What octane gas do you guys run?
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#9
Thanks guys I appreciate the info. I have to apologize when I ask things that have already been covered. It seems to tick some people off. If I do a search for what I'm looking for and I don't find the answer that I'm looking for that's when I post a thread.
#14
unless your engine is pinging, you should run whatever octane the manufacturer suggests (should say in your owner's manual).
running higher octane gasoline will reduce pining, but it can actually increase carbon build up.
higher octane does not mean the gas is "better"...it just means it is harder to burn (which is why it stops pinging).
carbon build-up is caused by incomplete combustion.
fuel harder to burn = more likelihood of incomplete combustion = carbon build-up.
engines are designed to run gasoline with a specific octane rating. if you run an octane level higher than what the engine is designed for, you can get incomplete combustion (because the gasoline is harder the burn than the engine was designed for, so the engine does not completely burn it).
the result, over the long-term, is carbon build-up.
now, once you already have carbon build-up, you may need to switch to (or continue running) higher octane fuel. the reason is that the carbon build up effectively reduces the volume of the combustion chamber, thereby raising the compression ratio (higher compression requires higher octane). also, the carbon deposits retain heat, thereby raising the temperature of the combustion chamber.
however, if you do not have pinging problems and your engine is stock, you should run the recommended octane level, not higher or lower.
running higher octane gasoline will reduce pining, but it can actually increase carbon build up.
higher octane does not mean the gas is "better"...it just means it is harder to burn (which is why it stops pinging).
carbon build-up is caused by incomplete combustion.
fuel harder to burn = more likelihood of incomplete combustion = carbon build-up.
engines are designed to run gasoline with a specific octane rating. if you run an octane level higher than what the engine is designed for, you can get incomplete combustion (because the gasoline is harder the burn than the engine was designed for, so the engine does not completely burn it).
the result, over the long-term, is carbon build-up.
now, once you already have carbon build-up, you may need to switch to (or continue running) higher octane fuel. the reason is that the carbon build up effectively reduces the volume of the combustion chamber, thereby raising the compression ratio (higher compression requires higher octane). also, the carbon deposits retain heat, thereby raising the temperature of the combustion chamber.
however, if you do not have pinging problems and your engine is stock, you should run the recommended octane level, not higher or lower.
#15
But some may look at higher Octane gas as insurance. For example - driving around town, local highway, etc. I'm sure 87 would work well in my truck fine. But when pushing the truck up mountain passes and hauling camping gear and a buddy or two or passing a semi when the road goes back from 4 lanes to 2 and you gotta haul ass the truck will ping with 87 sometimes, where as 89 it will not as an example. The previous owner of my truck used to run a camper on it. The truck handled the camper no problem weight wise but the big face of the camper really caused a lot of air resistance and of course the weight and gear too caused pinging with 87 going to interior camping spots that are higher altitude which requires climbing. So he switched to premium whenever he went camping and problem solved.
Last edited by CoedNaked; 08-07-2005 at 10:25 PM.
#18
87 works great for me. I once tried 85 but it had a slight ping so i never used it again. But...
One thing that really sucks about CO and is that our octane level is differnet. Here- its 85, 87, 91 but in CA and almost all other states its 87, 89, 91 or 92
So most of us Rocky Mountain people are forced to buy "mid-grade" which is the low-grade in other states.
It has nothing to do with our high elevation either. Anybody living in CO should read these articles about why we are getting screwed.
http://www.koaa.com/features/investi...iew.asp?ID=251
http://www.thedenverchannel.com/news/892152/detail.html
One thing that really sucks about CO and is that our octane level is differnet. Here- its 85, 87, 91 but in CA and almost all other states its 87, 89, 91 or 92
So most of us Rocky Mountain people are forced to buy "mid-grade" which is the low-grade in other states.
It has nothing to do with our high elevation either. Anybody living in CO should read these articles about why we are getting screwed.
http://www.koaa.com/features/investi...iew.asp?ID=251
http://www.thedenverchannel.com/news/892152/detail.html
Last edited by rocket; 08-08-2005 at 03:38 PM.
#19
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Joined: Nov 2002
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From: Far western Kentucky (transplanted from central PA)
87 in my '00 unless I know I'm going to tow long distance in which case I MAY go to 89 the fill-up prior to the trip.
When I had my '90 3.slow, I would alternate between 87 and 89 because I had occasional ping that I couldn't seem to get rid of and then an occasional 91 octane when I was going to tow.
The higher octane in my '90 seemed to pull the trailer better on hills. Other than that, I don't notice much difference. Lot's of threads on this topic over the years...
When I had my '90 3.slow, I would alternate between 87 and 89 because I had occasional ping that I couldn't seem to get rid of and then an occasional 91 octane when I was going to tow.
The higher octane in my '90 seemed to pull the trailer better on hills. Other than that, I don't notice much difference. Lot's of threads on this topic over the years...
Last edited by Rick F.; 08-08-2005 at 05:01 AM.