Fuel check question

[Travis Miller]

Originally Posted by Jody Lang

I have a question.

A bunch of us were having issues with fuel at a Division race in Sonoma. A few I believe were DQd a few on the edge. We were told to add some fresh, replace with fresh all that good stuff.

I bought some fresh fuel right out of a sealed barrel. Took it up and had it tested. I was told it was perfect. I asked what perfect was, and was told that it was right in the middle of the scale for the temperature.

If when a fuel goes stale or loses it's light ends from sitting in the car too long my question is this.

Why does fresh brand new fuel start out at the middle of the scale and not toward or at the top???

If going bad from sitting or you got the last 5 from the bottom of the barrel usually equates to flirting with the bottom of the scale, shouldn't fresh fuel start life at the top of the scale?

NHRA gives a plus or minus on its fuel measurements. Starting in the middle of the scale on fuel gives the competitor a cushion due to a deviation in production tolerance from the base reading of each fuel supplied by the fuel manufacturers.

Fuels that lose their light end chemicals can read the same as fuels that have had extra oxygenators "added to enhance the fuel". Since the meter reading goes in the same direction for lost light end chemicals as well as for added oxygenators, when the reading gets outside the allowable parameters, the fuel fails.

That being said, what can cause fuel to go bad. The first thing is that some racing fuel is more stable than others. The less stable fuel will lose its light end chemicals quicker than others. We have proven this by simply leaving a cup of fuel open to the air. Some fuels only take a few minutes to go bad, while others have a much longer "open" time.

For those having trouble with fuel, a few things can be checked. The jug that the fuel is stored in can be bad. A simple test is to tighten the lid and turn the jug upside down. If fuel leaks out of the lid, that is where the light end chemicals are escaping.

Check the cap on your fuel cell. One competitor who was consistantly having fuel fail on his first qualifying run discovered a crack in the cap that was allowing the light end chemicals to slowly escape over the period of time the car was stored between events.

Be sure to put a cap on the tank vent when the car is stored between events. Just don't forget to uncap the vent before you race.

The fuel check man testing the fuel will ask for another sample if the fuel tests bad on the first draw. That is usually caused by stale fuel in the length of line where the valve is mounted for fuel checking. That fuel does not get recirculated, can go stale and needs to be flushed.

If you do experience a failure at fuel check, bring your fuel jug down to have the fuel checked. Good fuel that went into the car and then fails can mean there is something wrong with the fuel system in the car. It could be contaminated foam in the fuel cell or a contaminated fuel filter.


Travis Miller

(Disclaimer: Opinions expressed by me on this forum are exactly that, my opinions.)

P.S. for 69Cobra....Fuel cannot be scooped out of the tank. Fuel must be drawn from a fuel line that is part of the fuel system. The best way is to use a fuel valve designed for drawing fuel.