Fuel question - not a simple one!
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My experience logging is with Kevin's (UMW) high speed logging tool in AZ with different blends of US 91 octane, Sunoco US 100 octane. I've also had the opportunity to run my car at over 100 deg F and 60 deg ambient.
Simon, I'd go with the higher octane for the safety factor. In absence of this you are relying on the car's (6) knock sensors to dial back timing and all manner of other things to protect the motor not maximize performance. If you're tracking the car at high speed i'd question whether you could do some damage before the timing is retarded.
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Simon, I'd go with the higher octane for the safety factor. In absence of this you are relying on the car's (6) knock sensors to dial back timing and all manner of other things to protect the motor not maximize performance. If you're tracking the car at high speed i'd question whether you could do some damage before the timing is retarded.
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Joined: Sep 2011
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From: Tucson, AZ
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Well I don't believe everything people tell me and this is why I am discussing it here.
My tech however says that "ethanol causes fuel system components made from brass, copper, and aluminium to oxidize".
Then I did some research and found this:
1) Water accumulation in the fuel tank - ethanol absorbs water from the air. The water condenses in the fuel tank and will pull the ethanol out of suspension with the petrol. This is bad news because it strips the octane out of the petrol, leaving you with a layer of octane-poor fuel on top and a water-ethanol layer mixture on the bottom. If this gets sucked into the combustion chamber, you will have poor starting and very rough running with potentially engine damage.
2) Deposits are likely to build up - Ethanol when mixed with water readily forms Gums in the fuel system much quicker than fuel without Ethanol. These Gums coat fuel system components including filters, carburettors, injectors, throttle plates and will then form varnish and carbon deposits in the intake, on valves, and in the combustion chamber.
3) Lower fuel mileage, Decreased performance and acceleration. Ethanol contains less chemical energy than petrol does, and this means less mileage for the driver. 3-5% drops in mileage are expected.
4) Corrosion of internal engine components - Water contamination may cause fuel system corrosion and severe deterioration.
Why would I not believe this, sounds plausible enough?
And as Pièce de résistance; as ethanol has 35% less chemical energy this offsets any gain 100 RON in theory gives you over 95 RON.
Bloody hell, I said at the beginning this ain’t a simple debate...
My tech however says that "ethanol causes fuel system components made from brass, copper, and aluminium to oxidize".
Then I did some research and found this:
1) Water accumulation in the fuel tank - ethanol absorbs water from the air. The water condenses in the fuel tank and will pull the ethanol out of suspension with the petrol. This is bad news because it strips the octane out of the petrol, leaving you with a layer of octane-poor fuel on top and a water-ethanol layer mixture on the bottom. If this gets sucked into the combustion chamber, you will have poor starting and very rough running with potentially engine damage.
2) Deposits are likely to build up - Ethanol when mixed with water readily forms Gums in the fuel system much quicker than fuel without Ethanol. These Gums coat fuel system components including filters, carburettors, injectors, throttle plates and will then form varnish and carbon deposits in the intake, on valves, and in the combustion chamber.
3) Lower fuel mileage, Decreased performance and acceleration. Ethanol contains less chemical energy than petrol does, and this means less mileage for the driver. 3-5% drops in mileage are expected.
4) Corrosion of internal engine components - Water contamination may cause fuel system corrosion and severe deterioration.
Why would I not believe this, sounds plausible enough?
And as Pièce de résistance; as ethanol has 35% less chemical energy this offsets any gain 100 RON in theory gives you over 95 RON.
Bloody hell, I said at the beginning this ain’t a simple debate...
That is exactly what I have always heard as well. The injectors fail quickly because electrolysis occurs with electricity, water and copper. I Use toluene mixed with pump gas to get a high octane rating and toluene helps evaporate water and is a GREAT knock preventative. 114 octane R+M/2. You can not run more than 40% toluene however, because it will eat the fuel lines/seals. I have been using that mix for about 8 years now w/o any problems. My 996TT will pull the timing back if I do not use the toluene mix.
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Joined: Jun 2009
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Interesting views. I spoke to my Porsche tech about it and he told me that running higher octane fuel in our cars is a complete waste of time, unless it is tuned for it. The ECU can only tune down, not up from the base tune. His advice is to run the fuel our cars are designed to run on and stop wasting the money. He also says 100 Ron has ethanol in it and that is no good for our engines. Great we have cars designed for 98 Ron which will soon be obsolete!
But an engine's octane requiremets can go up over time so the extra 2 octane points in 100 octane gasoline may not go to waste.
