Home » Public Forums » GMCnet » Fuel milage (Fuel octain)
| Fuel milage [message #89305] |
Sun, 20 June 2010 11:52  |
RickOH
Messages: 29
Registered: December 2006
Location: Coshocton OH
Karma: 0
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Junior Member |
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I have never seen any discussion about octane levels but this is what I found. I have always used regular 87 octane fuel since the engine dosen't seem to ping on it and I'm kind of a tight-wad. Was returning recently from Caloun GA meet and the last fuel fillup somewhere in KY, I decided to hit the 93 octane button.
I didnt notice anything special til we got close to home and started climbing some hills that I'm very familiar with. Normally with the cruise control set at 62 mph, the hills would drag me down to the 45-50 mph range. With the 93 octain the difference was amazing. Speed only dropped 3-4 mph.
Haven't had a chance to check fuel milage since, but I can't help think that it's got to be better. With 93 octain usually running about 20 cents more per gal than reg, the extra cost would only be about $8.00 per fillup. But getting an extra 80 miles per fillup would save about $25.00
Has anyone else checked this out?
Rick Little
78 Royale
Coshocton OH
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| Re: Fuel milage [message #89307 is a reply to message #89305] |
Sun, 20 June 2010 12:12  |
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Well I'm not sure about the octane, since that's the indicator of the fuels resistance to exploding before its supposed to.
What I do suspect though is that you got a different blend of fuel, and probably have found a source non diluted (ethanol added) gasoline. living in Southern California I can tell you that with the RFG they sell out here I saw all my vehicles including the ones I drive for work take up to a 20% hit in their mileage (yet the cost of the fuel went up) there are about 40 different blends of fuel sold around the country. I suspect you got some of the good stuff! Hell I wish I could get 93 our here, highest available out here is 91, unless you find one of the few stations selling 100 octane unleaded racing gas, but that's usually $8-$9 a gallon!! no thanks!!
Unless you have a knock sensor and computer advanced timing, I don't see how the higher octane itself could have helped, since most of our coaches still use a mechanical method of timing advance. what I suspect is you got fuel with a denser energy content!
try the experiment again using your locally available gas and compare the result, I'm very interested to find out what it is...
| rick wrote on Sun, 20 June 2010 11:52 |
I have never seen any discussion about octane levels but this is what I found. I have always used regular 87 octane fuel since the engine dosen't seem to ping on it and I'm kind of a tight-wad. Was returning recently from Caloun GA meet and the last fuel fillup somewhere in KY, I decided to hit the 93 octane button.
I didnt notice anything special til we got close to home and started climbing some hills that I'm very familiar with. Normally with the cruise control set at 62 mph, the hills would drag me down to the 45-50 mph range. With the 93 octain the difference was amazing. Speed only dropped 3-4 mph.
Haven't had a chance to check fuel milage since, but I can't help think that it's got to be better. With 93 octain usually running about 20 cents more per gal than reg, the extra cost would only be about $8.00 per fillup. But getting an extra 80 miles per fillup would save about $25.00
Has anyone else checked this out?
Rick Little
78 Royale
Coshocton OH
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73 Canyon Lands, (a.k.a. The Yellow Submarine) West Los Angeles CA
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| Re: [GMCnet] Fuel milage [message #89317 is a reply to message #89305] |
Sun, 20 June 2010 13:33 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Rick,
What you experienced has happened to lots of people.
Lot has to do with timing and load.
I will on occasion will put in higher octane when I know I will be driving
over hilly areas and have my timing bumped high.
As a 10 year old, I noticed that when our family went on trips.
On Sun, Jun 20, 2010 at 9:52 AM, rick little <lttlrck@yahoo.com> wrote:
>
>
> I have never seen any discussion about octane levels but this is what I
> found. I have always used regular 87 octane fuel since the engine dosen't
> seem to ping on it and I'm kind of a tight-wad. Was returning recently from
> Caloun GA meet and the last fuel fillup somewhere in KY, I decided to hit
> the 93 octane button.
>
> I didnt notice anything special til we got close to home and started
> climbing some hills that I'm very familiar with. Normally with the cruise
> control set at 62 mph, the hills would drag me down to the 45-50 mph range.
> With the 93 octain the difference was amazing. Speed only dropped 3-4 mph.
>
> Haven't had a chance to check fuel milage since, but I can't help think
> that it's got to be better. With 93 octain usually running about 20 cents
> more per gal than reg, the extra cost would only be about $8.00 per fillup.
