Fuel talk - octane, ethanol, etc.

[JasonL]

Sites won't go back and forth - aside from some disruption that forces them away from their typical supply point. With federal and province carbon & cap and trade regs, use of non-ethanol gasoline is much more expensive for suppliers.

This is why things are moving to E15. Fuel producers/importers must buy carbon 'credits' to enable the sale of fuel. As ethanol is plant-derived, participants get a break on the ethanol component in gasoline - and the cost of ethanol is lower than most other alternatives, so there is an incentive to maximize its use in fuel. Originally, the industry could get by putting it only in regular gas, then as things got tighter ethanol got pushed out to premium, and now some are trying to go to higher concentrations.

[newson48]

The Co-op station I got the sample from was our spec station in Strathmore. Around August of 2023.

Cheers
Blake

[JasonL]

I’ve found the ratio for manual jetting.
Pure ethanol wants 1.6 times more air than gasoline for optimal combustion. At a 10% blend, that means we should be going with jetting 6% bigger than with pure gasoline.
We’ve been focusing on the main jet - but this would also impact the needle jet - any idea how much of a difference each line in the needle makes?

[Jackmazury]

The needle is a much more finite adjustment. Generally the needle for Rotax here is run on the richer positions in Senior and Junior, and it is a spec needle so you can't richen further. This is also true for the inner and outer jets on Rotax.

I suggest getting the main jet correct and then fine tuning with the pin for certain characteristics you want.

[jash]

On the co-op gas, we tested it a bunch of times last year and I found it fluctuated between zero and about 7% ethanol, I did not see 10% ethanol at any point. There was no rhyme or reason to the fluctuations, just seemed like it was in there sometimes and other times not.

To me this is the biggest issue with the ethanol and racing, you don't know what percentage is in there without testing. However, after having to run C9 for a few races in Phoenix my pocketbook isn't a fan of running race fuel to get over this issue! The testing tube is easy to use.

[Tjfast]

An interesting note about the fluctuations I found is that if the previous fuel to be pumped is 87 or 89, there will still be some in the line when you start pumping. So that could be a source of some of the variation of ethanol. However, to counter this point, the amount of fuel that would result from this overlap would be so minor that it may not even have an impact. I could only see this being a thing to note if you are filling <5L.

[Jackmazury]

Race fuel is a curious case. It isn’t really necessary for the rotax or briggs engine, and if anything is detrimental to performance. The reason the US and larger Canadian series run it is exactly as outlined, consistency. The jump from ~$35 for 20L to $160 for 20L doesn’t pencil outside of the Shifter and possibly VLR where it is a reliability item for club racing.

Despite this they still often make the top 3 or top 5 show up with empty tanks to the grid and the series will provide fuel for the session in the USA.

[phil]

Jack- the US Trophy series is doing the empty tank, and locked pre-grid gate at the 3 minute mark to mimic the Grand Finals, and get the racers ready for how it's done there. That was the first race outside of the Grand Finals that I've seen it done at.

[JasonL]

Carson and I were at the track today and I stopped at the Co-op to get some gas to test. It had ethanol in it.

[Tjfast]

Were you able to record the %? If so, what was it?