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Author	Topic: Should I buy regular gas for my car?	Post a Reply Back to Topics

DerekS Champion Author Seattle Posts:3,751 Points:685,025 Joined:Mar 2008	Message Posted: Oct 29, 2012 3:41:41 PM Ignore DerekS Report Abuse 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]

DerekS

Champion Author
Seattle

Posts:3,751
Points:685,025
Joined:Mar 2008

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

Ignore DerekS Report Abuse

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)Ignore Short Messages

priceguy Champion Author Bakersfield Posts:12,836 Points:3,353,275 Joined:Sep 2003	Message Posted: Jan 4, 2013 3:39:33 PM Ignore priceguy Report Abuse y
2Tall Champion Author Maryland Posts:12,814 Points:2,945,380 Joined:Jun 2004	Message Posted: Jan 4, 2013 10:49:13 AM Ignore 2Tall Report Abuse yes
BUSSY Champion Author Dallas Posts:9,922 Points:1,544,415 Joined:Oct 2006	Message Posted: Jan 4, 2013 7:47:19 AM Ignore BUSSY Report Abuse See what you stirred up DerekS?
RNF Champion Author Indiana Posts:7,114 Points:2,876,870 Joined:Jun 2004	Message Posted: Jan 4, 2013 6:39:37 AM Ignore RNF Report Abuse 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.
Boyrr Champion Author Allentown Posts:15,196 Points:3,166,805 Joined:May 2004	Message Posted: Jan 4, 2013 6:00:51 AM Ignore Boyrr Report Abuse yup
MIT05 Champion Author Massachusetts Posts:4,182 Points:1,394,250 Joined:Aug 2008	Message Posted: Jan 4, 2013 5:23:36 AM Ignore MIT05 Report Abuse Regular.
TXBruin All-Star Author San Antonio Posts:682 Points:465,525 Joined:Sep 2011	Message Posted: Jan 4, 2013 5:20:07 AM Ignore TXBruin Report Abuse yes
hornet17 Champion Author Vancouver Posts:1,323 Points:440,865 Joined:Aug 2011	Message Posted: Dec 27, 2012 9:58:17 AM Ignore hornet17 Report Abuse 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.
hjl17 Champion Author Toronto Posts:2,844 Points:616,520 Joined:Jul 2011	Message Posted: Dec 27, 2012 9:34:15 AM Ignore hjl17 Report Abuse yes
russells350 Champion Author Montreal Posts:2,896 Points:608,245 Joined:Apr 2008	Message Posted: Dec 27, 2012 8:11:55 AM Ignore russells350 Report Abuse no
Buddy2264 Champion Author Tampa Posts:11,674 Points:2,363,970 Joined:Oct 2005	Message Posted: Dec 27, 2012 5:36:25 AM Ignore Buddy2264 Report Abuse If it works for you....
2Tall Champion Author Maryland Posts:12,814 Points:2,945,380 Joined:Jun 2004	Message Posted: Dec 27, 2012 4:41:27 AM Ignore 2Tall Report Abuse that works
Boyrr Champion Author Allentown Posts:15,196 Points:3,166,805 Joined:May 2004	Message Posted: Dec 13, 2012 7:03:08 AM Ignore Boyrr Report Abuse if you need it
wshokie12 Champion Author Winston-Salem Posts:1,335 Points:219,485 Joined:Aug 2012	Message Posted: Dec 13, 2012 1:28:48 AM Ignore wshokie12 Report Abuse Use what manual says. No more no less.
DI Champion Author Twin Cities Posts:20,208 Points:4,151,385 Joined:Apr 2001	Message Posted: Dec 9, 2012 12:21:11 AM Ignore DI Report Abuse 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.
PithyOpiner Champion Author Stockton Posts:16,220 Points:1,599,495 Joined:Jun 2008	Message Posted: Dec 8, 2012 8:53:21 PM Ignore PithyOpiner Report Abuse You are spot on. Rug is good enough for your car.
forresj Champion Author Wilmington Posts:2,800 Points:546,180 Joined:May 2005	Message Posted: Nov 22, 2012 11:27:02 AM Ignore forresj Report Abuse 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....
2Tall Champion Author Maryland Posts:12,814 Points:2,945,380 Joined:Jun 2004	Message Posted: Nov 21, 2012 11:50:36 AM Ignore 2Tall Report Abuse Read manual.
lissyking Veteran Author Miami Posts:400 Points:124,890 Joined:Oct 2012	Message Posted: Nov 20, 2012 10:19:53 AM Ignore lissyking Report Abuse According to the manual
PatAZ Champion Author Tucson Posts:9,253 Points:122,460 Joined:May 2008	Message Posted: Nov 20, 2012 10:00:22 AM Ignore PatAZ Report Abuse 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.
MIT05 Champion Author Massachusetts Posts:4,182 Points:1,394,250 Joined:Aug 2008	Message Posted: Nov 18, 2012 9:59:18 PM Ignore MIT05 Report Abuse Use what manual says.
deporresd Sophomore Author Illinois Posts:183 Points:140,220 Joined:May 2008	Message Posted: Nov 18, 2012 9:00:58 PM Ignore deporresd Report Abuse 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.
Boyrr Champion Author Allentown Posts:15,196 Points:3,166,805 Joined:May 2004	Message Posted: Nov 18, 2012 11:45:21 AM Ignore Boyrr Report Abuse if your machine needs the premium fuel, you need it
