octane rating?
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Mudding
Joined: Oct 2007
Posts: 105
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RE: octane rating?
Well.... It does appear that If the U.S. auto manufacturers finaly get it together and start offering small block deisel powered cars , the cost of diesel will be so high that it won't help the average driver save a buck. I noticed last week that diesel at our local cheapest gas station was 44 cents higher than reg.- Whats up with that ? I can remember(just barely) when I started driving 40 years ago, reg gas was right around 23cents / gal at that time diesel was 10 cents! Les than half the cost of reg.! Its true!
Anyhow... I would love to find a way to have a nice 4 or 5 cylinder diesel in a disco even if I have to give up some power. I've looked into conversions. The disco is so nice to drive if we could just get some mileage.
Anyhow... I would love to find a way to have a nice 4 or 5 cylinder diesel in a disco even if I have to give up some power. I've looked into conversions. The disco is so nice to drive if we could just get some mileage.
Rock Crawling
Joined: Nov 2007
Posts: 420
Likes: 4
From: Spring Grove,IL
RE: octane rating?
I have read that by using lower octane fuel, your engine's cpuwill detune and produce less horse power and lower your miles per gallon. It would be great if midgrade was 91 since premium is 93 at most stations around my area.True the difference is only a few dollars per tank, however in some places the credit card companys limit your amount you can spend.......
Three Wheeling
Joined: May 2007
Posts: 57
Likes: 0
RE: octane rating?
Flame suit on.
I have only had my 98 Disco for about 6 months. With 87 octane I get
15.7 mpg consistently. I just ran 5 tanks of 91 octane and
had a best of 15.1 and averaged 14.6 mpg. I can tell no difference in
performance.
I wanted to run the comparison before I installed my new 8mm wires and
plugs.
Mike
I have only had my 98 Disco for about 6 months. With 87 octane I get
15.7 mpg consistently. I just ran 5 tanks of 91 octane and
had a best of 15.1 and averaged 14.6 mpg. I can tell no difference in
performance.
I wanted to run the comparison before I installed my new 8mm wires and
plugs.
Mike
Mudding
Joined: Aug 2007
Posts: 134
Likes: 2
From:
RE: octane rating?
Octane is a measure of gasoline's volatility. Higher octane means it is more stable, combusts best at higher compression, and is less prone to premature detonation under pressure (pinging), all things being equal. Your engine is designed to operate most effeciently at a specific octane level (determined primarily by its compression ratio), so in general you should always use what the manual calls for. Conversely, using high octane fuel in engines designed for lower octanes can create drivability problems associated with incomplete combustion because the engine creates less pressure than the fuel requires. Of course, some newer vehicles are engineered with knock sensors and can actively adjust the timing to compensate for reduced octane. In those vehicles in some cases, it is permissable to use a lower octane as stipulted in the owners manual, however, generally perrformance is sacrificed. Also note that octane rating at the pump is an average of two different methods of determing octane. One is research octane, and the other is motor octane. If you look for it, the next time you're pumping gas, you'll notice R+M/2 on the octane rating sticker. This means it is possible that two different gasolines with the same octane rating, may have significantly different research and motor octane measurements, and can perform differently in your vehicle. Unfortunately, the majority of the damaging pinging that occurs is inaudible, so choose your source wisely, and pay attention to how your vehicle feels and sounds under load and during acceleration to prevent carbon build up and premature failure.
Thread Starter
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Mudding
Joined: Oct 2007
Posts: 105
Likes: 0
From:
RE: octane rating?
whew! you said a mouthful Jigray3! Sounds like you know what you're talking about. How do you figure Sooners gets worse mileage on the higher octane?
Oh well. I'l run the mileage tests on my 98 and see how I do.
Oh well. I'l run the mileage tests on my 98 and see how I do.
Recovery Vehicle
Joined: Sep 2007
Posts: 823
Likes: 75
RE: octane rating?
My book says 90-92 Octane. That's Mid-grade in some areas, isn't it? Premium is 93 Octane in our area. So, theoretically, mid grade, which is cheaper than Premium should work just fine, right?
Mark G
Mark G
Mudding
Joined: Jan 2007
Posts: 160
Likes: 0
From: San Diego, CA
RE: octane rating?
ORIGINAL: Sooners
Flame suit on.
I have only had my 98 Disco for about 6 months. With 87 octane I get
15.7 mpg consistently. I just ran 5 tanks of 91 octane and
had a best of 15.1 and averaged 14.6 mpg. I can tell no difference in
performance.
I wanted to run the comparison before I installed my new 8mm wires and
plugs.
Mike
Flame suit on.
I have only had my 98 Disco for about 6 months. With 87 octane I get
15.7 mpg consistently. I just ran 5 tanks of 91 octane and
had a best of 15.1 and averaged 14.6 mpg. I can tell no difference in
performance.
I wanted to run the comparison before I installed my new 8mm wires and
plugs.
Mike
Having said that, right now I am running my own test using 91 oct. (highest I can find here in So.Cal)
Winching
Joined: Aug 2006
Posts: 727
Likes: 2
RE: octane rating?
