Super Unleaded - not necessary?
07-18-07, 06:44 AM
#1
Super Unleaded - not necessary?
what do you guys think of this USA Today article?
Engines designed for regular fuel don't improve on premium and sometimes run worse. And today's engines designed for premium run fine on regular, too, their makers say, though power declines slightly.
But premium lovers are passionate. "I would simply curtail driving rather than switch grades," says Bill Teater of Mount Vernon, Ohio, who puts high-test in both his Cadillacs, though only one recommends it. He's sure both the DeVille and the Escalade run rough and lack pep on regular.
Prejudice and preference aside, engineers, scientists and the federal government say there's little need for premium.
When fuel's cheap, motorists are willing to pay 20 cents or so more for premium. But as gas prices sneak back up, the mental wrangle begins anew over whether it's OK to burn cheaper, regular-grade gas.
The answer almost always is yes.
"I personally use regular even though my owner's manual says you'll get better performance with premium," says Lewis Gibbs, consulting engineer and 45-year veteran at Chevron oil company. He's chairman of Technical Committee 7 on Fuels, part of the Society of Automotive Engineers (SAE) Fuels & Lubricants Council. Gibbs knows gas.
"My wife runs midgrade (89 octane) in her car, and it's a turbocharged engine" meant for 91-octane premium, he says.
Premium — gasoline having an octane rating 91 or higher — is just 12.1% of sales this year, down from 13.5% in 2002, when it was 22 cents a gallon cheaper, and well below the modern high of 20.3% in 1994, when it was 49 cents cheaper, according to industry and government data. Despite the allure of premium, once they abandon it, most motorists don't come back, the data suggest.
For every dime increase in the price, sales of premium gas drop 1%, Bob Johnson, general manager of gasoline and environmental services for the 7-Eleven chain, figures, based on data back to 1998.
The main advantage of premium-grade gas is that it allows automakers to advertise a few more horsepower by designing and tuning engines to take advantage of premium's anti-knock properties. But auto engineers generally agree that if you use regular in a premium engine, the power loss is so slight, most drivers can't tell.
"I go back and forth, and I'm hard-pressed to notice" whether there's regular or premium in the tank, says Jeff Jetter, principal chemist at Honda Research and Development Americas. He drives an Acura designed for premium.
Import brands, especially, use premium fuel to distinguish their upmarket models. Most Toyotas, for instance, are designed to run on regular or midgrade, while the automaker's Lexus luxury brand prefers premium. Same with Honda and its Acura luxury line.
"Generally, the more expensive the vehicle, the higher the expectation for performance and the more the customer is willing to pay for fuel," says Pete Haidos, head of product planning for Nissan in the USA.
Actually, the price debate is nearly worthless. At 20 cents more for premium, pumping 20 gallons of it instead of regular would cost $4 more. Annually, that's a difference of $171 for a vehicle that averages 14 miles per gallon — as some big sport-utility vehicles do — and is driven 12,000 miles a year.
Gasoline retailers and refiners like high-test because it's more profitable than regular-grade gas is. The retailer paid about 8 cents more for the premium you pay 20 cents more for — though that margin can swing wildly. Refiners make a few cents a gallon more on premium than on regular when they sell to wholesale distributors.
As long as it's clean
Profit is meaningless to the modern engine, which, regardless of what's specified in the owner's manual, hardly cares what you use — as long as it's clean.
Today's engines use highly evolved versions of a device called a knock sensor to adjust settings automatically for low-octane gas. And more engine control computers have adequate memory to allow separate sets of instructions for various octanes. The engine control computers keep pushing to maximize performance on whatever grade of fuel is used.
Extreme pressure inside the cylinders causes knock, which is the sound of the pistons literally rattling inside the cylinders. Too much too long can damage the engine. A little now and then won't.
The only modern engines that should really need premium are those with superchargers, which force-feed fuel into the cylinders. "You're driving along and just tramp the gas and the knock sensor cannot sense the knock fast enough in some cases," because the supercharger boosts pressure so fast, says Bob Furey, chemist and fuels specialist at General Motors.
