Get ready for 15% Ethanol
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10-09-2019, 12:05 PM
#17
Nordschleife Master
Apperently Delaware is not a state or doesnt have ethenol free gas
.
10-09-2019, 12:27 PM
#18
Drifting
Probably the biggest issue with Ethanol is that it's harmful for rubber on vintage cars. It's not an issue for 996-era cars, at least at 10%, and presumably not at 15%. I'd happily pay a premium (pun not avoidable) for ethanol-free for vintage cars, but ethanol-free is practically unobtanium in NJ.
For those of you that have run your 996 on both E-10 and ethanol-free, have you noticed any difference in power, drivability, gas mileage?
For those of you that have run your 996 on both E-10 and ethanol-free, have you noticed any difference in power, drivability, gas mileage?
10-09-2019, 12:53 PM
#19
Drifting
I'd take ethanol-free every time given a choice, but the answer isn't that clearcut.
Gas mileage-wise, E10 is worse. If E10 was cheaper than ethanol-free, then maybe worse mileage at lower cost would be a wash. I doubt E10 is cheaper than what it would be if we didn't have an E10 mandate, but I have no idea.
On the plus side, ethanol actually has a much higher octane rating at 113 octane versus a rating of around 85 for pure gas (without any other octane booster additives). Adding 10% Ethanol automatically raises octane of pure gas by about 2 rating points. A higher octane rating on its own doesn't increase power, it only helps prevent pre-detonation because higher octane rated fuel is actually more difficult to ignite (which seems counterintuitive). In modern cars like the 996, where the ignition adapts, higher octane rated fuel can produce more power because the ignition can advance the timing to the maximum limit the fuel you are running allows (while still preventing pre-detonation (pinging)).
I don't know anything about them, but they must use other additives to raise 85 octane pure gas and 87 octane E-10 to 92 or 93 for premium fuel. Performance-wise, I'm curious how 93 octane ethanol-free would compare to 93 octane E10 in the 996, or any car. Gas mileage would definitely be worse with 93 E10, but I haven't seen anything saying performance is worse (at the same octane level) with ethanol.
For vintage cars, ethanol is bad for rubber -- fuel lines, fuel pump diaphragms, etc. I don't think that is an issue in 996-era cars or later (or for vintage cars retrofitted with modern rubber everywhere in the fuel system, carbs, fuel pumps, etc.).
Gas mileage-wise, E10 is worse. If E10 was cheaper than ethanol-free, then maybe worse mileage at lower cost would be a wash. I doubt E10 is cheaper than what it would be if we didn't have an E10 mandate, but I have no idea.
On the plus side, ethanol actually has a much higher octane rating at 113 octane versus a rating of around 85 for pure gas (without any other octane booster additives). Adding 10% Ethanol automatically raises octane of pure gas by about 2 rating points. A higher octane rating on its own doesn't increase power, it only helps prevent pre-detonation because higher octane rated fuel is actually more difficult to ignite (which seems counterintuitive). In modern cars like the 996, where the ignition adapts, higher octane rated fuel can produce more power because the ignition can advance the timing to the maximum limit the fuel you are running allows (while still preventing pre-detonation (pinging)).
I don't know anything about them, but they must use other additives to raise 85 octane pure gas and 87 octane E-10 to 92 or 93 for premium fuel. Performance-wise, I'm curious how 93 octane ethanol-free would compare to 93 octane E10 in the 996, or any car. Gas mileage would definitely be worse with 93 E10, but I haven't seen anything saying performance is worse (at the same octane level) with ethanol.
For vintage cars, ethanol is bad for rubber -- fuel lines, fuel pump diaphragms, etc. I don't think that is an issue in 996-era cars or later (or for vintage cars retrofitted with modern rubber everywhere in the fuel system, carbs, fuel pumps, etc.).
Last edited by peterp; 10-10-2019 at 11:35 AM. Reason: Edited to clarify octane rating
10-09-2019, 10:54 PM
#21
E10 and E15 are ok for cars built in the last 20 yrs but only if you drive them, if they're sitting for 4-6 months or longer the ethanol will separate from the gas and it will absorb water/condensation in the tank from large temperature changes.
In florida we have ethanol free 87 and 90. We refer to the 90 as rec90 and most boaters will only use it in their outboard engines. I run only rec90 in my c4s and it's about 75c a gallon more than 87 and equal to 93.
In florida we have ethanol free 87 and 90. We refer to the 90 as rec90 and most boaters will only use it in their outboard engines. I run only rec90 in my c4s and it's about 75c a gallon more than 87 and equal to 93.
10-10-2019, 03:25 AM
#22
Three Wheelin'
The ethanol % was set in the original bill, the percent increases 5% every few years,,,
2020 was the 15% goal, I believe 2025 is the 20% mark but its been a long time since I
came across the bill..
2020 was the 15% goal, I believe 2025 is the 20% mark but its been a long time since I
came across the bill..
Last edited by pdxmotorhead; 10-12-2019 at 06:53 AM.
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10-10-2019, 10:20 AM
#23
Drifting
E10 and E15 are ok for cars built in the last 20 yrs but only if you drive them, if they're sitting for 4-6 months or longer the ethanol will separate from the gas and it will absorb water/condensation in the tank from large temperature changes.
