Carsten Pries of BMW M: the M3/M4 S55 engine is an animal with shocking capabilities

[Boss330]

Originally Posted by US///M3

How's the F80/82 different than the E36 M3 as far as M standing for marketing?
I thought 40-60 weight distribution in a RWD car is better.

The 991 Turbo has roughly 40/60 weight distribution and that is great for acceleration and braking. You get more power to the ground as weight transfers to the rear wheels and under braking the rear wheels are able to do a bigger share of braking as they have more weight and hence better traction.

But quite why a 60/40 distribution (like an Audi) is better for handling is not obvious to me

If there is one thing the Audis aren't getting good reviews on, it has to be their understeer and lack of agile handling...

[DieGrüneHölle]

Originally Posted by racedoc11

I'm expecting a quite few of these cars to be totaled when they first come.

Why? How is this car any more potent or dangerous than other current cars on the market?

[CanAutM3]

Originally Posted by Boss330

The 991 Turbo has roughly 40/60 weight distribution and that is great for acceleration and braking. You get more power to the ground as weight transfers to the rear wheels and under braking the rear wheels are able to do a bigger share of braking as they have more weight and hence better traction.

But quite why a 60/40 distribution (like an Audi) is better for handling is not obvious to me

If there is one thing the Audis aren't getting good reviews on, it has to be their understeer and lack of agile handling...

Have you read my post #40 in this thread?

[Boss330]

Originally Posted by CanAutM3

Have you read my post #40 in this thread?

Yes, and that explains the benefits of something like a 40/60 distribution. But perhaps not the benefit of 60/40 (as was swamp2's claim was significantly better than 50/50), or am I missing something here

[CanAutM3]

Originally Posted by Boss330

Yes, and that explains the benefits of something like a 40/60 distribution. but not a 60/40, or am I missing something here

That's because there is no handling benefit to a 60/40 (front/rear) distribution. IMO, this type of distribution is mostly a consequence of optimizing the "packaging" rather than the handling.

IIRC, swamp is also implying that a 40/60 (front/rear) is optimal, I don't recal he ever stated that front heavy cars handle better...

I can't comment on which is the "optimal" weight disrtibution. All I am saying is that rear weight bias makes the car easier to pivot, hence more nimble.

[JoeFromPA]

Exciting article and responses. I think "no one will be prepared for this engine" means the torque onslaught + gearing + low weight + fast revving attitude.

Something people haven't commented on too much is the concept of a much lighter rotating mass. So far we have significant weight savings in the crankshaft and driveshaft - two usually massive inertial points. If both have been lightened, this engine should respond amazingly given similar tuning.

...

On another note, stop with the commenting on "This weight distribution is better".

We've seen 40:60 weight distributions (911s) rock the racetrack. We've seen 50:50. We've seen 60:40. We've seen 45:55 (mid-engine).

Each has it's own advantages and it depends upon the track and conditions as well. Different weight distributions are better for different things.

[CanAutM3]

Originally Posted by JoeFromPA

On another note, stop with the commenting on "This weight distribution is better".

We've seen 40:60 weight distributions (911s) rock the racetrack. We've seen 50:50. We've seen 60:40. We've seen 45:55 (mid-engine).

True, true, FALSE, true.

Show me such a front weight biased car that rocked the race track against more rear biased cars...

[bmwluvr24]

Originally Posted by CanAutM3

That's because there is no handling benefit to a 60/40 (front/rear) distribution. IMO, this type of distribution is mostly a consequence of optimizing the "packaging" rather than the handling.

IIRC, swamp is also implying that a 40/60 (front/rear) is optimal, I don't recal he ever stated that front heavy cars handle better...

I can't comment on which is the "optimal" weight disrtibution. All I am saying is that rear weight bias makes the car easier to pivot, hence more nimble.

To me, it seems that the 40/60 works for a Porsche because of the fact that the engine is in the rear thus adding more traction. I don't think that the Porsche would share the same weight distribution characteristics if the engine were located mid or front.

[ORIGIN M.]

Nothing like 50/50

The car just melts in yours hands.

[Year's_End]

Originally Posted by phishhead24

To me, it seems that the 60/40 works for a Porsche because of the fact that the engine is in the rear and this compensates for the extra weight. I don't think that the Porsche would share the same weight distribution characteristics if the engine were located mid or front.

I thinly you're getting your weight ratios mixed up. There has definitely never been a P-car with anything even vaguely close to a 60/40 split.

[Year's_End]

Originally Posted by red-sauerkraut

Nothing like 50/50

The car just melts in yours hands.

It's just a base factor amongst many other things. You can have progressively handling cars with a 55/45 and 45/55 split as well.

