Quote:

---

The 110 race gas is rated by the Research method.
The 92 pump gas is rated by the (R+M) / 2 method. Rated by the Research method it'd be around 97 RON.

If the 110 has tetraethyl lead in it, adding the unleaded to it will not change the octane rating in direct proportion to the mix, because TEL follows the law of diminishing returns. So, the first gram changes the octane more than the second gram, which is more than the third gram, etc. This means that the last gram in the race gas turns into the first gram in the unleaded and the result is higher octane than you would expect, although lower than 110.

If the 110 is unleaded, then the octane changes in direct proportion to the mix. So 50/50 would get 97/2 + 110/2 = 103.5 RON.

R.

---