Regular Vs. Premium Fuel
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Regular Vs. Premium Fuel
The following was written by Dexter Ford, who supplies editorials to The Los Angeles Times and others.
By DEXTER FORD
Published: August 3, 2008
AT today's prices, it's understandable that drivers accustomed to
filling their gas tanks with premium would be looking for ways to
ease the financial pain.
Some relief may be as close as their next fill-up. Switching from
premium-grade to regular unleaded can save several dollars on each
tankful, given an average price difference of about 30 cents a
gallon, according to end-of-July figures compiled by AAA.
While using gasoline that carried a lower octane rating than the
engine required was once a sure path to disaster, that is no longer
the case. Nearly all automobiles sold in the United States since the
1990s will happily run on regular-grade 87-octane gasoline without
causing engine damage, a benefit of the electronic controls that now
manage all engine functions.
The octane number posted on the pump is a measure of a gasoline
blend's resistance to a condition called knocking. The knocking
sound — a rattling noise made by an engine under load, familiar to
drivers of older cars — is a result of out-of-control combustion, the
mixture of air and fuel burning erratically. The explosion rings the
metal of the engine block like a bell.
The higher the octane rating, the more temperature and pressure the
gasoline can withstand before it ignites on its own, rather than when
it is set off by the spark plug. An engine that calls for premium gas
typically has a higher compression ratio — it squeezes the air and
fuel mixture to higher pressures — which can improve both fuel
economy and power output. But such an engine requires the higher
octane rating to run properly.
Before the switch to fuel injection and computerized controls,
engines were subject to damage from prolonged knocking. But today's
engine management systems incorporate electronic knock sensors, which
detect the condition and adjust the ignition to stop the problem. As
a result, it is almost impossible to hurt a current engine by using
87-octane fuel, industry experts say.
"Modern engines prevent the damage from happening before it starts,"
said Patrick Kelly, a fuels analyst with the American Petroleum
Institute. "It wouldn't impact fuel economy. And it wouldn't impact
the emissions. What it would impact is the performance."
Of course, owners who do not heed the automakers' recommendations may
face consequences — the potential voiding of warranties, for
instance. But for the most part, manufacturers' fuel recommendations
include some wiggle room.
Porsche, for example, acknowledges that any of its modern production
cars can be run on regular fuel without the risk of damage.
A spokesman for Porsche North America, Tony Fouladpour, added a
caveat. "If you want the car to perform at its maximum capability,
the best choice would not be 87," he said. "But we do not forbid it."
Specifying premium fuel lets a car manufacturer squeeze out more
horsepower. BMW, for example, recommends that all the cars it sells
in the United States use premium fuel, but they will run on regular.
"There generally isn't any harm done to the engine by using lower-
octane fuel," said a BMW spokesman, Thomas Plucinsky. "Because our
engines do have very good forms of knock sensing and are able to deal
with lower-octane fuels, you will not have any drivability issues.
You will, however, lose some of the performance."
How much of a loss? Some indication can be found in the peak
horsepower numbers Hyundai recently released for its new Genesis
sedan. On premium, the 4.6-liter V-8 engine is rated at 375
horsepower. On 87-octane regular, it is 368.
That seven-horsepower difference — less than 2 percent — seems a
small penalty for saving 30 cents a gallon, especially when you can
regain that performance simply by filling up with premium.
Does using lower-octane fuel reduce mileage or increase emissions, as
some drivers believe? Not according to the Environmental Protection
Agency. "E.P.A. fuels engineers say that there isn't a meaningful
difference between regular and premium gasoline," said Dale Kemery, a
spokesman for the agency.
Still, the warning from some automakers can give an owner pause at
the pump. The manual for the Smart Fortwo repeats the warning issued
for other vehicles sold by Mercedes-Benz: "To maintain the engine's
durability and performance, premium unleaded gasoline must be used."
But even those stern words may have some room for interpretation.
Dave Schembri, president of Smart USA, told John Schwartz, a reporter
who was writing for this section's blog about his experiences in
buying a Smart, that he should not worry.