forresj Champion Author Wilmington Posts:2,800 Points:546,180 Joined:May 2005	Message Posted: Nov 18, 2012 10:28:59 AM Ignore forresj Report Abuse 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]
the1roadhog Champion Author Atlanta Posts:9,913 Points:2,058,530 Joined:Jun 2007	Message Posted: Nov 18, 2012 8:31:18 AM Ignore the1roadhog Report Abuse If the manny says ok, go for it.
twt Champion Author Virginia Beach Posts:8,756 Points:1,000,560 Joined:Mar 2005	Message Posted: Nov 18, 2012 8:26:33 AM Ignore twt Report Abuse Whatever works.
MertieMan Champion Author Lexington Posts:14,803 Points:2,898,535 Joined:May 2005	Message Posted: Nov 18, 2012 8:14:15 AM Ignore MertieMan Report Abuse As bad as I hate to admit this, I agree wholeheartedly with Farm Tech.
2Tall Champion Author Maryland Posts:12,814 Points:2,945,380 Joined:Jun 2004	Message Posted: Nov 18, 2012 8:00:46 AM Ignore 2Tall Report Abuse BMW recommends premium
Plebe123 Rookie Author Fresno Posts:42 Points:32,230 Joined:Oct 2012	Message Posted: Nov 2, 2012 12:25:08 AM Ignore Plebe123 Report Abuse Yes regular the others are too expensive.
twt Champion Author Virginia Beach Posts:8,756 Points:1,000,560 Joined:Mar 2005	Message Posted: Oct 31, 2012 3:52:01 AM Ignore twt Report Abuse 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
carinthuist Champion Author San Francisco Posts:2,262 Points:333,075 Joined:Mar 2012	Message Posted: Oct 31, 2012 2:43:30 AM Ignore carinthuist Report Abuse outstanding
BIRDlE Champion Author Omaha Posts:1,093 Points:1,600,190 Joined:Nov 2005	Message Posted: Oct 30, 2012 11:30:07 PM Ignore BIRDlE Report Abuse yes
FarmTech Champion Author Virginia Posts:12,176 Points:2,297,835 Joined:May 2006	Message Posted: Oct 30, 2012 9:47:41 PM Ignore FarmTech Report Abuse 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.
forresj Champion Author Wilmington Posts:2,800 Points:546,180 Joined:May 2005	Message Posted: Oct 30, 2012 6:13:45 PM Ignore forresj Report Abuse 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.
MIT05 Champion Author Massachusetts Posts:4,182 Points:1,394,250 Joined:Aug 2008	Message Posted: Oct 30, 2012 5:35:42 PM Ignore MIT05 Report Abuse Regular.
Gas_Buddy Champion Author Maryland Posts:25,991 Points:3,036,990 Joined:Aug 2004	Message Posted: Oct 30, 2012 1:45:54 PM Ignore Gas_Buddy Report Abuse 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?
ace12012 Champion Author Phoenix Posts:1,680 Points:326,860 Joined:Apr 2012	Message Posted: Oct 30, 2012 1:15:52 PM Ignore ace12012 Report Abuse no reason for me to buy premium.
Commute2 Champion Author District of Columbia Posts:1,163 Points:88,035 Joined:Sep 2005	Message Posted: Oct 30, 2012 12:25:48 PM Ignore Commute2 Report Abuse No get premium
PatAZ Champion Author Tucson Posts:9,253 Points:122,460 Joined:May 2008	Message Posted: Oct 30, 2012 11:14:18 AM Ignore PatAZ Report Abuse My BMW and others call for premium, I would not run anything but that in it.
MertieMan Champion Author Lexington Posts:14,803 Points:2,898,535 Joined:May 2005	Message Posted: Oct 30, 2012 5:39:12 AM Ignore MertieMan Report Abuse A BMW would mostly likely have to have premium gas.
olympusman2004 Champion Author Maryland Posts:1,686 Points:372,705 Joined:Apr 2012	Message Posted: Oct 30, 2012 4:27:49 AM Ignore olympusman2004 Report Abuse YES
Dreamer4one5 Sophomore Author Amarillo Posts:158 Points:103,480 Joined:Sep 2011	Message Posted: Oct 30, 2012 4:09:07 AM Ignore Dreamer4one5 Report Abuse 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.
diesdown Champion Author North Carolina Posts:1,700 Points:514,500 Joined:May 2011	Message Posted: Oct 29, 2012 7:08:54 PM Ignore diesdown Report Abuse I would not run 87 oct in a BMW or Mercedes gas vehicle.
gasscout_1 Veteran Author Grand Rapids Posts:334 Points:111,440 Joined:Jun 2012	Message Posted: Oct 29, 2012 6:53:54 PM Ignore gasscout_1 Report Abuse Yes unless your manual says Premium.
TrixieNY Champion Author Buffalo Posts:2,703 Points:656,800 Joined:Apr 2008	Message Posted: Oct 29, 2012 6:36:35 PM Ignore TrixieNY Report Abuse Yes or No
ster12 Rookie Author Wisconsin Posts:9 Points:7,010 Joined:Oct 2012	Message Posted: Oct 29, 2012 5:48:31 PM Ignore ster12 Report Abuse 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.
rxpx40 Sophomore Author Austin Posts:242 Points:89,485 Joined:May 2004	Message Posted: Oct 29, 2012 3:57:18 PM Ignore rxpx40 Report Abuse 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.
2004VHO Champion Author Texas Posts:5,236 Points:1,405,325 Joined:Aug 2005	Message Posted: Oct 29, 2012 3:49:49 PM Ignore 2004VHO Report Abuse 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.