Smoke992

In higher altitude regions, and where I live, 93 is just not available. Is running 91 consistently ok? The manual says not to floor it on 91 which seems laughable to me, given these people track gt3s here.

anykne have any feedback, or know where to get 93 octane in Colorado?

Richard_Wallace

You are fine with 91 - many regions do not have 93, you will be hard pressed to notice a difference between the two.

CodyBigdog

My two cents - Most modern cars have knock and other sensors to protect turbo engines. Using a lower octane gas could increase the chances of knocking under full throttle conditions. However, the sensors should tailor back the boost, and/or retard the timing to reduce the chances of knocking. So, the long story short is….I suspect running 91 or lower octane gas will NOT damage your engine, but there may be some minor reduction in performance,

But i would think this is a good question to run by the head of your local Porsche service department? That way you should get the scoop from someone that should know if this is a problem, or not.

NastyHabits

Slightly off topic, but what would the consensus be. 91 octane ethanol free, or 93 with 10% ethanol?

Michigan 992

FYI - the standard available fuel in Europe that all cars must be tested on is 95 RON. That is the same as 89 Pump Octane in the US. No alcohol in that fuel so it is pretty good that way. There is not always higher octane fuel available there so the European cars have to run good on that fuel without durability issues. Now if you are using a tune it is a whole different bet.

If I had my druthers, I would not use alcohol added fuels for durability and pollution reasons, but I am not allowed to say that in an official capacity.

Richard_Wallace

Almost no difference, there are a few studies by the military (extensive) on the addition of Ethanol on fuel and what negative or positive it causes on engine ware. They studied every major part of the engine and the effects of ethanol. Really nothing to worry about at all. You can look up a few very long studies on youtube, which are really fascinating, but the end result - ethanol at that percentage is not a concern.

aquatone

I am at 4,300' and frequently over 7,000' on 91 Octane. No problems at all and I do floor it when the mood strikes

F8Driver

The main thing I've noticed is that MPG suffers. The ECU quickly determines you're running lower octane and dials back its tune. I discovered this in West Texas, couldn't find 93 and the 91 tankful delivered a couple less MPG.

detansinn

As others have noted, it will run totally fine on 91 octane. In much of the United States, that’s all that you will find.

If you are running an aftermarket tune, be sure to run a 91 octane tune. The tunes tend to push the limits a bit and you don’t want a 93 octane tune running on 91 octane.

mrmichaelsankey

Not sure how the US/EU octane conversion goes, but I’ve run the 992 and macan on the 95 E10 stuff and it was ok, mpg went down but no issues.

wife put a bad tank of 95E10 in the macan the other day, started throwing up errors on the dash, “engine electrical fault”. Ran it down and put in a tank of the good stuff (99E5) and no more errors.

I’d say you’d be fine, just as long as it’s a station with regular use so the fuel hasn’t gone a bit off.

icanthelpit

93 is not needed in higher elevations due to lower air density resulting in less combustion air. The result is less fuel in cylinders resulting in less knock capability. 91 octane is fine in Colorado.

icanthelpit

Depends on the elevation where you are using it. Higher elevations need less octane. I avoid ethanol as much as I can in any gas tank car, lawnmower or otherwise.

DavidColorado

For a naturally aspirated engine, yes, but in a turbocharged engine - I understand that the turbo spins faster and makes up the difference. Up to a point, no loss in HP or torque. (Lots of data points on the Pikes Peak Hill Climb)

I Googled and found https://find93.com/, which lists very few sources in Colorado. Haven't verified them yet (thinking ahead, expecting delivery of my 992 in February).

icanthelpit

You go with that then. There will be a fixed volume of air for combustion that a turbo can inject into cylinders. Turbos do not have supercompressability capabilities at road car boost levels. BTW supercompressability is a real term.

Michigan 992

Depending on the engine, turbos generally can’t maintain sea level performance above 4000 feet in altitude unless they have a fair amount of throttle lag in normal driving. It is a trade off between maximum capability for maintaining peak power as you go up in altitude versus transient response.

The highest critical altitude that I remember for a modern turbo car engine is 7000 feet above sea level. That engine had a fair amount of transient lag compared to most modern road cars.