"You could use regular gas — there's no damage to the car," Mr.
Schembri said.
By DEXTER FORD
Published: August 3, 2008
AT today's prices, it's understandable that drivers accustomed to
filling their gas tanks with premium would be looking for ways to
ease the financial pain.
Some relief may be as close as their next fill-up. Switching from
premium-grade to regular unleaded can save several dollars on each
tankful, given an average price difference of about 30 cents a
gallon, according to end-of-July figures compiled by AAA.
While using gasoline that carried a lower octane rating than the
engine required was once a sure path to disaster, that is no longer
the case. Nearly all automobiles sold in the United States since the
1990s will happily run on regular-grade 87-octane gasoline without
causing engine damage, a benefit of the electronic controls that now
manage all engine functions.
The octane number posted on the pump is a measure of a gasoline
blend's resistance to a condition called knocking. The knocking
sound — a rattling noise made by an engine under load, familiar to
drivers of older cars — is a result of out-of-control combustion, the
mixture of air and fuel burning erratically. The explosion rings the
metal of the engine block like a bell.
The higher the octane rating, the more temperature and pressure the
gasoline can withstand before it ignites on its own, rather than when
it is set off by the spark plug. An engine that calls for premium gas
typically has a higher compression ratio — it squeezes the air and
fuel mixture to higher pressures — which can improve both fuel
economy and power output. But such an engine requires the higher
octane rating to run properly.
Before the switch to fuel injection and computerized controls,
engines were subject to damage from prolonged knocking. But today's
engine management systems incorporate electronic knock sensors, which
detect the condition and adjust the ignition to stop the problem. As
a result, it is almost impossible to hurt a current engine by using
87-octane fuel, industry experts say.
"Modern engines prevent the damage from happening before it starts,"
said Patrick Kelly, a fuels analyst with the American Petroleum
Institute. "It wouldn't impact fuel economy. And it wouldn't impact
the emissions. What it would impact is the performance."
Of course, owners who do not heed the automakers' recommendations may
face consequences — the potential voiding of warranties, for
instance. But for the most part, manufacturers' fuel recommendations
include some wiggle room.
Porsche, for example, acknowledges that any of its modern production
cars can be run on regular fuel without the risk of damage.
A spokesman for Porsche North America, Tony Fouladpour, added a
caveat. "If you want the car to perform at its maximum capability,
the best choice would not be 87," he said. "But we do not forbid it."
Specifying premium fuel lets a car manufacturer squeeze out more
horsepower. BMW, for example, recommends that all the cars it sells
in the United States use premium fuel, but they will run on regular.
"There generally isn't any harm done to the engine by using lower-
octane fuel," said a BMW spokesman, Thomas Plucinsky. "Because our
engines do have very good forms of knock sensing and are able to deal
with lower-octane fuels, you will not have any drivability issues.
You will, however, lose some of the performance."
How much of a loss? Some indication can be found in the peak
horsepower numbers Hyundai recently released for its new Genesis
sedan. On premium, the 4.6-liter V-8 engine is rated at 375
horsepower. On 87-octane regular, it is 368.
That seven-horsepower difference — less than 2 percent — seems a
small penalty for saving 30 cents a gallon, especially when you can
regain that performance simply by filling up with premium.
Does using lower-octane fuel reduce mileage or increase emissions, as
some drivers believe? Not according to the Environmental Protection
Agency. "E.P.A. fuels engineers say that there isn't a meaningful
difference between regular and premium gasoline," said Dale Kemery, a
spokesman for the agency.
Still, the warning from some automakers can give an owner pause at
the pump. The manual for the Smart Fortwo repeats the warning issued
for other vehicles sold by Mercedes-Benz: "To maintain the engine's
durability and performance, premium unleaded gasoline must be used."
But even those stern words may have some room for interpretation.
Dave Schembri, president of Smart USA, told John Schwartz, a reporter
who was writing for this section's blog about his experiences in
buying a Smart, that he should not worry.
"You could use regular gas — there's no damage to the car," Mr.
Schembri said.
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Re: Regular vs LPremium Fuel
Thanks for sharing that article. Very interesting. I guess when I think about it, it's piece of mind to pay the extra for the premium. There will always be a doubt in my mind if I run the 87 octane. We sure all waste more money than that on other vices and pleasures as in beer, golf, smoking, etc. Although one of my favorite beers is Sam Adams I mostly buy Mick Lite to save the money and calories. (my body hasn't noticed any knocking yet that I've noticed). 
You have to look at the numbers and see how much using 93 premium is costing you on an annual basis and ask yourself is it worth the switch. It's a personal decision. Kind of a gamble. It's like Dirty Harry say's " Do Ya Feel Lucky, Well, Do Ya?"
You have to look at the numbers and see how much using 93 premium is costing you on an annual basis and ask yourself is it worth the switch. It's a personal decision. Kind of a gamble. It's like Dirty Harry say's " Do Ya Feel Lucky, Well, Do Ya?"
Re: Regular Vs. Premium Fuel
Buried way down in the bottom of the article we have:
"The manual for the Smart Fortwo repeats the warning issued
for other vehicles sold by Mercedes-Benz: "To maintain the engine's
durability and performance, premium unleaded gasoline must be used."
My Volvo V90 called for Premium. With all it's electronics, it still did not like anything but Premium.
My Jeep Wrangler 4.0 is supposed to run on 87. And that's what I usually buy. But guess what? When I started buying 93 or 94 for the Crossfire I accidentally put some in the Wrangler - and it had more pick-up, and got noticeable better mileage... I haven't done it since, but it was interesting.
I do not plan to put anything other than Premium in the Crossfire...
regulations and provide satisfactory
fuel economy and optimum performance
when using high quality unleaded gasoline
having an octane rating of 91 or
higher. DaimlerChrysler Corporation requires
the use of 91 octane or higher premium fuel to
minimize the potential for engine damage.
Light spark knock at low engine speeds is not harmful to
your engine. However, continued heavy spark knock at
high speeds can cause damage and should be reported to
your authorized dealer immediately. Engine damage
resulting from operating with a heavy spark knock may
not be covered by the new vehicle warranty.
Poor quality gasoline can cause problems such as hard
starting, stalling and stumble. If you experience these
problems, try another brand of gasoline before considering
service for the vehicle.
Over 60 automobile manufacturers around the world
have issued and endorsed consistent gasoline specifications
(the World Wide Fuel Charter, WWFC) to define
DaimlerChrysler Corporation recommends the use of
gasolines that meet the WWFC specifications if they are
available.
Reformulated Gasoline
CAUTION!
MMT in Gasoline
Sulfur in Gasoline
If you live in the Northeast United States, your vehicle
may have been designed to meet California low emission
standards with cleaner burning California reformulated
gasoline with low sulfur. If such fuels are not available in
states adopting California emission standards, your vehicle
will operate satisfactorily on fuels meeting Federal
specifications, but emission control system performance
may be adversely affected.
Gasoline sold outside of California is permitted to have
higher sulfur levels, which may affect the performance of
the vehicle’s catalytic converter. This may cause the
CHECK ENGINE light to illuminate. DaimlerChrysler
Corporation recommends that you try a different brand
of unleaded gasoline having lower sulfur to determine if
the problem is fuel-related prior to returning your vehicle
to an authorized dealer for service.
"The manual for the Smart Fortwo repeats the warning issued
for other vehicles sold by Mercedes-Benz: "To maintain the engine's
durability and performance, premium unleaded gasoline must be used."
My Volvo V90 called for Premium. With all it's electronics, it still did not like anything but Premium.
My Jeep Wrangler 4.0 is supposed to run on 87. And that's what I usually buy. But guess what? When I started buying 93 or 94 for the Crossfire I accidentally put some in the Wrangler - and it had more pick-up, and got noticeable better mileage... I haven't done it since, but it was interesting.
I do not plan to put anything other than Premium in the Crossfire...
Owners Manual
Starting and Operating
Page 149
FUEL REQUIREMENTS
Your engine is designed to meet all emissionsStarting and Operating
Page 149
FUEL REQUIREMENTS
regulations and provide satisfactory
fuel economy and optimum performance
when using high quality unleaded gasoline
having an octane rating of 91 or
higher. DaimlerChrysler Corporation requires
the use of 91 octane or higher premium fuel to
minimize the potential for engine damage.
Light spark knock at low engine speeds is not harmful to
your engine. However, continued heavy spark knock at
high speeds can cause damage and should be reported to
your authorized dealer immediately. Engine damage
resulting from operating with a heavy spark knock may
not be covered by the new vehicle warranty.
Poor quality gasoline can cause problems such as hard
starting, stalling and stumble. If you experience these
problems, try another brand of gasoline before considering
service for the vehicle.
Over 60 automobile manufacturers around the world
have issued and endorsed consistent gasoline specifications
(the World Wide Fuel Charter, WWFC) to define
engine performance, and durability for your vehicle.
DaimlerChrysler Corporation recommends the use of
gasolines that meet the WWFC specifications if they are
available.
Reformulated Gasoline
Many areas of the country require the use of cleaner
burning fuel, referred to as “Reformulated Gasoline”.
Reformulated gasolines contain oxygenates and are specially
blended to reduce vehicle emissions and improve
air quality.
DaimlerChrysler Corporation supports the use of reformulated
gasolines. Properly blended reformulated gasolines
will provide excellent performance and durability
of engine and fuel system components.
burning fuel, referred to as “Reformulated Gasoline”.
Reformulated gasolines contain oxygenates and are specially
blended to reduce vehicle emissions and improve
air quality.
DaimlerChrysler Corporation supports the use of reformulated
gasolines. Properly blended reformulated gasolines
will provide excellent performance and durability
of engine and fuel system components.
Gasoline/Oxygenate Blends
Some fuel suppliers blend unleaded gasoline with materials
called oxygenates such as 10% ethanol, MTBE and
ETBE. Oxygenates are required in some areas of the
country during the winter months to reduce carbon
monoxide emissions. Fuels blended with these oxygenates
may be used in your vehicle.
called oxygenates such as 10% ethanol, MTBE and
ETBE. Oxygenates are required in some areas of the
country during the winter months to reduce carbon
monoxide emissions. Fuels blended with these oxygenates
may be used in your vehicle.
CAUTION!
DO NOT use gasolines containing Methanol. Use of
these blends may result in starting and drivabilityproblems and may damage critical fuel system components.
Problems that result from using methanol/gasoline blends
are not the responsibility of DaimlerChrysler
Corporation and may not be covered by the Limited
Warranty. While MTBE is an oxygenate made from
Methanol, it does not have the negative effects of Methanol.
are not the responsibility of DaimlerChrysler
Corporation and may not be covered by the Limited
Warranty. While MTBE is an oxygenate made from
Methanol, it does not have the negative effects of Methanol.
MMT in Gasoline
MMT is a manganese containing metallic additive that is
blended into some gasolines to increase the octane number.
Gasolines blended with MMT offer no performance
advantage beyond gasolines of the same octane number
blended into some gasolines to increase the octane number.
Gasolines blended with MMT offer no performance
advantage beyond gasolines of the same octane number
without MMT. Gasolines blended with MMT have shown
to reduce spark plug life and reduce emission system
performance in some vehicles. DaimlerChrysler Corporation
recommends using gasolines without MMT. Since
the MMT content of gasoline may not be indicated on the
pump, you should ask your gasoline retailer whether or
not his/her gasoline contains MMT.
MMT is prohibited in both Federal and California reformulated
gasolines.
In Canada, MMT can be used at levels higher than those
allowed in the United States. For this reason, it is even
more important to look for gasolines without MMT in
Canada.
to reduce spark plug life and reduce emission system
performance in some vehicles. DaimlerChrysler Corporation
recommends using gasolines without MMT. Since
the MMT content of gasoline may not be indicated on the
pump, you should ask your gasoline retailer whether or
not his/her gasoline contains MMT.
