Open letter to CRB re: Spec Fuels

[Marshall Mauney]

Board Members:

In the spirit of "Make it easy, make it fun", I would like to request a change to the rules covering the use of mandated or "spec" fuels.

It is clear that it is in everyone's best interest to control the fuels in use at our events, and many would argue that a mandated fuel selection, either single-spec or a selected list, is the most effective method for achieving this goal. However, I think it is equally clear that changing the fuel used in certain vehicles can create a significant amount of effort in tuning, and can risk damage to an engine. The range of specific gravities and stoichiometric ratios in available, currently-legal race fuels is wide enough to cause significant problems for teams whose cars have open-loop mixture control systems (such as FE), or systems with narrow control ranges.

Therefore, when a single spec fuel is mandated for a given event, such as this year's June Sprints, it creates a potential for problems in certain classes. This would be far easier to work with if the supps were to include the necessary relevant information about the fuel to be mandated; this information should include brand, blend/designation, specific gravity, stoichiometric ratio, and ethanol percentage.

As an example, the fuel information provided in the supps for the Runoffs is relatively complete, giving enough information for the competitors to source data from the manufacturer, and also giving time to work with the different allowable fuels prior to the event to insure that they work well in their applications.

In the case of the Sprints fuel, however, the only information given was octane level and "ethanol free", which is not enough information to either source detailed specifications or make preparations to run the fuel. "Run it and hope a piston doesn't melt" is not a rational approach to engine tuning, but that is what we are left with when insufficient technical data is available prior to an event.

In summary, while I am in favor of limiting the fuels that can be run at our events, I feel that when a spec fuel is mandated, we need to provide the competitors definitive identification of said fuel well prior to the event.

Thank you for your time and attention.

Marshall Mauney
Milwaukee Region FE #64
Nat'l Comp License 255530

[Marshall Mauney]

215 views and not a single comment?

[Brett Lane]

I've got one. If I remember correctly, certain levels of ethanol was causing engine problems a few years ago. If Road America and the Chicago region can guarantee there is no ethanol in the fuel and Enterprises signs off on it, that would be good enough for me.

Enterprises should have the final say, and be held to a certain level of responsibility if there are problems asociated with this fuel.

If ethanol is not the problem, shouldn't Enterprises be there to either supply or reflash everyone's ECU?

I've been out of the FE class for a while now, so please correct me if I'm wrong

[Daryl DeArman]

Just a thought....perhaps they are negotiating with different fuel suppliers and aren't sure which fuel will be settled on too far in advance.

Secondly, if you knew exactly what fuel was going to be used could somebody so inclined doctor their fuel to have the same DC and spec gravity??? Just a thought. Honestly, I have no idea how difficult that would be for somebody so inclined. I did race in a series with spec fuel that had a marker added to the fuel so that you couldn't brew your own so to speak.
In other words your fuel sample had to have the same DC, specific gravity AND marker.

[Marshall Mauney]

I've got one. If I remember correctly, certain levels of ethanol was causing engine problems a few years ago. If Road America and the Chicago region can guarantee there is no ethanol in the fuel and Enterprises signs off on it, that would be good enough for me.

So you're not worried about the stoich ratio? How do you set your fuel pressure to 1) get max power and 2) avoid an over-lean situation? Legal fuels in SCCA can have a stoich ratio anywhere from 13.7 to 14.9 - and that's only from a sampling that I've been able to find. This is a wide enough range to put you either way down on power or over-lean to the point of engine damage.

If ethanol is not the problem, shouldn't Enterprises be there to either supply or reflash everyone's ECU?

Flashing the ECU doesn't solve the fact that we don't have a closed-loop mixture control in our cars - nor does anyone in a class running a carburetor. It's not just about FE - it's a general principle.

I would also point out that with the limited number of sessions prior to qualifying (notice that the spec fuel for the Sprints isn't even available until halfway through the test day), someone whose "normal" fuel is radically different from the "spec" fuel will be at a significant disadvantage to someone whose "normal" fuel is very close to the "spec". Keeping the fuel spec secret makes that advantage much more pronounced.

Secondly, if you knew exactly what fuel was going to be used could somebody so inclined doctor their fuel to have the same DC and spec gravity???

There are lots of ways around this using chemical tracers, color, etc. Frankly, though, I would have no problem with the region not exposing the DC or total composition of the fuel - that's not something that has any effect on engine tuning. All you really need to know is stoich ratio and specific gravity to be able to calculate an expected tune from your baseline. Competitors don't need to know the performance characteristics of the fuel, just the information required to set up for the required mixture.

I did race in a series with spec fuel that had a marker added to the fuel so that you couldn't brew your own so to speak. In other words your fuel sample had to have the same DC, specific gravity AND marker.

Exactly. Even if you knew that the fuel was going to be Sunoco 260 GTX, for example, you wouldn't be able to duplicate the total profile.

[Brett Lane]

Hey Marshall,

I'm with you, and fully understand your frustration here. They should provide the fuel required during the entire event.

No one was commenting on your thread, so I thought I'd go ahead and throw myself under the bus! How'd I do?

[Marshall Mauney]

Hey Marshall,

I'm with you, and fully understand your frustration here. They should provide the fuel required during the entire event.

No one was commenting on your thread, so I thought I'd go ahead and throw myself under the bus! How'd I do?