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YOUR RESEARCHOctane rating
Reported or suspected cause
size of the nozzle
Reported cause
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Reported cause
I drove out there, right up to the pump and filled my can - only issue was the size of the nozzle.
Run aviation 100ll (big octane and always zero ethanol)
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Unsuccessful attempts
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Discussions that contain suggestions
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Suggestion
I could always remove the Cats and run Aviation 100LL (Big Octane and always Zero Ethanol), but I think I would get a lot of CEL lights flashing at me.
Leading evidence: 'size of the nozzle' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'size of the nozzle' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Run aviation 100ll (big octane and always zero ethanol)' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Discussions that performed work without a confirmed outcome
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Performed · outcome unconfirmed
It worked just fine, the CAT was removed and I was running high compression heads, but in those days the avgas access was a wee-bit easier.
Outcome qualification: Negation, uncertainty or missing explicit repair resolution overrides the raw extraction signal.
Run aviation 100ll (big octane and always zero ethanol)
Suggestion or failed attempt
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Unsuccessful attempts
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Discussions that contain suggestions
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Suggestion
I could always remove the Cats and run Aviation 100LL (Big Octane and always Zero Ethanol), but I think I would get a lot of CEL lights flashing at me.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
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Suggestion
Running higher octane that needed (91/93) is a waste unless you have a tune that supports it
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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Suggestion
The owners manual says the car is designed to run on 93, but can run on 90 minimum.
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
Run aviation 100ll (big octane and always zero ethanol)
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
I could always remove the Cats and run Aviation 100LL (Big Octane and always Zero Ethanol), but I think I would get a lot of CEL lights flashing at me.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
17 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 1 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261027T060112Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Filled up tonight and noticed a 93 minimum sticker on my gas filler door. Here in CA the best we get is 91 (car was originally from FL). Do these engines have knock sensors or am I going to have to stock up on octane booster from now on? How prone are these engines to detonation?
PetroCanada sells Ultra 94 in a few stations around town. That is what I will burn, but if I get caught I just put in a load of 91. Only the 991 and the 981 have the 93 Label on the gas door. The Cayenne has a 91 Label.
The owners manual says the car is designed to run on 93, but can run on 90 minimum. So 91 is OK, just the knock sensors may retard the timing a bit, at the expense of a bit of HP.
Don't bother with octane boost, like IMO says barely registers an increase and isn't worth it.
There is a station near me that sells 93 octane non-ethanol fuel and I've been dying to try a tank. He says he has many Porsche owners refuel there. Here we can have up to 10% ethanol in a gallon of gas. They charge like $5.25/gallon for the non-ethanol fuel. Why is it that "removing" or "not adding" something to the fuel makes it more expensive? Kind of like paying more for laundry soap that has no fragrance in it compared with one that has that crap in it. Why does it cost more to NOT add something.......
I think the Ultra94 up here does have Ethanol, but in Canada it can be hit and miss. It is added in sometime during the delivery process IIRC. I the next time I get some U94 I will take a sample and do the home test. I could always remove the Cats and run Aviation 100LL (Big Octane and always Zero Ethanol), but I think I would get a lot of CEL lights flashing at me. It is a bit tricky (aka illegal) to use in a car. The airport fuelers can only put it into an actual aircraft, no jerry cans allowed. But my current aircraft has 140 Gal fuel tanks, so I have a good built-in storage system
I did run 100LL in a modified MGB back in the early 80s. It worked just fine, the CAT was removed and I was running high compression heads, but in those days the avgas access was a wee-bit easier.
Just joking
Ethanol in gasoline improves octane, is notionally renewable but also reduces fuel mileage due to the fact ethanol has lower energy density (BTU/gallon) than hydrocarbons. The difference is dramatic--ethanol has about 2/3 the energy content of hydrocarbons than comprise motor gasoline. A 10% ethanol blend should yield about 4% lower MPG. There have been some issues with water absorption and separation in gasolines with high alcohol content when they were first being developed but I've heard nothing about this once they were widely introduced to the market.
My personal opinion is that charging a large premium for "alcohol free" fuel is playing on unfounded fears, not real science. But, if removing the ethanol from gasoline makes more ethanol available, cheaper, for my after-drive drink then I'm all for it!
It is priced per Gallon. It's not a gallon of gasoline with .1 gallon alcohol chaser on the side. It's like ordering a beer with 90% beer & 10% water substituted.
When I moved to Colorado from Texas 10 years ago I needed 100LL to run in my modified Harley. While in Texas I'd just go to the local A/P (San Marcos) and fill up my 5 gallon can - no problems. I showed up at Centennial A/P in Colorado with my 5 gallon can and asked for a "fill-up" and you would have thought I was asking for their first born children - they said "no" and BTW it's against the law. So I asked where I might find some 100LL and a fellow Harley rider told me to go to JeffCo A/P - they had a self service pump for aircraft with 100LL. I drove out there, right up to the pump and filled my can - only issue was the size of the nozzle. Sold the bike so don't know if that self-serve option is still available.
There are still self-serve options at a lot of small airports in both the US and Canada. But you 'technically' are only suppose to buy that gas for use in an aircraft. But if I was questioned about putting some in a 5-Gal cans, I would say it is for my Piper Cub, which is back on my Farm Strip. At our main airport (YBW) I even had the fuel guy turn me down when I asked that he fill up my aircraft Tug, which needed about 5 Gals. I then said hey you know as soon as you leave I will drain 5 Gal from my wings, and then call you back to top up my aircraft. He swore, but did fill up my Tug.
You are right you would need a Gas Can with a Big *** Mouth, as the aviation style fillers are normally some 2" wide.
It is not 100LL, but another way to get ethanol free gas is to buy it from a marina. At least up here all Marine gas is still ethanol free. But it is still mostly 91 Octane. They will pump into cans, they leave it up to you to make sure that gas goes into a boat.
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