Using heavier viscosity oil to increase fuel economy?

[n0rt0npr0]

James,

I switched from 5w30 to 10w40 to slow the oil consumption of my Geo Prism. (its got worn valve seals) I never run it low, I was just tired of topping off every 500 miles. I now top off every 2000 miles. But, I am getting better FE also. 31mpg consistently on a certain route as compared to 29mpg before. I think it does something for efficiency if you are mostly doing highway driving.
Since it definitely does lengthen engine response time, it will hurt "city" FE.

[chesspirate]

so, in this thread we've had confirmation of either "no change" or "slight increase" in FE... Why? this should be looked into a bit deeper i think, and if i wasn't under warranty, i'd try it myself.

I guess I could test on my wifes civic, but she isn't as precise as i'd like, so...

[jamescartagena]

Thanks for your results! I'm not noticing any lag with city driving but do notice the increase in mileage.

[jamescartagena]

I agree! I'm planning on trying it on my 97 F150. Average over the past 25000 miles is 20 mpg. I already have the same brand of oil (Walmart SuperTech 20w50) in the garage. Hopefully I can get to change the oil this weekend. This truck doesn't get driven as much as it used to 100 miles a week vs 500 miles a week. But, I hope to see some positive results, but will take more time to report them since I can go about 500 miles on one tank of gas.

[SVOboy]

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[krousdb]

Originally Posted by SVOboy

I mean, the insight uses 0w20, but this lubedev's ideas that would be the worst possible oil, yet all the ford and toyota hybrids use it!

While I can't speak for other Hybrids, I can tell you that Toyota recommends 5W-20 for the Prius. I just choose to use 0W-20. If it's good enough for 110 MPG over 1400 miles in my Prius, just think what I would get with a good gear lube oil, say 80W-90?

[SVOboy]

fuel economy forum
vegan recipes
green home improvement
honda gas mileage

[ZugyNA]

Originally Posted by brick

If you tally everything up, the total "percent boost" if you do everything should be 95-195%. That would bring my car up from the stock EPA estimate of 28.5mpg combined to 56-84mpg combined. Going by the raw numbers instead would put me at 49-71mpg So...does that pass the sanity test?

I'm sure some of those things do help somewhat, but I get the impression that not much actual research has gone into their claims. But thanks for the link just the same.

This old guy has been doing mileage research for 50 years....though some things he posts are political or a bit exaggerated. I don't really think too much of the Torco oil...except for the 2-cycle GP7 for the PIB.

As far as adding up those percentages...yea that's a bit overdone also...but don't think you could go wrong TRYING the things he mentions.

[WisJim]

The auto companies specify low viscosity oil in order to marginally improvrove their overall company fuel efficiency ratings, so they can comply with the government standards. If heavier oil gave better fuel efficiency in a new vehicle, they would be specifying it. There are a number of things on that website that make me want to laugh (or cry?), such as "NO engine can operate efficiently without some acetone in the fuel".

He also recommends overfilling the crankcase by one quart--the road to main seal failure on some cars.

I think some of his ideas are okay, and found elsewhere, but all in all I would take his info with a grain (cup?) of salt.

[Matt Timion]

Originally Posted by WisJim

There are a number of things on that website that make me want to laugh (or cry?), such as "NO engine can operate efficiently without some acetone in the fuel".

I think that any time people speak in absolutes I begin to stop listening to what they are saying.