CKRC Forums

Mark,
What is the cyclohexane testing method? What is the tolerance/variation that the club allows, and do we have a sense as to what level of “contamination” from prior fuel would result in a failed test?

While I suspect it might be a while before I and my family will be finishing in a position where we’d be subject to fuel testing, I’m curious as to how diligent we’d need to be with running the tank down before refilling for a race.

Jason

I have no idea what a cyclohexane test is (Mark will answer) but most of these questions can be answered in our supplementary regulations in section 36.2. A lot of words to say the club wants everyone on the same fuel, like tires and engines in many classes.

I find the easiest way to comply with the regs is to just use the spec fuel -- drain the tank before or after practice and put in fuel purchased Friday evening or Saturday morning of the event. Fuel from the week(s) before is 'likely' OK, but DQ's sour my mood so I try and avoid them. I've seen fuel in every kart checked after qualli on occasion, not just top-5.

...A follow up on ethanol in the Calgary area... I was chatting with one of our PQ folks today, and he mentioned that a certain big box chain sources their gasoline directly from Edmonton, and therefore has ethanol in it, and a another non-major brand has begun adding ethanol in the Calgary area to take advantage of available incentives.

Jason

JasonL wrote: Tue Sep 29, 2020 10:34 am Mark,
What is the cyclohexane testing method? What is the tolerance/variation that the club allows, and do we have a sense as to what level of “contamination” from prior fuel would result in a failed test?

While I suspect it might be a while before I and my family will be finishing in a position where we’d be subject to fuel testing, I’m curious as to how diligent we’d need to be with running the tank down before refilling for a race.

Jason

Its a long story but we once had a competitor fail with "Spec Fuel" that was down to his plastic fuel tank leaching chemicals from previous fuels ... Once we transferred the fuel to a new tank it passed !

Clarification:

The meter we use does not measure cyclohexane, it is supposed to use it as a reference. However, since you can't just walk into 7-11 and buy a quart of cyclohexane, we simply use a sample of fuel from the approved source, zero the meter against it and then check competitors fuel for variance from that sample. I don't know what the allowed tolerances are but I want to say it's in the range of 3-5 units.

I don't know -but I strongly suspect- that differing oil mixes and temperature will have an effect on the readings.

36.2 The Digatron DT-15 fuel tester will be set at –75 in Cyclohexane. The competitor’s mixed gas and oil must read
zero or negative to be legal (+1 is illegal). This rule does not allow the use of performance additives, only gasoline
and oil may be used.
Spec gasoline the fuel must register +/10 points on the Digatron DT-15 fuel tester after that meter has been zeroed
on that gas as mixed with the specified oil(s) if required by class regulations.
Competitor’s fuel samples will be taken from the kart’s gas tank, fuel line to the carburetor or carburetor bowl.