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Author Topic: Should I buy regular gas for my car? Back to Topics
DerekS

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Seattle

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Message Posted: Oct 29, 2012 3:41:41 PM

Please don't just post yes or no.

A relative's BMW recommends premium. Another car recommends mid-grade. Both cars say regular is acceptable.

The BMW definitely runs smoother with premium. I tested it by having them put several consecutive tankfuls (not just one) and then having me drive it without knowing what was in the tank. My conclusion: use premium for that particular car, but not necessarily all BMWs. It improves smoothness driving up a hill, particularly.

The car that recommends mid-grade drives fine with regular. The EPA tested the car and it gets 1 mpg better with premium. I agree generally. My figure is 0.7 mpg but I know it is not 2 mpg. At about 1 mpg, the cost of premium gets competitive with regular but regular is still cheaper. Premium is 20 cents/gallon more and, after my calculations, with better gas mileage, it is about 13 cents more. My conclusion: use regular for that car.

What do you think about my analysis?



[Edited by: DerekS at 10/29/2012 3:42:37 PM EST]
REPLIES (newest first) Post a Reply
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priceguy
Champion Author Bakersfield

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Message Posted: Jan 4, 2013 3:39:33 PM

y
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2Tall
Champion Author Maryland

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Message Posted: Jan 4, 2013 10:49:13 AM

yes
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BUSSY
Champion Author Dallas

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Message Posted: Jan 4, 2013 7:47:19 AM

See what you stirred up DerekS?
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RNF
Champion Author Indiana

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Message Posted: Jan 4, 2013 6:39:37 AM

The manufacturer gives you the option of what type of gas to use.

Definitely, use the less expensive gas with very little loss of performance.
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Boyrr
Champion Author Allentown

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Message Posted: Jan 4, 2013 6:00:51 AM

yup
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MIT05
Champion Author Massachusetts

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Message Posted: Jan 4, 2013 5:23:36 AM

Regular.
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TXBruin
Champion Author San Antonio

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Message Posted: Jan 4, 2013 5:20:07 AM

yes
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hornet17
Champion Author Vancouver

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Message Posted: Dec 27, 2012 9:58:17 AM

Love the champion author responses....

back to the original post. Seems to make sense what you have determined. The added extra cost of premium isn't worth the increase in gas mileage, it's a cost analysis and it makes more economical sense to buy the cheaper gas.
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hjl17
Champion Author Toronto

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Message Posted: Dec 27, 2012 9:34:15 AM

yes
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russells350
Champion Author Montreal

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Message Posted: Dec 27, 2012 8:11:55 AM

no
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Buddy2264
Champion Author Tampa

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Message Posted: Dec 27, 2012 5:36:25 AM

If it works for you....
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2Tall
Champion Author Maryland

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Message Posted: Dec 27, 2012 4:41:27 AM

that works
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Boyrr
Champion Author Allentown

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Message Posted: Dec 13, 2012 7:03:08 AM

if you need it
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wshokie12
Champion Author Winston-Salem

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Message Posted: Dec 13, 2012 1:28:48 AM

Use what manual says. No more no less.
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DI
Champion Author Twin Cities

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Message Posted: Dec 9, 2012 12:21:11 AM

It's amazing the number of people who don't read what was written. DerekS wrote "A relative's BMW _recommends_ premium. Another car _recommends_ mid-grade." [emphasis added] so the manual does not say that they are _required_.

My understanding is that manufacturers _recommend_ premium because that's what they use for their testing and it yields slightly better numbers but ones that are only measurable by instruments, not by humans.

Concerning your cost-benefit analysis, that's exactly how you should look at it. Better mileage doesn't necessarily mean lower cost.
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PithyOpiner
Champion Author Stockton

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Message Posted: Dec 8, 2012 8:53:21 PM

You are spot on. Rug is good enough for your car.
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forresj
Champion Author Wilmington

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Message Posted: Nov 22, 2012 11:27:02 AM

If you car doesn't require premium, then use regular. Don't use premium if your car doesn't require it. You're just throwing your money away to the oil fat cats and terrorists. BMW automobiles run better on premium because they have higher compression engines. Check the compression ratio on your car. If the compression ratio is higher than 13.5, then use premium.

