Premium Gas NOT Needed

[jtantare]

My Volvo 960 owner's manual likes to have it both ways. Says the engine was designed to delived maximum power on 91 but 87 is the minimum. Engine is non turbo with 10.7:1 CR. I used to run 91 (best you can get in California) but switched to 87 100% of the time. Car has the same power and fuel economy with both but it starts easier with 87 octane. Why waste the money

 

[andyfish]

My car(04 Subaru WRX) clearly states 91 octane required. However by accident usually I put 87 octane in it and feel/hear no difference and no significant difference in mileage delivered.

After working at no name brand fuel station in college for a few months I learned that it was really just the ends of name brand fuel tankers ie Mobil, Exxon, Shell, or Gulf sold at a slightly lower rate to rid themselves of extra fuel to carry back to port.

 

[Triple_Se7en]

quote:

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Originally posted by Audi Junkie:
BTW- as prices go up, the extra $.18c makes LESS difference. At $1.50 a gallon, it's a more signifigant percent increase. At $2.50/g it matters less.

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You're forgetting the key difference that $1.50 more per tankful at $2.45 per gallon brings to my minivan.....

....a better running engine & slightly better gas mileage (.5MPG)

 

[Greaser]

My Jeep's 4.0L 8.8-1, cast iron ,tractor motor will run on kerosene if need be but perfers week old moonshine..very picky

 

[Brian Miller_dup1]

I had Superchips Custom Tuning write 3 programs for my Ranger 3.0L.

The 93 octane program kicks butt! You can really tell a difference over the stock performance, and even over the 87 octane program that I had them write (so it's not just the shift points that are making a difference).

Plus I'm getting about 3MPG better and better performance with the 93 octane. To me it's worth the extra $2.00 to $2.50 at fill up.

Even in an engine designed for 87, with the ECU programmed to run 93 it does make a difference.

Brian

 

[motorguy222]

quote:

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Originally posted by Brian Miller:
I had Superchips Custom Tuning write 3 programs for my Ranger 3.0L.

The 93 octane program kicks butt! You can really tell a difference over the stock performance, and even over the 87 octane program that I had them write (so it's not just the shift points that are making a difference).

Plus I'm getting about 3MPG better and better performance with the 93 octane. To me it's worth the extra $2.00 to $2.50 at fill up.

Even in an engine designed for 87, with the ECU programmed to run 93 it does make a difference.

Brian

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You are talking about an engine that has more or less been modified,this changes the scope of things.

For the vast majority of people,as the article stated,Premium gas isnt needed.

 

[DR Racing]

The BTU content is the same for both 91 & 87 fuel. If you manual says run 91 use it. There is inaudible pinging that your ear can't hear that will shorten the life of your engine if your car does not have a knock sensor. Higher altitudes will also have an effect on how much octane you need. In Denver CO the oil company's sell 89 as premium because they know that you don't need 91 at 5000 ft. My GSR calls for 91 but because I live in Palmdale CA at 3000 ft I run 89 with out a problem. There is no good reason to run more octane than your engine needs but there are very good reasons to run the required octane. Dan

 

[y_p_w]

I believe the energy content of fuel has many variables, including the crude used, the refining process, and the amount of oxygenates added.

BTW - I found an interesting article on the disappearance of 92 octane premium unleaded in California in 2001. I remember reading some short blurbs on the subject in AutoWeek.

http://www.sportcompactcarweb.com/editors/technobabble/0102scc_technobabble/

quote:

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Somewhere in the upper ranges of the stack are the components of gasoline. There are between 10 and 15 different blend stocks, each with a different octane rating, which are mixed together to make gasoline.

The crude oil being used and little else determine the amount of each blend stock available for mixing. Generally, if you just dump all the blend stocks into a bucket, you end up with something around 88 or 89 octane. If you're selective and only mix the good stuff, you can make 92, 93 or even 95 octane. But once you take out the good stuff, you're left with crap--something like 85 octane. Then you have to leave enough good stuff in the bucket to bring this ***-water up to at least 87 octane. This limits the amount of 95-octane gas you can make. If you make 93-octane premium instead, you use up less of the high-octane stocks, allowing you to make a higher proportion of premium fuel.

