[serge]

Originally Posted by elucas730

Heavier
More drivetrain losses
Different weight distribution
More understeer
All leading to a car that is slower and doesn't handle as well, even with an LSD.

How do you know that the Xi is slower? Any comparos yet? and why should the AWD handle worst than the RWD? And what about the "LSD"?

Talking about being biased without knowing $hit...

[Former_Boosted_IS]

You guys have to understand I definitely can drive a high horsepower vehicle. My Lexus IS300 had over 500 rwhp on 21 psi. It was an extremely built vehicle that even had a feature shoot in a magazine. The car however was not an LSD car and I can tell you that tire spin was a problem. The biggest tire I could fit was a 255x30, and I feel like that was an issue as well. What is the largest tire you can fit in the back of this car without rubbing and without rolling/shaving the fender well?

Also if it matters, the suspension will be changed the day I get the car to lower it. Does that affect things differently on an AWD vehicle? Powerwise, I would be hoping for 400 rwhp at some point. 400 rwhp = major tire spin on the IS300 and I hated that. It was unsafe first and you just wasted so much power and I don't want to do that again.

[elucas730]

Originally Posted by serge

How do you know that the Xi is slower?

Common sense. It is heavier and you lose more horsepower through an AWD drivetrain than you do through a RWD drivetrain. A car that is heavier and puts less power to the wheels will always be slower than a lighter car than puts more power to the wheels. It's just plain common sense.

[Former_Boosted_IS]

Originally Posted by elucas730

Common sense. It is heavier and you lose more horsepower through an AWD drivetrain than you do through a RWD drivetrain. A car that is heavier and puts less power to the wheels will always be slower than a lighter car than puts more power to the wheels. It's just plain common sense.

Not trying to get in the middle, but putting power to the wheels is irrelevant. Putting power to the ground without spin is the only thing that is important.

[elucas730]

Originally Posted by Former_Boosted_IS

Not trying to get in the middle, but putting power to the wheels is irrelevant. Putting power to the ground without spin is the only thing that is important.

As stated earlier, people are cutting 1.9x 60' times (or maybe even lower) on stock tires. Throw on some stickier tires and you're even lower.

[Former_Boosted_IS]

Originally Posted by elucas730

As stated earlier, people are cutting 1.9x 60' times (or maybe even lower) on stock tires. Throw on some stickier tires and you're even lower.

What power level do those guys have?

[bnj]

Originally Posted by e36jakeo

The AWD vs RWD argument is one for the ages. There are proponents for both.

Unless you really need the extra traction of AWD due to needing to climb hills in the snow I say go with RWD. Carrying around the extra weight and friction of AWD in a car originally designed to be RWD is counterproductive. In terms of safety, the stability control is now so good that having RWD is not a real safety concern. Get yourself some good snow tires for the winter and you will be amazed what a RWD BMW can do.

RWD completely separates the throttle from the steering, which offers much better steering feel and the ability to turn the car with the throttle. Learn how to take advantage of this separation at a car control clinic or track day or two. Then get the LSD and you will understand why BMW builds the best handling sedans on the planet.

If you are purchasing the car more for its straight-line speed then maybe the AWD would be a good purchase just for pure traction reasons.

What causes the traction deficit in accelerating the car is too much power for the wheel considering the traction coefficient. Now if you direct the power via multiple wheels, the power will be less per wheel and the traction will be lost later. Where this is NOT necessary is at straight line (high speed). It IS beneficial in curves and at low speed (also in straight line).

Capability of a 4wd car is just amazing because of its ability to get grip a tad better than RWD.

I remember even 996 Porsche was faster in 4wd form than in RWD when tested. And Porsche is traditionally RWD and not front engine car. Front engine cars have weight distribution more front biased than Porsche and thus are able to get more grip through their front wheels. The Porsche test was in TV by Top Gear. The difference was not huge.

I am very pleased with my RWD 335. (xi was not in the market, and if I'm in a hurry I can take my fast A to B AWD car ) But dissing xi does not make sense. My 4wd car is almost 20 years old, but still some car mags claim it to be the best handling car ever built. It's classic (World Rally Champion 6 times in the row) and all "best handling" claims are subjective. But there is nothing wrong in 4wd handling. E.g. if driving Mitsu EVO, you notice that it is very fast in the curves. Sport Auto just had a comparison test of EVO, STI and 335i. Evo was rated the best and to be the best driver's car. And this was in dry tarmac. Have some rain, snow, gravel, whatever dirt in the pavement and there is no need to even have this discussion.

[bnj]

Elucas, you haven't get back to the weight distribution. Nor that the general claim of RWD being faster than xi would be too accurate. Under which conditions, which track? Remember that xi has the advantage of having more traction.

