It should be, shouldnt it? Makes sense.

What is interesting to me is that when Chevron was trying to push isosyn 15w-40 Delo a few years back, they proved in an SAE paper that there was negligible difference between running their oil and Delvac 1.

Look closely at the test data. You could get the same type of results just by having the same driver in the same truck without changing anything, just doing a bunch of test runs.

The problem with these tests is not just the variables in driver/truck. The problem also is the way they can interpolate the results. Notice the arrows where it is says "acceptable 2 percent range". That means that they ignore values that they don't like when they do the "increased mileage" calculations. If I do my own calculations without this fuzzy math, the "test vehicle" with Amsoil actually got worse mileage (5.771 gal.fuel consumed) than the control vehicle ( 5.629 gal consumed) with Texaco.

Just as way of showing more about J1321, this is an example of a test run by PAVE that showed a 3.04% variance just by changing the thermostat. http://www.evanscooling.com/assets/pdfs/Type-II-Fuel-Report-for-Evans-final.pdf

Exactly my point. the same can be had with lower viscosity CONVENTIONAL oil, in this test.

Then drop it down to 0° F.

Not the point of the test. Stop changing the subject, Pablo.

Didn't think I changed the subject, just pointing out the obvious. Point is - although the usual guys want to twist it - you can get a small but noticeable change in MPG using oils with a lower viscosity at any given temperature. I don't think Amsoil is cheating, lying, conniving or otherwise falsifying the results in any way.

You mean that a 5W-40 provides better fuel economy than a 15W-40?
Who knew?
I have no doubt that the fuel savings claimed are real, but there are a number of synthetic 5W-40s that probably would have done as well.

It should.

Exactly.

That's not the point of the this thread. I have no doubt in my mind that ANY 5w40 oil would have produced similar results when compared to 15w40 like it was in this test.

I personally don't like going down in viscosity for the sake of fuel economy. The engine manufacturer specified a certain oil thickness FOR A REASON.

Just my on the matter

I don't think any of the viscosities selected are outside those recommended (?)

Definitely within the recommended viscosity spec... for that specific temperature.

Like i said though, the same can be had with a Conventional oil so besides the extended drain ability of the Synthetic, (which is what they should be advertising) it's a pointless test.

Bingo!




Exactly! Its an adverstisement. Put a SOPUS product, or a Mobil product in the sump and expect similar results. All this was is an attempt by a marketing dept do show Amsoil gave better mpg, when in reality it was the change in viscosity that was responsible for the gains. IMO that would be the letter "D", in the word FUD. And I'll still bet they did everything they could by changing shift points etc to tweak the results a bit more. Once again JMO.

As a side note Amsoil isn't the only company that uses FUD in their advertising.

The question is not so much whether the SAE test method is valid, but rather, what should we conclude.

Do we conclude:

1. AMSOIL Synthetic Lubricants Increase Fuel Economy ( as the title of the article says), or

2. Lower Viscosity Lubricants Increase Fuel Economy, or

3. Synthetic Lubricants Increase Fuel Economy, or

4. Lower Viscosity Synthetic Lubricants Increase Fuel Economy, or

5. All of the above

Tom NJ

I know what Amsoil wants us to conclude. LOL