Here's some light reading:

http://auto.howstuffworks.com/premium-gas-luxury-vehicles1.htm

....BMW says that regular gasoline is acceptable because nowadays modern engines have "knock sensors". These sensors send a signal to the vehicle's Engine Control Unit (ECU), sometimes called an Engine Control Module (ECM), which then adjusts the engine's timing -- when the spark plugs fire -- to reduce or prevent the knock. Because these sensors are so effective, cars with knock sensors rarely experience engine knock, even when running on regular unleaded gasoline. However, because the timing is slightly adjusted when low-octane fuel is present, the car's performance and fuel efficiency is diminished slightly, too.

Is the loss in performance dramatic enough to notice? For most people, the answer is probably no. According to one estimate, a car running on regular unleaded instead of premium will take about a half a second longer to accelerate from zero to 60 mph (97 kilometers per hour). Unless you're drag racing, it's unlikely that this will matter. Still, it's conceivable that you might find yourself in a situation where that half second just might matter -- merging safely with highway traffic, for instance. So, it's really up to you to decide if this is important.

Some experts claim that the loss in fuel efficiency when using regular gas in a luxury or high-performance car will be so great that it will actually cancel out the savings you get from buying cheaper low-octane gas. This point is debatable, but you should keep it in mind.

Another reason that people use premium unleaded fuel is that they believe it will keep their car's engine cleaner. This is because some fuel companies advertise that they add special detergents to their higher grades of gas. However, U.S. Environmental Protection Agency regulations require that all grades of gas have detergent in them. Yes, the premium grades often have more detergent, but the lower octane fuels can keep your engine clean, too. If you have reason to believe that an unusual amount of buildup has collected in your engine, simply buy a detergent additive at your local auto store and add it to the tank yourself.

So, unless your owner's manual says that your luxury car "requires" premium gas, it isn't going to hurt your car if you don't use it. And regular gas isn't going to have a significant impact on your engine's performance, either. Basically, it's up to you to decide whether the small impact that it does have is worth the extra cost of premium fuel....
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2Tall
Champion Author Maryland

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Message Posted: Nov 21, 2012 11:50:36 AM

Read manual.
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lissyking
Veteran Author Miami

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Message Posted: Nov 20, 2012 10:19:53 AM

According to the manual
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PatAZ
Champion Author Tucson

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Message Posted: Nov 20, 2012 10:00:22 AM

If you own a car that says it requires premium use it. If you try to cut corners by using regular you can't afford to own the car.
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MIT05
Champion Author Massachusetts

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Message Posted: Nov 18, 2012 9:59:18 PM

Use what manual says.
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deporresd
Sophomore Author Illinois

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Message Posted: Nov 18, 2012 9:00:58 PM

I have always followed this rule of thumb. If all things are equal, and the manual says it s acceptable, then use regular. I'd only consider a higher grade if the performance suffers.
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Boyrr
Champion Author Allentown

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Message Posted: Nov 18, 2012 11:45:21 AM

if your machine needs the premium fuel, you need it
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forresj
Champion Author Wilmington

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Message Posted: Nov 18, 2012 10:28:59 AM

If you car doesn't require premium, then use regular. Don't use premium if your car doesn't require it. You're just throwing your money away to the oil fat cats and terrorists. BMW automobiles run better on premium because they have higher compression engines. Check the compression ratio on your car. If the compression ratio is higher than 13.5, then use premium.

Here's some light reading:

http://auto.howstuffworks.com/premium-gas-luxury-vehicles1.htm

....BMW says that regular gasoline is acceptable because nowadays modern engines have "knock sensors". These sensors send a signal to the vehicle's Engine Control Unit (ECU), sometimes called an Engine Control Module (ECM), which then adjusts the engine's timing -- when the spark plugs fire -- to reduce or prevent the knock. Because these sensors are so effective, cars with knock sensors rarely experience engine knock, even when running on regular unleaded gasoline. However, because the timing is slightly adjusted when low-octane fuel is present, the car's performance and fuel efficiency is diminished slightly, too.

Is the loss in performance dramatic enough to notice? For most people, the answer is probably no. According to one estimate, a car running on regular unleaded instead of premium will take about a half a second longer to accelerate from zero to 60 mph (97 kilometers per hour). Unless you're drag racing, it's unlikely that this will matter. Still, it's conceivable that you might find yourself in a situation where that half second just might matter -- merging safely with highway traffic, for instance. So, it's really up to you to decide if this is important.

