Sunoco race fuel?

[stilh036prohog]

Does anyone run this stuff? I use to run 100ll that I got from the airport I worked at. You had to retune your saws thou. It lasted longer then pump gas. This isn't an oil thread but gas. Maybe in a hot saw. Just thinking?

 

[stilh036prohog]

Does anyone run this stuff? I use to run 100ll that I got from the airport I worked at. You had to retune your saws thou. It lasted longer then pump gas. This isn't an oil thread but gas. Maybe in a hot saw. Just thinking?

 

[Huskybill]

We never ran airplane fuel but one guy speed cutting got caught using it. We Can smell the difference in this fuel. But I’m not sure what the difference is in octane? We always ran high test. Does Sunoco still offer the highest octane pump gas.?

 

[stilh036prohog]

Yes they have lead and no leadl up to 115 I think.

 

[IyaMan]

You guys should use the history search here. The octane debate has long since been hammered out.

High octane does not mean high energy. It has no benefit in chainsaws and can actually reduce performance. Its made for higher compression engines to prevent pre-detonation ("knocking"). Its also for when using turbo-chargers and to prevent vapor lock when airplanes are high up in thinner atmospheric pressure.

Same goes for your car. Overpaying for high octane gas (above 87) is utterly pointless and a waste of money unless you drive a Ferrari or a modded car with more than 10.5:1 or 11:1 compression. But of course, Sunoco will never tell you that.

 

[Huskybill]

Back around the 70’s we used the Sunoco high test in our high compression, shaved head drag race engines. I think it was Sunoco 260?

 

[Canyon Angler]

Same goes for your car. Overpaying for high octane gas (above 87) is utterly pointless and a waste of money unless you drive a Ferrari or a modded car with more than 10.5:1 or 11:1 compression. But of course, Sunoco will never tell you that.

+1 And even in the high-compression engines of today, they're often getting away with lower octane by using knock sensors and manipulating the spark and/or valve timing with computers, and unless you really have your foot into it, you can often get away with lower octane than you would with a vintage engine of equal compression ratio.

Bottom line: Unless your engine is knocking due to preignition (read: trying to run backwards), there is no benefit to running higher-octane fuels, and there may actually be a penalty for running the super-uber-high-test: Since they're increasing octane with ethanol (now that MTBE has been banned), higher-octane gasoline-based fuels may actually have fewer BTUs per gallon than lower-octane versions, due to there being a greater percentage of ethanol in the higher-octane versions. Or that's my understanding...which is why you can often get more MPG with non-ethanol fuels than with gasohol.

In my small engines and boats, I just use ethanol-free 89 octane which is what they sell in marinas and a few gas stations around here.

 

[full chizel]

High octane fuel is not needed. There is a reason NASCAR only uses 98 octane E15 now. Yeah, its special formulated for them but still only 98 octane.

 

[RedneckChainsawRepair]

90 e free all you need.

 

[ericm979]

All my Stihl equipment calls for 89 octane. We have blender pumps here. Which means that the first gallon or two is whatever was pumped last. I assume that was the lowest octane. So to be sure I got at least 89, I get 5 gallons of 91. E0 is rare and expensive here so I use the commonly available E10. Between treating it with stabilizer and rotating fuel every 6 weeks or so, it's fine. I have multiple pieces of 20+ year old equipment that's always had E10 used in it and are still on the original fuel line and never had a carb rebuild or replacement. OTOH I cleaned out a lot of gummed up motorcycle carbs back in the day before ethanol in gas. If you leave fuel in the carb it can gum up the passages wether it has ethanol in it or not.

I used to run half unleaded race gas and half pump gas in my competition off road two stroke motorcycles. I had some detonation/overheating problems on some of them. Also the race gas lasts longer. But it was super expensive then and I'm sure it's more now. It's not worth it for saws and other OPE.

 

[stilh036prohog]

The 100ll last longer in storage.

 

[BlacknTan]

I can get Sunoco Optima locally for a pretty decent price...

https://www.sunocoracefuels.com/fuel/optima

 

[RTK]

The 100ll last longer in storage.

Almost indefinitely

 

[Joseph W Santora]

Back around the 70’s we used the Sunoco high test in our high compression, shaved head drag race engines. I think it was Sunoco 260?

Sunoco 260...... Action to be used, not abused.

 

[BlackCoffin]

Unless you have the static compression the use a specified octane of fuel, it’s going to act as a parasitic draw on your horsepower. Higher octane fuel carries the potential for more thermal energy in the right situation and builds more power. Without the supporting energy from higher compression, it takes more work to burn fuel with higher octane efficiently therefor dragging down your combustion cycle since your lower compression is struggling to meet the energy level the fuel is supplying/requiring. There are other points to make as well but this one is pretty black and white.

 

[Stihl 041S]

Mere child’s play.
The Battle Of Britain was won mainly because 15 points higher octane gave them 34 MPH increase at 10,000 ft.
Germans wondered WTF????
Oh yeah. The RR and Packard Merlins made the most HP on 150 octane fuel.

 

[Joseph W Santora]

The Merlins were supercharged.

 

[lone wolf]

We never ran airplane fuel but one guy speed cutting got caught using it. We Can smell the difference in this fuel. But I’m not sure what the difference is in octane? We always ran high test. Does Sunoco still offer the highest octane pump gas.?

I think they do.

 

[Stihl 041S]

The Merlins were supercharged.

Multiple supercharged...........
And the Packard Merlin made more HP.
Surprised RR

 

[Joseph W Santora]

The two stage supercharged merlins came out a year after the battle of britain.