Here is some original discussion about the tester, and how its tests, how its different then old tester... Some some info, isnt the answer to the original questions but will answer others. This was from back in July 07.
"Proposed SCTA / BNI Gas / Fuel Definition and Scrutineering Program
Background: The SCTA Rule book for years has made a classical distinction between “Gas” Classes and “Fuel” Classes. Traditionally, Gas meant gasoline that could be bought at the pump of the race car store or at the airport (AvGas), and Fuel meant Methanol and Nitro-Methane. These liquids have varying energy yields that were so dramatically different that it was deemed that they should run in separate classes. Over the years many companies began blending Gasolines that were higher in octane, had more additives (that were presumed to add power) and many components that deterred detonation (the prime killer of gasoline engines). The SCTA developed a theory that gasolines could be insured by using a test method called “The Dielectric Constant Test”.
They established a top limit for a dielectric constant measure of 2.3 on a relative test meter (the Digitron) as compared to cyclohexane as the zero point on the comparator scale. This method was used for some years until the Digitron meter went missing – then the testing stopped and we used a method of providing “Event Gas” and every one who wanted to compete in the “Gas” classes had to use gas form a specific source and their tanks had to be sealed to prevent tampering.
Recently we bought a new meter from Precision Fuel Testing Systems – the FT-K01 - and found that lots of “pump gasses” and some “race gasses” would measure more than the 2.3 on the DC Scale. The two main reasons for this were that the FT-K01 has a different test dynamic method than the old Digitron, and of even more impact is that many of the modern gasses are blended with ethanol for both environmental and engine safety reasons. The SCTA Board revised the rule for the limit of DC to be 6.0 and still call the liquid “Gas”. We are now faced by yet another dilemma. Race gas that has been in use at Speed Week for over 10 years and many off the shelf premium pump gasses measure over that 6.0 DC level.
Gasoline is a blend of combustible fuel made basically from parafins and isoparafins with many different airomatics added. All of these components are basic hydro carbons with varying molecular structures. The varying molecular structures decompose and re unite with oxygen from the air intake of the engine in different sequences and in different conditions. The result is that their reaction produces heat – pressure to move the piston. The key is to produce the pressure in and orderly sequence – yet in time to be useful to the departing piston by transferring power. A flame front that has lots of heat (pressure) that reached the piston part 50 deg ATDC is quite worthless to a racing engine. Nowadays, blenders are adding oxyegenates such as ethers (ethanols, alcohols etc) and Oliphants (double bonded loose valance molecular structures) and other stuff to their blends for many reasons, most of which relate to more effective burn sequences therefore more efficient fuel use and potentially more power. Pump gas manufacturers are also adding ethanols to improve burn completeness for environmental considerations albeit at some power cost. That is why some pump gases will fail the current dc tests – yet are probably acceptable gasolines.
The general consensus is that without adding Methanol or Nitro Methane but allowing any of these other modern additives – the maximum power enhancement one could expect with a perfect tune for the revised / reblended gasoline is about 4 – 5%. Generally this would require an engine built to the fuel spec (i.e. lower compression, slower or faster maximum revolution design, changed r/l ratios etc.) and that might in itself reduce the total power enhancement achievable. But – back to the problem – gas blends are changing and we use gas – we don’t own the gas manufacturing industry – how do we co-exist and achieve our objective “Methanol and Nitro – Methane not be allowed in “Gas Classes”
What should we do???
Our intent is that Methanol and Nitro – Methane not be allowed in “Gas Classes”. We do not care what mixture is being run in a “Fuel Class” entry. Blends of Gasolines are being revised constantly to improve many aspects of hydrocarbon fuel use. We can’t keep up with the testing methodologies nor the blending techniques, but we can insure that our original objectives are met.
Our original objectives were that Methanol and Nitro – Methane not be allowed in “Gas Classes”.
The addition of even 2 % Methanol to Gasoline will raise the DC meter to 20 or more. I don’t know why one would do that because Methanol does not yield much more BTU that Gas (about 1.5%). The addition of 1 % Nitro Methane will raise the DC constant to about 35 +. Again, I don’t know why one would do that because Nitro-Methane and Gas don’t mix well and you would get some very rapidly varying fuel mixtures during a single run. There are other additives and mixing components that also might impact the dielectric constant but do not constitute violation of our original intent. Again Our (SCTA / BNI) original intent was to prohibit Methanol and Nitro-Methane in Gasoline. Hence the establishment of a some DC ceiling of 20 or so would detect the possibility of gasoline tampering but not necessarily prove. "
Jon