Burning regular when the owner's manual specifies premium won't void the warranty, nor damage the engine, even the most finicky automakers say. "You're giving up perhaps just a little bit of performance that a customer wouldn't really even notice, it's so slight," says Furey.
Automakers say they don't test premium engines on regular to check the difference, but some auto engineers estimate that power declines roughly 5%.
"We can't guarantee the vehicle will perform as specified if other than premium fuel is used," says Mercedes-Benz spokeswoman Michelle Murad. All U.S. Mercedes engines specify premium.
All Porsche engines are designed for premium, too, but it's not available everywhere. "Our cars must be able to drive all over the world, and so we are able to run on regular," says Jakob Neusser, director of powertrain development at Porsche's research and development center in Weissach, Germany. "You don't have to feel that a mechanical problem or anything else will happen" using regular gas, even in the highest-performance, regular-production Porsches.
Premium, in fact, sometimes is worse fuel than regular. It resists knock because it's harder to ignite than lower-octane fuels. As a result, some engines won't start as quickly or run as smoothly on premium, notes Gibbs, the SAE fuel expert.
High-test does have a potential fuel economy benefit. It is slightly denser than lower-octane gas, meaning there's a little more energy in a gallon. But the small difference is hard to measure in real-world use, and that same density can contribute to undesirable buildup of waste products inside the engine.
No data show that engines designed strictly for regular run better or longer on premium.
The Federal Trade Commission, in a consumer notice, emphasizes: "(I)n most cases, using a higher-octane gasoline than your owner's manual recommends offers absolutely no benefit. It won't make your car perform better, go faster, get better mileage or run cleaner."
There is "no way of taking advantage of premium in a regular-grade car," says Furey.
"There is no gain. You're wasting money," insists Jim Blenkarn, in charge of powertrains at Nissan in the USA.
"No customer should ever be deluded into thinking there's any value in buying a higher grade of octane than we specify," says Toyota's Paul Williamsen, technical expert and trainer.
But premium retains a mystique.
Some people feel almost guilty, as if they are abusing their cars, when they don't burn premium, says gasoline retailer Jay Ricker, president of Ricker Oil of Anderson, Ind., which operates 28 stations. "They go all the way down to 87 (octane), but maybe every fourth tank they put in the good stuff."
Sam Turner has seen the appeal, too. He's president of Favorite Markets of Dalton, Ga., which operates 139 outlets in three states.
He recalls visiting one of his stations during a price war with a nearby station, which had cut the price of premium to just 4 cents more than regular, instead of the usual 20-cent difference.
"A customer was waiting and asked me if I was going to match the guy across the street. I said, 'Yeah,' and he said, 'Good. For 4 cents, I'm gonna buy super.' "
Contributing: Barbara Hansen
Engines designed for regular fuel don't improve on premium and sometimes run worse. And today's engines designed for premium run fine on regular, too, their makers say, though power declines slightly.
But premium lovers are passionate. "I would simply curtail driving rather than switch grades," says Bill Teater of Mount Vernon, Ohio, who puts high-test in both his Cadillacs, though only one recommends it. He's sure both the DeVille and the Escalade run rough and lack pep on regular.
Prejudice and preference aside, engineers, scientists and the federal government say there's little need for premium.
When fuel's cheap, motorists are willing to pay 20 cents or so more for premium. But as gas prices sneak back up, the mental wrangle begins anew over whether it's OK to burn cheaper, regular-grade gas.
The answer almost always is yes.
"I personally use regular even though my owner's manual says you'll get better performance with premium," says Lewis Gibbs, consulting engineer and 45-year veteran at Chevron oil company. He's chairman of Technical Committee 7 on Fuels, part of the Society of Automotive Engineers (SAE) Fuels & Lubricants Council. Gibbs knows gas.
"My wife runs midgrade (89 octane) in her car, and it's a turbocharged engine" meant for 91-octane premium, he says.
Premium — gasoline having an octane rating 91 or higher — is just 12.1% of sales this year, down from 13.5% in 2002, when it was 22 cents a gallon cheaper, and well below the modern high of 20.3% in 1994, when it was 49 cents cheaper, according to industry and government data. Despite the allure of premium, once they abandon it, most motorists don't come back, the data suggest.
For every dime increase in the price, sales of premium gas drop 1%, Bob Johnson, general manager of gasoline and environmental services for the 7-Eleven chain, figures, based on data back to 1998.
The main advantage of premium-grade gas is that it allows automakers to advertise a few more horsepower by designing and tuning engines to take advantage of premium's anti-knock properties. But auto engineers generally agree that if you use regular in a premium engine, the power loss is so slight, most drivers can't tell.
"I go back and forth, and I'm hard-pressed to notice" whether there's regular or premium in the tank, says Jeff Jetter, principal chemist at Honda Research and Development Americas. He drives an Acura designed for premium.
Import brands, especially, use premium fuel to distinguish their upmarket models. Most Toyotas, for instance, are designed to run on regular or midgrade, while the automaker's Lexus luxury brand prefers premium. Same with Honda and its Acura luxury line.
"Generally, the more expensive the vehicle, the higher the expectation for performance and the more the customer is willing to pay for fuel," says Pete Haidos, head of product planning for Nissan in the USA.
Actually, the price debate is nearly worthless. At 20 cents more for premium, pumping 20 gallons of it instead of regular would cost $4 more. Annually, that's a difference of $171 for a vehicle that averages 14 miles per gallon — as some big sport-utility vehicles do — and is driven 12,000 miles a year.
Gasoline retailers and refiners like high-test because it's more profitable than regular-grade gas is. The retailer paid about 8 cents more for the premium you pay 20 cents more for — though that margin can swing wildly. Refiners make a few cents a gallon more on premium than on regular when they sell to wholesale distributors.
As long as it's clean
Profit is meaningless to the modern engine, which, regardless of what's specified in the owner's manual, hardly cares what you use — as long as it's clean.
Today's engines use highly evolved versions of a device called a knock sensor to adjust settings automatically for low-octane gas. And more engine control computers have adequate memory to allow separate sets of instructions for various octanes. The engine control computers keep pushing to maximize performance on whatever grade of fuel is used.
Extreme pressure inside the cylinders causes knock, which is the sound of the pistons literally rattling inside the cylinders. Too much too long can damage the engine. A little now and then won't.
The only modern engines that should really need premium are those with superchargers, which force-feed fuel into the cylinders. "You're driving along and just tramp the gas and the knock sensor cannot sense the knock fast enough in some cases," because the supercharger boosts pressure so fast, says Bob Furey, chemist and fuels specialist at General Motors.
Burning regular when the owner's manual specifies premium won't void the warranty, nor damage the engine, even the most finicky automakers say. "You're giving up perhaps just a little bit of performance that a customer wouldn't really even notice, it's so slight," says Furey.
Automakers say they don't test premium engines on regular to check the difference, but some auto engineers estimate that power declines roughly 5%.
"We can't guarantee the vehicle will perform as specified if other than premium fuel is used," says Mercedes-Benz spokeswoman Michelle Murad. All U.S. Mercedes engines specify premium.
All Porsche engines are designed for premium, too, but it's not available everywhere. "Our cars must be able to drive all over the world, and so we are able to run on regular," says Jakob Neusser, director of powertrain development at Porsche's research and development center in Weissach, Germany. "You don't have to feel that a mechanical problem or anything else will happen" using regular gas, even in the highest-performance, regular-production Porsches.
Premium, in fact, sometimes is worse fuel than regular. It resists knock because it's harder to ignite than lower-octane fuels. As a result, some engines won't start as quickly or run as smoothly on premium, notes Gibbs, the SAE fuel expert.
High-test does have a potential fuel economy benefit. It is slightly denser than lower-octane gas, meaning there's a little more energy in a gallon. But the small difference is hard to measure in real-world use, and that same density can contribute to undesirable buildup of waste products inside the engine.
No data show that engines designed strictly for regular run better or longer on premium.
The Federal Trade Commission, in a consumer notice, emphasizes: "(I)n most cases, using a higher-octane gasoline than your owner's manual recommends offers absolutely no benefit. It won't make your car perform better, go faster, get better mileage or run cleaner."
There is "no way of taking advantage of premium in a regular-grade car," says Furey.
"There is no gain. You're wasting money," insists Jim Blenkarn, in charge of powertrains at Nissan in the USA.
"No customer should ever be deluded into thinking there's any value in buying a higher grade of octane than we specify," says Toyota's Paul Williamsen, technical expert and trainer.
But premium retains a mystique.
Some people feel almost guilty, as if they are abusing their cars, when they don't burn premium, says gasoline retailer Jay Ricker, president of Ricker Oil of Anderson, Ind., which operates 28 stations. "They go all the way down to 87 (octane), but maybe every fourth tank they put in the good stuff."
Sam Turner has seen the appeal, too. He's president of Favorite Markets of Dalton, Ga., which operates 139 outlets in three states.
He recalls visiting one of his stations during a price war with a nearby station, which had cut the price of premium to just 4 cents more than regular, instead of the usual 20-cent difference.
"A customer was waiting and asked me if I was going to match the guy across the street. I said, 'Yeah,' and he said, 'Good. For 4 cents, I'm gonna buy super.' "
Contributing: Barbara Hansen
07-18-07, 06:59 AM
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i use premium gas only. wouldn't want to take any chances. plus, it's only 20 cents more than regular, i know that it does add up in the long run but in the short run, it's not so bad. hahaha
07-18-07, 07:40 AM
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07-18-07, 07:41 AM
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Really interesting, thanks for that info. But I think I will drain this tank of premium and put in a fresh tank or 87 and see if there is any difference. It never made a difference in my pops 95 Aurora that said "Premium Unleaded Only" on the dash and at the fuel tank door.
07-18-07, 07:50 AM
#6
On any ultra high compression or boosted motor, you run a much higher chance of permanently damaging the motor by running lower octane fuel. Try putting in a tank of 87octane in a Ferrari 360 and run it to redline a few times 
Same thing with a boosted car, put 87 octane in a boosted 600-700HP Supra and see what happens to the motor. In these specific cases, yes it is CRITICAL to run premium fuel or even better if an even higher grade can be found.
However, for STOCK normal production factory cars...it's perfectly fine to run regular gas. If the engine was designed in mind to run on regular, you will gain zero benefit from using premium. A common misconception by most when they think premium will clean out the motor better than regular. Fact is premium doesn't contain any more cleaners or detergents, it just has more anti-detonants added in and this is only going to be beneficial for high performance engines. If your motor was designed for premium, running regular won't hurt it. You will usually suffer a power loss and reduced gas mileage because the engine computer has to throttle back on the ignition timing(thus lowering engine efficiency) to protect itself from damage.
Same thing with a boosted car, put 87 octane in a boosted 600-700HP Supra and see what happens to the motor. In these specific cases, yes it is CRITICAL to run premium fuel or even better if an even higher grade can be found.However, for STOCK normal production factory cars...it's perfectly fine to run regular gas. If the engine was designed in mind to run on regular, you will gain zero benefit from using premium. A common misconception by most when they think premium will clean out the motor better than regular. Fact is premium doesn't contain any more cleaners or detergents, it just has more anti-detonants added in and this is only going to be beneficial for high performance engines. If your motor was designed for premium, running regular won't hurt it. You will usually suffer a power loss and reduced gas mileage because the engine computer has to throttle back on the ignition timing(thus lowering engine efficiency) to protect itself from damage.
07-18-07, 07:53 AM
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Second time posting this info:
I believe they require premium because of the bump in timing to get more power out of these engines, therefore premium fuel is required to keep from pinging (detonation) which will hurt/kill your motor. If you want to use 87 octane, then i'd look into lowering your timing so that you can safely use the lower octane fuel.
This is just a guess as i don't know what base timing is set at, but most cars requiring super unleaded have bumped up timing which requires a higher octane level to avoid detonation. This was the case in my Cobra and is pretty much where i learned all about timing, detonation and higher octane fuel to avoid pinging.
Plus, the owners manual says super unleaded only. Lexus doesn't have a stake on what profits the oil companies make, so if they say to use a higher octane fuel, then it's for a reason. I suppose you can use the lower octane fuel if you just cruise around without ever getting on the gas, but if you need to gun it, then you'd better have an ear out for detonation. It sounds like tiny rocks in a can when shaken vigorously.
EDIT:
It looks like Jeff beat me to it.
I believe they require premium because of the bump in timing to get more power out of these engines, therefore premium fuel is required to keep from pinging (detonation) which will hurt/kill your motor. If you want to use 87 octane, then i'd look into lowering your timing so that you can safely use the lower octane fuel.
This is just a guess as i don't know what base timing is set at, but most cars requiring super unleaded have bumped up timing which requires a higher octane level to avoid detonation. This was the case in my Cobra and is pretty much where i learned all about timing, detonation and higher octane fuel to avoid pinging.
Plus, the owners manual says super unleaded only. Lexus doesn't have a stake on what profits the oil companies make, so if they say to use a higher octane fuel, then it's for a reason. I suppose you can use the lower octane fuel if you just cruise around without ever getting on the gas, but if you need to gun it, then you'd better have an ear out for detonation. It sounds like tiny rocks in a can when shaken vigorously.
EDIT:
It looks like Jeff beat me to it.
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07-18-07, 08:03 AM
#8
David, almost all modern engines...and especially higher performance spec factory engines have very sophisticated anti-knock/timing-retarding systems. As I said, you can run regular fuel in a factory production car as long as the motor is STOCK. Manufacturers design the cars from the factory to run anywhere in the world even with the worst possible fuel conditions. We did a test in a BMW M3 E46 and put regular gas in it and ran it to redline(8000RPM) all over town till we drained the tank and the car did suffer a pretty big performance hit(keep in mind the M3 has a 11.5:1 compression engine). It felt like we lost approximately 25-30% power output. However, we didn't experience any detonation nor hear any knock. And yes...it was a loaner when my friend's M5 went in for service
We also did the same test with a Honda S2000 which has a 12:1 compression motor from the factory(240hp out of 2.0L is no joke)!!! Power suffered really badly in the 6000-9000rpm VTEC range but still no knock or detonation.
However, I'm not sure how a Ferrari would fare with a tank of 87octane and driven that hard heh...
We also did the same test with a Honda S2000 which has a 12:1 compression motor from the factory(240hp out of 2.0L is no joke)!!! Power suffered really badly in the 6000-9000rpm VTEC range but still no knock or detonation.
However, I'm not sure how a Ferrari would fare with a tank of 87octane and driven that hard heh...
Last edited by JeffTsai; 07-18-07 at 08:09 AM.
07-18-07, 08:52 AM
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On any ultra high compression or boosted motor, you run a much higher chance of permanently damaging the motor by running lower octane fuel. Try putting in a tank of 87octane in a Ferrari 360 and run it to redline a few times Same thing with a boosted car, put 87 octane in a boosted 600-700HP Supra and see what happens to the motor. In these specific cases, yes it is CRITICAL to run premium fuel or even better if an even higher grade can be found.
However, for STOCK normal production factory cars...it's perfectly fine to run regular gas. If the engine was designed in mind to run on regular, you will gain zero benefit from using premium. A common misconception by most when they think premium will clean out the motor better than regular. Fact is premium doesn't contain any more cleaners or detergents, it just has more anti-detonants added in and this is only going to be beneficial for high performance engines. If your motor was designed for premium, running regular won't hurt it. You will usually suffer a power loss and reduced gas mileage because the engine computer has to throttle back on the ignition timing(thus lowering engine efficiency) to protect itself from damage.
