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    93 Octane

    Anyone know where to find 93 Octane?

    My dealer said not to worry... something about 2007 knock sensors.

    On occasion, at low speeds, I hear some knocking. I don't think I'm lugging the engine.

    Re: 93 Octane

    if you have knocking you want higher octane not lower, I run mine of Shell 99 octane and it loves it

    Re: 93 Octane

    Yeah, Silver, 93 is recommended- I believe it's the highest octane available in the States. But I can only find 91.. so far.



    Re: 93 Octane

    Guys, I fear we're talking at cross purposes.

    In the EU, we refer to 98 RON as being optimal for our 997s. In the US, 98 RON is equivalent to 93 AKI and 93 CLC.

    So, I believe when SVNSVN refers to 90 and 91 octane, he is actually referring to octane levels under AKI or CLC.

    FYI 90 CLC and 90 AKI are equivalent to 95 RON.

    Richard, AFAIK your car will run just fine on 90 AKI or 91 AKI. No problem. However, 93 AKI will be optimal for you if you can find it.

    Sorry if I've been stating what people already know but it may clarify matters for those with less knowledge/experience here.

    BTW, here in the UK, I use a Shell station locator which is great because you can actually select a filter so that only stations that sell Shell V Power (the successor to Shell Optimax) are listed. Perhaps you have a similar website for the major brands in the US.

    Here's the UK link:

    http://www.multimap.com/clients/places.cgi?client=shell&lang=en&db=GB

    Re: 93 Octane

    94 Octane gas is available up in Vancouver BC so I always try to get some whenever I'm up there. I haven't had the chance to put some in my TT yet but I'm hoping to the next time I head up there.

    Re: 93 Octane

    I should add that we also have BP Ultimate which is 98 RON. Tesco (supermarket) is also selling 99 RON fuel (but I still wouldn't touch a supermarket branded fuel).

    [There have been some media scandals in the past when Tesco claimed their regular unleaded fuel was 95 RON and it turned out to be sometimes as low as 93 RON].

    Also, FWIW, in Germany Shell V Power is 100 RON, in the UK it is 99 RON and in Belgium it is 98 RON. Same named product, different specification.

    Re: 93 Octane

    Thanks Easy! I'm sure it'll be OK as the dealer said...I just would prefer to find the 93, as it's recommended. I know it's gotta be out there.

    Re: 93 Octane

    Richard,

    The following is stated on page 4 of the US 2006 Carrera Owner's Manual:

    "Your engine is designed to provide optimum performance and fuel economy using unleaded premium fuel with an octane rating of 98 RON (93 CLC or AKI). Porsche therefore recommends the use of these fuels in your vehicle.

    Porsche also recognizes that these fuels may not always be available. Be assured that your vehicle will operate
    properly on unleaded premium fuels with octane numbers of at least 95 RON (90 CLC or AKI), since the engine's "Electronic Oktane knock control" will adapt the ignition timing, if necessary."

    So, honestly, no doubt here, PAG itself says your car will run just fine on 90 AKI.

    Re: 93 Octane

    OT: Richard you have to clear your PM register - I couldn't send a nasty reply regarding the "special messages"

    Re: 93 Octane

    Quote:
    easy_rider911 said:

    Porsche also recognizes that these fuels may not always be available. Be assured that your vehicle will operate
    properly on unleaded premium fuels with octane numbers of at least 95 RON (90 CLC or AKI), since the engine's "Electronic Oktane knock control" will adapt the ignition timing, if necessary."

    So, honestly, no doubt here, PAG itself says your car will run just fine on 90 AKI.




    Nice work e_r911,


    That's one of the first things I learned and memorized about these cars.

    Would be nice if there was some way for the engine diagnostics to _indicate_to_us_ on the dash or elsewhere that we're ACTUALLY getting the octane we paid for (i.e. we're not getting ripped off at pump).

    Re: 93 Octane

    We used to have 94 oct here in the Northeast, but now only 93 and it is available everywhere.

    Re: 93 Octane

    I should say that AFAIK there appears to be no real benefit in having fuel which is above the 98 RON (93 AKI, 93 CLC) octane level.

    I guess the oil companies have cottoned onto the fact that people will pay to buy 99 RON or 100 RON fuel even though it exceeds the optimal 98 RON octane level because of some 'perceived superiority'. The fact is though that we are paying a little extra for fuel (e.g. 99 RON) which is needlessly richer than 98 RON.

