01-09-2014, 04:11 PM
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#1
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Registered User
Join Date: Nov 2013
Location: Colorado
Posts: 442
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octane effects power and engine temp?
Hey guys/gals. I topped off my fuel tank last night, about half empty, with 87 octane with no ethanol. this morning I noticed less power. This evening I noticed even less power and the engine was not as snappy to rev and it was running warmer than usual. Oil looks clean, no condensates, coolant level is topped off and clean. I topped off the tank on my way home tonight, 91 octane, the highest I can get here, the engine ran at normal temp and the engine felt a little stronger but not as strong as I'm used to. Did I just get some bad gas? I was able to squeeze 3.4 gallons of 91 octane while topping off tonight.
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01-09-2014, 05:12 PM
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#2
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Registered User
Join Date: Feb 2005
Location: It's a kind of magic.....
Posts: 6,273
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Quote:
Originally Posted by jdlmodelt
Hey guys/gals. I topped off my fuel tank last night, about half empty, with 87 octane with no ethanol. this morning I noticed less power. This evening I noticed even less power and the engine was not as snappy to rev and it was running warmer than usual. Oil looks clean, no condensates, coolant level is topped off and clean. I topped off the tank on my way home tonight, 91 octane, the highest I can get here, the engine ran at normal temp and the engine felt a little stronger but not as strong as I'm used to. Did I just get some bad gas? I was able to squeeze 3.4 gallons of 91 octane while topping off tonight.
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Ethanol is lower total BTU content than gas by about 1/3, so any fuel containing a level of ethanol is going to be down on power and mileage.
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“Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein
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01-09-2014, 05:15 PM
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#3
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Registered User
Join Date: Nov 2013
Location: Colorado
Posts: 442
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Quote:
Originally Posted by JFP in PA
Ethanol is lower total BTU content than gas by about 1/3, so any fuel containing a level of ethanol is going to be down on power and mileage.
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will the engine run noticebly hotter too?
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01-09-2014, 05:19 PM
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#4
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Registered User
Join Date: Dec 2006
Location: shoreham, ny
Posts: 1,619
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Why would you put 87 in???
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996 3.4 engine with 2.7 986 5speed transmission
Ebay Headers, Fabspeed high flow cats, JIC Cross, IPD Plenum, H&R Coilovers, B&M Short Shifter, AEM Uego Gauge Type Analog, Apexi S-AFC Select, 987 air box, Litronics, 2000 Tails and side markers, painted center console, 18" 987 S-Wheels, GT3 Front bumper with splitter.
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01-09-2014, 05:22 PM
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#5
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Registered User
Join Date: Nov 2013
Location: Colorado
Posts: 442
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Quote:
Originally Posted by JAAY
Why would you put 87 in???
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Its all the station had that I stopped at. They were the last station in the region that wasn't putting 10% ethanol in the gas. But, I think I would be better with 91 and 10% ethanol?
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01-09-2014, 05:28 PM
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#6
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Registered User
Join Date: Nov 2013
Location: Colorado
Posts: 442
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Quote:
Originally Posted by jdlmodelt
Its all the station had that I stopped at. They were the last station in the region that wasn't putting 10% ethanol in the gas. But, I think I would be better with 91 and 10% ethanol?
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I didn't notice, it must have happened recently, my wife said there is a new sticker that indicates 10% ethanol plus the inferior 87 octane. double whammy
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01-09-2014, 06:21 PM
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#7
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Registered User
Join Date: Nov 2013
Location: Colorado
Posts: 442
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my idle is rock solid
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01-09-2014, 07:37 PM
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#8
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Registered User
Join Date: Sep 2013
Location: Chandler, AZ
Posts: 1,796
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87 octane??? In a Porsche?? Ferdinand Porsche is rolling over in his grave.
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03 Carrera
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78 911SC
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01-10-2014, 02:34 AM
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#9
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Rennzenn
Join Date: Feb 2005
Location: Virginia
Posts: 1,369
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This is slightly off topic, but may be of interest. Occasionally I have access to non-ethanol 93 octane fuel. I keep track of my mpg and maintenance using an app on my iphone. I find that with the non-ethanol I get about 1-2 mpg better highway mileage, and that it improves another 1-2 mpg in the warmer months. Here's the skinny:
Summer, non-ethanol, 26-28 mpg
Summer, ethanol, 25-27 mpg
Winter, non-ethanol, 24-26 mpg
Winter ethanol, 23-25 mpg
This data was collected since mid May 2013 over 23,000 miles in a 1999 911 C4. I had noticed similar trends earlier in my 2000 986S.
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01-10-2014, 04:48 AM
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#10
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Registered User
Join Date: Feb 2005
Location: It's a kind of magic.....
Posts: 6,273
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Quote:
Originally Posted by jdlmodelt
will the engine run noticebly hotter too?
