Octane Difference
04-09-2004, 06:11 AM
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Octane Difference
HEY PPL,
JUST WONDERING,
CAN ANYONE TELL THE DIFFERENCE BETWEEN THE GAS OCTANES( 87, 89, 91 AND 93)? MY MANUAL SAID TO USES 87 BUT FOR BETTER PROFORMANCE USES 91. RIGHT NOW, I'M USING 93....THAT S H I T GOES DOWN LIKE WATER....I'M THINKING ABOUT USING 89. WHAT DO U GUYS THINK???
JUST WONDERING,
CAN ANYONE TELL THE DIFFERENCE BETWEEN THE GAS OCTANES( 87, 89, 91 AND 93)? MY MANUAL SAID TO USES 87 BUT FOR BETTER PROFORMANCE USES 91. RIGHT NOW, I'M USING 93....THAT S H I T GOES DOWN LIKE WATER....I'M THINKING ABOUT USING 89. WHAT DO U GUYS THINK???
Octane
04-09-2004, 06:43 AM
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In some cases, the carbon build-up inside an older engine can cause higher compression, thus necessitating the need for higher octane - or more importantly a method of "cleaning" it off.
A general rule of thumb is to follow what the manufacturer recommends unless you have a mod that creates the need. Otherwise you are just dumping extra money down the toilet.
A general rule of thumb is to follow what the manufacturer recommends unless you have a mod that creates the need. Otherwise you are just dumping extra money down the toilet.
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04-09-2004, 10:46 AM
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Originally Posted by bulldog-yota
What do you drive?
I HAD A 91 LEGEND COUPE....SOLD LAST YEAR AND BOUGHT A 03 4RUNNER SR5 V6.
OLD CAR.....
NEW CAR
Last edited by 91bulldog; 04-09-2004 at 10:52 AM.
04-09-2004, 11:10 AM
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I use 91 here in Cali. I'm 300 feet. Depending on your elevation, try different octanes and see what it does for you. In theory the higher altitude the less octane value you need.
In theory with modern engines like yours the engine managemnt will adjust to provide the optimum performance for the conditions. SO it will adnace timing till it senses pinging and start retarding it, etc. This means with higher octane it should push for a bit better engine performance which normally means better mileage. However there are a number of people that do not notice the difference.
I run on 91 and get pretty good mileage if I look on the forums, maybe it is just driving style. But I get 15-16 in town and 20-22 on the highway normally. I typically drive fast 80mph on the highway and go faster than traffic in town, but I dont drag race, etc.
Try a couple of tanks of 87, 89, 91 and 93 and see what works for you. For me it makes a difference for other people it doesn't. Your engine will be fine down to 87, as it will retard timing if it needs to.
Dont expect car mileage with a SUV.
In theory with modern engines like yours the engine managemnt will adjust to provide the optimum performance for the conditions. SO it will adnace timing till it senses pinging and start retarding it, etc. This means with higher octane it should push for a bit better engine performance which normally means better mileage. However there are a number of people that do not notice the difference.
I run on 91 and get pretty good mileage if I look on the forums, maybe it is just driving style. But I get 15-16 in town and 20-22 on the highway normally. I typically drive fast 80mph on the highway and go faster than traffic in town, but I dont drag race, etc.
Try a couple of tanks of 87, 89, 91 and 93 and see what works for you. For me it makes a difference for other people it doesn't. Your engine will be fine down to 87, as it will retard timing if it needs to.
Dont expect car mileage with a SUV.
04-09-2004, 11:40 AM
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A little off topic, but here in Wyoming (where I'm visiting) the low grade gas is only 85 octane. Whats with that? I was hesitant at first, but at $1.68/gallon I couldn't afford NOT to get it!! NO problems yet.
04-09-2004, 01:05 PM
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Originally Posted by <96 Runner>
Gapguy-
Is the town you bought the fuel in at a higher altitude?
Is the town you bought the fuel in at a higher altitude?
I see these low octanes all over the southwest, but NEVER have I seen it in CA. Seems to run fine for me.
04-10-2004, 07:55 PM
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The altitude is the key to the octane ratings: the higher you go the less octane you need for detonation due to the thinner air. Here in CO, we sell 85, 87 & 91 unless you're in the southwest corner of the state (Durango, Cortez, etc.) where they sell 86, 88, 91 as they do in most of AZ & NM. The lower octane prevents knocking, pinging, and carbon build-up while still maintaining the same combustion characteristics.
One question I do have is about ethanol. Supposedly it has a higher octane rating than "pure" gasoline and helps raise octane levels when mixed with gas like many states do. Would that make it safer to run with a SC in a pinch if premium gas wasn't available?
One question I do have is about ethanol. Supposedly it has a higher octane rating than "pure" gasoline and helps raise octane levels when mixed with gas like many states do. Would that make it safer to run with a SC in a pinch if premium gas wasn't available?
04-11-2004, 09:14 PM
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also a lower octane will burn faster but not cleaner, to combat this problem evrey two tanks i add one pint of STP or if it is cheaper A.T.F. lot of cleaning power in A.T.F.
04-11-2004, 09:54 PM
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no atf is transmission fluid there are so many detergants in atf it will clean almost anything you dont have to try it but works very well learned it from a old timer
