Have no formula to offer.
Best I can offer is use a heavy string in place of the belt to come up with the total distance the belt will have traverse. With the string you won't be able to put any force on the tensioner. It will be fully extended. So the length you come up with be too long. A WAG is an inch shorter than the string might be ok. But you might end up having to try 2 (or more) belts before you find the right one.
Another thought. Any chance the company that offers the 2.95" upper pulley and OD lower pullley provide any recommendation for a correct belt to use?
Best I can offer is use a heavy string in place of the belt to come up with the total distance the belt will have traverse. With the string you won't be able to put any force on the tensioner. It will be fully extended. So the length you come up with be too long. A WAG is an inch shorter than the string might be ok. But you might end up having to try 2 (or more) belts before you find the right one.
Another thought. Any chance the company that offers the 2.95" upper pulley and OD lower pullley provide any recommendation for a correct belt to use?
