed the F30 335i RWD has full traction from a roll is the speed at which it'll slowly pull away from the F30 335i AWD.

[Jamesons Viggen]

Originally Posted by verbs

It's not going to be 80. At whatever speed the F30 335i RWD has full traction from a roll is the speed at which it'll slowly pull away from the F30 335i AWD.

OK.

63.215mph.

That is when it will happen.

[KevRyd]

And it is an imperical fact that the RWD will beat the AWD? I'm not so sure

Kevin

[Jamesons Viggen]

Originally Posted by KevRyd

And it is an imperical fact that the RWD will beat the AWD? I'm not so sure

Kevin

At a certain speed yes. It's the math physics of it, I know you hate when I bring up numbers.

It's at what speed that is the question.

You are talking about two otherwise identical cars.

You are adding weight and you are slightly diminishing the power that reaches the ground due to higher losses of the Xdrive drivetrain. These are not opinions, I promise.

BUT, those negatives are used as a positive thanks to the gains in traction utilized in slipper situations or in the dry at launch....but it's launch up to a certain speed. At a certain speed, that launch advantage is over, there is no traction to take advantage as you are already moving. Instead, the negtives are still with you, the 150-200lbs, the drivetrain loss.

When already moving, two identical cars, adding weight and making less power to the wheels are never and have never been positive attributes. Power to weight ratio is one of the hallmarks that you just cannot get away from.

Two identical cars, but one being heavier, is NEVER-EVER the faster car.

Now if you throw traction into it from different drive wheels, then you can have the heavier car be faster due to traction. But only for so long. That is the key.

[Kayani_1]

I have because that is some thing that is important to me. Besides a slight room in rear seats the F30 335i has nothing to offer that is superior to the E9x 335i.

I would take a E92 335is over any F30 335i M sports on track and off track. The E92 335is offers greater overall performance and better driving dynamics than a F30 335i M sport. So if I was in a market I would buy that over the F30 335i M-sport and its lack of performance upgrade and inferior steering feel/feedback.

So enjoy your F30 335i with inflated sticker price and no upgrade in performance as well as poor steering feel and feedback.

I have enjoyed my E92 Cobb tuned 335i for over 4 years and will continue to do so. The current F30 335i offers no upgrade for me to desire it.

Originally Posted by KevRyd

Good for you I believe you have beat the shit out of the steering propaganda!

You can have your e90, I hope you love it when you roll the odo because a love like that should be forever! You like truck-like steering, I dont. you think the x90 is better good for you!

Hace a nice day!

[Jamesons Viggen]

Originally Posted by Kayani_1

I have because that is some thing that is important to me. Besides a slight room in rear seats the F30 335i has nothing to offer that is superior to the E9x 335i.

I would take a E92 335is over any F30 335i M sports on track and off track. The E92 335is offers greater overall performance and better driving dynamics than a F30 335i M sport. So if I was in a market I would buy that over the F30 335i M-sport and its lack of performance upgrade and inferior steering feel/feedback.

So enjoy your F30 335i with inflated sticker price and no upgrade in performance as well as poor steering feel and feedback.

I have enjoyed my E92 Cobb tuned 335i for over 4 years and will continue to do so. The current F30 335i offers no upgrade for me to desire it.

I do not understand your hangup on comparing the 335is to the 335 MSport when they are not equivalent models.

Car makers bring out higher performing variants as a model line ramps up, to keep it fresh.

The E92is(there is no such thing as an E90is sedan) came out years after the E92. It was the highest spec, highest performing, most expensive 3 series without stepping up to the M3.

Now, in the E46, again, years after it was introduced, there was the ZHP, offered on coupe, vert and sedan, again bridging the gap a bit closer to the M3.

But for the E9x, they kept it just for the coupe and vert.

The F30 is a new model launch. So why compare a 2dr end of run performance variant to the sedan? To be a bit more fair, as I said, Canada for '14 will offer a top of the line MSport sedan with PPK, suspension, etc. That would be a bit more fair to compare and hopefully such a car makes it to the US. If not, all available parts are there, the car tested here with PPK shows the added power helps out...now imagine the suspension and other MP upgrades.

