Gasoline: reg vs premium

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Old 03-13-03, 09:25 PM
fishbearpanic
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Cool Gasoline: reg vs premium

I drive a '94 Toyota pu with 2.4L 22re. I have a multiple-part question, so here goes. I always use 87 octane (midgrade here), and am wondering what the differences would be if I used anything else, why other states have different octane ratings for the same level of gas (reg, mid, and premium), and if there is anything I could do to increase gas milage (I live at 8500 feet). Thanks, y'all.
 
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Old 03-14-03, 12:54 AM
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Octane is a fuel stability rating. The higher the Octane numbers the more stable the fuel. When I say “stable” I mean that it dose not detonate on it’s own under compression. If you put a low grade fuel in an engine with a high compression ratio there is a good chance that the compression will heat the fuel enough to cause the fuel to combust with out a spark. When this happens all sorts of bad things can happen, bent valves, broke rods, shattered lifters to name just a few. To increase mileage keep you tires inflated to proper pressure, make sure you engine is not running rich, and that you timing is accurate and that your plugs are gaped correctly.
 
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Old 03-14-03, 03:17 AM
Joe_F
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Follow the fuel recommendations in the owner's manual. Anything else is a waste of money.

Most vehicles run fine on 87 octane. Some states due to geography can rate it less. Avoid that. Stick with 87 minimally.

If you don't get any knocking or pinging at 87, that grade is fine for your vehicle. If you get knocking/pinging, change the brand of fuel or step up one grade. Only high end models or high compression performance engines benefit from high octane pump gas.

Change your fuel filter regularly and you should be fine.
 
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Old 03-14-03, 11:21 AM
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Re: Gasoline: reg vs premium

Originally posted by fishbearpanic
I drive a '94 Toyota pu with 2.4L 22re. I have a multiple-part question, so here goes. I always use 87 octane (midgrade here), and am wondering what the differences would be if I used anything else, why other states have different octane ratings for the same level of gas (reg, mid, and premium), and if there is anything I could do to increase gas milage (I live at 8500 feet). Thanks, y'all.
As Joe mentioned, it's best using what's recommended in the owners manual. If you have any problems with that then you need to work on the engine. I've lived and worked at altitudes over 10,000 feet. If you have a fuel injected engine than it should have sensors on the engine to compensate for altitude changes, if your vehicle is carbureted than you might be able to lean out your jets some. the best suggestion I have is to keep the engine properly tuned and you can switch over to 100% synthetic oils like Amsoil in the engine,tranny,tranfer case and front and rear ends. You'll notice a difference especially when it's real cold outside.
 
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Old 03-15-03, 06:52 PM
fishbearpanic
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Thanks everyone! This made me think of one more thing- is there any difference between brands, or between mom & pop stations or chains? Thanks again
 
  #6  
Old 03-16-03, 10:24 AM
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Here in my town the cheapest gas station(a no namer)sells Sinclair gas. The same truck that delivers gas to this station also delivers to the Sinclair station...I'll let you take it from there.
 
  #7  
Old 03-16-03, 11:43 AM
Dan Meyer
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I would like to comment on octane. It doesn't have anything to do with stability. Without going into technical detail, it has to do with the speed at which it "burns". The higher the octane, the slower it burns.
Using a lower octane then required will do much more harm than using a higher octane.
As far as what station is selling what or whose gasoline, there is a lot exchanging between oil companies.
 
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Old 03-16-03, 04:23 PM
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I never actually went to the trouble of looking up the definition of it I just took what my college professors said for the truth. So I looked it up at several Internet resources and dug out a a couple of my old college texts. They all said the same thing. That octane is the ability of gasoline to resist premature ignition under compression, or how stable it is to compress. But here is what some other rescorces said.


Handymanusa.com Said:

"Octane ratings measure a gasoline’s ability to resist engine knock, a rattling or pinging sound that results from premature ignition of the compressed fuel-air mixture in one or more cylinders. Most gas stations offer three octane grades: regular (usually 87 octane), mid-grade (usually 89 octane) and premium (usually 92 or 93). The ratings must be posted on bright yellow stickers on each gasoline pump.”

HowStuffWorks.com Said:

"The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening.
Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting.
The name "octane" comes from the following fact: When you take crude oil and "crack" it in a refinery, you end up getting hydrocarbon chains of different lengths. These different chain lengths can then be separated from each other and blended to form different fuels. For example, you may have heard of methane, propane and butane. All three of them are hydrocarbons. Methane has just a single carbon atom. Propane has three carbon atoms chained together. Butane has four carbon atoms chained together. Pentane has five, hexane has six, heptane has seven and octane has eight carbons chained together.
It turns out that heptane handles compression very poorly. Compress it just a little and it ignites spontaneously. Octane handles compression very well -- you can compress it a lot and nothing happens. Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane (or some other combination of fuels that has the same performance of the 87/13 combination of octane/heptane). It spontaneously ignites at a given compression level, and can only be used in engines that do not exceed that compression ratio."
 
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Old 03-16-03, 10:15 PM
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Octane determines the volatility of the gas, which causes pre-ignition (spark knock) when the volatility is too high. As the burn speed goes up, the ability to resist combustion under compression goes down, causing spark knock, so both views expressed here apply.
 

