Quote:
Originally Posted by 304065
On we go. One invisible mod is the 130mm pulley instead of the small '66 one, this turns the fan faster for better cooling (yes, I know we debate this). The question: will it fit inside the '66 engine mount? Answer?
130mm pulley: no way to change the belt without a partial drop.
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The reason to abandon the early motor mount (cradle) is the fact the mount offers less structural rigidity than later versions. All of the later mounts offer a reinforcing plate that mounts directly to the case.
As for the fan cooling better with a larger pulley, the only way there is a
debate is if one side totally ignores the aeroelastic characteristics of a ducted-fan configuration. The rpm of the engine/ crank dictates the pulley diameters. Low rpm engine can use a large pulley. 6100rpm defined as low rpm. John's engine will most likely spend a great deal of time well above that number.
All factory Porsche race engines that used a vertical fan addressed this issue. They used small diameter fan to reduce tip speed and smaller pulleys.
I have posted speed charts and ducted fan theory and the opposition has used anecdotal evidence. There's no debate, science and math vs. "we did it and it worked !" It's the big lie. No matter how many times you tell a lie, it's still untrue.
Even the later street engine addressed this issue with a two speed pulley. This pulley allows the fan to spin slower than the alternator. Why is that? Porsche factory doesn't understand dynamic harmonics as they apply to ducted fans? No, the factory gets it. It's the goofy "bigger is better" folks that don't understand.
Rant over, you can put your head back in the sand. Thanks for coming up long enough to listen.