Quote:
Originally Posted by usmc2801
wanna fabricate a cage for my bike???
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You mean like this? LOL!
Quote:
Originally Posted by JClark
I'll let Adam tackle the man hours part, but its a lot of long, long days. He's done many cages, but this is his first in an E36 BMW so it will take longer. Now that he has measurements of the whole thing, if he was do do another one it would take much less time.
Estimating the number of feet used (by what he have left over) it's about 107-110 feet of 1.75x.095 DOM steel @ 1.7lb/ft = 182-187lb. I'll put it back on the scales next week to see exactly how much we used.
You can make a bare bones cage and have it come out lighter, but I have to make a minimum weight requirement for the class I race in, so might as well have the weight be in structural tubing than in a lead block behind the pass seat. At this rate, I still may have to add up to 40lbs back in.
Once stripped, these cars are extremely light in the back, which is why we went super strong behind the driver, and on the lighter end in front of the driver. Since I prob have 40lbs to work with after we're done, I can add weight back in where needed.
As a general rule, it's faster to be light and unbalanced than heavy and balanced so that will always overrule, but I have to make that minimum weight requirement anyway. Hoping to hit it with a +2-5lbs buffer for scale variance (yes they do weigh you and check periodically).
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Around 190lbs is actually lighter than I thought it would be, I was thinking about 240~250lbs. Adding weight to the car sometimes can be to your advantage, it is all about getting more out of it than what you put in. Not only because of safety, the increase structural rigidity alone is well worth the 190lbs IMO. I've seen and read about people in Japan doing hybrid cages, replacing the higher parts of the cage with titanium to save weight and lower the the cg of the car. Not sure if it is legal for SCCA/FIA spec.
I wish I can have a track car like you....