Last edited by cheese; 03-18-03 at 07:59 PM.
  #10  
Old 03-17-03, 03:42 AM
Joe_F
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I tend to agree with Dan on this---he is in the industry.

Again, in the long haul, if you use what is recommended by the manual (most say 87), and have no pinging/knocking, you are OK.
 
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Old 03-17-03, 04:43 AM
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Did Dan Meyer actually say, "there is a lot exchanging between oil companies". Thought he was the, "buy only the big brand names" guy, LOL.
 
  #12  
Old 03-17-03, 06:10 AM
Joe_F
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I'd actually like to see an oil company put out published, public reports proving their motor oil is better than brand X. You see a lot of marketing hype on motor oil, but none disproves the other brand or clearly states theirs is better with any tangible evidence.

I'd also like to see another independent study (like the CR study) done to determine the actual oil quality between brands to see if there is a difference.

Dan, what brand(s) do you recommend?
 
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Old 03-17-03, 01:39 PM
fishbearpanic
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I was told by a couple of mechanics that I know pretty well in the local auto shop that some places, Total, in perticular, uses more alchohol or something in the gas and that it is better to use a brand like Conoco. Is this true?
 
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Old 03-17-03, 07:48 PM
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I have been an auto technician for along time and have come to the conclusion that there are no great differences between quality oil brands. I feel this way even more after reading the CR report. I just say buy a name brand oil that you feel comfortable with.
 
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Old 03-18-03, 06:00 AM
Joe_F
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Thumbs up

I agree. I have used various brands with no problem.

It is maintenance practices more than marketing hype that keeps your vehicle running a long time trouble free .

But I'm curious to Dan's reply here.
 
  #16  
Old 03-18-03, 01:47 PM
Dan Meyer
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As I mentioned in my post on gasoline, I didn't want to get technical. But Weldgod did so he gave a lot of information.

One thing I might mention, Ethyl corp. ran tests on gasoline with ethanol in it (Sun, Marathon, Citgo, etc) and found that with the typical 10% addition of ethanol, it would reduce mileage from 10 to 20 per cent. I understand that some auto manufacturers (Ford)with certain engines state in the manual NOT to use ethanol.
Ethanol also will damage certain parts in fuel systems.

Tow Guy: I have always said to buy major brands of ENGINE OIL, NOT gasoline (except I will never use gas with ethanol in it).
I buy the lowest price.
 
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Old 03-18-03, 09:27 PM
Joe_F
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Dan:

But if there is "exchanging" between oil companies, how do you know whose oil you're going to get on the shelf, irrespective of the brand on the bottle?

I have yet to see anything published in the oil industry on a consumer level that disproves one brand over another or has proof that one brand is markedly better than another. Have oil companies done REAL world vehicle (not laboratory) testing and wear analysis? I've yet to see anything tangible in 15+ years I have been driving.

With that in mind, it's more marketing hype than actual consumer benefit to me. Millions of fleet miles have proven ZERO difference as has Consumer Reports among others.
 
  #18  
Old 03-19-03, 04:33 AM
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I was pulling your chain, Dan; I knew where you were going.

Latest stats on Sam's Club oil:

'95 Camry - 149,000
'94 Chevy W-4 - 339,000 [199,000 on short block]
 
  #19  
Old 03-19-03, 03:00 PM
Dan Meyer
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JoeF - ya I know, these oil questions get lenghty. In regard to your comment on "exchanging", Tow guy had it right, I was ONLY referring to gasoline and fuels(diesel fuel, home heating oil) -. not engine or industrial oils. As a matter of fact, there was an article in todays news about how gasoline gets exchanged so much that no one can be sure just who's gas they are buying.
The reason you don't see any hype on engine oils is because it would get to be a real "pissing" contest between oil companies. And they don't want that.
 
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Old 03-19-03, 03:15 PM
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Then there's either zero difference or there's nothing to prove . How then, does a parts store decide which brand to carry?

Answer: Price and whatever the warehouse carries.

All the carmakers do it, "Brand X car is much roomier than the the Footmobile and comes with a standard V6!!!!" LOL.

Again, I have seen no evidence to prove one brand is better than the other. Like TowGuy states, he and I have high mileage cars with "cheap" engine oil and no problems. Billions of fleet miles prove there is negigible if any difference in motor oil brands .

Sounds like marketing hype to me more than anything else .
 
  #21  
Old 03-19-03, 11:46 PM
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I use Pennzoil because it's what my dad used and I like the yellow packing. By the way I work for Conico Phillips (ConLips) but not in direct production of oil, I work in vehicle and specialty equipment. Sense we are already talking about it I just have to ask. What is everyone’s opinion on synthetic vs. conventional vs. blend oil? Worth the money or not?
 
  #22  
Old 03-20-03, 04:20 AM
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RUN FOR YOUR LIVES; HERE COMES THE CONV/SYN WAR! LOL

My $.02 worth - no, not worth it. Refer to my previous post.
 
  #23  
Old 03-20-03, 06:36 AM
Joe_F
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Matt:

There have been numerous discussions about this on this forum. Suggest you look them up.

I agree with TowGuy. We could argue this until we are all old and grey.
 
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