How does ethanol in gas affect 356 engine/fuel system?

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Brian R Adams
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Re: How does ethanol in gas affect 356 engine/fuel system?

#121 Post by Brian R Adams » Mon Nov 22, 2021 4:01 pm

Martin Benade wrote:
Mon Nov 22, 2021 3:53 pm
How is that identified? Here in Ohio all stations have only the choice of octane- three flavors, with some alcohol. Everything I run seems happy enough in spite of most other people’s hatred of alcohol in gasoline.
Martin,

I cannot vouch for PureGas.org accuracy nationwide, but you can try their interactive map and zero in on your locale to sleuth it out:

https://www.pure-gas.org/extensions/map ... atecode=OH

PS Before the Maverik chain arrived in my area, the only ethanol-free gas was sold as "racing fuel" by a few stations, which was very expensive (I believe) 100 octane stuff. That may be all that is available in Ohio.
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Re: How does ethanol in gas affect 356 engine/fuel system?

#122 Post by Martin Benade » Mon Nov 22, 2021 6:00 pm

I guess it’s real. One BP station in my area has it. I called and verified it. I wonder if that just varies according to what they are given. It’s in an upscale suburb where the locals aren’t thinking about alcohol in their fuel.
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Re: How does ethanol in gas affect 356 engine/fuel system?

#123 Post by Tim Dawson » Tue Nov 23, 2021 7:43 am

David Jones wrote:
Mon Nov 22, 2021 11:12 am
Tim, I am somewhat confused by your description of the gasoline you have available .....
Hello David. Thanks for that helpful explanation. I think avgas might be going a little far, but it seems the best solution in the UK is to at least fill the car with Esso premium (ethanol free) if it's going to be over-wintered.
Apparently the E5 designation on petrol pumps means 'up to 5% ethanol'. So far I can only establish that in Esso's case that means zero ethanol!

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Re: How does ethanol in gas affect 356 engine/fuel system?

#124 Post by Brian R Adams » Tue Nov 23, 2021 2:17 pm

Tim Dawson wrote:
Tue Nov 23, 2021 7:43 am
Hello David. Thanks for that helpful explanation. I think avgas might be going a little far, but it seems the best solution in the UK is to at least fill the car with Esso premium (ethanol free) if it's going to be over-wintered.
Apparently the E5 designation on petrol pumps means 'up to 5% ethanol'. So far I can only establish that in Esso's case that means zero ethanol!
Tim, I'd be reluctant to take someone at Esso's remark as fact. (I'm assuming they don't state that in writing anywhere.) But even if it has 5% that's better than E10. It probably does contain somewhat less than 5% anyway, and possibly 0%, but that strikes me as an odd way to market ethanol-free. I suppose it's a quirk of your industry regulations. It might be politically unpalatable to advertise the planet-killing juice is readily available.
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Re: How does ethanol in gas affect 356 engine/fuel system?