Same thing with a boosted car, put 87 octane in a boosted 600-700HP Supra and see what happens to the motor. In these specific cases, yes it is CRITICAL to run premium fuel or even better if an even higher grade can be found.However, for STOCK normal production factory cars...it's perfectly fine to run regular gas. If the engine was designed in mind to run on regular, you will gain zero benefit from using premium. A common misconception by most when they think premium will clean out the motor better than regular. Fact is premium doesn't contain any more cleaners or detergents, it just has more anti-detonants added in and this is only going to be beneficial for high performance engines. If your motor was designed for premium, running regular won't hurt it. You will usually suffer a power loss and reduced gas mileage because the engine computer has to throttle back on the ignition timing(thus lowering engine efficiency) to protect itself from damage.
07-18-07, 09:29 AM
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i want to hear from others who have triend regular instead of premium in their v8 gs's. i tried 89 regular once because at the time gas prices were just brutal, and the loss in power was very noticable... almost like driving a gs300 (sorry gs300 folks that wasn't meant to be an insult 
).
).
07-18-07, 09:46 AM
#11
I run mid-grade and hi-grade, but I'm gonna try regular at my next fill-up. I don't notice any performance difference between mid and hi.
My wife's '98 Cadillac STS owner's manual stated that premium was preferred, however, lower grades could be substituted as long as you don't hear bad noises. This has been my mantra at the pump after reading that.
Brian
My wife's '98 Cadillac STS owner's manual stated that premium was preferred, however, lower grades could be substituted as long as you don't hear bad noises. This has been my mantra at the pump after reading that.
Brian
07-18-07, 09:59 AM
#12
I usually tell everyone to run what you want but as long as you accept what the manufacture recommends. People come into the dealer complaining that it runs fine with 87, BUT, this happens. Why can't they accept that may be WHY Lexus says high test. I've noticed a better performance and mileage with high test in all of my cars, so the extra money is fine by me. To each is his own.
But good article, thanks for the info.
But good article, thanks for the info.
07-18-07, 09:59 AM
#13
It's funny how people see the premium price and choose to run regular, when if you add up the pennies, it's only like $6-7 more per tank.
Then there's the people who buy regular gas, then spend $6 on the octane booster, thinking they saved money that way.
If you need to go somewhere, (which we all need to, that's why we have cars) why would you cheap out on gas (only saving 6-7 dollars) and then have poorer performance and less gas mileage?
If you are getting less gas mileage, you will be filling up more often. If that's the case, wouldn't you end up spending more money trying to save a few dollars?
I just get used to paying $50 at the pump at fill up. No biggie to me anymore.
Then there's the people who buy regular gas, then spend $6 on the octane booster, thinking they saved money that way.
If you need to go somewhere, (which we all need to, that's why we have cars) why would you cheap out on gas (only saving 6-7 dollars) and then have poorer performance and less gas mileage?
If you are getting less gas mileage, you will be filling up more often. If that's the case, wouldn't you end up spending more money trying to save a few dollars?
I just get used to paying $50 at the pump at fill up. No biggie to me anymore.
07-22-07, 05:57 PM
#15
nice
great discussion...thanks for the comments. the two competing views that i've heard (from reliable sources) were expressed in this thread.
like most gs400 owners, i want maximum performance so the extra few dollars a tank is worth it, whether it factually helps or not, i play it safe...if i had an es300 it might be different.
just thought it interesting.
see ya at the pump.
like most gs400 owners, i want maximum performance so the extra few dollars a tank is worth it, whether it factually helps or not, i play it safe...if i had an es300 it might be different.
just thought it interesting.
see ya at the pump.
Last edited by liazon; 07-22-07 at 06:00 PM.