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It could, but that could also be related to the overall quality of the gas as well.
__________________
“Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein
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01-10-2014, 07:12 AM
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#11
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Registered User
Join Date: Oct 2008
Location: O.C. CA
Posts: 3,709
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Quote:
Originally Posted by j.fro
This is slightly off topic, but may be of interest. Occasionally I have access to non-ethanol 93 octane fuel. I keep track of my mpg and maintenance using an app on my iphone. I find that with the non-ethanol I get about 1-2 mpg better highway mileage, and that it improves another 1-2 mpg in the warmer months. Here's the skinny:
Summer, non-ethanol, 26-28 mpg
Summer, ethanol, 25-27 mpg
Winter, non-ethanol, 24-26 mpg
Winter ethanol, 23-25 mpg
This data was collected since mid May 2013 over 23,000 miles in a 1999 911 C4. I had noticed similar trends earlier in my 2000 986S.
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I think it's directly on topic. Consumer reports observes a average 15% reduction in MPG with gasohol.
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OE engine rebuilt,3.6 litre LN Engineering billet sleeves,triple row IMSB,LN rods. Deep sump oil pan with DT40 oil.
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01-10-2014, 07:16 AM
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#12
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Registered User
Join Date: Oct 2008
Location: O.C. CA
Posts: 3,709
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Quote:
Originally Posted by jdlmodelt
Its all the station had that I stopped at. They were the last station in the region that wasn't putting 10% ethanol in the gas. But, I think I would be better with 91 and 10% ethanol?
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This must be a high elevation location. High altitude reduces octane requirement since the lower oxygen content richens the air/fuel ratio.
__________________
OE engine rebuilt,3.6 litre LN Engineering billet sleeves,triple row IMSB,LN rods. Deep sump oil pan with DT40 oil.
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01-10-2014, 07:51 AM
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#13
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Registered User
Join Date: Feb 2005
Location: It's a kind of magic.....
Posts: 6,273
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Quote:
Originally Posted by BYprodriver
I think it's directly on topic. Consumer reports observes a average 15% reduction in MPG with gasohol.
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Brought to you by your Federal Nannies, along with less fuel stability, faster and higher levels of water contamination, and endless corrosion of expensive fuel system components......your tax dollars in action.
__________________
“Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein
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01-10-2014, 07:59 AM
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#14
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Registered User
Join Date: Oct 2008
Location: O.C. CA
Posts: 3,709
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Money truly is the root of most evil!
__________________
OE engine rebuilt,3.6 litre LN Engineering billet sleeves,triple row IMSB,LN rods. Deep sump oil pan with DT40 oil.
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01-10-2014, 09:17 AM
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#15
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Registered User
Join Date: Sep 2013
Location: California
Posts: 466
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Quote:
Originally Posted by JFP in PA
Brought to you by your Federal Nannies, along with less fuel stability, faster and higher levels of water contamination, and endless corrosion of expensive fuel system components......your tax dollars in action.
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I knew there was a reason I liked JFP. Fuggin Nannystate no doubt imposing stupid demands on it's people and over a hoax just adds insult to injury
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01-10-2014, 09:20 AM
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#16
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Registered User
Join Date: Jun 2012
Location: Peoria IL
Posts: 529
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Quote:
I keep track of my mpg and maintenance using an app on my iphone..
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What's it called?
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01-10-2014, 12:32 PM
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#18
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Registered User
Join Date: Nov 2013
Location: Colorado
Posts: 442
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improvement
I added octane booster to this tank till I get all the non 91 octane out. I also changed the oil. I discovered that my oil cap does not seal when it is tightened down. How come these engines have a vacuum at the oil fill tube instead of pressure?
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01-10-2014, 02:13 PM
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#19
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Registered User
Join Date: Feb 2005
Location: It's a kind of magic.....
Posts: 6,273
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Quote:
Originally Posted by jdlmodelt
I added octane booster to this tank till I get all the non 91 octane out. I also changed the oil. I discovered that my oil cap does not seal when it is tightened down. How come these engines have a vacuum at the oil fill tube instead of pressure?
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The AOS also lowers the pressure in the sump to a vacuum around -5 inches of water so that the low tension piston rings can properly seal.................
__________________
“Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein
Last edited by JFP in PA; 01-10-2014 at 02:54 PM.
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01-11-2014, 11:11 AM
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#20
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Registered User
Join Date: Nov 2013
Location: Colorado
Posts: 442
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running much better
Well, Changed the oil after 7k miles. still look pretty nice. discovered the loose oil cap and remedied that. added the octane booster and also topped off this morning with another 91 octane fuel. and she is running a lot stronger and temperature didn't climb much above 180 driving up in the mountains. I have a 160 degree thermostat. I was pretty nervous a couple of days ago with the acting up. low power, overheating.
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