    In my own case, I would be happy if Shell V Power was 'only' 98 RON but it happens to be 99 RON. The real reason why I buy it anyway is because of the additives in the fuel to keep the engine clean inside.

    Re: 93 Octane

    Just come to Michigan Richard. There's 93 at just about every station..

    Re: 93 Octane

    Recommended/needed octane is directly related to altitude above sea level... Since I live in Florida, we have 93 octane EVERYWHERE as we're one tsunami away from being the world's largest sand-bar.

    At higher altitudes with thinner air, the octane ratings available decrease proportionately. Wherever you're at, going with the "Premium" offering at the pump should do you fine...

    You could run regular in your car, and the knock-sensors would keep it from pinging.... but at the cost of retarded ignition timing, which lowers performance...

    Re: 93 Octane

    Quote:
    69bossnine said:
    Since I live in Florida, we have 93 octane EVERYWHERE as we're one tsunami away from being the world's largest sand-bar.





    ROTFLOL.

    Thanks, THAT's a good one!

    (I hope it NEVER happens though)

    Re: 93 Octane

    Unfortunately, in California we don't commonly have anything over 91. In Europe they do sell some higher stuff but even the factory said not to bother with buying the highest available, and that the Super Blei Frei was good enough. If you're going racing perhaps it would be nice to get the max potential out of your engine,--maybe mixing in a suitable percentage of unleaded aviation gas to get the least amount of detuning by the valves.

    Dan

    Re: 93 Octane

    If you live in Southern CA, Unical 76 in south OC, corner of La Paz and the 5 freeway sells 105 octane gas.

    Re: 93 Octane

    Aviation gas is formulated for aviation motors, and I've been told can be highly aggressive/corrosive to the fuel system components in your car's engine... If you want to toss in a few gallons of nice fuel, use far-more-accessible unleaded racing fuels like 100-octane Cam-2..

    I run 5 gallons of 114-octane Sunoco leaded in every tank of 93 unleaded I run in my Boss 429... Otherwise, it pings to high-heaven, and isn't happy.

    Re: 93 Octane

    Quote:
    edz61 said:
    If you live in Southern CA, Unical 76 in south OC, corner of La Paz and the 5 freeway sells 105 octane gas.



    Exactly, you can buy unleaded race fuel fairly commonly, just use the internet to find the station nearest you servicing it... Not that you need it for your 997, but just FYI...

    Re: 93 Octane

    Quote:
    69bossnine said:
    At higher altitudes with thinner air, the octane ratings available decrease proportionately. Wherever you're at, going with the "Premium" offering at the pump should do you fine...



    Right on 69bossnine. Further more, during the "winter" months (something like mid-October through mid-April) we can readily get 91 octane here in Denver but during the other months generally the highest easily found octane is 89. There are the few stations that offer 91 year round but they are harder to find.

    The reasoning behind the winter/summer octane number has to do with how much ethanol they mix in to help keep polution numbers down during the season changes.

    Re: 93 Octane

    Here is a page which list 100 octane gas for sale in CA.

    http://www.3dman.com/Ducky/Hot_fuel.htm

    Every once in while I get a wild hair and mix the 100 octane 50/50 in my C2S. Lot's of fun! With a GIAC Chip you can have a special 'racing fuel' setting that REALLY lights up the motor if you have a full tank of 100 octane.
    For cheaper thrills the Sunoco 95 Octane is good fun but likely not available in CA. My East Coast friends certainly know about the 95 octane Sunoco.
    I think the main reason the octane in Denver is so low is the altitude, not polution. As you approach sea level the octane available generally increases.

    Re: 93 Octane

    Many thanks for the info, gents

    I thought it would be no problem finding 93, even in the boondocks of California.

    Thanks again, Easy. I know, I should've RTM thoroughly.



    PJ, done deal. I hope your Birthday was awesome!

    Re: 93 Octane

    Check out this link. Scroll down and on the right you'll see a "mixing" table for combining different octanes

    http://www.idavette.net/hib/fuel/page2.htm

    Octane and Altitude?

    Not sure I follow the logic that octane and altitude are related.

    Octane ratings are measured on a single cyninder engine in a lab. Done the old fashioned way with a lab tech adjusting a blend of ref fuel which includes iso-octane (= 100).