In florida we have ethanol free 87 and 90. We refer to the 90 as rec90 and most boaters will only use it in their outboard engines. I run only rec90 in my c4s and it's about 75c a gallon more than 87 and equal to 93.
In florida we have ethanol free 87 and 90. We refer to the 90 as rec90 and most boaters will only use it in their outboard engines. I run only rec90 in my c4s and it's about 75c a gallon more than 87 and equal to 93.
10-10-2019, 10:28 AM
#24
Captain Obvious
Super User
Super User
I'd take ethanol-free every time given a choice, but the answer isn't that clearcut.
Gas mileage-wise, E10 is worse. If E10 was cheaper than ethanol-free, then maybe worse mileage at lower cost would be a wash. I doubt E10 is cheaper than what it would be if we didn't have an E10 mandate, but I have no idea.
On the plus side, ethanol is actually much higher octane -- 113 octane versus around 85 for raw gas (without any other octane booster additives). Adding 10% Ethanol automatically raises octane of pure gas by about 2 points. Higher octane on its own doesn't increase power, it only helps prevent pre-detonation because higher octane fuel is actually more difficult to ignite (which seems counterintuitive). In modern cars like the 996, where the ignition adapts, higher octane fuel can produce more power because the ignition can advance the timing to the maximum limit the fuel you are running allows (while still preventing pre-detonation (pinging)).
I don't know anything about them, but they must use other additives to raise 85 octane pure gas and 87 octane E-10 to 92 or 93 for premium fuel. Performance-wise, I'm curious how 93 octane ethanol-free would compare to 93 octane E10 in the 996, or any car. Gas mileage would definitely be worse with 93 E10, but I haven't seen anything saying performance is worse (at the same octane level) with ethanol.
For vintage cars, ethanol is bad for rubber -- fuel lines, fuel pump diaphragms, etc. I don't think that is an issue in 996-era cars or later (or for vintage cars retrofitted with modern rubber everywhere in the fuel system, carbs, fuel pumps, etc.).
Gas mileage-wise, E10 is worse. If E10 was cheaper than ethanol-free, then maybe worse mileage at lower cost would be a wash. I doubt E10 is cheaper than what it would be if we didn't have an E10 mandate, but I have no idea.
On the plus side, ethanol is actually much higher octane -- 113 octane versus around 85 for raw gas (without any other octane booster additives). Adding 10% Ethanol automatically raises octane of pure gas by about 2 points. Higher octane on its own doesn't increase power, it only helps prevent pre-detonation because higher octane fuel is actually more difficult to ignite (which seems counterintuitive). In modern cars like the 996, where the ignition adapts, higher octane fuel can produce more power because the ignition can advance the timing to the maximum limit the fuel you are running allows (while still preventing pre-detonation (pinging)).
I don't know anything about them, but they must use other additives to raise 85 octane pure gas and 87 octane E-10 to 92 or 93 for premium fuel. Performance-wise, I'm curious how 93 octane ethanol-free would compare to 93 octane E10 in the 996, or any car. Gas mileage would definitely be worse with 93 E10, but I haven't seen anything saying performance is worse (at the same octane level) with ethanol.
For vintage cars, ethanol is bad for rubber -- fuel lines, fuel pump diaphragms, etc. I don't think that is an issue in 996-era cars or later (or for vintage cars retrofitted with modern rubber everywhere in the fuel system, carbs, fuel pumps, etc.).
Just to make this clear, 2 point in octane is only 0.2 octane and not 2 octane.
10-10-2019, 12:03 PM
#25
Drifting
All of the above is "behind the scenes" because they still use other additives to raise the octane to 93 for premium, whether the base is pure gas or E10, it's just that fewer octane boosting additives are needed for E10 to reach 93 because ethanol raises octane on its own. If my prior post implied that E10 had higher a higher octane rating, then I get the point of confusion, I was just saying that ethanol does have a "behind the scenes" benefit of raising octane. I am *NOT* an expert at all, so please correct me if I'm wrong, but I think the math is what it is. I absolutely hate E10, so it pains me to say something good about it, but I'm trying to be objective.
10-10-2019, 12:24 PM
#26
Captain Obvious
Super User
Super User
no problem, I understand. Just wanted to make sure people don't think that 1 octane point is 1 octane. The fuel additive market (such as Octane Booster and other brands) exploit this and make people think that they can easily raise the octane of a lower grade fuel to something much higher when all they are doing is increasing the rating by only 0.2 octane.
10-11-2019, 01:29 AM
#27
Three Wheelin'
On Alchy free 93 Unleaded , my 996 jumps about 5MPG up..
And you can feel the engine running smoother especially at idle..
Bio fuels are about the money, not function..
And you can feel the engine running smoother especially at idle..
Bio fuels are about the money, not function..
10-11-2019, 08:57 AM
#28
Three Wheelin'
Join Date: Jun 2016
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There is no ethanol free 93 where I live.
Last edited by strathconaman; 10-11-2019 at 01:56 PM. Reason: My memory is good, it is just short.
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10-14-2019, 09:42 PM
#30
Drifting