#125 Post by David Jones » Tue Nov 23, 2021 2:46 pm

Because I was heavily involved in quantifying the quality of gasoline in the refinery in which I worked before retirement I still retain an interest in the goings on as regards gasoline evolvement so forgive me for posting the following. Don't think I am a lover of ethanol, on the contrary I do not believe that in the long run it is really beneficial to use except perhaps in Brazil where it is economically feasible because it is derived from sugar cane. Following screed is I believe factual in content so decide for yourself what is best to use.
Ethanol adds two to three points of octane to ordinary unleaded gasoline, so it boosts the performance of your engine. Because of its high oxygen content, ethanol burns more completely than ordinary unleaded gasoline and reduces harmful tailpipe emissions. Ethanol prevents gas line freeze-up.
Ethanol which is an oxygenate can cause damage to fuel system hardware and has a low energy content which can reduce range.
Many people think high-octane gasoline is more powerful than low octane gasoline. This is not true. The energy produced from a gallon of high and low octane gasoline is almost the same. Any minor variation depends on what additives are used by refiners and blenders. The key features of high-octane gasoline are a higher ignition temperature and a slower burning rate.
The higher ignition temperature of high octane gasoline reduces the chance of detonation from "hot spots" within the engine's cylinders and minimizes pre-ignition. A slower burn rate allows for more efficient use of the ignited fuel's pressure buildup to be converted to mechanical energy instead of heat. That is why a high performance engine will run smoother and will feel more powerful when high-octane gasoline is used.
Using a low-octane gasoline whose ignition temperature is too low causes pre-ignition. Low-octane automotive gasoline (87-octane) has a typical ignition temperature of 300 degrees Celsius; high-octane (93-octane) automotive gasoline has a typical ignition temperature of 400 degrees Celsius. Aviation gasoline is blended to ignite at 500 degrees Celsius. High compression and high cylinder temperature will cause the fuel to ignite before the sparkplug fires.
Detonation occurs after the spark plug fires. Ideally, when the spark plug fires and ignites the fuel, a progressive flame path develops producing a smooth increase in temperature and pressure within the engine cylinder to drive the piston. Detonation occurs when other ignition sources ignite the fuel charge. Red-hot bits of carbon and hot spots in the cylinder also ignite the fuel causing a second or third flame path to develop. This phenomenon causes the gasoline charge to burn instantaneously, producing a violent increase in cylinder pressure and temperature.
If you use a fuel with lower-octane than is recommended by the engine's manufacturer, this can cause serious damage to the pistons, valves, cylinders, heads, and bearings in a short period of time. Low-octane gasoline ignites quickly and produces a pressure-temperature peak that can exceed the design limit of the engine. This condition is exacerbated the more you run the engine. The heat buildup can not be dissipated fast enough from within the cylinder, causing more pre-ignition and uncontrolled detonation.
If your engine is designed to use low-octane fuel, the use of a higher-octane gasoline will not improve performance. Engine dynamics, timing and compression ratio are what determine which gasoline octane the engine manufacturer recommends. It is possible to burn the exhaust valves if you use a high-octane gasoline in an engine that is designed to use 82-octane gasoline. Retarded ignition timing and a slower fuel burn rate can increase exhaust temperature because the fuel charge is still burning at high pressure when the exhaust valve opens. Excessive heat and pressure will quickly erode the valves and seats.
Ethanol is going to be with us for a very long time so we all have to get used to it and act accordingly. Using leaded gasoline is not a realistic option unless you have a local gas station that carries it and you are happy paying more for it. The higher price is probably not going to be offset by the improved gas mileage and the reality is that the 10% corn derived ethanol added to gas though it has downsides is probably not quite as bad as it appears but I would personally prefer to see it not used when it has a negative cost impact to the consumer overall.
If I had known I would live this long I would have pushed the envelope a little harder.
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Re: How does ethanol in gas affect 356 engine/fuel system?

#126 Post by Brian R Adams » Tue Nov 23, 2021 3:18 pm

David Jones wrote:
Tue Nov 23, 2021 2:46 pm
Ethanol adds two to three points of octane to ordinary unleaded gasoline, so it boosts the performance of your engine.
...
Ethanol ... has a low energy content which can reduce range.
David,

As always I look forward to your essays on these matters. In this example I learned a few things yet again. Thanks!

When you say ethanol "boosts performance" I might have assumed that means "better range and more power" from a volume of fuel. Are you saying ethanol can boost power while also reducing range?

I ask because my experience is that it reduces range and reduces power, both. Does it depend on the design and tune of the engine?
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Re: How does ethanol in gas affect 356 engine/fuel system?

#127 Post by David Jones » Tue Nov 23, 2021 3:48 pm

Maybe a little confusing statement as it can be taken out of context. Ethanol has an octane rating of 109 so in that regard it can be called a performance booster if you have a higher CR because you could add a lot of it to 87 octane and use it in your high CR Porsche engine. Indy cars now use 85% ethanol as their preferred fuel because not only does it permit higher CR but it also runs cooler. Downside is that they have to refuel more often than if they used straight gasoline. Compare an indy car to an F1 car on mpg and we find around 2 mpg for an indy car versus 6 for an F1 and the F1 car at 1.6 liters develops an available power unit hp of around 1000 versus the indy car at around 750 hp in a 2.3 ltr engine. Just imagine an engine the same size as your stock 356 developing over 1000 hp. It actually beggars belief to me.
If I had known I would live this long I would have pushed the envelope a little harder.
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Re: How does ethanol in gas affect 356 engine/fuel system?