In the Midwest, where an extensive customer base of good old boys in pickup trucks consume vast quantities of 87 octane, demand for premium fuel is low enough to make genuine high-octane premium.

In California, however, Lexus-driving executives suck down premium fuel like it's Evian, so 92 was the rule.

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So the increased demand for premium in California means that there's less of the higher octane stock to blend with the lower octane stock to make it saleable. So the answer is to reduce the octane rating of premium to the minimal requirement (91), and keep enough high octane stock to turn low octane fuel into 87 octane.

 

[jtantare]

quote:

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Originally posted by Brian Miller:


Even in an engine designed for 87, with the ECU programmed to run 93 it does make a difference.

Brian

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There is no 92 octane in california. Best you can get anywhere in the state is 91. Its calle California Swill.

 

[y_p_w]

quote:

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Originally posted by jtantare:

quote:

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Originally posted by Brian Miller:


Even in an engine designed for 87, with the ECU programmed to run 93 it does make a difference.

Brian

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There is no 92 octane in california. Best you can get anywhere in the state is 91. Its calle California Swill.

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Read the article in my link above. Apparently the problem is that premium unleaded is so popular in California. By making so much 92 octane, refiners were running the risk of a shortage of high octane "blend stock". They had to save enough of the high octane stock to blend with their low octane fuel to make it an acceptable 87 octane. So the solution was to lower premium unleaded to 91, which meant slightly less of the high octane stock had to be used for that purpose. Otherwise the refiners were risking the possibility that they would have excess 85 octane unleaded that they wouldn't be able to sell.

While you'd think refiners would want to sell a lot of the high profit 92 octane, I think they're more worried that they would have excess low octane fuel that is unsuitable for passenger cars.

 

[Rickey]

Re:"Premium Gas NOT Needed" I call bull on the premise of the topic. Why did they ask a race car driver (Joe Nemechek).I suggest they should have asked his mechanic instead. Premium gas IS needed in many applications. Cut and paste from a previous post: Just to sumerize my thoughts on this topic: A large number of authorities and media outlets have appearantly "parroted" the notion that anything beyond 87 octaine isn't useful in an engine spec'd for 87 octaine. For background on this do a keyword search on the word "octaine", look at how many entities report the EXACT same verbage. When I see this sort of thing happen my B.S. and propaganda detectors both go off. I feel that such broad statements about octaine are overeaching. If octaine and ignition timing were the only variables in the equation then that sort of statement could fairly be made. However when barometric pressure, humidity, ambient temp, engine load, compression ratio, driving style ETC. are entered into the equation there is pleanty of room for any engine to require more than 87 octaine under certain conditions. If said engine has a properly operating knock sensor and ECM then the spark will be retarded and only the briefest or no audible knock will be noted. So the blanket statment that all is ok if you use 87 octaine and hear no spark knock is B.S. in my opinion. Retarded ignition timing less than what the preprogramed timing table calls for IS going to equal less efficent operation and MORE emissions for the cat and environment to clean up in my opinion. Flame suit on. Rickey.

 

[motorguy222]

In a few posts a while back,fueltankerman seemed to state some of the things that the 20/20 report stated.

The gas leaves the same place and additives are added when the gas is put into the tanker.

Here is the link to fuel tanker man's post:

http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=5;t=002231#000000

In the 20/20 report,it says:

"Some cars do need higher octane — older cars that knock, and cars with high-compression, high-revving engines like Ferraris, Bentleys, Jaguars, Acuras, Mercedes and Corvettes."

It also says this:

"mechanics, and car makers will tell you that for 90 percent of the cars sold today, high octane is no better than regular gas. It won't give you better mileage, more power or a cleaner engine."

"...."what every expert told us."

