Originally Posted by HinshawWRX
As very little is in the intercooler/system at any one time, you'll never truly see any difference.
If you cut your stock top mount open right now. Ever single surface of it will have a fine oil film. The if the thickness of the oil film was known and the heat transfer coefs of the oil were known you could easily do the math to see how much it reduces the efficiency by. Octane wise, we know the octane of the oil, we dont know what mass is in the air stream. And the ratio of the oil mass to the fuel mass in the intake charge will determine how much it lowers the octane by.