[Accelerometer]

Originally Posted by Richbot

I have yet to be asked to accelerate from a standing start more than once in competition. xDrive would be great if the car weighed the same and had the same CG and weight distribution as the rear drive (sDrive? wait for it...) 335, but it doesn't, so it's not. I own a 335xi and it's a turd to drive at more than 7/10ths. It weighs nearly 200lbs more than my M3 sedan. Woopdedoo I can launch hard from a stoplight to 60 without wheelspin, and get a ticket because none of the stoplights around here are in 60mph zones...

xDrive's great if you don't want to worry about traction, terrible for all other purposes IMO

^^^This, xDrive has its purposes and sporty/track driving isn't one of them. The only reason I ordered our F30 with xDrive was due to my wife's extreme aversion to oversteer situations in rain/snow. I knew it would be a compromise in the handling department but hey its my wife's car and I wanted her to be happy and safe. Is it still fun in the twisties? Yes. Would it be even more fun if it didn't have xDrive? Yup.

[KevRyd]

what is the weight difference between the AWD and the RWD?

Originally Posted by Jamesons Viggen

I do not understand your hangup on comparing the 335is to the 335 MSport when they are not equivalent models.

Car makers bring out higher performing variants as a model line ramps up, to keep it fresh.

The E92is(there is no such thing as an E90is sedan) came out years after the E92. It was the highest spec, highest performing, most expensive 3 series without stepping up to the M3.

Now, in the E46, again, years after it was introduced, there was the ZHP, offered on coupe, vert and sedan, again bridging the gap a bit closer to the M3.

But for the E9x, they kept it just for the coupe and vert.

The F30 is a new model launch. So why compare a 2dr end of run performance variant to the sedan? To be a bit more fair, as I said, Canada for '14 will offer a top of the line MSport sedan with PPK, suspension, etc. That would be a bit more fair to compare and hopefully such a car makes it to the US. If not, all available parts are there, the car tested here with PPK shows the added power helps out...now imagine the suspension and other MP upgrades.

[Accelerometer]

Originally Posted by KevRyd

what is the weight difference between the AWD and the RWD?

Per BMWUSA:
335i xDrive: 3,710 lbs
335i RWD: 3,555 lbs

Difference: 155 lbs

[Jamesons Viggen]

Originally Posted by KevRyd

what is the weight difference between the AWD and the RWD?

The MSport in this test, 8spd auto Xdrive with 18" wheels:

3731 lb (53/47%)

The MSport in the Habeous Popum Test, 8spd auto RWD 19" wheels(adds 13-15lbs vs 18" wheels)

3605lbs (51.5/48.5%)

Now to be exact, if we subtract the 15lbs for the 19" wheels to equip the cars as closely as possible) that comes out to 141lbs. BMW sites have data as well, but they not get into specifics the way the mags do.

[KevRyd]

Would be interesting to see what that 4% would mean in terms of real world performance. Audi S4 is 3900 Lbs ++ with AWD.

Kevin

Originally Posted by Jamesons Viggen

The MSport in this test, 8spd auto Xdrive with 18" wheels:

3731 lb (53/47%)

The MSport in the Habeous Popum Test, 8spd auto RWD 19" wheels(adds 13-15lbs vs 18" wheels)

3605lbs (51.5/48.5%)

Now to be exact, if we subtract the 15lbs for the 19" wheels to equip the cars as closely as possible) that comes out to 141lbs. BMW sites have data as well, but they not get into specifics the way the mags do.

[Jamesons Viggen]

Originally Posted by KevRyd

Would be interesting to see what that 4% would mean in terms of real world performance. Audi S4 is 3900 Lbs ++ with AWD.

Kevin

When you go into a completely different car and drivetrain, it gets murky. The S4 is not offered in RWD to compare. The S4 has ALWAYS, back since the B5 days been heavier than a similar 3 series. The S4 is a bit different as it offers sports differentials that makes its AWD more of an aide than the 335. Only the X5/6M get the nifty AWD. The S4 is a bit more FWD in it's architecture, a S4 in FWD would not be a very good car lol.

[300hp]

Speaking of the S4 the results are in

http://m.motortrend.com/roadtests/sedans/1307_2013_audi_s4_first_test/

I don't know what to make of this review it seems lukewarm

[drob23]

Originally Posted by 300hp

Speaking of the S4 the results are in

http://m.motortrend.com/roadtests/se...s4_first_test/

I don't know what to make of this review it seems lukewarm

I'd say pretty good for a ~4000 lb 4 door sedan. Lateral G and figure 8 numbers are ballpark M3. Rear sports differential and active torque vectoring are game changers for AWD cars. Evo has one, GTR has one, X5M has one...even M5. Hopefully, BMW will follow suite and add one to their performance lineup and fix the geometry problem with the CV joint so the xdrive can have a proper sports suspension.