 

[y_p_w]

I think it would be silly to require an average econobox to use premium just because there are rare cases where the ECU might retard the timing. I think there's an interest in keeping the proportion of cars needing premium down.

There's only so much high octane blending fuel to go around. If demand for premium unleaded was 50% of the market, there might be a glut of unusable low octane fuel. I suppose it might be possible to try and sell more 85 octane in Colorado.

 

[1999nick]

quote:

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Originally posted by Brian Miller:
I had Superchips Custom Tuning write 3 programs for my Ranger 3.0L.

The 93 octane program kicks butt! You can really tell a difference over the stock performance, and even over the 87 octane program that I had them write (so it's not just the shift points that are making a difference).

Plus I'm getting about 3MPG better and better performance with the 93 octane. To me it's worth the extra $2.00 to $2.50 at fill up.

Even in an engine designed for 87, with the ECU programmed to run 93 it does make a difference.

Brian

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When you rechip it for 93, it is no longer designed to run on 87. The timing curve is advanced, resulting in more power and fuel economy. On most stock engines designed for maximum performance on 91 or 93 octane, the computer will automatically retard the timing to compensate for the use of 87 octane. A slight to moderate amount of power and economy is lost.

My Nissan Maxima states in the manual that 87 octane is OK, but for maximum power the use of premium is recommended. I compromise, and use mid-grade. I am old and retired, and don't drive that much any more. Some months I only have to fill up one time, so I probably save about $1.50 per month. Hmmm-I might have to rethink that and begin to use premium. I believe I could squeeze that $1.50 into my monthly budget.

 

[1sttruck]

If you have a newer car and/or live in the flatlands maybe premium isn't needed, but living on a hill we find that our cars need premium. Both have recently had two to three bottles of fuel system cleaner and a few tanks of MMO, and they still prone to pinging without premium.

This is simple stuff to figure out; use regular, then use premium, if it pings on regular and doesn't ping on premium then maybe, just maybe you should use the premium :^)

 

[97tbird]

I know also my car is supposed to run 87 when it was built, but it does ping now (108k miles) without 93...I know it shouldn't do that, but for some reason it does, even after a , complete fuel system cleaning, MAF cleaning, use of FP, tune-up etc.

That's the only reason i use 93 oct., not because I thought it was better. I only started using as a "solution" to the pinging.

 

[grcmptrnrd]

quote:

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Originally posted by benjamming:
Gary,

Have you seen data showing that premium yields an increase in performance in say a Honda Accord that specs regular gas?

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Here you go: Car and Driver: Regular or Premium?

Remembered reading this a while back, just took a bit to find it again.

 

[kenw]

excellent read, thanx for posting the link.

in summary: in spite of the pontifications of the self-annointed websperts, just do what the car maker says and shutup....

 

[Gary Allan]

Well, the test proves that in an Accord ...you may lose power ..and it proves that it's not worth it from a cost stand point. It does prove that there is performance gain from it's use in some instances. Generally, I agree that it's a waste of money. It can, however, increase drivability in certain situations and service duties.

but I'll quote myself to make sure that I'm not misunderstood

quote:

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I will admit that I've had 87 spec'd engines that could care less what's in them ..the same "feel". OTOH, I've had engines that respond quite well to its use. Did they get any better gas mileage ..not to any degree I could see. Did they knock and complain less and give smoother hot weather/high load drivabilty? Yes.

Right now with the price of fuel ...I'm never tempted to push the 93 button on the pump.

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[kenw]

Gary, I saw the same smoothness increase in a definitely low compression 91 camry v6 (2.5L, 8.5:1).

No power increase in the least, no mileage increase that I could document, but it idled much smoother and much quieter on 91. But definitely not worth 20c/gal just to have it make a bit less noise idling in the driveway.....

The difference is VERY noticeable in my 97 camry v6 (3.0L, 10.5:1). Power, engine noise and to a lesser degree mileage are all noticeably improved. The way i drive, mileage is not something i am too hung up about... But then, the book says: "For best performance, use 91 or higher..."