Horsepower wars coming to a close, weight wars begin. BMW fires first salvo

[BMW269]

M3 E30: 200 PS
M3 E36: 286 PS (+86 PS)
M3 E46: 343 PS (+57 PS)
M3 E92: 420 PS (+77 PS)
M3 F32: 450 PS (+30 PS)

BMW M3 EVOIII E30: 238 PS
BMW M3-R E36: 326 PS (+88 PS)
BMW M3 CSL E46: 360 PS (+34 PS)
BMW M3 GTS E92: 450 PS (+80 PS)
BMW M3 CSL E92: (not known yet)
BMW M3 "CSL" F32: 480 PS (+30 PS)



When you look at the power incread compared to the previous, the M3 F32 is going to get the lowest HP increase ever in M3 history. But as I already said before many time, the M3 F32, unlike the M5 and M6 F1X, is going to be the first successor to be lighter than its predecessor. The M3 F32 sould weight under 1600 kg, that would be 55/75 kg lighter than the M3 E92. In fact it could end up being even lighter than the M3 E46, this means 1550 kg (EU). Of course the figured weight would be of the standard M3, so with 6MT if it still stays available, and without to many technolgy/comfort features such as head-up-display and so, and if S55/S53 is lighter, or at least not any heavier than S65.

[mkoesel]

Originally Posted by Levi

M3 E30: 200 PS
M3 E36: 286 PS (+86 PS)
M3 E46: 343 PS (+57 PS)

I thought the E36 was closer to 315PS?

[AM150]

Originally Posted by Mahzari

I don't want to get into an argument with you because you do have some good points.... But...

If you have two identical accidents, the car with a higher torsional rigidity will receive "less" damage. The BMW Z3 convertible has a torsional rigidity of 5,600Nm/deg and the Bugatti Veyron has one of 60,000Nm/deg. Which would rather be a passenger in if they both hit a tree head on at 50mph? Another way to look at it is to imagine an egg and an aluminum tube being thrown at a brick wall, the egg will get smashed while the aluminum might get dented.

Now, I think the only thing stopping cars from becoming lighter is the price of light materials. Also, just because something is light does not mean in cannot be strong. Carbon fiber is five times stronger than steel but the only reason a Kia Rio does not come with a carbon fiber chassis is because it is very expensive.

This isn't entirely true. Since torsional stress is a function of force and distance from a point, and force is (in all cases relevant to this discussion) a function of mass.

A bigger, heavier car requires much higher rigidity than a smaller, lighter car in order to maintain the same deflection through the real world exercise.

Secondly a highly rigid structure is not necessarily beneficial in a crash like you are describing (I'm not sure a head on collision would have a whole lot to do with torsional rigidity anyway), sure a highly stiff structure would suffer less damage than a less stiff one (all else being equal) but it would also more likely injure or kill the occupants than a less stiff one. A safe car's goal in a crash is to dissipate energy over as long a period of time as possible and direct the forces around the passenger cabin, not to withstand an impact intact.

[Erhan]

Originally Posted by Scoobe

If you had the choice, would you choose an M3 with the current 414hp rating but be 300lbs lighter, or a different M3 with 450hp and the current 3700lb weight? The thrust to weight would be exactly the same at 8.2lph. I think just about everyone here would take the lighter car with less horsepower.

I, like many enthusiast would take the lighter car with same power. But we're the 1% of M3 owners, so don't expect anything light from BMW. You will get torque though, lots of it. So have a 2nd bank account for rear tires.

[bruce.augenstein@comcast.]

Originally Posted by Mahzari

...If you have two identical accidents, the car with a higher torsional rigidity will receive "less" damage.

How so? "Torsional rigidity" describes resistance to body flex under load, such as when your right front wheel hits a bump. When that happens, the body will flex by some amount as the right front "bends up" under the load. More torsional rigidity, less body flex. Suspension engineers like this because they don't have to compromise suspension settings as much, and are free to pay more strict attention to ideal compression and rebound rates. Drivers tend to like this as well, because the car feels more of a piece from behind the wheel.

In my opinion, BMWs tend to have the best ride/handling compromise, model by model, partly because they are rigid.

However, all this said, there is no direct correlation between torsional rigidity and crashworthiness.

None.

The absolute best you can say is that a vehicle with a very good torsional rigidity probably needs a fair amount of material to make it so, therefore intrusion into the cabin in a particular accident may possibly be less likely. In addition, the extra weight is never a disadvantage in a collision, and will often be an advantage, as previously mentiond.

However, you could also say that a vehicle with very good torsional rigidity might in fact be naturally more dangerous to its occupants, assuming more material in its construction, because you need a bunch of "crush" in order to ease the G load on driver and passengers.

Originally Posted by Mahzari

The BMW Z3 convertible has a torsional rigidity of 5,600Nm/deg and the Bugatti Veyron has one of 60,000Nm/deg. Which would rather be a passenger in if they both hit a tree head on at 50mph?

