Fuel for 2-stroke F500

[B17overhead]

One recommendation I have received is to run 110 octane in a professionally built 493, 494, 593. I assume that's RON, but maybe I'm wrong. I wonder what fuels the veterans in this class are finding acceptable?

I can readily get VP U4.4 as well as Renegade SX2 just down the street 10 minutes away.

[TDI PILOT]

I'm pretty sure U 4.4 is illegal for SCCA racing. There was a big issue with a competitor using this fuel in F1000 a couple years ago. He lost his competition license for a period of time. Since then the SCCA has raised the DC maximum limits in the fuel though so its possible it may be ok. I would check the GCR then compare that to the manufacturers specs.

[B17overhead]

I'll check DCs to see if SX2 or U4.4 are ok, but wonder what people are running typically? Whatever is available at the track?
I'd really like to run Sunoco 260GT+ since it is unleaded and maybe a little safer to get on ur hands and lungs.

[veloscaraptor]

I'm using the last of the Gulf mach110 that came with the car when I bought it. Will switch to cam2 leaded 110 (which is what the car originally ran on) when I run out.

[cory mcleod]

From a compliance perspective, it only matters if you are running Majors. Fuel is never checked at Regionals. For Majors, they test the fuel available at the track and certify that it's compliant, so it just makes sense to run that fuel. With the small amount of fuel we use, the price difference is not worth a potential DQ.

Specific to Rotax F500s, there are many opinions. I've been told that our engines don't need anything more than 92-93 octane for peak performance. I've also been told that leaded gas helps avoid detonation, but many people run unleaded. My carbs are set up for 110 leaded, so that's what I use. I don't bath in the gas, so I'm not worried about lead poisoning.

[B17overhead]

Thanks Cory, but what brand and model is that: VP110?
.. and is that 110 rating you say you use the (R+M)/2 average or is it ROM 110?

I'm interested in actual race gas brand and model number vs. user experience (Hopefully track as well as dyno).
Mixed pump gas with race or straight pump gas is not under consideration.
Aviation gas is another I won't use.

I've researched the lead aspect and there is no evidence 2-strokes like lead. Some have theorized it helps lubricate the rings, but that's what the oil is for. Lead is just one approach to get anti-knock performance versus using more of some other chemicals.

In the end, the mfg. anti-knock rating of the gas and specific heat is about all that matters. If it is rated 91 leaded or 91 unleaded, it makes no difference.

[mmi16]

Thanks Cory, but what brand and model is that: VP110?
.. and is that 110 rating you say you use the (R+M)/2 average or is it ROM 110?

I'm interested in actual race gas brand and model number vs. user experience (Hopefully track as well as dyno).
Mixed pump gas with race or straight pump gas is not under consideration.
Aviation gas is another I won't use.

I've researched the lead aspect and there is no evidence 2-strokes like lead. Some have theorized it helps lubricate the rings, but that's what the oil is for. Lead is just one approach to get anti-knock performance versus using more of some other chemicals.

In the end, the mfg. anti-knock rating of the gas and specific heat is about all that matters. If it is rated 91 leaded or 91 unleaded, it makes no difference.

Track fuel brand at 'most' tracks is Sunoco. Some tracks only have 110 Leaded available; others have 112 & 116 Leaded in addition and/or in place of 110 leaded. There are unleaded grades available.

[David Ferguson]

Here is data for the VP Fuels 110 octane fuel

https://vpracingfuels.com/product/vp-110/

[preform resources]

AHAH ! Leave it ti Ferg to straighten things out !!!
Dave

[B17overhead]

AHAH ! Leave it ti Ferg to straighten things out !!!
Dave

I'm always appreciative for any help or info, but it was actually MMi16 who hit the mark and gave me exactly what I was looking for:
"Track fuel brand at 'most' tracks is Sunoco. Some tracks only have 110 Leaded available; others have 112 & 116 Leaded in addition and/or in place of 110 leaded. There are unleaded grades available."