Manthey in Excellence Magazine
#31
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That said, I don't think he's trying to say that, in terms of FEEL, removing 33 pounds of unsprung/rotational mass at the wheels is the same as pulling 198 pounds out of the car by changing seats, removing A/C etc. That much is obvious -- but he is directly addressing something all of us have known for a long time: that cutting weight at the wheels is more valuable than deleting or minizing the weight of a "static" part somewhere on the car. He's assigning a ratio, and going on record with the ratio Porsche uses. That said, the fact that he backs away from Porsche's ratio is highly interesting to me -- a hint that it's a bit less than a perfect model.
Remember that this is the guy who was tasked with developing Porsche's 911-based race cars when Flacht got too busy with the RS Spyder. That tells me that 1) he knows what he is doing, 2) Porsche thinks he knows what he is doing, 3) Manthey has an unprecedented relationship with Porsche and Weissach-Flacht, and 4) Manthey would know Porsche's parameters.
Frankly, I wouldn't be surprised if some of the mods Manthey made were based on hints from Weissach -- though it's also possible that a line is drawn when it comes to the road cars. Such matters are highly complicated these days...
pete
#33
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Perhaps what Manthey is saying is that the “efficiency” of removing unsprung rotational mass is 6 or 7 times greater than the efficiency of removing sprung mass from the vehicle’s body in terms of the benefit to some given performance metric. For example, if hypothetically a 10% reduction of total vehicle mass (holding everything else constant) resulted in a 1.5% reduction in ¼-mile drag time (just a random example), then you could say that removing vehicle mass had an efficiency of 15% (10% * 0.15 = 1.5%) as measured by the results of that particular test.
Perhaps they have some particular test in mind (a lap of the ‘Ring?), and they believe removing wheel/tire mass is 6 or 7 times more “efficient” (in terms of the change in results it produces) than reducing sprung vehicle mass? Just a thought.
I too would love to know more about this metric, considering the high quality of the source.
Perhaps they have some particular test in mind (a lap of the ‘Ring?), and they believe removing wheel/tire mass is 6 or 7 times more “efficient” (in terms of the change in results it produces) than reducing sprung vehicle mass? Just a thought.
I too would love to know more about this metric, considering the high quality of the source.
#35
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