Answer: I have no idea, and neither do you.

Imagine the Bugatti is infinitely rigid, and the only thing that happens when you hit a tree is that the paint gets blemished. In that case, the occupants would almost surely die because of the massive G-force spike they would undergo.

Ideally, the Bugatti would crush right back to the firewall in that collision, meaning it stops from 50 in, say, four or five feet. This is infinitely better than it coming to a halt in zero feet. Capiche?

In the Z3, BMW has designed it such that in a 50 mph tree hit, the front end would crush (including any subframe materials), the engine would drop down (so it wouldn't smash back into the cabin), and the car would shorten itself up back almost to the firewall. This is how you maximize occupant safety. In effect, you weaken everything up except the passanger nacelle - and torsional rigidity is pretty much a non-issue in this circumstance.

Originally Posted by Mahzari

Another way to look at it is to imagine an egg and an aluminum tube being thrown at a brick wall, the egg will get smashed while the aluminum might get dented.

This is simple nonsense. As already pointed out, this isn't how it works.

Originally Posted by Mahzari

Now, I think the only thing stopping cars from becoming lighter is the price of light materials. Also, just because something is light does not mean in cannot be strong. Carbon fiber is five times stronger than steel but the only reason a Kia Rio does not come with a carbon fiber chassis is because it is very expensive.

"Strong" really isn't the issue. In the aforementioned 40 mph head-on between the Smart Car and the Suburban, the Suburban would slow down to, say, 25 mph, while the Smart Car would go into instant reverse at 25 mph. Imagine the G forces when going from 40 mph to minus 25 mph in roughly the blink of an eye, compared to going from 40 mph to 25 mph in roughly the blink of an eye.

If the Smart Car were infinitely rigid, the results would be even worse for the occupants, because crush zones mitigate peak Gs, as is obvious and and has already been mentioned.

[Mahzari]

I admit that I do not know enough about crash physics and realize now that a head on collision was not the best choice, however, I never said infinite stiffness because that wouldn't absorb or deflect any of the force. The car still has crumple zones and that is where the impact is absorbed, the chassis stays rigid which is exactly what you want.

Robert Kubica Crash - Canada 2007

If the actual chassis of this car was any less stiff it would have not been able to keep up to the force of the a) nearly head on impact, b) roll, or c) skid

Mark Webber Crash - Valencia 2010

What about here?

[BMW269]

Originally Posted by mkoesel

I thought the E36 was closer to 315PS?

The 286 PS engine is a 3.0l I6. At mid-life-cycle it got an increase to 3.2l and produced 321 PS. But this engine did not get to the U.S.

[Norsk]

As long as the cars feel solid, not flaky like some of those Corvettes, Fiero and even Smart cars ... then it's all good.

[mtla4]

I did not read the whole thing but that's why america is loaded with useless suvs and many other retarded cars while the rest of the world have all the good cars. Bigger does not mean safer. Also it's way cheap to slap a bigger and then using lightweight materials.IMO all the weight is added by sensors, hard drives, wiring, bigger wheels, thicker glass for NVH.

Anyhow I've always been told either the car takes the hit or you take it and to think about driving does involves a risk like anything in life.

[ScarecrowBoat]

Originally Posted by Crimson92

with less weight you dont need more horsepower.

that being said id love the current m3 with 300-400 pounds less junky in the trunk.

The current M3 with about 500lbs shaved off of it would still need nearly 414hp to achieve the same top speed. Above 120 mph or so, weight becomes almost negligible as the aerodynamics of the car start to be the biggest factor is top speed. Obviously, lighter weight helps a ton with acceleration under 100mph and cornering/braking at any speed. My point is, give me a few hundred pound lighter car, but keep the same HP!

[Serious]

Originally Posted by Mahzari

I admit that I do not know enough about crash physics and realize now that a head on collision was not the best choice, however, I never said infinite stiffness because that wouldn't absorb or deflect any of the force. The car still has crumple zones and that is where the impact is absorbed, the chassis stays rigid which is exactly what you want.

Robert Kubica Crash - Canada 2007

If the actual chassis of this car was any less stiff it would have not been able to keep up to the force of the a) nearly head on impact, b) roll, or c) skid

Mark Webber Crash - Valencia 2010

What about here?

f1 cars use impact attenuators to dissipate energy in a crash rather than crumple zones.

Also that BMW CF plant (it's actually SGL group) hasn't been built yet and other manufacturers have bought into SGL lately as well, so it isn't solely a bmw operation.

[Q4P]

I want to believe this but BMW has made cars heavier and heavier... I would definitely want the future to bring lighter cars but I just don't see this happening in this segment.

[InTheNightKitchen]

Originally Posted by E90Fleet

Some may be interested to know the USA is highly involved with making BMW's Carbon Fiber.