[Jamesons Viggen]

Originally Posted by 300hp

Speaking of the S4 the results are in

http://m.motortrend.com/roadtests/se...s4_first_test/

I don't know what to make of this review it seems lukewarm

Those numbers make it an exact match for the Xdrive PPK. The fact that the S4 is nearly 300lbs heavier, shows how comically underrated the 3.0T is. It would not surprise me if it made 330whp.

[drob23]

Originally Posted by Jamesons Viggen

Those numbers make it an exact match for the Xdrive PPK. The fact that the S4 is nearly 300lbs heavier, shows how comically underrated the 3.0T is. It would not surprise me if it made 330whp.

I think you also have to consider the DCT on the S4. Launch control dumps the clutch at 3k RPM, and I can tell you from personal experience that the necklash is brutal. The 2010-2012 S4 was slightly faster with better gearing and harsher clutch control from the TCU.

While the sport AT on the F30 is fantastic, it still has a torque converter. Even with brake torquing the crap out of it, you're still going to have loss, especially when shifting. I guess the new ZF8 on the 2014 will have more aggressive locking control, will be interesting to see how this feels on the road.

[Jamesons Viggen]

Originally Posted by drob23

I think you also have to consider the DCT on the S4. Launch control dumps the clutch at 3k RPM, and I can tell you from personal experience that the necklash is brutal. The 2010-2012 S4 was slightly faster with better gearing and harsher clutch control from the TCU.

While the sport AT on the F30 is fantastic, it still has a torque converter. Even with brake torquing the crap out of it, you're still going to have loss, especially when shifting. I guess the new ZF8 on the 2014 will have more aggressive locking control, will be interesting to see how this feels on the road.

That is all well and good-you are talking more about the launch, but look at the trap speeds, nearly identical.

So that means the power to weight ratio is nearly identical even though the S4 weights nearly 300lbs more. So again, that means the 3.0T is making at least 25-30whp more than the PPK N55 in order to compensate for the weight and have the same trap.

[300hp]

Originally Posted by Jamesons Viggen

That is all well and good-you are talking more about the launch, but look at the trap speeds, nearly identical.

So that means the power to weight ratio is nearly identical even though the S4 weights nearly 300lbs more. So again, that means the 3.0T is making at least 25-30whp more than the PPK N55 in order to compensate for the weight and have the same trap.

+1

[drob23]

Originally Posted by Elk

xDrive will transfer power away from the front wheels if these wheels start to spin. This will make the car handle more like a RWD car as the friction available to the front wheels can now be used to turn the car. In this one way, xDrive "improves" handling - but only by solving a problem xDrive itself caused in the first place. Irony at its best.

(As an aside, I am continually amused xDrive proponents wholly ignore this problem - as well as the default 40:60 default drive ratio - both of which compromise handling.)

Not sure I agree with your analysis of xdrive. Unlike a mechanical center differential like quattro or Subaru Symmetrical AWD, the computer used to control the clutch pack on xdrive is capable of changing the torque split anywhere from 0/100 to 50/50 (F/R). This can be done *a priori*, i.e. coded into the software in addition to mediating wheel slip in low mu conditions. If BMW engineers want to change the torque split to 0/100 (F/R) past 40 MPH, then they can do that. So the 40/60 split you harp on is really just the optimal split for launching the car and doesn't really mean much after the car is moving.

This is unlike a mechanical center diff which essentially appropriates torque based on the "path of least resistance", which is influenced by the nominal gearing of the center diff (40/60 for current gen of quattro). If you want to make an Audi handle more like a RWD car, the only way to do it is to replace the center diff with an aftermarket component.

BMW on the other hand can simply tweak their software. So from a pure performance point of view, the xdrive is the superior center differential technology since the computer can turn it into a RWD car if it so desires. The way Audi deals with the understeer is to stick on the rear differential, but that's a whole different discussion.

Now does an xdrive car understeer more than a RWD car (based on drivetrain, not weight/distribution)? Of course it does, based on the pure fact drive force is going to the front wheels. But BMW engineers can simply code this out if they want to. So unless you have access to BMW's calibration tables, then I can't really see how one can definitively argue that xdrive hurts the F30's performance other than the added weight and the lack of sports suspension.