#128 Post by Brian R Adams » Tue Nov 23, 2021 6:25 pm

David Jones wrote:
Tue Nov 23, 2021 3:48 pm
Maybe a little confusing statement as it can be taken out of context. Ethanol has an octane rating of 109 so in that regard it can be called a performance booster if you have a higher CR because you could add a lot of it to 87 octane and use it in your high CR Porsche engine. Indy cars now use 85% ethanol as their preferred fuel because not only does it permit higher CR but it also runs cooler. Downside is that they have to refuel more often than if they used straight gasoline. Compare an indy car to an F1 car on mpg and we find around 2 mpg for an indy car versus 6 for an F1 and the F1 car at 1.6 liters develops an available power unit hp of around 1000 versus the indy car at around 750 hp in a 2.3 ltr engine. Just imagine an engine the same size as your stock 356 developing over 1000 hp. It actually beggars belief to me.
I'm obliged to you for those motorsports figures, very interesting! Are your F1 figures from the pre-hybrid era? It'd be most useful to compare "apples-to-apples" IndyCar to F1, both running conventional IC gasoline engines but with different ethanol content.
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Re: How does ethanol in gas affect 356 engine/fuel system?

#129 Post by David Jones » Tue Nov 23, 2021 7:02 pm

F1 and indycar hp numbers are as of 2021.
One should add that indycars are about the same weight but don't have power steering and less efficient aerodynamics.
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Re: How does ethanol in gas affect 356 engine/fuel system?

#130 Post by Tim Dawson » Sat Nov 27, 2021 8:43 am

[/quote]

Tim, I'd be reluctant to take someone at Esso's remark as fact. (I'm assuming they don't state that in writing anywhere.)
[/quote]

Actually it is in writing on their website. The E5 rating here means anything less than 5%!

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Re: How does ethanol in gas affect 356 engine/fuel system?

