91 Ethanol Free vs 93 Ethanol
03-14-2018, 11:09 PM
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91 Ethanol Free vs 93 Ethanol
Hello,
I have an 07 C4S with the F77 package from Champion Motorsport. What are the thoughts on running 91 Ethanol free vs. Mobil 93 with ethanol. Anyone else out there with a GIAC tune try ethanol free?
tia
Mike
I have an 07 C4S with the F77 package from Champion Motorsport. What are the thoughts on running 91 Ethanol free vs. Mobil 93 with ethanol. Anyone else out there with a GIAC tune try ethanol free?
tia
Mike
03-14-2018, 11:28 PM
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Buy the highest octane you can (93) from the busiest national brand station you can find. Don't get hung up about 10% ethanol.
03-15-2018, 08:15 AM
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I asked this question to Jake Raby and Tony Callas during my M96/M97 engine building class and they said the higher octane even with a little ethanol is better as it prevents pre-ignition.
03-15-2018, 08:46 AM
#5
Pure ethanol has a Octane rating higher than gas (113) so the ethanol boosts the octane rating of the gas. 10% Ethanol boosts 2 points and 15% boosts three starting from 85 Octane gas. Energy density is lower so MPG suffers a bit so its a bit of a tradeoff - let alone the 'ethanol is bad' debate......
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03-15-2018, 05:36 PM
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Better yet, 94 octane, 0% ethanol 
that's what I get here locally at Chevron, but then again we don't have a big farm lobby mandating ethanol!
that's what I get here locally at Chevron, but then again we don't have a big farm lobby mandating ethanol!
03-15-2018, 05:39 PM
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03-15-2018, 05:43 PM
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06-02-2018, 03:12 PM
#11
Here's another view on ethanol -
“The bore scoring which dogged 911s in
particular has been eliminated on the 9A1,” says
JZM’s Steve McHale. He has always attributed
this wear to ethanol in petrol rather than the
engine running too hot or excess thinning of the
oil. “The proportion of ethanol in petrol varies,”
he says, “but it is higher than the claimed five
per cent.” Ethanol not only causes corrosion, it
reacts with the M96/7’s Lokasil cylinders.
Page 62 of this PDF
https://www.google.com/url?sa=t&rct=...e6Oc2NU2Eq9Hfy
“The bore scoring which dogged 911s in
particular has been eliminated on the 9A1,” says
JZM’s Steve McHale. He has always attributed
this wear to ethanol in petrol rather than the
engine running too hot or excess thinning of the
oil. “The proportion of ethanol in petrol varies,”
he says, “but it is higher than the claimed five
per cent.” Ethanol not only causes corrosion, it
reacts with the M96/7’s Lokasil cylinders.
Page 62 of this PDF
https://www.google.com/url?sa=t&rct=...e6Oc2NU2Eq9Hfy
06-02-2018, 03:16 PM
#12
Additional research - bottom line: do not use ethanol in your Porsche.
Another topic is the detrimental effect of ethanol blends and FAME (fatty acid methyl ester) based biofuels. Biodiesel components are not as stable as the lubricant and will eventually deteriorate through oxidation, creating gums and deposits and changing the viscosity profile of the oil. The incompatibilities between biofuels and engine materials can cause leaching or corrosive wear of the metal surfaces. Ethanol also increases water solubility in oil, which can lead to internal corrosion of some engine components. In addition, as the ethanol oxidizes in a high-temperature environment, aggressive chemicals such as aldehydes and acids can occur and then act as powerful corrosives on engine components.
https://www.google.com/url?sa=t&rct=...FV3TwGYcW7IGxJ
Another topic is the detrimental effect of ethanol blends and FAME (fatty acid methyl ester) based biofuels. Biodiesel components are not as stable as the lubricant and will eventually deteriorate through oxidation, creating gums and deposits and changing the viscosity profile of the oil. The incompatibilities between biofuels and engine materials can cause leaching or corrosive wear of the metal surfaces. Ethanol also increases water solubility in oil, which can lead to internal corrosion of some engine components. In addition, as the ethanol oxidizes in a high-temperature environment, aggressive chemicals such as aldehydes and acids can occur and then act as powerful corrosives on engine components.
https://www.google.com/url?sa=t&rct=...FV3TwGYcW7IGxJ
06-02-2018, 05:22 PM
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Additional research - bottom line: do not use ethanol in your Porsche.
Another topic is the detrimental effect of ethanol blends and FAME (fatty acid methyl ester) based biofuels. Biodiesel components are not as stable as the lubricant and will eventually deteriorate through oxidation, creating gums and deposits and changing the viscosity profile of the oil. The incompatibilities between biofuels and engine materials can cause leaching or corrosive wear of the metal surfaces. Ethanol also increases water solubility in oil, which can lead to internal corrosion of some engine components. In addition, as the ethanol oxidizes in a high-temperature environment, aggressive chemicals such as aldehydes and acids can occur and then act as powerful corrosives on engine components.
https://www.google.com/url?sa=t&rct=...FV3TwGYcW7IGxJ
Another topic is the detrimental effect of ethanol blends and FAME (fatty acid methyl ester) based biofuels. Biodiesel components are not as stable as the lubricant and will eventually deteriorate through oxidation, creating gums and deposits and changing the viscosity profile of the oil. The incompatibilities between biofuels and engine materials can cause leaching or corrosive wear of the metal surfaces. Ethanol also increases water solubility in oil, which can lead to internal corrosion of some engine components. In addition, as the ethanol oxidizes in a high-temperature environment, aggressive chemicals such as aldehydes and acids can occur and then act as powerful corrosives on engine components.
https://www.google.com/url?sa=t&rct=...FV3TwGYcW7IGxJ
06-02-2018, 06:42 PM
#14
06-03-2018, 09:36 AM
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Cool by me if you want to track down these stations and only use that gas, but don't most of these non-ethanol or pure gas stations only have 87 or maybe 89 octane without the ethanol? I am sure there are some 93 out there, but way more trouble than its worth.