> But getting an extra 80 miles per fillup would save about $25.00
>
> Has anyone else checked this out?
>
> Rick Little
> 78 Royale
> Coshocton OH
>
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
_______________________________________________
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: Fuel milage [message #89373 is a reply to message #89305] |
Sun, 20 June 2010 21:40 |
kingd
Messages: 592
Registered: June 2004
Karma: 2
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Senior Member |
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A fuel tanker driver in Toronto told me that all 91 Octane in Toronto has NO, ZERO, NADA, Ethanol. I guess he should know. The same truck drops at different brand stations. However Sunoco 94 (now Petro Canada 94 brag about having 10% Ethanol. Shell state on their 91 Octane pumps "No Ethanol" Maybe I'll try the mileage vs cost thing. Unforetuneatley the 3.0 Mitsubushi motro doesn't have a knock sensor so may not get the best results.
DAVE KING
Yes, for Road Racing classes eg Formula V that can use street gas the ethanol is a fuel cell problem. I saw the bladder from a fuel cell manufactured in 2010 and it stated 10% Ethanol was OK in the cell.
DAVE KING
lurker, wannabe
Toronto, Ontario, Canada
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| Re: Fuel milage [message #89786 is a reply to message #89305] |
Fri, 25 June 2010 00:09 |
Luvn737s
Messages: 1106
Registered: June 2007
Karma: 2
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Senior Member |
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During our recent trip from Phoenix to Yellowstone and back, I found some budget fuel marked 85 octane along side 87 BLEND, 89 BLEND and 91 (or 93, I forget). Assuming the lack of the words BLEND meant the absence of ethanol, I blended my own mixture of 60/40 91 to 85 octane for the high altitude drive. No knocks or pings I could discern. Where did 85 come from? Is it for running in ATV's?
Randy
1973 26' Painted Desert
Ahwatukee (Phoenix) AZ
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| Re: Fuel milage [message #89801 is a reply to message #89305] |
Fri, 25 June 2010 07:15 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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| rick wrote on Sun, 20 June 2010 12:52 |
I have never seen any discussion about octane levels but this is what I found. I have always used regular 87 octane fuel since the engine dosen't seem to ping on it and I'm kind of a tight-wad. Was returning recently from Caloun GA meet and the last fuel fillup somewhere in KY, I decided to hit the 93 octane button.
I didnt notice anything special til we got close to home and started climbing some hills that I'm very familiar with. Normally with the cruise control set at 62 mph, the hills would drag me down to the 45-50 mph range. With the 93 octain the difference was amazing. Speed only dropped 3-4 mph.
Haven't had a chance to check fuel milage since, but I can't help think that it's got to be better. With 93 octain usually running about 20 cents more per gal than reg, the extra cost would only be about $8.00 per fillup. But getting an extra 80 miles per fillup would save about $25.00
Has anyone else checked this out?
Rick Little
|
Rick,
This has been discussed at some length but it was a while ago. It is much more likely that the fuel rate improvement was more a result of the absences of alcohol (ethanol) in the fuel. Quite a number of refiners have trouble makes 91 rating octane motor
fuel.
In a properly maintained and effective tuned engine, the alcohol acts mostly like a filler. That is to say that if you are fueling with 10% OH, your mileage will decrease at least the same amount. (This sure does sound like a government subsidized program, doesn't it?)
If you can find alcohol free fuel, you will probably find the same improvement you saw with premium.
If your engine is effectively tuned for an 87 R+M/2 then the high grade fuel will actually make little or no difference in performance, slower burn may actually increase the exhaust temperature (you will never notice the change).
Matt (at Sault Saint Marie - waiting for Engineer's Day at the locks to start)
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: Fuel milage [message #89813 is a reply to message #89305] |
Fri, 25 June 2010 08:12 |
kingd
Messages: 592
Registered: June 2004
Karma: 2
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Senior Member |
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Bruce, my "understanding of Ethanol in "gasoline" in Ontario, is that for each "company" and I don't know if this means refiner, marketer or what, that in a year, presumably calendar, 5% of all the fuel sold had to be Ethanol. This was supposed to go to 10% but the Government says there are some negatives to going to 10% so they stayed a 5. Shell as you know has 3 grades, Bronze, Silver, Gold. The pumps in Toronto indicate Bronze may contain up to 10% Ethanol, Silver may contain up to 5% and Gold(premium) contains no ethanol. I presume what is posted on the Shell pumps is not a lie.
