Gas Octane

[K4fxd]

I just saw at ACE today canned fuel with 93 octane rating on the can. Somebody is still making it. The marina on the Ohio river used to carry it, but no more.

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[GregO]

There is no way to make a small engine carb alcohol safe. Thats why hardware stores sell E0 in a can.

We should not be using food crops to use as motor fuels. Ethanol is at best net zero as far as energy to produce and energy returned.

The amount of ground water/potable water used to process ethanol is staggering.
ACE Ethanol in Northwestern Wis has wrecked the local water table. The area spring fed rivers are now just a trickle of their former self.

 

[WildHorse]

There is no way to make a small engine carb alcohol safe. Thats why hardware stores sell E0 in a can.

We had E10 up here since 1986. My lawnmower and snowblower are 25 years old. That's 25 years of E10. No problems with regular maintenance.

 

[engineermike]

I’m guessing Canada isn’t as humid as the gulf coast. I’ve personally disassembled many carbs that were victim to ethanol absorption of water, leading to severe corrosion of aluminum. Again, for anything vented to atmosphere, ethanol is no good.

Im also guessing that a small lawnmower or snowblower lives most of its life in a semi-climate controlled area with lower humidity.

 

[GregO]

There is a way to wash the ethanol out.

 

[engineermike]

@GregO a Refinery fuels blending engineer once explained to me that old gasoline evaporates the light ends out. With them goes the octane rating and cold starting ability. However, the heavier ends left behind have a higher energy density. So if the engine can’t benefit from the octane it will actually make more power using old gas.

 

[engineermike]

There is a way to wash the ethanol out.

Very true; it’s just not something you want to do every time you cut grass.

 

[ORRadtech]

We had E10 up here since 1986. My lawnmower and snowblower are 25 years old. That's 25 years of E10. No problems with regular maintenance.

Part of a company a buddy and I owned in the late '90s into the early 2000s was lawn maintenance. We cut roughly 300 yards twice a month in the summer. Ran strictly 87 pump gas in everything. 2 & 4 cycle, mowers, trimmers, blowers, everything. The only issues we ever had was if the tool was stored for the winter without being run dry. Even then it only took about 20 minutes to pull and clean the carb.

 

[GregO]

@GregO a Refinery fuels blending engineer once explained to me that old gasoline evaporates the light ends. Out with them goes the octane rating and cold starting ability. However, the heavier ends left behind have a higher energy density. So if the engine can’t benefit from the octane it will actually make more power using old gas.

I’ve followed Dyno Tech Jim since day one, I’ve learned a lot from him and the engine masters in his circle since he opened his Superflow Dyno for public tuning and validation. Record setting Pro level racers have been nitrogen blanketing drummed fuel for decades. It’s one of the secrets most overlook.
Mike, I think this blog has merit and you’ll agree.
http://www.dynotechresearch.com/blog/archives.asp?chosenMonth=3&chosenYear=2013

 

[GregO]

Very true; it’s just not something you want to do every time you cut grass.

5 gallons is manageable.
https://phillittleracing.com/pages/remove-ethanol-from-gas-at-home

 

[GJarrett]

5 gallons is manageable.
https://phillittleracing.com/pages/remove-ethanol-from-gas-at-home

Question: As I understand it, ethanol raises octane. So if you (for example) do what that link instructs and remove the ethanol from the gas, doesn't it lower the octane rating? In other words, I have a 93 tune; if I do that, won't it lower the octane rating below my tune requirement?

 

[GregO]

Question: As I understand it, ethanol raises octane. So if you (for example) do what that link instructs and remove the ethanol from the gas, doesn't it lower the octane rating? In other words, I have a 93 tune; if I do that, won't it lower the octane rating below my tune requirement?

Correct, -2 to -3 octane numbers lower.

 

[shogun32]

I have a 93 tune; if I do that, won't it lower the octane rating below my tune requirement?

your tune doesn't *require* anything. It simply moved the upper limits or the rate of change. Your engine/tune will adapt to observed 87 just fine.

 

[WildHorse]

If we assume a 91 octane rating for E10, moving to E30 would result in an increase of about 3 to 5 octane points, bringing the octane rating to approximately 94-96. Split the difference and say 95.

 

[engineermike]

your tune doesn't *require* anything. It simply moved the upper limits or the rate of change. Your engine/tune will adapt to observed 87 just fine.

Eh, I wouldn’t be giving out that advice. If the tuner moved the borderline tables up like FRP does (and myself and others), it will send it deep into knock very fast and severe knock events will happen. The stock tune starts it out at values safe on 87 and “sneaks up” on knock so the knock events are low magnitude which doesn’t do much damage.

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