I don't think that formula is a good idea,it will only tell you the really broken ones. Ut as an example i had a 07 g2500 gmc van last week and it had a 4.8 liter so with you formula 4.8 x 40 = is 192 now look at this graph before [2007 GMC Savana 2500, Fuel ... Login to read more.

Files Referenced: