Premium Gas?

[Canopy]

This is an interesting article. Makes a distinction between "required" and "recommended" octane. If "recommended" in manual, then car should run OK on regular gas, but suffer a little in performance. If "required", the implication is that you have to run it on premium.

My 1996 LS 400 manual states: "Select premium unleaded gasoline with a Research Octane Number of 96 (Octane Rating 91) or higher for optimum engine performance. However, if such premium type cannot be obtained, you may temporarily use unleaded gasoline with an octane number as low as 91."

Of course, it doesn't say what the octane rating is for Octane Number 91. Has anyone tried Regular or Mid-Grade? What's the result? Is it heresy to even try it?

Here's the article:

Special Reports

Do You Really Need Premium?

And Answers to Other Gasoline Questions

By Edmunds.com Editors

Date Posted 07-05-2005

Buying premium gas is like taking vitamins — you can't always feel the difference and yet you know it's the right thing to do. But as gas prices climb, paying the extra dime per gallon for premium is like adding insult to injury. Eventually, the thought is bound to jump into your head: do I really need to pop for premium?

Until about 15 years ago, if a car called for premium gas and you pumped in regular, the car began to knock and ping and even vibrate. But that was before they essentially put a laptop under the hood of the automobile, said Dr. Loren Beard, senior manager of Environmental and Energy Planning, for Daimler Chrysler. Now, sensors take readings and tune the engine as you drive by adjusting the timing for whatever fuel you put in the tank.

The result is that a car that calls for the midgrade gasoline will usually run on regular without knocking, Beard said. However, its performance will suffer slightly. How much? It will be perhaps a half-second slower going from zero to 60 mph.

Volvo cars call for "premium fuel [91 octane or better] for optimum performance and fuel economy," said Wayne Baldwin, product/segment manager S60/S80. "However, there is absolutely nothing wrong with using 87 octane as the knock sensors and engine management system 'protect' the engine from knocking."

Baldwin, a former rally driver who competed in SCCA Pro Rally events said that engines have changed a lot in the past 15 years. "Cars built before 1990 probably do not have knock sensors and many brands back then relied on high-compression ratios for the best performance. Today [performance comes from] electronically controlled spark curves, turbos, variable valve timing, supercharging and knock sensors."

Issues of performance aside, Baldwin said you should never use gasoline that causes your car to knock. "Constant knocking or detonation is a real bad thing for engines," he said.

When choosing what grade of gasoline to use, Steve Mazor, principle auto engineer for Auto Club of Southern California, said it is important to read the owner's manual carefully. The key is to figure out whether premium gasoline is "required" or "recommended." If it is recommended then a driver could opt to use a lower grade of gas, if they were willing to accept slightly reduced performance and fuel economy.

However, Mazor added, "We don't recommend that people switch down. Let's say you switch down to regular, and you have to accelerate to avoid an accident and it doesn't accelerate fast enough. The Auto Club can't be responsible for causing that situation."

Edmunds.com has a Volvo S40 in its fleet, so we consulted the owner's manual to see the exact phrasing in regard to fuel requirements. It said, "Volvo engines are designed for optimum performance on unleaded premium gasoline with an AKI (Anti Knock Index) of 91 or above. The minimum octane requirement is AKI 87." It appears that Volvo is making a recommendation for premium gas but is not requiring it.

In Edmunds.com's Forums debates abound over the pros and cons of using different fuel grades. One member even suggested there was only one type of gasoline, no difference — except for price — between regular and premium. Other members recommended using premium gas even if the manual called for regular. We put this question to Mazor and Beard.

Mazor: "All this does is do a very good job of draining your wallet. People used to put in a tank of premium to get 'the good stuff' to help their engines stay clean. But now they put detergents in all grades so it doesn't really get you anything."

Beard: "If you have car designed to run on 87 [octane], it doesn't help to run it on higher-octane-level gas. But there are several exceptions." He said that the 3.5-liter Chrysler engines are designed to run on midgrade gas (89 octane) and it allows them to advertise a certain peak horsepower. However, it will run well on regular gas. "The difference is very small," he said.

Interestingly, Mazor noted that at some gas stations, there are only two grades of gas. However, they blend the regular and premium at the pump to produce the midgrade gasoline. This allows them to have only two underground tanks for the gas storage.

In Edmunds' forums some drivers expressed concern about the quality of gas sold at independent gas stations and advised sticking to the so-called "name" brands of gasoline.

"Typically the only difference is the additive package they put in the gas," Beard said. The additive package is often put into the gas as the tanker is filled up at the refinery. A common additive is a detergent agent. "The law requires a certain level of detergents in gasoline. Shell for example is putting in more detergent — whether that has a measurable effect to the driver is debatable."

Detergents have a marked effect on engine deposits. "If you take apart a modern engine that has been running on a modern fuel, and compare this to an old engine that was running on old gas, you can see an obvious difference," Mazor said.

The biggest difference between today's gas and the gas sold 15 years ago is the removal of lead. Taking out the lead, and developing effective catalytic converters to more completely burn emissions, have radically cut pollution.

While oil companies like to advertise the magical powers of their gasoline, it appears that there is very little difference between brands. Most drivers fill up at the nearest gas station or the one for which they carry a credit card.

Does a gas expert like Beard have a preference when buying gas? "I just watch the light on the dash. After it has been on for a day I get nervous and go to the closest station available."

[TexasLexus94]

I've had to use regular on my '94 LS when I've pulled into a station that was out of premium (in Az.), and found that there was no difference. Although I don't drive my 11 year old car like a dragster at any time. No knocks or anything else.

Curiously, I've owned a '90 Eclipse, and now own a '95 MX-5 Mazda-both turbos-and never put anything but premium in them. Guess a turbo is a different animal?

[akewlguy]

In my eyes gas is 2.50 (regular) to 2.70 (premium) a gallon.

So the .20/2.50... That is 8% more..

So at the pump when I pay $50 dollars I could pay $46.00.

Four times a month I could save $16 a month or $192.

Although I would like to think that engineers at LEXUS are wrong and misguiding me I have to think about their track record. They build a car in 1990 that is better then most American cars in 2005. So I will spend the extra $200 bucks to keep my second love or LS400 happy!

Cheers to LEXUS!

[SKperformance]

So agree akewlguy

I'll skip a few bigmacs to keep my inflated idea of good and bad working perfectly with my cars with me wasting my money on premium.

That slight difference can be huge depending on the car and it only gets worse over time as carbon build up.

[akewlguy]

Hey dont eat to many bigmacks.. You got to look good in that LEXUS! :)

[cary1952]

It has been my experience that the lower the octane, the better the gas mileage.

This is an interesting article.  Makes a distinction between "required" and "recommended"  octane. If "recommended" in manual, then car should run OK on regular gas, but suffer a little in performance.  If "required", the implication is that you have to run it on premium. 

My 1996 LS 400 manual states: "Select premium unleaded gasoline with a Research Octane Number of 96 (Octane Rating 91) or higher for optimum engine performance.  However, if such premium type cannot be obtained, you may temporarily use unleaded gasoline with an octane number as low as 91."

Of course, it doesn't say what the octane rating is for Octane Number 91.  Has anyone tried Regular or Mid-Grade?  What's the result?  Is it heresy to even try it?

Here's the article:

Special Reports

Do You Really Need Premium?

And Answers to Other Gasoline Questions

By Edmunds.com Editors

Date Posted 07-05-2005

Buying premium gas is like taking vitamins — you can't always feel the difference and yet you know it's the right thing to do. But as gas prices climb, paying the extra dime per gallon for premium is like adding insult to injury. Eventually, the thought is bound to jump into your head: do I really need to pop for premium?

Until about 15 years ago, if a car called for premium gas and you pumped in regular, the car began to knock and ping and even vibrate. But that was before they essentially put a laptop under the hood of the automobile, said Dr. Loren Beard, senior manager of Environmental and Energy Planning, for Daimler Chrysler. Now, sensors take readings and tune the engine as you drive by adjusting the timing for whatever fuel you put in the tank.

The result is that a car that calls for the midgrade gasoline will usually run on regular without knocking, Beard said. However, its performance will suffer slightly. How much? It will be perhaps a half-second slower going from zero to 60 mph.

Volvo cars call for "premium fuel [91 octane or better] for optimum performance and fuel economy," said Wayne Baldwin, product/segment manager S60/S80. "However, there is absolutely nothing wrong with using 87 octane as the knock sensors and engine management system 'protect' the engine from knocking."

Baldwin, a former rally driver who competed in SCCA Pro Rally events said that engines have changed a lot in the past 15 years. "Cars built before 1990 probably do not have knock sensors and many brands back then relied on high-compression ratios for the best performance. Today [performance comes from] electronically controlled spark curves, turbos, variable valve timing, supercharging and knock sensors."

Issues of performance aside, Baldwin said you should never use gasoline that causes your car to knock. "Constant knocking or detonation is a real bad thing for engines," he said.

When choosing what grade of gasoline to use, Steve Mazor, principle auto engineer for Auto Club of Southern California, said it is important to read the owner's manual carefully. The key is to figure out whether premium gasoline is "required" or "recommended." If it is recommended then a driver could opt to use a lower grade of gas, if they were willing to accept slightly reduced performance and fuel economy.

However, Mazor added, "We don't recommend that people switch down. Let's say you switch down to regular, and you have to accelerate to avoid an accident and it doesn't accelerate fast enough. The Auto Club can't be responsible for causing that situation."

Edmunds.com has a Volvo S40 in its fleet, so we consulted the owner's manual to see the exact phrasing in regard to fuel requirements. It said, "Volvo engines are designed for optimum performance on unleaded premium gasoline with an AKI (Anti Knock Index) of 91 or above. The minimum octane requirement is AKI 87." It appears that Volvo is making a recommendation for premium gas but is not requiring it.

In Edmunds.com's Forums debates abound over the pros and cons of using different fuel grades. One member even suggested there was only one type of gasoline, no difference — except for price — between regular and premium. Other members recommended using premium gas even if the manual called for regular. We put this question to Mazor and Beard.

Mazor: "All this does is do a very good job of draining your wallet. People used to put in a tank of premium to get 'the good stuff' to help their engines stay clean. But now they put detergents in all grades so it doesn't really get you anything."

Beard: "If you have car designed to run on 87 [octane], it doesn't help to run it on higher-octane-level gas. But there are several exceptions." He said that the 3.5-liter Chrysler engines are designed to run on midgrade gas (89 octane) and it allows them to advertise a certain peak horsepower. However, it will run well on regular gas. "The difference is very small," he said.

Interestingly, Mazor noted that at some gas stations, there are only two grades of gas. However, they blend the regular and premium at the pump to produce the midgrade gasoline. This allows them to have only two underground tanks for the gas storage.

In Edmunds' forums some drivers expressed concern about the quality of gas sold at independent gas stations and advised sticking to the so-called "name" brands of gasoline.

"Typically the only difference is the additive package they put in the gas," Beard said. The additive package is often put into the gas as the tanker is filled up at the refinery. A common additive is a detergent agent. "The law requires a certain level of detergents in gasoline. Shell for example is putting in more detergent — whether that has a measurable effect to the driver is debatable."

Detergents have a marked effect on engine deposits. "If you take apart a modern engine that has been running on a modern fuel, and compare this to an old engine that was running on old gas, you can see an obvious difference," Mazor said.

The biggest difference between today's gas and the gas sold 15 years ago is the removal of lead. Taking out the lead, and developing effective catalytic converters to more completely burn emissions, have radically cut pollution.

While oil companies like to advertise the magical powers of their gasoline, it appears that there is very little difference between brands. Most drivers fill up at the nearest gas station or the one for which they carry a credit card.

Does a gas expert like Beard have a preference when buying gas? "I just watch the light on the dash. After it has been on for a day I get nervous and go to the closest station available."

←

[akewlguy]

Interesting.. Do you have statistical data to support your case?

