how much 91 octane do you mix with 104 octane to get 100 octane?

i kow there should be a conversion table on the cans, but there is not. i almost always use torco so im not up on the mixing

 

Provideing you have a 25 gallon tank starting with empty tank it takes 7 gallon of 91 octane and 18 gallon of 104 18x 104=1872
7x91 = 637 is thus explained add 1872 and 637 together and you should have 2509 divide 25 into 2509 and you should have 100.36 octane i hope this helps thanks

 

Here's a few examples on how to determine octane rating.:

91 octane x 5 gallons = 455
104 octane x 11 gallons = 1144
455 + 1144 = 1599
1599 / 16 (total gallons) = 99.93 octane

91 octane x 4 gallons = 364
104 octane x 10 gallons = 1040
364 + 1040 = 1404
1404 / 14 (total gallons) = 100.28 octane

91 octane x 3 gallons = 273
104 octane x 9 gallons = 936
273 + 936 = 1209
1209 / 12 (total gallons) = 100.75 octane

By changing the number of gallons for each octance you can figure out the total octane rating. Email chayes1213@charter.net and ask if he still have the Excel speadsheet on octane rating. He sent it to me awhile ago but I deleted it.