I weighed my 2015 M4 and 2017 M4 ZCP at the same time

[dmk08]

My 16 ZCP M4 6MT was 3607 stock with a full tank of fuel. Should be 35xx with my new wheels and tires. Shaved about 6lb per corner.

[M3steve2014]

Originally Posted by CanAutM3

The 20" 666M wheel-tire combo add over 21lb compared to the 18" 513M

http://f80.bimmerpost.com/forums/sho...M#post21346383

Extra unsprung weight times 7 is a lot! 21x7 is like a 150lb person in the car. Will be able to feel that. Thought they were "weight optimized" wheels as well. Good info.

[CanAutM3]

Originally Posted by M3steve2014

Extra unsprung weight times 7 is a lot! 21x7 is like a 150lb person in the car. Will be able to feel that. Thought they were "weight optimized" wheels as well. Good info.

Where did you get that number (7x) from ?

I don't believe there exists a correlation factor for UN-SPRUNG mass.

If you are talking about the effect of ROTATING mass, then I suggest you

[trey100]

** Double Post **

[trey100]

Originally Posted by CanAutM3

for doing this, it is always interresting to gather weight data.

A few pointers:

Unsprung weight does not have any direct incidence on acceleration, but has a strong incedence on handling.

Rotating mass however does impact acceleration, but not necessarily to the extent most believe. The mass factor of wheels is about 1.5x while the one of tires is about 2x. So the added effective mass of the 666M over the 513M is no more than ~40lb, which is less the the moonroof to CF roof difference . Every bit counts, but it is not a night and day difference.

The CP and non-CP have pretty much the same torque plateau up to 5500rpm, as you stated. But the CP has more power from then on, and that is where it matters for ultimate acceleration. I think the "slower" CP we've seen are more about test-to-test variance.

Fuel tank size has not changed, it is still 60 liters.

Also note that the MPE is 18lb lighter than the stock exhaust, a bit less than the 26lb you suggested.

So your CP is ~84lb heavier. 21lb of that is from the 666M, leaving ~63lb from other options such as HK sound system (more speakers and amps add a fair bit of weight), full leather and the driver's assistance gizmos.

I had posted this article awhile back as I was surprised at the results of the test data relative to unsprung weight savings.

http://blog.caranddriver.com/tested-...-fiber-wheels/

[CPWINCH]

my 2017 M4 weighs 3,574lbs (CF roof, 18s,). This was before the weight reduction.

[CanAutM3]

Originally Posted by trey100

I had posted this article awhile back as I was surprised at the results of the test data relative to unsprung weight savings.

http://blog.caranddriver.com/tested-...-fiber-wheels/

Once again: not UN-SPRUNG mass, but ROTATING mass. Those are two very distinct things and folks keep mixing them up.

And yes, I remember this article. It is flawed.

What they completely omitted to mention is that the GT350R tires have quite a smaller rolling radius that the GT350's. There was a good discussion on the forum about the results of this particular C&D test. When doing the math, it was discovered that the smaller rolling radius provides more advantage than the 58lb lighter CF wheel. Big fail from C&D on this one IMO .

[trey100]

Originally Posted by CanAutM3

Once again: not UN-SPRUNG mass, but ROTATING mass. Those are two very distinct things and folks keep mixing them up.

And yes, I remember this article. It is flawed.

What they completely omitted to mention is that the GT350R tires have a quite a smaller rolling radius that the GT350. There was a good discussion on the forum about the results of this particular C&D test. When doing the math, it was discovered that the smaller rolling radius provides more advantage than the 58lb lighter CF wheel. Big fail from C&D on this one IMO .

Ahh. Didn't even think about comparing wheel diameters but the acceleration improvement is pretty significant so it must have been quite different.

[CanAutM3]

Originally Posted by trey100

Ahh. Didn't even think about comparing wheel diameters but the acceleration improvement is pretty significant so it must have been quite different.

Yes, the tire diameters are quite different. Further, these C&D acceleration tests are done in top gear at relatively low RPM, where the Voodoo torque curve sharply increases with RPM. The shorter gearing provided by the smaller radius wheel has a compounding effect of torque multiplication and putting the engine in more advantageous power band for a given road speed. 58lb on the wheels is a fair bit and does help acceleration, but nowhere near the extent of what is shown in the C&D test.