Some experts claim that the loss in fuel efficiency when using regular gas in a luxury or high-performance car will be so great that it will actually cancel out the savings you get from buying cheaper low-octane gas. This point is debatable, but you should keep it in mind.

Another reason that people use premium unleaded fuel is that they believe it will keep their car's engine cleaner. This is because some fuel companies advertise that they add special detergents to their higher grades of gas. However, U.S. Environmental Protection Agency regulations require that all grades of gas have detergent in them. Yes, the premium grades often have more detergent, but the lower octane fuels can keep your engine clean, too. If you have reason to believe that an unusual amount of buildup has collected in your engine, simply buy a detergent additive at your local auto store and add it to the tank yourself.

So, unless your owner's manual says that your luxury car "requires" premium gas, it isn't going to hurt your car if you don't use it. And regular gas isn't going to have a significant impact on your engine's performance, either. Basically, it's up to you to decide whether the small impact that it does have is worth the extra cost of premium fuel....


[Edited by: forresj at 11/18/2012 10:30:22 AM EST]
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the1roadhog
Champion Author Atlanta

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Message Posted: Nov 18, 2012 8:31:18 AM

If the manny says ok, go for it.
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twt
Champion Author Virginia Beach

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Message Posted: Nov 18, 2012 8:26:33 AM

Whatever works.
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MertieMan
Champion Author Lexington

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Message Posted: Nov 18, 2012 8:14:15 AM

As bad as I hate to admit this, I agree wholeheartedly with Farm Tech.
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2Tall
Champion Author Maryland

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Message Posted: Nov 18, 2012 8:00:46 AM

BMW recommends premium
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Plebe123
Rookie Author Fresno

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Message Posted: Nov 2, 2012 12:25:08 AM

Yes regular the others are too expensive.
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twt
Champion Author Virginia Beach

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Message Posted: Oct 31, 2012 3:52:01 AM

If your vehicle says it will run on either grade and you want to save money, use regular. Is the price of the gas worth 1 mile more per gallon? Duh
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carinthuist
Champion Author San Francisco

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Message Posted: Oct 31, 2012 2:43:30 AM

outstanding
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BIRDlE
Champion Author Omaha

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Message Posted: Oct 30, 2012 11:30:07 PM

yes
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FarmTech
Champion Author Virginia

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Message Posted: Oct 30, 2012 9:47:41 PM

Buy what the Owner's Manual states to use for that vehicle. Period. End of Discussion.

If you can not afford the fuel that vehicle requires, then sell it. Buy a vehicle you can afford.
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forresj
Champion Author Wilmington

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Message Posted: Oct 30, 2012 6:13:45 PM

Do yourself a favor and save a couple of bucks. Use regular if it's fine. Don't help the rich get richer and don't help fund the terrorists.
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MIT05
Champion Author Massachusetts

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Message Posted: Oct 30, 2012 5:35:42 PM

Regular.
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Gas_Buddy
Champion Author Maryland

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Message Posted: Oct 30, 2012 1:45:54 PM

Should you buy regular gas for your car?

I don't know. As for "What do you think about my analysis?", I don't know. Seriously. Buy you, in your original post, already answered your own question.

First you're talking about what the manufacturer of a relative's car recommends, and you say that you had them put in consecutive tankfuls of premium, you drove the car, and you say the car "definitely runs smoother" with premium. Of course you're not telling us anything about your driving or your driving conditions; that is, you didn't say anything about the test "controls" under which you conducted your tests in order to compare the "smoothness" (whatever that means, or how you determined it).

And you didn't say anything about the controls of the test such as who else drove it during your (extended?) testing period. Were you the only test driver? How many test drives/miles driven were there? Were were the test conditions for each test drive? How many fill-ups? Did you start your test with a completely drained fuel tank to begin your testing? And for how many test drives/how many miles did you conduct your tests.

How did you reach your conclusion "use premium for that particular car, but not necessarily all BMWs. Why not? What's your determining criteria to make that statement? As for "It improves smoothness driving up a hill, particularly.", I doubt that you can substantiate your findings. Chances are your foot on the pedal is what determined your hill climbing smoothness, not a fuel octane difference.

As for "The car that recommends mid-grade... The EPA tested... I agree generally." Glad to see the EPA can depend on your testing methods, but I personally doubt that your testing was under the same conditions or as extensive as that of the EPA.

It seems you're saying two different things, or reached two different conclusions. You're saying (about two unidentified vehicles other than one is a relative's BMW of unknown condition) that premium makes one drive "smoother" and the other gets better fuel economy using premium but you want to save money so you recommend using (for this unknown vehicle) regular gas. Apparently "smoothness" has nothing to do with the second vehicle.

The bottom line, to me, I don't think very much of your analysis because didn't analyze. You and the cars did some random things, or had random results.

To go back to your original question, the topic title "Should I buy regular gas for my car?", I don't know. You said you tested a relative's car; tell us more about YOUR car. Or are you looking to drive your relative's car full time? Or, are you looking to save money at the pump. If you're looking for maximum performance (based on what the manufacturer built the vehicle to do, then follow the dealer's recommendation for fuel; use premium or mid-grade (respectively). If you're looking to save money, and you're not as concerned about optimum performance (based on dealer recommendations), then use the lower grade of octane.

Not asking you to agree or disagree, what do you think about my analysis?
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ace12012
Champion Author Phoenix

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Message Posted: Oct 30, 2012 1:15:52 PM

no reason for me to buy premium.
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Commute2
Champion Author District of Columbia

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Message Posted: Oct 30, 2012 12:25:48 PM

No get premium
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PatAZ
Champion Author Tucson

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Message Posted: Oct 30, 2012 11:14:18 AM

My BMW and others call for premium, I would not run anything but that in it.
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MertieMan
Champion Author Lexington

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Message Posted: Oct 30, 2012 5:39:12 AM

A BMW would mostly likely have to have premium gas.
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olympusman2004
Champion Author Maryland

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Message Posted: Oct 30, 2012 4:27:49 AM

YES
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Dreamer4one5
Sophomore Author Amarillo

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Message Posted: Oct 30, 2012 4:09:07 AM

Our 2005 Silverados manufacturer recommended minimum octane rating is 87 (regular). However, running on "regular" the truck develops a range of ticks/pings and knocks. Not to mention condensation dripping from the exhaust pipe, rough idle and horrible hesitation when accelerating. My conclusion from our experience, Nothing less than 89 Minimum (and that's only in emergency). Under "normal" circumstances, we use 90-93 Octane (minimal or NO ethanol).

Cleaning and repairing the mess and deterioration that regular fuel causes is not worth the savings at the pump. The cost of using premium fuel saves us money in the long run.

Regular @ $3.31/G x 22 Gallons = 72.82
Premium @ $3.64/G x 22 Gallons = 80.08

That's a difference of $7.26. Small savings/big compromise.
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diesdown
Champion Author North Carolina

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Message Posted: Oct 29, 2012 7:08:54 PM

I would not run 87 oct in a BMW or Mercedes gas vehicle.
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gasscout_1
Veteran Author Grand Rapids

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Message Posted: Oct 29, 2012 6:53:54 PM

Yes unless your manual says Premium.
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TrixieNY
Champion Author Buffalo

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Message Posted: Oct 29, 2012 6:36:35 PM

Yes or No
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ster12
Rookie Author Wisconsin

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Message Posted: Oct 29, 2012 5:48:31 PM

Its best to use what is recommended for your car on the other hand if you have a car with a carburetor i would run the high octane because the ethanol eats away at the o-rings. Also with the ethanol you will notice that the co-2 sensor will get clogged faster.
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rxpx40
Veteran Author Austin

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Message Posted: Oct 29, 2012 3:57:18 PM

Use the octane rating recommended by the manufacturer. BMW's typically have a higher compression ratio. If you don't know what that is- google is your friend. My BMW motorcycle requires min 91 octane. Usually that is premium where. At best I can find 93 octane. If your car has a low compression ratio you would be only throwing money away by running high octane fuel. If your car is turbo-charged, you must go with higher octane rating lest you risk damaging major engine components, including the turbo.
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2004VHO
Champion Author Texas

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Message Posted: Oct 29, 2012 3:49:49 PM

I would run the premium if it were my car.

Sure you might save $4.50 of a tank full of gas, but you will loose much more than that in fuel economy & engine performance by running the "cheeper" octane gas....

Next time, buy a car that has an engine NOT requiring premium fuel.
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