quote:
Originally posted by nortones2:
Kev99sl: agrred that vehicles have a mix of sppeds and loads, but the mfr doesn't know whether the driver is the blue rinse type, or pushy rep. who lives on the autobahn or mway. The vehicle has to cater for both. As for "heavy" oils, the fuel consumption of small engined cars seems to be perfectly OK on the diet provided by 10w-40 etc. However, if your vehicle population includes a large proprtion of 4x4's with a large frontal area and 2 ton weight, then somehow there has to be a compensatory reduction. Albeit minute, when you consider returns like 10-15mpg from gasoline engined SUV's. What improvement in mpg will a 20 weight oil give? Raise the mpg to a range 11- 16.5mpg? Just curious.