[sharocks]

What dealer in Mass is this?

[m34m]

Bloated pigs. Too big too heavy overcompensated for by too much power from an uninspiring motor. Wow compelling. Could not be further away from the true spirit of a BMW M3.

[Haagen-Dazs]

No carbon ceramics on the 2015?

[Arcades]

Yay my gal is lighter!! lol~ Though I have full Akra and rims...

Still good to know~ if it is right or wrong. Cool to read anyway~

[135iDCT]

heavy

[FuriousLucy]

Originally Posted by Rocklobster

I recently traded in my 2015 M4 for a 2017 with the comp package. I was curious to see exactly how much these cars weighed so i brought my corner scales with me and the dealership humored me and had a tech weigh the cars during my transaction process. Both Cars weighed sans driver.

Specs:
2015 (white) M4, DCT, 18" wheels, tank about 2gal from full, lighting package, exec package, M adj suspension, carbon roof, half cloth/leather seats. Front splitters & spoiler are the only non-OEM pieces on the car.

2017 (Blue) M4 with Comp package, MPE, lighting package, carbon roof, driver assistance + package, exec package, full leather, DCT. Gas was about 1/3 full when weighed so we filled it up afterwards and put 9.7 gal in. Subtract 1.7 for an even 8 gal to bring the two cars at least nearly the same volume of gas from full.

Both cars have the HK sound system.

2015 = 3612 lbs
2017 = 3628 (lbs as weighed) + approx 6.2 lbs/gal @ 40-50 deg F x 8 gal = 3678 lbs

Considerable difference of 66 lbs that may be mostly in the wheels and tires, and perhaps the stiffer suspension components but also all the driver assistance plus crap surely adds weight. What's interesting is supposedly the stock M4 exhaust is about 18 lbs heavier than the MPE so it seems to me these cars should be closer. Were they to have the same exhaust the 2017 ZCP would be about 84 lbs heavier.

Seems apparent this is one reason why the ZCP is "slower" in a straight line according to some reviews.

I like the info. Also trading non-ZCP for an M4 ZCP w/ the MPE, will have Carbon Ceramics. Why a heavier wheel and more unsprung weight? (I have grown to like them, at first I thought bad thoughts about them). I don't go to track anymore, and would really love AWD, looking at the new Audi RS5.

[CanAutM3]

Originally Posted by Haagen-Dazs

No carbon ceramics on the 2015?

The OP did not mention CCB for both his cars, so I assume they are both shod with the iron rotors.

As a tidbit, the CCB are worth 14~15lb on the F8X, so they would not explain the whole difference.

[Ghostriderf80]

Also 666 add 20 whp as I am told by BMW special sources. If you have ever taken them off they are like feathers.

[Paul-Bracq-BMW]

Some hilarious responses about the weight difference between the "regular" car and CP ;-)

But shame on BMW for making a so called "Competition Package" heavier than the standard car. Imagine Porsche doing it for their cars and all hell would break loose!

[Maxis]

So the"Competition Package" is heavier than the standard car.

[gmd2003]

Originally Posted by CanAutM3

The OP did not mention CCB for both his cars, so I assume they are both shod with the iron rotors.

As a tidbit, the CCB are worth 14~15lb on the F8X, so they would not explain the whole difference.

Crazy that my friends E92 M3 CP with DCT and a 100% full tank was 3615 stock . Proves BMW's lightweight marketing BS lol . Finally glad someone posted an actual full tank weight .

[CanAutM3]

Originally Posted by gmd2003

Crazy that my friends E92 M3 CP with DCT and a 100% full tank was 3615 stock . Proves BMW's lightweight marketing BS lol . Finally glad someone posted an actual full tank weight .

My DCT F82 weighs ~130lb less than my DCT E92 did, both with a full tank of fuel weighed on the same corner balancing scales.

[Dave07997S]

Just a footnote guys. I have seen cars with exact same builds, both with full tank of fuel still be off by 20lbs on the same scale.

Dave