I recently filled up with Gold. It was 13 cents per liter more than Bronze. I'm going to attempt to see if my "mileage" goes up approx 13-15 percent. I have a way to check specific gravity between Bronze and Gold and that might be a clue as to whether there is Ethanol in the Gold.
DAVE KING
DAVE KING
lurker, wannabe
Toronto, Ontario, Canada
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| Re: [GMCnet] Fuel milage [message #89826 is a reply to message #89801] |
Fri, 25 June 2010 10:36 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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At high altitude, you'll find much lower rating as thin air is equal to
extra low compression.
On Fri, Jun 25, 2010 at 5:15 AM, Matt Colie <mcolie@chartermi.net> wrote:
>
>
> rick wrote on Sun, 20 June 2010 12:52
> > I have never seen any discussion about octane levels but this is what I
> found. I have always used regular 87 octane fuel since the engine dosen't
> seem to ping on it and I'm kind of a tight-wad. Was returning recently from
> Caloun GA meet and the last fuel fillup somewhere in KY, I decided to hit
> the 93 octane button.
> >
> > I didnt notice anything special til we got close to home and started
> climbing some hills that I'm very familiar with. Normally with the cruise
> control set at 62 mph, the hills would drag me down to the 45-50 mph range.
> With the 93 octain the difference was amazing. Speed only dropped 3-4 mph.
> >
> > Haven't had a chance to check fuel milage since, but I can't help think
> that it's got to be better. With 93 octain usually running about 20 cents
> more per gal than reg, the extra cost would only be about $8.00 per fillup.
> But getting an extra 80 miles per fillup would save about $25.00
> >
> > Has anyone else checked this out?
> >
> > Rick Little
>
> Rick,
>
> This has been discussed at some length but it was a while ago. It is much
> more likely that the fuel rate improvement was more a result of the absences
> of alcohol (ethanol) in the fuel. Quite a number of refiners have trouble
> makes 91 rating octane motor
> fuel.
>
> In a properly maintained and effective tuned engine, the alcohol acts
> mostly like a filler. That is to say that if you are fueling with 10% OH,
> your mileage will decrease at least the same amount. (This sure does sound
> like a government subsidized program, doesn't it?)
>
> If you can find alcohol free fuel, you will probably find the same
> improvement you saw with premium.
>
> If your engine is effectively tuned for an 87 R+M/2 then the high grade
> fuel will actually make little or no difference in performance, slower burn
> may actually increase the exhaust temperature (you will never notice the
> change).
>
> Matt (at Sault Saint Marie - waiting for Engineer's Day at the locks to
> start)
> --
> Matt & Mary Colie
> '73 Glacier 23 Chaumiere (say show-me-air)
> SE Michigan - DTW 3.2/4R
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Fuel milage [message #89839 is a reply to message #89813] |
Fri, 25 June 2010 11:44 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Here's a quote from Ken Burton back in Aug 09:
"Go to the drug store and ask for a few free empty medicine bottles. They
are usually brown and graduated up the sides. Fill the bottle with water to
the first graduation. Then fill the bottle with gasoline. You do not even
need to turn on the pump. Put on the cap and shake for 5 seconds. Let it
settle for 5 to 10 seconds and read the water level.
If the water line has risen there is ethanol in the fuel. It will be very
obvious. Dump the bottle and go on you way to another station. Cap the
bottle and use it again. A bottle usually lasts me for many months. I
usually have 2 or 3 pre-filled with water in my truck. We are not allowed
to use alcohol fuel in our airplanes so when we buy auto gas at an unknown
station we always check for alcohol."
Ken H.
On Fri, Jun 25, 2010 at 9:12 AM, Dave King <kingd@sympatico.ca> wrote:
> ... I have a way to check specific gravity between Bronze and Gold and that
> might be a clue as to whether there is Ethanol in the Gold.
>
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: Fuel milage [message #89895 is a reply to message #89305] |
Fri, 25 June 2010 17:22 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Senior Member |
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""I didnt notice anything special til we got close to home and started climbing some hills that I'm very familiar with. Normally with the cruise control set at 62 mph, the hills would drag me down to the 45-50 mph range. With the 93 octain the difference was amazing. Speed only dropped 3-4 mph. ""
Higher octane fuel slows the propagation of the flame front in the cylinder--in effect retarding the timing. Unless you advance the timing, higher octane can result in reduced performance, not increased performance.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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