Having read the whole study, i've come to the conclusion that the test is severally flawed with many reasons...

• two different trucks
• two different drivers
• too many variables in driver error to accurately calculate fuel consumption
• test truck received a SECOND FLUSH
• A dyno with controlled weather conditions was NOT USED

Looking at the baseline and test results, the before / after numbers of the test truck using Amsoil are so small that i'm shocked how any actual and TRUE numbers were pulled from this.

The fact that the test truck received a SECOND flush of all the fluids alone could account for the 6% difference. I feel that it could have gotten the same results with a SECOND flush of conventional lube, since the second flush would help to further remove / clean the internals, helping everything run more efficiently, resulting in improvements.

I feel that a dyno and lab controlled testing is the only way to truly spot the difference. Old engines with 750,000 miles of wear should not be used as the testing equipment. A new block that is fully broken in should be used.

It's the same with Royal Purple and their silly oil tests.
They take a car with old synthetic oil of another brand and run it on a dyno, taking HP readings. They then change the oil to RP and run another dyno which results in more power, claiming that it's their oil which is the cause.

^The same can be had by simply changing the used oil with new oil OF THE SAME BRAND!!

Well then the testing procedure is bogus. I can achieve a 6% difference in my fuel consumption average by simply letting off the gas 200 feet sooner then test run #1 and bam! 6% difference and i didn't change a thing with the car!

A vehicle should be strapped to a dyno AFTER receiving 2 or 3 oil changes of conventional lube having the engine idle for x amount of time between changes to circulate the oil and leave a good film on every part. THEN begin testing.

Same with lube #2. Do a few oil changes, running the engine x amount of time to insure the oil has plenty of time to do it's thing and leave a good film on all the internals. THEN strap the car to the dyno and begin testing.

That way it's 100% accurate and the oil inside is 100% concentration of oil #1 and it's formulation vs 100% concentration of oil #2 and it's formula.

It makes sense to me.

Then fire off a note to the SAE telling them that their procedure is flawed.

Amsoil also let some noob claim in their magazine that moly is a solid and bad for engines. Amsoil has very tacky and sketchy marketing sometimes.

Why wouldn't MPG be improved if a lower viscosity lube is used in the engine, tranny and differential?

Why wouldn't MPG be improved if a lower viscosity lube is used in the engine, tranny and differential?

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

Why wouldn't MPG be improved if a lower viscosity lube is used in the engine, tranny and differential?

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.

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.

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

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.

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.

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

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

Just publishing this study, in my eyes, lowers the credibility of Amzoil claims even lower, similar to the "4 ball" results.

Come on, it's a "study" in the AMSOIL rag, not an SAE/Lancet publication, but a fluff piece for the already interested/initiated/converted.

Don't know how that detracts from what anyone thinks of the company, when any company is free to pay money to put their statements in the middle of your evening news without your participating in their koolaid.

In heavy vehicle drive-lines there is a lot of lubricant to get up to operating temperature - in my case a total of around 30+ quarts(32+ litres) in each vehicle.

SAE/Lancet

Yep. And they still use misleading marketing to this day.

It's called math, bud.

Come on, it's a "study" in the AMSOIL rag, not an SAE/Lancet publication, but a fluff piece for the already interested/initiated/converted.

Don't know how that detracts from what anyone thinks of the company, when any company is free to pay money to put their statements in the middle of your evening news without your participating in their koolaid.

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.

I noticed the same thing, they plainly cheated. How shameful.

You guys don't even understand the test. How can you criticize it? Take your Amsoil hate hat off and read the text, nice and slow.

You call something cheating and a company shameful because you jump to conclusions? Wow.

OK my friend. I will walk you through the reading. Look at the page 3 of the "study". There are 7 test measurements. The highest 3 are discarded and the lowest 3 (1.00) were used to calculate the 6% "improvement".

Is this the way to do an objective study?

There is no hate on my part, just science.

I did read it.

You do not understand how the J1321 (type II) standard works. Even if the run 1 was rejected on legitimate ground (I doubt), the testing should have been stopped at the run 6 as you have 3 results already within 2% (1.04-1.05), instead, run 7 was added and the lowest readings of 1.00 were selected. This is in clear violation of the J1321 protocol.

If you use the proper calculation, the fuel saving is in the 2% range, as expected.

How can you argue when the facts are obvious?

Wait, you said the Amsoil test vehicle got worse MPG. Now you are changing your tune?

You can choose the readings from the test to get the numbers you do and Amsoil chooses the most consistent under 2% numbers.

Why do you put words in my mouth? I never said that.

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.

I noticed the same thing, they plainly cheated. How shameful.

such baloney. It's ADVERTISING! Everyone plays with the numbers.

I don't get it why Amsoil is such a target. We've all heard equally questionable claims from other manufacturers.

Why the 'grudge match' against the big A?

Maybe it's advertizing all right, but they made it appear like a study while clearly it's not. A lot of not so sophisticated readers will fall for this "scientific" study. This is the same misleading advertizing they do with the 4 ball scar test and similar.

I actually think Amsoil is a good product, but they employ some really sleazy marketing. I sure hate being lied to.

Maybe it's advertizing all right, but they made it appear like a study while clearly it's not. A lot of not so sophisticated readers will fall for this "scientific" study. This is the same misleading advertizing they do with the 4 ball scar test and similar.

I actually think Amsoil is a good product, but they employ some really sleazy marketing. I sure hate being lied to.