The raw chemical fibers are sourced from Japan
They are then "cooked" into carbon fibers in Moses lake USA
Then they are sent so Germany where they are "weaved" into fabric
Finally the fabric goes to BMW Landshut that makes the parts

If this is true, it seems so irrational all that hand changing, and extremely costly!

[merchomini]

I would like.........................


Less weight more horsepower..........................thanks.....

[shanecarmaster1]

I hear angels singing in my head now - This is what we all wanted to hear forever!!

[SCOTT26]

There is something people are overlooking with the i3 and i8 is that their respective weights are actually significant because they are individually developed models for a purpose.

Now with other manufacturers adapting electrified powertrains to current models their weight goes up and it is not a minimal increase.

What is signifcant for BMW is that they started the CFRP process very early so they took the initial expense hit early now that is in production of a reasonable volume for the M3 and forthcoming M6 Coupe's. BMW M can actually fit the CFRP cost-effectively now to these models.

If Audi or Mercedes-Benz had to do so on the RS5 and C63 respectively they would be more expensive.

[hotrod182]

Power to weight ratio is important...but you need all out horsepower if you are looking at ultra triple digit speeds. Aerodynamics is such a big factor at higher speeds. Hence a Lotus can be very quick down low, but runs out of steam at upper speeds. A heavy Bently might not be very quick down low due to the heavy weight hurting the power to weight ratio..but can still top out at close to 200mph.

[SCOTT26]

FYI - The new 3er will NOT BE @ FRANKFURT

It will launch in the Autumn in preperation for a Geneva premiere coinciding with the European on-sale date.

[bruce.augenstein@comcast.]

Originally Posted by Mahzari

I admit that I do not know enough about crash physics and realize now that a head on collision was not the best choice, however, I never said infinite stiffness because that wouldn't absorb or deflect any of the force. The car still has crumple zones and that is where the impact is absorbed, the chassis stays rigid which is exactly what you want.

No, that's not what you want in a passenger car. What you need for passenger safety is for the front and rear of the car to be relatively "weak", in order to provide controlled crush zones. You fortify the cabin in order to prevent deformation as much as possible and thus provide maximum safety to the occupants, but unless you provide crush zones, they're gonna die anyway from a huge G spike.

In an F1 car, priorities are different. The reason the entire chassis is very rigid is that you are trying to deform the hell out of it with four plus Gs in the turns, and you need max stability in order for the suspension to be stable and work properly under those conditions.

Originally Posted by Mahzari

Robert Kubica Crash - Canada 2007

Originally Posted by Mahzari

If the actual chassis of this car was any less stiff it would have not been able to keep up to the force of the a) nearly head on impact, b) roll, or c) skid

Agreed, but the chassis isn't stiff from front to back in order to provide crashworthiness, as already explained. You're not providing crush zones because they interfere with max performance, and the driver is paid to take the risk. Instead, you provide runoff areas and tire walls in order to minimize injury. Of course, that's not possible on the street.

Voila. Crush zones.

Originally Posted by Mahzari

Mark Webber Crash - Valencia 2010

Originally Posted by Mahzari

What about here?

Same deal.

And by the way - none of this directly relates to torsional rigidity as an important part of occupant safety, because it is of little consequence in that regard. More torsional rigidity is a good thing, but it's not a safety issue.

[LarThaL]

Has anybody thought about just going back to smaller cars. The 1M is larger than the E30 M3. Look at how big the 5 and 7 series have gotten. If you combine new efficient engine technology with new lighter materials technology AND make cars smaller like they used to be, just imagine what you could accomplish in terms of fuel economy, emissions, and all aspects of performance. I still don't fully understand why manufacturers continue to make cars bigger and bigger. I thought the e39 M5, for instance, was very nicely sized. Why did it have to get so much bigger?

[Erhan]

Originally Posted by VVG

Has anybody thought about just going back to smaller cars. The 1M is larger than the E30 M3. Look at how big the 5 and 7 series have gotten. If you combine new efficient engine technology with new lighter materials technology AND make cars smaller like they used to be, just imagine what you could accomplish in terms of fuel economy, emissions, and all aspects of performance. I still don't fully understand why manufacturers continue to make cars bigger and bigger. I thought the e39 M5, for instance, was very nicely sized. Why did it have to get so much bigger?

One problem of getting a small car is you get a small or pathetic engine. You will never see an exciting engine in a 1 series bimmer.

[Erhan]

Originally Posted by niceworkbavaria

The current M3 with about 500lbs shaved off of it would still need nearly 414hp to achieve the same top speed. Above 120 mph or so, weight becomes almost negligible as the aerodynamics of the car start to be the biggest factor is top speed. Obviously, lighter weight helps a ton with acceleration under 100mph and cornering/braking at any speed. My point is, give me a few hundred pound lighter car, but keep the same HP!

True, but how often do you go above 120mph? Even in race tracks, you usually achieve this on the start/finish straight. So yes obviously I would one the light and powerful (not torque-y), but if I have to choose one, I'd choose lightness over power.