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In terms of design, it looks to me like the BCR standard replacement and the Best Machine caps are very similar. However, IIRC, BRC used some type of 6061 vs. Best using a 7075-type aluminum. What are the pros & cons of these two different materials, everything else being the same?

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In terms of design, it looks to me like the BCR standard replacement and the Best Machine caps are very similar. However, IIRC, BRC used some type of 6061 vs. Best using a 7075-type aluminum. What are the pros & cons of these two different materials, everything else being the same?

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borrowed from the internet...

Internet facts:

7075 T6:
Ultimate Tensile Strength 83000 psi
Shear Strength 48000 psi

6061 T6:
Ultimate Tensile Strength 42000 psi
Shear Strength 27000 psi

7075 T6 is serious stuff, and is very expensive. I would be careful of someone claiming to be selling it.

Hope this helps

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Every body has a reason to use a certain material for any given purpose. Just because one material has a higher tensile strength does not make it superior for a given product. 7075 is very hard and is no where near as shock absorbant as 6061 materials. I tested multiple types of aluminum and had likely the # 1 Metalurgists in motorsport to offer his opinion on what material would be best before deciding on what we finished up using. There is a reason for using what we did. By the way -- our failure rate was pretty much non existant. I sold thousands of caps over a fifteen year period and never had a complaint of failure on one cap. Now was there an engine failure --i am sure there was but never ever had even a picture of one of my caps that had broken. I never ever had a customer rag me that they had a part fail due to material. Just food for thought.

Greg

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I'll second that! Its not always about absolute tensile strength.