Bash Hat

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?

Ahsai

91 is fine. There are two knock sensors, one per bank.

Bash Hat

Thanks Ahsai!

Atrox

No 93 in my town, forced to use 91. When I do get 93 the performance diff is negligible.

Imo000

Octane boosters are a scam. When they state that it raises the octane by one point they usually don't tell you that 1 point is only 0.1 octane.

5CHN3LL

Race fuel, on the other hand, is not a scam.

sctanton52

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.

Cosmo Kramer

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.

JayG

Running higher octane that needed (91/93) is a waste unless you have a tune that supports it

DBJoe996

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.......

JayG

What the market will bear

sctanton52

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

02TX996Cab

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!

extanker

high test.....enough with the HBO drama

Byprodriver

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.