ORIGINAL: b c
Well.... It does appear that If the U.S. auto manufacturers finaly get it together and start offering small block deisel powered cars , the cost of diesel will be so high that it won't help the average driver save a buck. I noticed last week that diesel at our local cheapest gas station was 44 cents higher than reg.- Whats up with that ? I can remember(just barely) when I started driving 40 years ago, reg gas was right around 23cents / gal at that time diesel was 10 cents! Les than half the cost of reg.! Its true!
Anyhow... I would love to find a way to have a nice 4 or 5 cylinder diesel in a disco even if I have to give up some power. I've looked into conversions. The disco is so nice to drive if we could just get some mileage.
Well.... It does appear that If the U.S. auto manufacturers finaly get it together and start offering small block deisel powered cars , the cost of diesel will be so high that it won't help the average driver save a buck. I noticed last week that diesel at our local cheapest gas station was 44 cents higher than reg.- Whats up with that ? I can remember(just barely) when I started driving 40 years ago, reg gas was right around 23cents / gal at that time diesel was 10 cents! Les than half the cost of reg.! Its true!
Anyhow... I would love to find a way to have a nice 4 or 5 cylinder diesel in a disco even if I have to give up some power. I've looked into conversions. The disco is so nice to drive if we could just get some mileage.
If you're not aware of how this is a national security concern and the fact it has not been made a top priority by various North American governments you'll need to catch up a bit. The other major advantage is a significant reduction in toxic emissions, about 95-99% depending on the toxin when switching off petroleum based fuels.
This is why not having diesel engines available is so infuriating, it removes the option of not contributing to the above issues.
TReK
Joined: Apr 2005
Posts: 2,111
Likes: 2
From: Dallas TX
RE: octane rating?
ORIGINAL: jigray3
Octane is a measure of gasoline's volatility. Higher octane means it is more stable, combusts best at higher compression, and is less prone to premature detonation under pressure (pinging), all things being equal. Your engine is designed to operate most effeciently at a specific octane level (determined primarily by its compression ratio), so in general you should always use what the manual calls for. Conversely, using high octane fuel in engines designed for lower octanes can create drivability problems associated with incomplete combustion because the engine creates less pressure than the fuel requires. Of course, some newer vehicles are engineered with knock sensors and can actively adjust the timing to compensate for reduced octane. In those vehicles in some cases, it is permissable to use a lower octane as stipulted in the owners manual, however, generally perrformance is sacrificed. Also note that octane rating at the pump is an average of two different methods of determing octane. One is research octane, and the other is motor octane. If you look for it, the next time you're pumping gas, you'll notice R+M/2 on the octane rating sticker. This means it is possible that two different gasolines with the same octane rating, may have significantly different research and motor octane measurements, and can perform differently in your vehicle. Unfortunately, the majority of the damaging pinging that occurs is inaudible, so choose your source wisely, and pay attention to how your vehicle feels and sounds under load and during acceleration to prevent carbon build up and premature failure.
Octane is a measure of gasoline's volatility. Higher octane means it is more stable, combusts best at higher compression, and is less prone to premature detonation under pressure (pinging), all things being equal. Your engine is designed to operate most effeciently at a specific octane level (determined primarily by its compression ratio), so in general you should always use what the manual calls for. Conversely, using high octane fuel in engines designed for lower octanes can create drivability problems associated with incomplete combustion because the engine creates less pressure than the fuel requires. Of course, some newer vehicles are engineered with knock sensors and can actively adjust the timing to compensate for reduced octane. In those vehicles in some cases, it is permissable to use a lower octane as stipulted in the owners manual, however, generally perrformance is sacrificed. Also note that octane rating at the pump is an average of two different methods of determing octane. One is research octane, and the other is motor octane. If you look for it, the next time you're pumping gas, you'll notice R+M/2 on the octane rating sticker. This means it is possible that two different gasolines with the same octane rating, may have significantly different research and motor octane measurements, and can perform differently in your vehicle. Unfortunately, the majority of the damaging pinging that occurs is inaudible, so choose your source wisely, and pay attention to how your vehicle feels and sounds under load and during acceleration to prevent carbon build up and premature failure.
Well said.
If you are getting the same mpg on lower octane are you sure
that its not the same fuel.
Some people will sell 87 as 92 and most people will never
know.
Always use a national brand as they have oversight on whats in the tanks.
You can use what you want or use what your LR calls for.
Mudding
Joined: Aug 2007
Posts: 134
Likes: 2
From:
RE: octane rating?
ORIGINAL: b c
whew! you said a mouthful Jigray3! Sounds like you know what you're talking about. How do you figure Sooners gets worse mileage on the higher octane?
Oh well. I'l run the mileage tests on my 98 and see how I do.
whew! you said a mouthful Jigray3! Sounds like you know what you're talking about. How do you figure Sooners gets worse mileage on the higher octane?
Oh well. I'l run the mileage tests on my 98 and see how I do.
