By John Copeland

In the previous four segments of this series, we've discussed the specific factors that influence fuel performance, commonly used fuel tech procedures, and the subject of oxygenators and other additives. Hopefully we've laid the groundwork for this month's subject: the actual test results. We've tested fuels and additives, both for performance and for legality.

Now on to the additives. In order to minimize non-addictive variances, we mixed all additives with a base fuel of Shell Premium, 93 octane, purchased in Lafayette. This base fuel was then mixed with Burris oil at 20:1, as outlined above. That resulting fuel read ?36 on the Digatron meter, just as before.

The test procedure was as follows: the Digatron meter probe was immersed in a measured quantity of base fuel. Then the additive being tested was slowly added to the base sample until the meter reading exceeded 0.00 or until it became apparent that the testing would not exceed the 0.00 mark. At that point, the percentage by volume of the additive being tested was calculated to determine the threshold of legality for that particular additive. Here are the results:

To help you interpret these results, 1.00 percent by volume is 1.28 ounces per gallon, or about one tablespoon of additive per gallon. From these results we can determine that it is extremely unlikely that a fuel mixture could pass the meter and contain enough Propylene Oxide, Nitro Methane, Nitro Propane, or Ethyl Ether to accomplish any measurable performance gain. It is also apparent that the Digatron test is insufficient to detect significant quantities of the other flue additives tested. Obviously, other testing procedures will be required to detect these.

There is a third test worthy of consideration that has come to our attention since the second segment of this series was written. We are indebted to Art Verlengiere of RLV and Mark Weaverling, the highly regarded West Coast karting innovator, for sharing their experience with this test with us. The testing procedure is relatively simple, although it requires more accurate measurements and a careful procedure.

Exactly equal amounts of the sample fuel, water and straight methanol are combined in a graduated cylinder or other accurately calibrated container. The methanol will completely dissolve in the water, but the fuel will separate and rise to the top. Once the fuel has separated from the water and methanol solution, the line of separation should be exactly at a point two-thirds up from the bottom of the container.

The use of an accurate graduated cylinder of at least 100ml capacity is recommended, allowing use of 30ml samples of each item. In this case, the separation line between the fuel portion of the mixture and the water/methanol portion should be exactly at 60ml from the bottom, leaving the fuel portion at exactly the 30ml that were originally added. Any reduction of this 30ml volume would indicate the presence of some additive that has left the fuel and gone into solution in the water/methanol solution. For our test, we again used Unocal race gas as the base fuel and used 20 percent of each additive being tested. (See chart #4 for results:)

As you can see, this test does a good job of picking up some of these additives, particularly the Nitro Propane, 1,4 Dioxane and Klotz Coxoc. While it's a little more difficult to do this test, it's another valuable weapon in the tech man's arsenal and its occasional use should help deter fuel tampering.

As this is written, we are in contact with tech officials at the National Hot Rod Association, International Hot Rod Association, and the U.S. Powerboat Association, all exchanging information about gasoline tech inspection and sharing ideas to help police this area. We'll pass along any new developments as they become available.

We've pretty well used up our space for this month, but don't despair. Next month we'll have specific test results on the performance of using the various additives we've discussed here. We'll give you actual dyno results from using each of these products, vs. unadulterated race gas. Hopefully we'll see just what you can expect to gain from using these additives. But you'll have to wait until next month for that. See you then.

The Question of Fuel - Part 6