regular gas is disapearing over here


Desi

Desi

GT Owner
Jan 30, 2006
302
Germany
Does anybody know if using gas with 95 octane regularily would harm the engine on the long run? Very strange development here in Germany. The petro companies first raised the prices for "regular" gas with 91 octane to the same level as "super" gas with 95 octane (=same price) and now regular gas with 91 disapeared at first gas stations e.g. at Shell. Only gas with 95 and 100 octane available now. I don't think that this way a higher octane figure would harm anything but wanted to ask the GT brain :wink Can you observe the same development in the US?

Thanks
Desi
 
This higher rating seen in Europe is an artifact of a different underlying measuring procedure. In most countries (including all of Europe and Australia) the "headline" octane that would be shown on the pump is the RON, but in the United States, Canada and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, this means that the octane in the United States will be about 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US and Canada, would be 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90–91 US (R+M)/2, and deliver 98 (RON), 99 or 100 (RON) labeled as Super Unleaded.

http://en.wikipedia.org/wiki/Octane_rating
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Since the FGT is recommended to run on 91+ ((R+M)/2) - this should equate to a ~95+ RON rating in Germany I believe to your post....:thumbsup

I run constantly 93/94 octane in the US with a stock tune for the Whipple @ 19 PS1 and will change the tune when I fill or blend to equal 100 octane ((R+M)/2).
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What I fear in the US is that more cars and stations are moving to the lower octane "regular" stranding the higher octane users (following the examples set by kalifornia) ....... while it appears in europe is it going the other way.
 
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Mad
thanks for your quick and comprehensive feedback!

Desi
 
Mike-
I was really impressed with the depth of your octane knowledge!!!
That is until I got to the wikipedia reference. I sumarize all the RON, MON, PON nomenclature is explained there. Very good job of summarizing this topic for the owners however. I suspect the conversion from prominant posting of the RON in europe and going to the averaged octane rating (RON + MON)/2 is likely the cause as you post.

And Desi to answer your question, you will never hurt or damage the engine by running a higher than required octane. You will only be wasting money for octane "protection" which the engine does not need nor can it use. The stories about running a tank of premium gas to "clean out the engine", obtain better fuel mileage, increase spark plug life, etc. are all myths. There is no benefit whatsoever in using 91/93 octane in an engine which has a (mechanical) requirement for 87 octane. The oil companies love to infer these premium use attributes as margins on higher octane fuel are undoubtedly higher and they make more money. But there is absolutely no engineering basis for using a slower burn rate fuel (higher octane) in and engine which does not require its use.
 
Indy GT said:
You will only be wasting money for octane "protection" which the engine does not need nor can it use. The stories about running a tank of premium gas to "clean out the engine", obtain better fuel mileage, increase spark plug life, etc. are all myths. There is no benefit whatsoever in using 91/93 octane in an engine which has a (mechanical) requirement for 87 octane. The oil companies love to infer these premium use attributes as margins on higher octane fuel are undoubtedly higher and they make more money. But there is absolutely no engineering basis for using a slower burn rate fuel (higher octane) in and engine which does not require its use.
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Exactly. :thumbsup
 
Good to know! But as I wrote, we will have no choice in future as the lower octane gas (91/93) will disapear from the market over here (only 95 and 100 octane). But the other way 'round would be worse :biggrin

Desi

Indy GT said:
Mike-
And Desi to answer your question, you will never hurt or damage the engine by running a higher than required octane. You will only be wasting money for octane "protection" which the engine does not need nor can it use. The stories about running a tank of premium gas to "clean out the engine", obtain better fuel mileage, increase spark plug life, etc. are all myths. There is no benefit whatsoever in using 91/93 octane in an engine which has a (mechanical) requirement for 87 octane. The oil companies love to infer these premium use attributes as margins on higher octane fuel are undoubtedly higher and they make more money. But there is absolutely no engineering basis for using a slower burn rate fuel (higher octane) in and engine which does not require its use.
Click to expand...
 
Indy GT said:
Mike-
I was really impressed with the depth of your octane knowledge!!!
That is until I got to the wikipedia reference.
Click to expand...


Actually Dick,

traveling Europe over the last decade I knew there was a 5 point Octane difference but when Desi asked the question I decided to take it upon myself to find out why :biggrin
 
I wish the higher octane stuff were more readily available in CA like it is in other states. Then I could add in some timing. Dropping the high octane stuff would be even worst!
 
Hey Mike, wondering what kind of dyno numbers you getting with the stock whipple tuned for 93-94 octane?
 
