I'm using Wallace Racing Calculator to determine my Conv slip %

Using 132.66 mph/7000 Rpm at the line/ 4:56 gear ratio/ and the advertised roll out of my tires as 97"

I came up with 17.511 %


I tried varying the rpm and tire size a little figuring I might be going a little under what I think I see on the tack or thinking I might have to acct for tire growth but it still comes in as what I think is a way high slip percentage.

For some reason I was expecting somewhere around a 5 or 6 % number.

Can this be right?