I mean for 8 fill ups you used reg and saw a 24MGP. The for four premium you saw a 22MPG? This would have to be during similar highway and city driving conditions..

[cary1952]

Do I have proof??? Only my personal experience and knowledge of chemistry. Higher octane gas burns faster, and produces more power. Less Octane produces less pickup, performance, but burns slower so better gas mileage, does that makes sense? I have used 85 octane in mountainous areas (high altitude) and have very impressive mpg's in my LS430. Most people think the opposite, but there are dead wrong. think about racing fuel 100-104 octane or alcohol . burns VERY fast . Lots of power and acceleration but terrrible mpg.

Also, we have ethanol where i live. Octane rating is 89 with 10% ethanol. It is about 5-8 cents CHEAPER a gallon than 87 (pure). I use it alot instead of regular but I think i get best mileage with regular. So it depends on the price for what I use. Sometimes I do one tank of one and another tank of the other.

I havent used premium for year, including several mercedes, bmw's, 1 porche, and 4 lexus. The only time i use premium in all these years, is when I was doing some autocross racing.

I have had no problem running 87 or even less octane. Try 3 tankfuls yourself and you decide.

Cary in SD.

Interesting.. Do you have statistical data to support your case?

I mean for 8 fill ups you used reg and saw a 24MGP. The for four premium you saw a 22MPG? This would have to be during similar highway and city driving conditions..

←

[Kennyr]

Do I have proof??? Only my personal experience and knowledge of chemistry.  Higher octane gas burns faster, and produces more power. Less Octane produces less pickup, performance, but burns slower so better gas mileage, does that makes sense?  I have used 85 octane in mountainous areas (high altitude) and have very impressive mpg's in my LS430.  Most people think the opposite, but there are dead wrong.  think about racing fuel 100-104 octane or alcohol . burns VERY fast . Lots of power and acceleration but terrrible mpg. 

Also, we have ethanol where i live.  Octane rating is 89 with 10% ethanol. It is about 5-8 cents CHEAPER a gallon than 87 (pure).  I use it alot instead of regular but I think i get best mileage with regular. So it depends on the price for what I use.  Sometimes I do one tank of one and another tank of the other.

I havent used premium for year, including several mercedes, bmw's, 1 porche, and 4 lexus.  The only time i use premium in all these years, is when I was doing some autocross racing.

I have had no problem running 87 or even less octane.  Try 3 tankfuls yourself and you decide.                        I agree. I only use 85 to 87 octane and even when I have tried premium there was no diff in miles per gallon or performance I can feel.

Cary in SD.

Interesting.. Do you have statistical data to support your case?

I mean for 8 fill ups you used reg and saw a 24MGP. The for four premium you saw a 22MPG? This would have to be during similar highway and city driving conditions..

←

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[SKperformance]

variables that can make lower octane produce higher milage

more highway distance travelled

colder weather

bad ignition timing or reduced spark from wires ,plugs,rotor and caps.

[razahyde]

hmm idk about that topic it doesnt have any real evidence if it reduces MPG then why didnt they do a test on that its farely simple process and when they say youll lose MPG and performance for regular so if im correct then my theory should be right say you get 20 mpg with premium and you get about 17 with regular premium costs 2.20 and regular is 2.00 so if you do the math right 5 gallons of premium is $11 and that turns to 100 miles total then regular 5 gallons of gas is 10 and that turns to 85 miles total so thats a 15 mpg difference between the two and you save a dollar there in gas by getting regular but u sacrifice performance and MPG so if you think about it then wouldnt you be better off getting premium which has better performance and better MPG because really in the long run premium would be a better deal if i did the math right but what do i kno haha am i on to something or do i have no point at all lol

-khalid

[akewlguy]

I thought premium burned hotter not faster.

A dragster has massive amounts of fuel being forced into engine..

According to my fuel experts premium is harder to ignite. It has nothing to do with buring faster. A ping is a pre ignition from compression or carbon.

So for those who drive the 87 or 89. Does anyone have high mileage over 200k? With just straight 87 or 89 octain.