I'm sure RWD is faster in a straight line at high speeds with no engine tuning.
I'm sure xi is a lot faster (better lap time by a huge margin) around a slow track with poor traction and tuned engine.

[who's ur daddy?]

Let's clarify something about the 335xi, it's faster 0-60 by .1 than the 335i according to BMW. I think top end it'll lose to the 335i, but for low end, the 335xi seems to have the advantage. It's not a lot, but I'm actually quite stunned the 335xi is faster. I recall always checking out previous BMW AWD models and they'd be about .5 seconds slower. Maybe the Xdrive system is more efficient now or perhaps there now is enough power to make full use of the AWD. I dunno.

[catdog]

Originally Posted by who's ur daddy?

Let's clarify something about the 335xi, it's faster 0-60 by .1 than the 335i according to BMW. I think top end it'll lose to the 335i, but for low end, the 335xi seems to have the advantage. It's not a lot, but I'm actually quite stunned the 335xi is faster. I recall always checking out previous BMW AWD models and they'd be about .5 seconds slower. Maybe the Xdrive system is more efficient now or perhaps there now is enough power to make full use of the AWD. I dunno.

I am stunned too with the great handling of my xi, yesterday was in a long 270 degree on-ramp and was going at a good clip and gave it more gas the car started to understeer but i did not let off and actually gave a bit more gas to check its limit (close to terminal understeer) and guess what happened, the car snapped out of understeer as it seemed the xdrive transferred more power to the rear and actually got the car out of understeer...into neutral even with a little more gas...unbelievable! Really i am very impressed with the current xdrive system and people are simply not giving it enough credit. Which is as well, it will remain as well kept a secret whic goes nicely with the e90's 335 wolf in sheep clothing, low-key...

[catdog]

Originally Posted by who's ur daddy?

Let's clarify something about the 335xi, it's faster 0-60 by .1 than the 335i according to BMW. I think top end it'll lose to the 335i, but for low end, the 335xi seems to have the advantage. It's not a lot, but I'm actually quite stunned the 335xi is faster. I recall always checking out previous BMW AWD models and they'd be about .5 seconds slower. Maybe the Xdrive system is more efficient now or perhaps there now is enough power to make full use of the AWD. I dunno.

Well then if you dunno then how can you be sure that it's going to be that much slower at higher speeds than 0-30 mph? The xdrive may be efficient enough at higher speeds, perhaps we need more data before masking assumptions, that's all

I can tell you with dtc off and flooring the car there is no tire squeak the thing just bolts out...

[bnj]

Originally Posted by who's ur daddy?

Let's clarify something about the 335xi, it's faster 0-60 by .1 than the 335i according to BMW. I think top end it'll lose to the 335i, but for low end, the 335xi seems to have the advantage. It's not a lot, but I'm actually quite stunned the 335xi is faster. I recall always checking out previous BMW AWD models and they'd be about .5 seconds slower. Maybe the Xdrive system is more efficient now or perhaps there now is enough power to make full use of the AWD. I dunno.

The reason is the power. In accelerating there are 1. the traction limited and 2. the power limited parts. With much power, the traction limited part is emphasized when compared to a car with less power. With tuning, the traction limited part will play even higher role...

At 180km/h xi disengages 4WD and functions as RWD.

[bnj]

Originally Posted by catdog

I am stunned too with the great handling of my xi, yesterday was in a long 270 degree on-ramp and was going at a good clip and gave it more gas the car started to understeer but i did not let off and actually gave a bit more gas to check its limit (close to terminal understeer) and guess what happened, the car snapped out of understeer as it seemed the xdrive transferred more power to the rear and actually got the car out of understeer...into neutral even with a little more gas...unbelievable! Really i am very impressed with the current xdrive system and people are simply not giving it enough credit. Which is as well, it will remain as well kept a secret whic goes nicely with the e90's 335 wolf in sheep clothing, low-key...

Also RWD has understeer when pushed.

Nice that you got the guts to see how it behaves to the limit. And nice it behaved well

[Sniz]

Originally Posted by bnj

What might be RWD 60' times with those wider DRs in the rain?

There are many problems w/ this question. You wouldn't run Drag Radials in the rain, nor would you be drag racing in the rain.....tracks are closed.

Plus, I dont think anyone has been testing launching techniques for the rain.

[serge]

Originally Posted by elucas730

Common sense. It is heavier and you lose more horsepower through an AWD drivetrain than you do through a RWD drivetrain. A car that is heavier and puts less power to the wheels will always be slower than a lighter car than puts more power to the wheels. It's just plain common sense.

According to your theory, cars like the STI or the Evo should be faster if they were FWD instead of AWD right?