#131 Post by Mike Horton » Sat Nov 27, 2021 3:38 pm

David Jones wrote:
Tue Nov 23, 2021 2:46 pm
Because I was heavily involved in quantifying the quality of gasoline in the refinery in which I worked before retirement I still retain an interest in the goings on as regards gasoline evolvement so forgive me for posting the following. Don't think I am a lover of ethanol, on the contrary I do not believe that in the long run it is really beneficial to use except perhaps in Brazil where it is economically feasible because it is derived from sugar cane. Following screed is I believe factual in content so decide for yourself what is best to use.
Ethanol adds two to three points of octane to ordinary unleaded gasoline, so it boosts the performance of your engine. Because of its high oxygen content, ethanol burns more completely than ordinary unleaded gasoline and reduces harmful tailpipe emissions. Ethanol prevents gas line freeze-up.
Ethanol which is an oxygenate can cause damage to fuel system hardware and has a low energy content which can reduce range.
Many people think high-octane gasoline is more powerful than low octane gasoline. This is not true. The energy produced from a gallon of high and low octane gasoline is almost the same. Any minor variation depends on what additives are used by refiners and blenders. The key features of high-octane gasoline are a higher ignition temperature and a slower burning rate.
The higher ignition temperature of high octane gasoline reduces the chance of detonation from "hot spots" within the engine's cylinders and minimizes pre-ignition. A slower burn rate allows for more efficient use of the ignited fuel's pressure buildup to be converted to mechanical energy instead of heat. That is why a high performance engine will run smoother and will feel more powerful when high-octane gasoline is used.
Using a low-octane gasoline whose ignition temperature is too low causes pre-ignition. Low-octane automotive gasoline (87-octane) has a typical ignition temperature of 300 degrees Celsius; high-octane (93-octane) automotive gasoline has a typical ignition temperature of 400 degrees Celsius. Aviation gasoline is blended to ignite at 500 degrees Celsius. High compression and high cylinder temperature will cause the fuel to ignite before the sparkplug fires.
Detonation occurs after the spark plug fires. Ideally, when the spark plug fires and ignites the fuel, a progressive flame path develops producing a smooth increase in temperature and pressure within the engine cylinder to drive the piston. Detonation occurs when other ignition sources ignite the fuel charge. Red-hot bits of carbon and hot spots in the cylinder also ignite the fuel causing a second or third flame path to develop. This phenomenon causes the gasoline charge to burn instantaneously, producing a violent increase in cylinder pressure and temperature.
If you use a fuel with lower-octane than is recommended by the engine's manufacturer, this can cause serious damage to the pistons, valves, cylinders, heads, and bearings in a short period of time. Low-octane gasoline ignites quickly and produces a pressure-temperature peak that can exceed the design limit of the engine. This condition is exacerbated the more you run the engine. The heat buildup can not be dissipated fast enough from within the cylinder, causing more pre-ignition and uncontrolled detonation.
If your engine is designed to use low-octane fuel, the use of a higher-octane gasoline will not improve performance. Engine dynamics, timing and compression ratio are what determine which gasoline octane the engine manufacturer recommends. It is possible to burn the exhaust valves if you use a high-octane gasoline in an engine that is designed to use 82-octane gasoline. Retarded ignition timing and a slower fuel burn rate can increase exhaust temperature because the fuel charge is still burning at high pressure when the exhaust valve opens. Excessive heat and pressure will quickly erode the valves and seats.
Ethanol is going to be with us for a very long time so we all have to get used to it and act accordingly. Using leaded gasoline is not a realistic option unless you have a local gas station that carries it and you are happy paying more for it. The higher price is probably not going to be offset by the improved gas mileage and the reality is that the 10% corn derived ethanol added to gas though it has downsides is probably not quite as bad as it appears but I would personally prefer to see it not used when it has a negative cost impact to the consumer overall.
Amen, again, David... !
Mike

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Re: How does ethanol in gas affect 356 engine/fuel system?

#132 Post by Phil Planck » Sat Nov 27, 2021 4:08 pm

In Michigan it is called recreational or rec gas. Available near most large lakes as apparently outboard engines dont like it. Pumps I have seen are located remote from regular pumps.
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Re: How does ethanol in gas affect 356 engine/fuel system?

#133 Post by Martin Benade » Sat Nov 27, 2021 6:35 pm

No doubt illegal for road use if anyone is watching.
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Re: How does ethanol in gas affect 356 engine/fuel system?

#134 Post by Brian R Adams » Sat Nov 27, 2021 6:42 pm

Tim Dawson wrote:
Sat Nov 27, 2021 8:43 am
Actually it is in writing on their website. The E5 rating here means anything less than 5%!
Tim, this feels like two ships passing in the night. But what I would be reluctant to credit is an offhand comment like "Just between us, our E5 actually has zero ethanol in it." I'm guessing you won't find an affirmation in print. When one needs ethanol-free, one needs something marketed and labeled as such. The "blue" stuff here says "ETHANOL FREE" behing the foliage.
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Re: How does ethanol in gas affect 356 engine/fuel system?

#135 Post by Mike Horton » Sat Nov 27, 2021 7:53 pm

As no 2 engines, or cars are alike, these days, and based on years of reading David's Career experiences, In my tired old original '68 912 engine, with only an 022 distributor changed in before my ownership, in my 275 mi./week Interstate 27 commute, at 3300'-3700' elevation, after replacing the factory 55 idle fuel jets with the pre-'68, non US smog tune jetting, 57.5, and with 127.5 main fuel jets, on one all Interstate trip, with the stock diameter tires, stock gears, the factory 912 5th gear, almost identical to the 356 SC 4th gear ratio, I got an all time high of 32 mpg, with normal oil temp, and the then speed limit of 65 mph (69 mph daytime), on the 10% corn fuel, at about 91 pump marked octane. A sample size of 1...

...oh, the av gas, does Not have road taxes added, thus, technically not legal...
Mike

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