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      12-20-2010, 12:55 AM   #39
swamp2
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Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

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Quote:
Originally Posted by Eau Rouge View Post
Swamp, you went to a lot of trouble, but it was interesting reading.
Most of the effort was just digging around for measurements and weight values for the new base 3er. After that not much work really.

Quote:
Originally Posted by Eau Rouge View Post
E30 M3: 1,202 kg/220 hp = 5.46 hp/kg

E36 M3: 1,461 kg/286 hp = 5.11 hp/kg

Wt:HP ratio 5.11/5.46 = 0.94 (or a 6% decrease in the wt:hp ratio in the E36 in relation to the E30)
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E46 M3: 1,571 kg/343 hp = 4.58 hp/kg

Wt:HP ratio 4.58/5.11 = 0.90 (or a 10% decrease in the wt:hp ratio in the E46 in relation to the E36)
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E92 M3: 3.8 kg * 420 hp = 1,596 kg (Wt/hp source: Official BMW M3 International Launch information (Please see attachment page 17). Yes, the official “unladen” weight is 3704 or 1,683 kg which doesn’t quite mesh with the equally “official” 3.8kg-to-1hp. )

Wt:HP ratio 3.8 kg/4.58 kg = 0.83 (or a 17% decrease in the wt:hp ratio of E92 in relation to the E46)

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Over four generations the weight-to-horsepower ratio has been reduced by 6%, 10%, and 17% while horsepower has increased by 30%, 20%, and 22%. At the same time, weight has increased by 22%, 8%, and 2%.

It is probably a safe bet that the next generation M3 will follow tradition by being a better performer than the previous generation. Not knowing the extent to which performance improvement is targeted poses the greatest obstacle to getting a handle on this "puzzle". To wit: Will the next generation attempt to match the massive performance increase over a previous generation as was achieved with the E92M3 or will the performance increase be more akin to that of the E36M3 vis a vis the E30M3?

Scenarios

In order improve the kg/wt ratio of the 5th generation M3 at what would be a historical average – (6%+10%+17%) / 3 = 7.67%) – such would be achieved by increasing horsepower to 455 with no weight increase whatsoever would result in a “new” kg:hp ratio would be 3.51kg/hp.

If weight does increase as many suspect that it will, including myself, and let’s suppose the increase is a mere 25kg, an additional 17 horsepower would be needed to offset the weight increase while retaining a 7.67% decrease in weight to horsepower that results in the improved 3.51kg/hp.

On the other hand, if the design team of the next generation M3 targeted a replication of what was achieved with the E92 versus the E46 – a combination of minimal weight increase and massive power increase – the next generation would gain approximately 30 kg to weigh in at 1,628 kg (+2%) while power would increase by 92hp to 512hp (+22%), and that translates into a 3.18 kg/hp ratio.
Good analysis of the numbers. Many car manufacturers have claimed that this recent hp war is over. Even folks like Ferrari are working on equal power or slight power gains along with weight loss (although the 458 sure did not follow this stated path...). Your power and weight figures show both some of the hp war as well as the bulging trend and then also the slowing of the bulging, with perhaps even a reversal in sight.

Your last scenario, along with most of the other unrealistically optimistic estimates or hopes posted here in this thread are really that. They are simply unrealistic based on insuring the next M3 keeps its place in the BMW M line up, just below the M5.