    The US reports octane as the ave of two numbers: the research octane number (RON) and the motor octane number (MON). Both are measured under different loads and at different RPM's. Nothing special about either method. A typical US gasoline might be measure 85 on MON scale and 93 RON. Check our the pump the next time you fill up and you'll see the octane labeled as (R+M)/2.

    Winter gasoline includes butane to increase the vapor pressure for those living in cold climates. Butane also helps the refiners meet their octane targets as it is a high octane blending component. Ethanol is a whole different subject but let me just say that it's in your gasoline because of the success of a very powerful lobby. While it's good for energy independence, it's a dasaster in all other areas (think pollution, CO2 make, price of tortillas).

    Dr Dave

    Re: Octane and Altitude?

    Is it true that you would need a different ECU map to utilize higher octane fuel than 93, for those of us in the states? I don't believe the higher octane fuel can just be added and the programming is dynamic enough to take advantage of the fuel.

    Re: Octane and Altitude?

    Quote:
    mvd said:
    Not sure I follow the logic that octane and altitude are related.

    Octane ratings are measured on a single cyninder engine in a lab. Done the old fashioned way with a lab tech adjusting a blend of ref fuel which includes iso-octane (= 100).

    The US reports octane as the ave of two numbers: the research octane number (RON) and the motor octane number (MON). Both are measured under different loads and at different RPM's. Nothing special about either method. A typical US gasoline might be measure 85 on MON scale and 93 RON. Check our the pump the next time you fill up and you'll see the octane labeled as (R+M)/2.

    Winter gasoline includes butane to increase the vapor pressure for those living in cold climates. Butane also helps the refiners meet their octane targets as it is a high octane blending component. Ethanol is a whole different subject but let me just say that it's in your gasoline because of the success of a very powerful lobby. While it's good for energy independence, it's a dasaster in all other areas (think pollution, CO2 make, price of tortillas).

    Dr Dave




    Conversely, I don't understand how your post has anything to do with addressing the relationship between altitude and octane requirement...

    I coulda given you my shadetree-mechanic explanation, but a quick google tap, and I got this at the top of the page..

    7.11 What is the effect of altitude?

    The effect of increasing altitude may be nonlinear, with one study reporting
    a decrease of the octane requirement of 1.4 RON/300m from sea level to 1800m
    and 2.5 RON/300m from 1800m to 3600m [27]. Other studies report the octane
    number requirement decreased by 1.0 - 1.9 RON/300m without specifying
    altitude [38]. Modern engine management systems can accommodate this
    adjustment, and in some recent studies, the octane number requirement was
    reduced by 0.2 - 0.5 (R+M)/2 per 300m increase in altitude.
    The larger reduction on older engines was due to:-
    - reduced air density provides lower combustion temperature and pressure.
    - fuel is metered according to air volume, consequently as density decreases
    the stoichiometry moves to rich, with a lower octane number requirement.
    - manifold vacuum controlled spark advance, and reduced manifold vacuum
    results in less spark advance.

    Re: Octane and Altitude?

    "Shadetree mechanic" Good one!

    We are talking about two different things as I misread your post to suggest that altitude causes the fuel's octane to decrease ("At higher altitudes with thinner air, the octane ratings AVAILABLE decrease proportionately"). Obviously, the fuel's the same and there's no change in it's octane rating. Sorry for the misread.

    What I think you were trying to say (and your google post confirms) is that the octane required to prevent knocking decreases as the elevation increases (excluding, of course, turbos and blowers). Agreed?

    Now back to my shadetree, Dave

    Re: Octane and Altitude?

    Sorry not to be scientific enough -
    You will notice better performance without an ECU change if you use higher octance gas (up to what seems to be 95 octane).
    For 100 octance gas get a GAIC chip upgrade - you can select programs such race fuel and even go back to stock mapping.
    I simply have never found any more than 91 octane gas at altitude. It may be that knock resistance is higher but performance also sucks, I don't care what you are driving.
    Concersely I have noticed higher octance gas the closer I travel to sea-level(except CA?). Chime in East-Coast Sunoco 95 fans.

    Re: Octane and Altitude?

    I sometimes get 4-6 gallons of 100 octane at Infinion Point (SEARS POINT) in the Bay Area. I mix it with 91 hoping to get 94 octane total. Makes a BIG difference for me but anything over 94 is just a waste for reasons already mentioned.

    Re: Octane and Altitude?

    Porsches run fine in CA with 91. If you hear knocking there is some problem because the ECU does handle 91, or you are lugging it, God forbid. Ask your dealer to test it.

     
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