Fuel octane ratings
#16
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Originally Posted by John Boggiano
I'm interested to see that the GT3 specs only mention running on 98 octane fuel.
Now, while I realise the advantages of this, and the fact that the engine was designed to run out it, it's simply not available everywhere.
Presumably, filling with 95 octane (much more widely available) will hurt only performance, and not the engine? Not that I'm suggesting it long-term, you understand, but sometimes it might be unavoidable for a tankful or so...
Now, while I realise the advantages of this, and the fact that the engine was designed to run out it, it's simply not available everywhere.
Presumably, filling with 95 octane (much more widely available) will hurt only performance, and not the engine? Not that I'm suggesting it long-term, you understand, but sometimes it might be unavoidable for a tankful or so...
Last autumn I did the PCA Treffen (highly recommended, BTW), and the PAG employees filled the cars with VPower exclusively (southern Germany, at about $6.90/U.S. gallon) and it was labeled '100 Oktan', which if we could get in the U.S., would be 95 octane by our measure. PM if you want to see a photo of the pump.
In England one can buy 'BP Ultimate 102', which is 102 by their measure, and 96 by ours, plus it meets FIA F1 specs. I think Shell's competing fuel is Optimax.
HTH,
Jim
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OK, guys. Thanks for all the info.
So the Euro (RON) rating works out at 5 to 6 points higher than the equivalent Octane (USA) rating. And Porsche still recommends 98RON or 93 Octane wherever the car is marketed. But it seems some people have no option but to use lower grades.
I guess I'll only do so if and when it becomes absolutely necessary and then be gentle with it.
Just as a final confirmation, could someone in CA (and therfore running 91 Octane) please confirm for me that the fuel flap still states '93'?
So the Euro (RON) rating works out at 5 to 6 points higher than the equivalent Octane (USA) rating. And Porsche still recommends 98RON or 93 Octane wherever the car is marketed. But it seems some people have no option but to use lower grades.
I guess I'll only do so if and when it becomes absolutely necessary and then be gentle with it.
Just as a final confirmation, could someone in CA (and therfore running 91 Octane) please confirm for me that the fuel flap still states '93'?
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Thanks, Jim.
Suggests to me that there may be some difference in the ECU or elsewhere to allow for the lower grade in ceratin markets, as the Euro cars (well mine, at least) simply state '98 RON'.
Suggests to me that there may be some difference in the ECU or elsewhere to allow for the lower grade in ceratin markets, as the Euro cars (well mine, at least) simply state '98 RON'.
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Originally Posted by John Boggiano
Suggests to me that there may be some difference in the ECU or elsewhere to allow for the lower grade in ceratin markets
Originally Posted by John Boggiano
the Euro cars (well mine, at least) simply state '98 RON'.
#22
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Originally Posted by mvd
If I were responsible for US applications of the ECU, I'd design for 93 (RON + MON)/2 so those fortunate enough to get it aren't penalized. I'd also design the ECU to retard the ignition as necessary for 92 and 91 gasolines. In other words, a single ECU for all US gasolines (which is what we have).
?
?
Jim
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Originally Posted by mrpc12
We only get 91 Octane in California so I'm sure there is no problem using 95.
#25
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in Pennsylvania, a few Sunoco stations have GT100. $8.19/gallon. Almost as expensive as gas in Europe
most Sunocos here only carry 93 octane though
you could put 5 gallons of GT100 in and then top off with 93.
http://www.sunocoinc.com/site/Consum...T100Locations/
most Sunocos here only carry 93 octane though
you could put 5 gallons of GT100 in and then top off with 93.
http://www.sunocoinc.com/site/Consum...T100Locations/
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OK, guys, this has been an extremely informative discussion, but it's time for me to hang my head in shame.
Although I had 'read' the manual when I took delivery, it's only last night that I found the time (been too busy driving!
) to read it cover-to-cover. Buried inside on two separate occasions is the news I was seeking - my engine will run perfectly happily on 95RON, but (obviously) will only give optimal performance on 98RON. Now why couldn't Porsche just have given that option on the fuel flap and in the 'beginners start here' bits of the manual?
Still, I've ended up not only with the answer to my question, but a working knowledge of worldwide fuel grades and how they are calculated. Thanks, everyone.
Although I had 'read' the manual when I took delivery, it's only last night that I found the time (been too busy driving!
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
Still, I've ended up not only with the answer to my question, but a working knowledge of worldwide fuel grades and how they are calculated. Thanks, everyone.
#30
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Okay, here are two pumps, one in Bavaria last fall, the other here in the Midwestern U.S. as of last Saturday -- assuming I got them attached correctly. The Bavarian pump isn't marked as to method, so I'm guessing RON. The U.S. pump is (R+M)/2.