[Chowbow]

I don't think there's enough of a difference in performance of the vehicles for most people to argue that crap out of it. Unless you can cut consistent 1.6x 60' times at the strip with AWD, who cares if BMW / C&D / R&T / MT lists the 0-60mph time as 0.1 seconds faster for the xi. A lot of "performance" comes down to the driver anyway. I took an LS1 that was running 12.6s all day long at test and tune and ran a 12.4 on my first pass. Then another guy took it out and slapped down a 12.2 on his first pass, and 12.1 on the second pass. The owner of the vehicle had 4 time slips that day running 12.6 or slower... it's not the car most of the time.

The question is, can YOU launch an AWD or RWD car? If so, neither one makes a big difference. You can abuse an AWD car more and it was a little comforting that you can actually drive it a little more sloppy and have a safety net when things get a little out of hand. When I got my 335 I still wanted a RWD though because I find it a bit more fun with on-throttle oversteer and I live in a calm climate with no need for AWD.

I will mention that an AWD car can get great traction, but only if you don't break it... I had 100+ 1/4 mile passes on my S4 and I was killing rear diffs from the launches. The clutch and syncros were breaking too but that is a given on a car that gets drag raced quite a bit. So you might get great times, but be prepared to replace components too. The same can be said for RWD cars but there is typically more drivetrain shock from an AWD launch.

Out of curiosity, can the clutch in a 335xi handle a 6-7k launch? What kind of 60' times are people cutting with those?

[catdog]

Originally Posted by Chowbow

I don't think there's enough of a difference in performance of the vehicles for most people to argue that crap out of it. Unless you can cut consistent 1.6x 60' times at the strip with AWD, who cares if BMW / C&D / R&T / MT lists the 0-60mph time as 0.1 seconds faster for the xi. A lot of "performance" comes down to the driver anyway. I took an LS1 that was running 12.6s all day long at test and tune and ran a 12.4 on my first pass. Then another guy took it out and slapped down a 12.2 on his first pass, and 12.1 on the second pass. The owner of the vehicle had 4 time slips that day running 12.6 or slower... it's not the car most of the time.

The question is, can YOU launch an AWD or RWD car? If so, neither one makes a big difference. You can abuse an AWD car more and it was a little comforting that you can actually drive it a little more sloppy and have a safety net when things get a little out of hand. When I got my 335 I still wanted a RWD though because I find it a bit more fun with on-throttle oversteer and I live in a calm climate with no need for AWD.

I will mention that an AWD car can get great traction, but only if you don't break it... I had 100+ 1/4 mile passes on my S4 and I was killing rear diffs from the launches. The clutch and syncros were breaking too but that is a given on a car that gets drag raced quite a bit. So you might get great times, but be prepared to replace components too. The same can be said for RWD cars but there is typically more drivetrain shock from an AWD launch.

Out of curiosity, can the clutch in a 335xi handle a 6-7k launch? What kind of 60' times are people cutting with those?

+1

also like to hang the tail out, did plenty of that with e46 m3 and e60 m5 and got my 997S not 4S but decided to go xi for daily driver and have been positively impressed even in dry weather and can wait for sloppy conditions of winter driving. I can tell you that although traction control has come a long way, it simply kills power too much in low-traction conditions and makes them no fun... and if you shut off dsc in wet with lsd you can almost guarantee a trip to the body shop. best of all 3 was actually 997 which is actually great in bad weather with winter tires c/w m3/m5 with similar winter tires because of rear engine.
i think that 335 with xi and extra 40-80 whp is going to be the ideal daily driver 24/7/365

[Rips335iCoupe]

Originally Posted by Evo8MRto335I

what is wrong with a BMW AWD?

Nothing, but Audi makes the best mechanical AWD system in the world, and that’s what I would buy if I wanted an AWD car. Use to own an Audi 3.2 TT Quattro, and it was awesome.

[catdog]

Originally Posted by Rips335iCoupe

Nothing, but Audi makes the best mechanical AWD system in the world, and that’s what I would buy if I wanted an AWD car. Use to own an Audi 3.2 TT Quattro, and it was awesome.

Have you driven a new x-drive 3 or 5 series? If not then you can't make that blanket statement. Audi 4-wheel drive ---> terminal understeer

[T Bone]

X Drive can send torque 100% front to back and disengages at high speeds. It is completely variable unlike Quattro.

So there is very little parasitic drivetrain loss caused by Xdrive versus a mechanical system like Quattro. Also, it will not plow like a Quattro.

Not only will the XI launch harder but it will not suffer high speed losses.

[catdog]

Originally Posted by T Bone

X Drive can send torque 100% front to back and disengages at high speeds. It is completely variable unlike Quattro.

So there is very little parasitic drivetrain loss caused by Xdrive versus a mechanical system like Quattro. Also, it will not plow like a Quattro.

Not only will the XI launch harder but it will not suffer high speed losses.

Thanks TBone :rocks:

[Chowbow]

OK I hear all these statements about Xi's launching harder. Where are the 60' numbers?