MMT is prohibited in both Federal and California reformulated
gasolines.
In Canada, MMT can be used at levels higher than those
allowed in the United States. For this reason, it is even
more important to look for gasolines without MMT in
Canada.
Materials Added to Fuel
All gasoline sold in the United States is required to
contain effective detergent additives. Use of additional
detergents or other additives is not needed under normal
conditions and would result in unnecessary cost. Therefore,
you should not have to add anything to the fuel.
contain effective detergent additives. Use of additional
detergents or other additives is not needed under normal
conditions and would result in unnecessary cost. Therefore,
you should not have to add anything to the fuel.
Sulfur in Gasoline
If you live in the Northeast United States, your vehicle
may have been designed to meet California low emission
standards with cleaner burning California reformulated
gasoline with low sulfur. If such fuels are not available in
states adopting California emission standards, your vehicle
will operate satisfactorily on fuels meeting Federal
specifications, but emission control system performance
may be adversely affected.
Gasoline sold outside of California is permitted to have
higher sulfur levels, which may affect the performance of
the vehicle’s catalytic converter. This may cause the
CHECK ENGINE light to illuminate. DaimlerChrysler
Corporation recommends that you try a different brand
of unleaded gasoline having lower sulfur to determine if
the problem is fuel-related prior to returning your vehicle
to an authorized dealer for service.
Last edited by ppro; 08-17-2008 at 05:24 AM.
Re: Regular Vs. Premium Fuel
"Before the switch to fuel injection and computerized controls,
engines were subject to damage from prolonged knocking. But today's
engine management systems incorporate electronic knock sensors, which
detect the condition and adjust the ignition to stop the problem. As
a result, it is almost impossible to hurt a current engine by using
87-octane fuel, industry experts say."
If you start retarding the ignition to adjust for pre-ignition,(that is how it "adjust") you will loose power and will have to make up for that power by more acceleration. More accelarator...less fuel mileage. So you save a few cents a gallon at the pump, but it takes more fuel to compensate.So how much are you really saving? Not worth it to me.
engines were subject to damage from prolonged knocking. But today's
engine management systems incorporate electronic knock sensors, which
detect the condition and adjust the ignition to stop the problem. As
a result, it is almost impossible to hurt a current engine by using
87-octane fuel, industry experts say."
If you start retarding the ignition to adjust for pre-ignition,(that is how it "adjust") you will loose power and will have to make up for that power by more acceleration. More accelarator...less fuel mileage. So you save a few cents a gallon at the pump, but it takes more fuel to compensate.So how much are you really saving? Not worth it to me.
Re: Regular vs LPremium Fuel
just get a BP (not a sponser) card and get 5 cents off for each dollar you spend on gas, right now prm gas is 4.02 per gal in south florida, my cost with my bp card at a bp station is 3.80 per gal. save that way if you want to use prem.
off subject but another thing that i do, (my ID was stolen 4 years ago) is when i buy gas i end the cents in the same as the dollar, example if my gas is 40 dollars i end the pump $40.40 if 27 i end it $27.27 and so on this way when i get my bill and there is a amount for say 21 dollars and 70 cents $21.70 I know i didn't buy that and i call and despute it.
off subject but another thing that i do, (my ID was stolen 4 years ago) is when i buy gas i end the cents in the same as the dollar, example if my gas is 40 dollars i end the pump $40.40 if 27 i end it $27.27 and so on this way when i get my bill and there is a amount for say 21 dollars and 70 cents $21.70 I know i didn't buy that and i call and despute it.
Re: Regular Vs. Premium Fuel
true, i see better mpg using cars on premium than regular. i guess cuz the slightly more power u get, the less throttle u use, less gas u use. end of the day it prolly evens out but i like having the extra response on tap. 
if carburated and OBD1 cars use anything other than recommended, they will cause damage because there is nothing to detect knock or wrong mixture. too much fuel or too much octane can cause the cyliner to cool too much and warp. these cars need mixture tuning, timming, etc, if you want to change fuel type.