While everyone hates ethanol in small quantities it doesn't appear to affect the engine in any material way. Many areas of the USA (for instance) have been running gasoline with up to 10% ethanol (though I read that refiners do not go up to the full 10% but stop in the 7% to 8% range) in it and apparently suffering no harm other than a bit of less fuel efficiency.
Switching from straight gas to a gas/ethanol blend (at least up to around 7% to 8%) will see the fuel consumption will drop a bit unless one is real disciplined in monitoring fuel consumption before and after switching to gas with ethanol in it he probably won't notice.
You poor things... having to live with 100 octane gas with a bit of ethanol in it. We in CA for instance have to live with 91 octane (granted ron+mon/2) with ethanol in it.
On a long road trip in my 03 Turbo I recently had a chance to run 93 octane gas in my Turbo for over 1000 miles and the engine did perk up a noticable amount and gas mileage increased a bit. The 93 gas had ethanol in it. The 2 extra octane points that really made the difference.
Buy your name brand 100 octane gas from a busy station and enjoy.
Sincerely,
Macster.
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Joined: Jun 2009
Posts: 2,190
From: Benton County, AR
Rep Power: 147
Well I don't believe everything people tell me and this is why I am discussing it here.
My tech however says that "ethanol causes fuel system components made from brass, copper, and aluminium to oxidize".
Then I did some research and found this:
1) Water accumulation in the fuel tank - ethanol absorbs water from the air. The water condenses in the fuel tank and will pull the ethanol out of suspension with the petrol. This is bad news because it strips the octane out of the petrol, leaving you with a layer of octane-poor fuel on top and a water-ethanol layer mixture on the bottom. If this gets sucked into the combustion chamber, you will have poor starting and very rough running with potentially engine damage.
2) Deposits are likely to build up - Ethanol when mixed with water readily forms Gums in the fuel system much quicker than fuel without Ethanol. These Gums coat fuel system components including filters, carburettors, injectors, throttle plates and will then form varnish and carbon deposits in the intake, on valves, and in the combustion chamber.
3) Lower fuel mileage, Decreased performance and acceleration. Ethanol contains less chemical energy than petrol does, and this means less mileage for the driver. 3-5% drops in mileage are expected.
4) Corrosion of internal engine components - Water contamination may cause fuel system corrosion and severe deterioration.
Why would I not believe this, sounds plausible enough?
And as Pièce de résistance; as ethanol has 35% less chemical energy this offsets any gain 100 RON in theory gives you over 95 RON.
Bloody hell, I said at the beginning this ain’t a simple debate...
My tech however says that "ethanol causes fuel system components made from brass, copper, and aluminium to oxidize".
Then I did some research and found this:
1) Water accumulation in the fuel tank - ethanol absorbs water from the air. The water condenses in the fuel tank and will pull the ethanol out of suspension with the petrol. This is bad news because it strips the octane out of the petrol, leaving you with a layer of octane-poor fuel on top and a water-ethanol layer mixture on the bottom. If this gets sucked into the combustion chamber, you will have poor starting and very rough running with potentially engine damage.
2) Deposits are likely to build up - Ethanol when mixed with water readily forms Gums in the fuel system much quicker than fuel without Ethanol. These Gums coat fuel system components including filters, carburettors, injectors, throttle plates and will then form varnish and carbon deposits in the intake, on valves, and in the combustion chamber.
3) Lower fuel mileage, Decreased performance and acceleration. Ethanol contains less chemical energy than petrol does, and this means less mileage for the driver. 3-5% drops in mileage are expected.
4) Corrosion of internal engine components - Water contamination may cause fuel system corrosion and severe deterioration.
Why would I not believe this, sounds plausible enough?
And as Pièce de résistance; as ethanol has 35% less chemical energy this offsets any gain 100 RON in theory gives you over 95 RON.
Bloody hell, I said at the beginning this ain’t a simple debate...
The Turbo's fuel tank (all modern cars in fact have pretty much the same fuel tank vent/vapor recovery system) is pretty much sealed so the tank does not breathe in and out like gas tanks of old. While the ethanol does have an affinity for moisture it doesn't get exposed to that much, unless the car is left sitting unused for a long period of time.
The Turbo fuel tank has one high pressure pump and two siphon jets. These siphon jets agiate the fuel like you would not believe. The fuel if it stratifies any will be instantly mixed up and the main pump will not ingest any water from the stratification that might take place. Again though this assumes the car is used once in a while.