[bmwluvr24]

Originally Posted by Year's_End

I thinly you're getting your weight ratios mixed up. There has definitely never been a P-car with anything even vaguely close to a 60/40 split.

Yeah, I went back and edited.

[Boss330]

Originally Posted by CanAutM3

That's because there is no handling benefit to a 60/40 (front/rear) distribution. IMO, this type of distribution is mostly a consequence of optimizing the "packaging" rather than the handling.

IIRC, swamp is also implying that a 40/60 (front/rear) is optimal, I don't recal he ever stated that front heavy cars handle better...

I can't comment on which is the "optimal" weight disrtibution. All I am saying is that rear weight bias makes the car easier to pivot, hence more nimble.

Agree on 60/40, but here swamp2 clearly says that 60/40 is significantly better...

http://f80.bimmerpost.com/forums/sho...6&postcount=18

[biglare]

Engine is an animal with shocking capabilities..... blah blah blah! I don't think it's going to be much different than the 1M engine with a proper tune on it. The torque will be the most fun, but if someone has not driven a 1M with a tune on it then it will be loads of new fun compared to an E9x M3. The day to day driving of the 1M is just overall more fun than a E9x M3. It's the torque that makes you drive with a constant smile.

The only difference that I am hoping for is that the torque is there at all times on the track for the new M3/4. With the 1M it can kind of come on quick and keeps you on your toes. If the torque delivery is slightly smoother, then we have some improvements over a tuned 1M engine. Just my thoughts.

At any rate, I'm looking forward to the real life comparison!

[Jadar]

This car just makes me smile more and more!!!

Can't wait to see it at the Chicago auto show.

[bradleyland]

Originally Posted by CanAutM3

This article is full of flaws. It assumes that the path the car travels is linked to the mid point between the front and rear axles; since only the front wheels are steered, this simply isn't true (even on cars that have rear wheel steer, the fronts still do most of the steering). On rear weight biased car, the article concludes that the rear wheels need to cary more lateral load. This is correct, but since they also carry more normal (vertical) load, it becomes a moot point.

A car, as it travels through a bend, also needs to pivot on itself to keep the proper heading. The car does not pivot around its CG nor does it pivot around its "middle". The car pivots around the mid point between the two rear wheels (assuming zero slip angles). Imagine the front wheels steered at 90deg and this becomes very obvious.

To calculate the moment of inertia of an object pivoting around a point, the natural moment of inertia of the object needs to be added to the mass of the object times the square of the distance of its CG relative to the pivot point.

So the closer the CG is to the rear axle, the easier it is to pivot a vehicle. Hence the benefit of a rear weight bias.

The counter point is that when the rear tires start to slip more than the fronts (oversteer), the pivot point progressively moves away from the rear axle towards the front axle. So once you loose the back end on a rear weight biased car, it becomes much more difficult to bring it back.

This is such a fantastic reply. Well said

I'll add that weight distribution is only one factor. You can have a 40/60 (front/rear) weight distribution and still have a horrible handling (and probably dangerous) car. As CanAutM3 mentioned in the last paragraph, the rear-biased car will rotate more easily, but beyond the limit of traction, that rotation can bite you. The trick is in finding the balance between "rotates well" and "wants to swap ends, so watch out".

As has been pointed out, the one thing you don't want is front-heavy weight distribution. You're fighting an up-hill battle at that point. Kudos to BMW for working hard at hitting the 50/50 number, which I would consider a minimum acceptable distribution.

[bradleyland]

Originally Posted by Boss330

Agree on 60/40, but here swamp2 clearly says that 60/40 is significantly better...

http://f80.bimmerpost.com/forums/sho...6&postcount=18

Having seen swamp2's contributions in other threads, I'm nearly positive that was just a transpositional error. He meant 60-rear, 40-front distribution.

[hyperboost]

lets wait and see

[JoeFromPA]

Originally Posted by CanAutM3

True, true, FALSE, true.

Show me such a front weight biased car that rocked the race track against more rear biased cars...

What, you want examples of Evo's and STI's and what not beating rear weight biased vehicles around a track somewhere?

C'mon, all factors are not equal. I can provide plenty of that. My point was there is more to the equation that simple weight distribution.

For example, a vehicle with more of it's mass closer to the lowest, most central point may handle better than a car with simply an equal distribution of weight across both axles.

[stefan]

Another stunning review of the S55 courtesy of BMW Marketing.

[S65V8]

Originally Posted by stefan

Another stunning review of the S55 courtesy of BMW Marketing.

My thoughts exactly, I mean, what's this guys going to say, "meh, the car is 'ok'..." I don't think so broski

All cynicism aside, I'm liking this car more and more I see it in real picts and videos. I bore easily, so I'm ready for something new and shiny...and FAST.

[barcius13]

Very unbiased opinion