OBD2 cars have more programing, they can detect knock and adjust the amount of air/fuel mixture and timming automatically adjust, so this will not cause damage.
if carburated and OBD1 cars use anything other than recommended, they will cause damage because there is nothing to detect knock or wrong mixture. too much fuel or too much octane can cause the cyliner to cool too much and warp. these cars need mixture tuning, timming, etc, if you want to change fuel type.
OBD2 cars have more programing, they can detect knock and adjust the amount of air/fuel mixture and timming automatically adjust, so this will not cause damage.
Last edited by racermp; 08-17-2008 at 06:58 AM.
Re: Regular vs LPremium Fuel
I guess if buying premium was keeping food off the table and me from paying my bills I'd cut somewhere, maybe to mid grade on the gas. Fortunately that's not the case and until a Mercedes factory engineer comes out and says its ok to use regular I'm sticken' with premium.
Pat
Pat
Re: Regular Vs. Premium Fuel
Many locations are now puting ETOH in their lower octane gas .....that raises the octane number & they sell it as premium. In reality this kind of premium has much less energy/ gallon than pure gas with the same octane rating, or even less energy / gallon than pure gas with a lower octane rating. You will not go as far or as fast with a premium fuel that has ETOH in it!!!!!! In fact, the pump that says 87 octane may have a much higher real octane rating if it has ETOH in it .....all they are required to say on the pump is what the "minimum" rating is of the fuel. It's even possible that if ETOH is in every grade of gas at a station....that in reality it's all the same.....maybe all is 92 octane.....they just list 3 different grades to make people that want to think they are buying premium. Only way to be semi-sure of what you're getting is to question the owner of the station & maybe even ask to see his invoices.
Re: Regular Vs. Premium Fuel
I dont have a crossfire, YET, but now I drive a 1992 Deville and it requires premium. It is a 4.9L V8 with a compression ratio of 9.5:1. I put regular in the car when it had 80K miles b/c premium became a rip-off, and now the car has 103k miles and not one problem. To be honest with you, it is safer to run premium b/c that is whats suggested, but regular wont do any harm b/c the computers and knock sensors. If my 92 Deville V8 can handle regualr gas, I'm sure a Crossfire can.
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Re: Regular Vs. Premium Fuel
Guy, you are absolutely correct- your Caddy requires premium fuel or it will knock. This article applies to the more modern technology of today's computer-driven cars and trucks.
I posted the article for information only- it is not my intention to encourage anyone to switch from premium to regular fuel: I was passing along information so y'all can make your own choice. I have used regular in my Crossfire without a problem and have been unable to tell the difference (other than in the pocket book) between it and premium.
I would imagine most will continue to run premium fuel but if someone decides to run regular in their crossfire (or most modern cars out there today) then it's nice to know that it can be done without risk or harm.
Skip
I posted the article for information only- it is not my intention to encourage anyone to switch from premium to regular fuel: I was passing along information so y'all can make your own choice. I have used regular in my Crossfire without a problem and have been unable to tell the difference (other than in the pocket book) between it and premium.
I would imagine most will continue to run premium fuel but if someone decides to run regular in their crossfire (or most modern cars out there today) then it's nice to know that it can be done without risk or harm.
Skip
Re: Regular Vs. Premium Fuel
Originally Posted by The Beep
Buy premo...or else...
Certain recipe for engine disaster, going to cost much more than the few cents saved per fillup as well you will not get as good gas mileage.
Most cars will run fine on regular, not this one...
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Re: Regular Vs. Premium Fuel
The SRT-6's manual says premium fuel so not to damage the motor, so you MUST use PREMIUM....if your vehicle does not require it...please dont waste your money...and it rises the price for the Premium users since more people consume the premium....supply and demand....
ok got a little ahead of my self...point is use premium only if it says so on the MANUAL :-)
ok got a little ahead of my self...point is use premium only if it says so on the MANUAL :-)
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