Using a quality fuel bought from a busy station (so the gas is fresh) with a good detergent package will ensure the fuel system remains deposit free.
There is some fall off in mileage as ethanol does have less energy. A few percent is in the ballpark.
And while corrosion is always a possibility it doesn't seem to be occuring in cars that are used regularly, even cars that are stored for sometimes months during the off season, though proper preparation including adding some gasoline stablizer is recommended.
I'm talking about for instance one example was an otherwise immaculate 993 Turbo S left to sit unused for 3 years. The fuel tank, pump, lines, injectors were shot and had to be replaced. The fuel turned to something nasty and there was no way to remove it.
We for instance in CA have been using gas with around 7% to 8% ethanol for years now and there have not been any real problems.
My 02 Boxster has covered nearly 250K miles and its original injectors are still just fine. The fuel pump failed... at around 200K miles. None of the aluminum hose bands or the electrical connectors show any signs of corrosion. The plastic housing is a bit yellowed and the hoses (plastic) are a bit discolored but by no means does the pump look like it spent years submerged in gasoline with ethanol in it.
My Turbo has over 77K miles and every one of these miles except around 1000 were with 91 octane gas (the highest octane gas available here in CA) blended with around 7% to 8% ethanol and the fuel system and the engine is just fine.
Really, relax. A bit of ethanol won't kill your car's fuel system or the engine. If you want a bit of extra comfort arrange to use a bottle or two of Techron according to the directions on the bottle say every year or so. Not much oftener cause this stuff is itself a bit of a harsh detergent, but it will remove fuel system, injector, valve, combustion chamber and even exhaust (O2 sensors even converter) deposits. But if you buy a quality gasoline and from a busy station (to avoid 'stale' gas) the car will be fine, unless you park it up for 3 years...
Sincerely,
Macster.
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Off topic, but living in Ca with max 91 RON available, I wish I had your conundrum! At least I'm lucky enough to live near one of the rare stations selling 100 at exhorbitant prices to splash in a few gallons to get the avg. closer to the 93 the car is designed for.
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Posts: 1,870
From: San Diego, San Francisco
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Interesting views. I spoke to my Porsche tech about it and he told me that running higher octane fuel in our cars is a complete waste of time, unless it is tuned for it. The ECU can only tune down, not up from the base tune. His advice is to run the fuel our cars are designed to run on and stop wasting the money. He also says 100 Ron has ethanol in it and that is no good for our engines. Great we have cars designed for 98 Ron which will soon be obsolete!
At least Europe is forward thinking in increasing octane rating as opposed to the US which keep decreasing octane ratings. Wish we had your problem. Get your car flashed for the higher octane rating so you don't feel your wasting your money at the pump or when you push down hard on the loud pedal. Tuners can tune upward for higher octane gas.
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Joined: Sep 2011
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From: Tucson, AZ
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Under certain conditions the ethanol (with water) can attack those metals, but seldom does a car see conditions in which water builds up to a dangerous level and the car is left unused long enough for the corrosion to work its damage. (A car left unused -- not weeks, not even months but years -- with no preparation is about the only condition I'm aware of.)
The Turbo's fuel tank (all modern cars in fact have pretty much the same fuel tank vent/vapor recovery system) is pretty much sealed so the tank does not breathe in and out like gas tanks of old. While the ethanol does have an affinity for moisture it doesn't get exposed to that much, unless the car is left sitting unused for a long period of time.
The Turbo fuel tank has one high pressure pump and two siphon jets. These siphon jets agiate the fuel like you would not believe. The fuel if it stratifies any will be instantly mixed up and the main pump will not ingest any water from the stratification that might take place. Again though this assumes the car is used once in a while.
Using a quality fuel bought from a busy station (so the gas is fresh) with a good detergent package will ensure the fuel system remains deposit free.
There is some fall off in mileage as ethanol does have less energy. A few percent is in the ballpark.
And while corrosion is always a possibility it doesn't seem to be occuring in cars that are used regularly, even cars that are stored for sometimes months during the off season, though proper preparation including adding some gasoline stablizer is recommended.
I'm talking about for instance one example was an otherwise immaculate 993 Turbo S left to sit unused for 3 years. The fuel tank, pump, lines, injectors were shot and had to be replaced. The fuel turned to something nasty and there was no way to remove it.
We for instance in CA have been using gas with around 7% to 8% ethanol for years now and there have not been any real problems.