Desi said:
Does anybody know if using gas with 95 octane regularily would harm the engine on the long run? Very strange development here in Germany. The petro companies first raised the prices for "regular" gas with 91 octane to the same level as "super" gas with 95 octane (=same price) and now regular gas with 91 disapeared at first gas stations e.g. at Shell. Only gas with 95 and 100 octane available now. I don't think that this way a higher octane figure would harm anything but wanted to ask the GT brain :wink Can you observe the same development in the US?

Thanks
Desi
Click to expand...

You actually had much more chance of harming your car before with the 91RON. I've been on to the octane difference between US/ Euro-Aust for many years now. It actually has really pissed me off with tuning scenarios here many times now with different cars. We had up until recently a Shell 100RON product here, that was the equiv of US 96PON. Unfort Shell reneged and took it off the market recently(damn them), so the best service station fuel I can now run is 98RON or approx 93PON. This has proved frustrating with tuning both my Cobra and GT as you just can't creep the timing up as much as we'd like to max out the HP potential as some of the US owners are getting.

If anything Desi, it worries me to imagine running a GT on 91RON European or 87PON US(sorry but I want check the manual to see where Ford endorse that low a octane # for an engine of the GT's stock performance). Your car should run much smoother on the 95RON anyway, the fuel companies did you a huge favor there. Just remember if tune your car at all for more performance(a decent timing increase to make it worth it), you'll will really need to run the 98RON as a min.
 
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Desi - 91 RON is very bad for the car- detonation is highly possible - My grandfather puts it in his Lada!
Our cars are made for not less than 95 RON - and 100 RON would be the best to put in it - especially if the car is modded.

Good luck!
 
BlackICE said:
I wish the higher octane stuff were more readily available in CA like it is in other states. Then I could add in some timing. Dropping the high octane stuff would be even worst!
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You might want to check out some of your local Shell stations. There is one down by us that offers 100 octane at the pump.
 
Indy GT said:
But there is absolutely no engineering basis for using a slower burn rate fuel (higher octane) in and engine which does not require its use.
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Just a clarification, higher octane fuels do not have a slower burn rate. octane is not related to burn rate.
 
mousecatcher said:
Just a clarification, higher octane fuels do not have a slower burn rate. octane is not related to burn rate.
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My understanding is that the higher the octane the cooler it burns? Is that correct?
 
I beg to differ with you mousecatcher.

But I will give you the floor to explain to us your understanding of WHAT the fuel octane number is and WHY that number is an important consideration for an internal combustion engine.

We can then go from there.....
 
OK, I'll play the straight man for Indy GT. I say octane, an eight carbon straight chain with 18 hydrogens, is perfect because of it's compressability, and was assigned a number of 100, upon which all other internal combustion engine burning substances are based. The more compressible, the more efficient and most probably cooler burning.

OK Indy, run with it. This is my Xmas present to you, a clean soapbox.

Your buddy Frank
 
Octane number is a measurement of fuel’s resistance to engine knock. Engine knock is an abnormal combustion associated with using gasoline with too low of an octane number. Ordinarily, your vehicle will not benefit from using a higher octane than is recommended in the owner’s manual.

http://www.api.org/aboutoilgas/gasoline/gasoline-octane.cfm
 
+1. My understanding as well.
The higher the octane, the greater the tolerance to detonation - allowing a higher compression ratio and/or higher combustion chamber temperatures. Very valuable in sc/tc cars.
OTOH (and now I'm on shakier ground), accommodating or better yet optimizing for varying octane levels is a function of the ability of an ECU to 'sense' that variance. Typically with a knock sensor or the like.
I don't believe that our GT's have such a sensor, or any other mechanism to test for pre-ignition. They are instead pretuned for a base octane level.
So, notwithstanding the fact that detonation can create excess heat, which the GT can sense, which will then trigger retarding of the spark, higher octane fuels in the GT, for a standard tune, will be wasted. No?


BlackICE said:
Octane number is a measurement of fuel’s resistance to engine knock. Engine knock is an abnormal combustion associated with using gasoline with too low of an octane number. Ordinarily, your vehicle will not benefit from using a higher octane than is recommended in the owner’s manual.

http://www.api.org/aboutoilgas/gasoline/gasoline-octane.cfm
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t32b said:
So, notwithstanding the fact that detonation can create excess heat, which the GT can sense, which will then trigger retarding of the spark, higher octane fuels in the GT, for a standard tune, will be wasted. No?
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More than 91 octane is a not needed in a stock FGT that is functioning properly. If you have mods, or an aftermarket tune then you may need a higher octane to maintain the safety margin that Ford has designed into the car.
 
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MAD IN NC said:
Actually Dick,

traveling Europe over the last decade I knew there was a 5 point Octane difference but when Desi asked the question I decided to take it upon myself to find out why :biggrin
Click to expand...

You're awesome Mike!
 
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