How does synthetic yield better gas mileage?

[Bryanccfshr]

Nope. Very anectdotal infomercial.
How were variables controled (heat and humidity)? Were the oils ran up to operating temperature? Were the viscosities similar? How many runs of each?
Some one has to pay for "pimp my ride" Etc...It's advertisers.

 

[rpn453]

Quote:

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I recall seeing a test on one of the automotive shows on either Speed Channel or SPIKE. They put a car on the dyno, measuring horsepower with dino fluids in the car. Then after replacing engine oil, rear end and maybe transfluid (not sure) with synthetic fluids (I think they used RP) the dyno showed around a 5 hp gain. Does this prove synthetic reduces friction?

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No. If I remember correctly, the fluids they used were thinner. I think the engine oil was a thinner grade, and the transmission and differential oils used had a lower "W" rating. Since neither of those would have been up to full operating temperature, the gear oils would have been thinner and are likely responsibly for much of the power gain to the wheels. Using synthetic gear oils that can provide a lower "W" rating over conventional oils does make sense as a means to increase fuel economy in a lot of applications, since they run relatively cool under the operating conditions that most users will subject them to, especially in colder climates.

 

[Bryanccfshr]

The infomercial.. http://www.royalpurple.com/sport_truck/sport_truck.html