My 02 Boxster has covered nearly 250K miles and its original injectors are still just fine. The fuel pump failed... at around 200K miles. None of the aluminum hose bands or the electrical connectors show any signs of corrosion. The plastic housing is a bit yellowed and the hoses (plastic) are a bit discolored but by no means does the pump look like it spent years submerged in gasoline with ethanol in it.
My Turbo has over 77K miles and every one of these miles except around 1000 were with 91 octane gas (the highest octane gas available here in CA) blended with around 7% to 8% ethanol and the fuel system and the engine is just fine.
Really, relax. A bit of ethanol won't kill your car's fuel system or the engine. If you want a bit of extra comfort arrange to use a bottle or two of Techron according to the directions on the bottle say every year or so. Not much oftener cause this stuff is itself a bit of a harsh detergent, but it will remove fuel system, injector, valve, combustion chamber and even exhaust (O2 sensors even converter) deposits. But if you buy a quality gasoline and from a busy station (to avoid 'stale' gas) the car will be fine, unless you park it up for 3 years...
Sincerely,
Macster.
The Turbo's fuel tank (all modern cars in fact have pretty much the same fuel tank vent/vapor recovery system) is pretty much sealed so the tank does not breathe in and out like gas tanks of old. While the ethanol does have an affinity for moisture it doesn't get exposed to that much, unless the car is left sitting unused for a long period of time.
The Turbo fuel tank has one high pressure pump and two siphon jets. These siphon jets agiate the fuel like you would not believe. The fuel if it stratifies any will be instantly mixed up and the main pump will not ingest any water from the stratification that might take place. Again though this assumes the car is used once in a while.
Using a quality fuel bought from a busy station (so the gas is fresh) with a good detergent package will ensure the fuel system remains deposit free.
There is some fall off in mileage as ethanol does have less energy. A few percent is in the ballpark.
And while corrosion is always a possibility it doesn't seem to be occuring in cars that are used regularly, even cars that are stored for sometimes months during the off season, though proper preparation including adding some gasoline stablizer is recommended.
I'm talking about for instance one example was an otherwise immaculate 993 Turbo S left to sit unused for 3 years. The fuel tank, pump, lines, injectors were shot and had to be replaced. The fuel turned to something nasty and there was no way to remove it.
We for instance in CA have been using gas with around 7% to 8% ethanol for years now and there have not been any real problems.
My 02 Boxster has covered nearly 250K miles and its original injectors are still just fine. The fuel pump failed... at around 200K miles. None of the aluminum hose bands or the electrical connectors show any signs of corrosion. The plastic housing is a bit yellowed and the hoses (plastic) are a bit discolored but by no means does the pump look like it spent years submerged in gasoline with ethanol in it.
My Turbo has over 77K miles and every one of these miles except around 1000 were with 91 octane gas (the highest octane gas available here in CA) blended with around 7% to 8% ethanol and the fuel system and the engine is just fine.
Really, relax. A bit of ethanol won't kill your car's fuel system or the engine. If you want a bit of extra comfort arrange to use a bottle or two of Techron according to the directions on the bottle say every year or so. Not much oftener cause this stuff is itself a bit of a harsh detergent, but it will remove fuel system, injector, valve, combustion chamber and even exhaust (O2 sensors even converter) deposits. But if you buy a quality gasoline and from a busy station (to avoid 'stale' gas) the car will be fine, unless you park it up for 3 years...
Sincerely,
Macster.
I'm sure most cars do fine, but some engines do carry a very slight current to the injectors, even with the ignition off. This makes the injectors go out fast. The early 90-94 Nissan 300ZXTT had that issue where the US cars were going through injectors like crazy, but none in Japan. Our ethanol is a contributor because of water in the fuel line and the copper injectors. They did correct the circuitry with a new engine wire harness after 94 though. Most tuners I know refuse to tune a car with E85, even though it has a high octane, because it just does not combust as well, from what they tell me. (condensed version) I'm thrilled with my 93 tune in AZ where I do 91 pump and 2 gal. Toluene. It never pulls back timing.
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I'm sure most cars do fine, but some engines do carry a very slight current to the injectors, even with the ignition off. This makes the injectors go out fast. The early 90-94 Nissan 300ZXTT had that issue where the US cars were going through injectors like crazy, but none in Japan. Our ethanol is a contributor because of water in the fuel line and the copper injectors. They did correct the circuitry with a new engine wire harness after 94 though. Most tuners I know refuse to tune a car with E85, even though it has a high octane, because it just does not combust as well, from what they tell me. (condensed version) I'm thrilled with my 93 tune in AZ where I do 91 pump and 2 gal. Toluene. It never pulls back timing.
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