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Maintenance & Repair What about fuel types & gas mileage?
281 messages, Last post on Sep 22, 2009 at 3:52 PM
You are in the Maintenance & Repair Forum. Your Host is mr_shiftright
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Replying to: kvngwynth (Jun 15, 2005 12:46 pm) Believe it or not, the designers of modern automobile engines understand the combustion process quite well, and they are very adept at developing engines that operate properly on certain grades of fuel. If your car has a fuel recommendation of Regular, then Regular is what you should be using. Period, full stop, then end. By using fuel with a higher octane rating in said car, you will be reducing your fuel economy, reducing your power and reducing your wallet in similar proportions. Best Regards, Shipo |
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Replying to: shipo (Jun 15, 2005 12:59 pm)  Dear Shipo... Not wanting to rain on your parade either... but... HOW COME THEN ALL MY CARS THAT HAD POWER PROBLEMS WHEN I BOUGHT THEM USED WITH A TANK FULL OF STANDARD GAS LOST MORE THAN 75% OF THEIR POWER PROBLEMS WHEN I CHANGED THE GAS TO PREMIUM?  And they lost all their "knocking" problems if any. So it seems that "they", the cars do love premium better? They simply run smoother... By the way, just my two cents, if a used car already pings constantly either don't buy it or be prepared to do real doctoring on the car.  1974 Renault 12 TL 1982 Toyota Celica XT Coupe with the 22R engine 1989 Suzuki Corsica 1991 BMW 5 series 1989 Nissan Sentra Coupe, "special" engine 1995 Saturn SC2  Logically all your arguements do make sense technically 'tho. But IMHO I think you have just forgotten that older cars need better gas... The newer the car, the better the condition all the components are still in so the lesser octane boost it needs to run as well as an older car using higher octane. Hence thus... It is just like choosing between butter and margarine. True margarine is lower in fat, etc. but true butter does make a lot of things simply taste better when cooked or baked with it compared when cooked or baked with margarine... Ironically when you have to do with a lesser, older car, the best you can do is to make the best out of the car, thereby making the best out of the whole situation for yourself. Like who wouldn't love the 4 dollars loaf of wheat bread... a lil margarine on it already tastes fine. But when you gotta do with the 1 dollar loafs of bread... a lil butter instead of the margarine helps a lot again. Now the difference between a 4 dollars loaf of bread and a 1 dollar loaf of bread is small, but try comparing a 25,000 dollars car with the 3,000 dollars car...  Still, I know you probably mean well with your advise to all the others on here, so be safe, be happy okay? Sincerely, Gwyneth
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Replying to: kvngwynth (Jun 15, 2005 1:58 pm) Your anecdotal evidence not withstanding, I stand by my statements. The fact is that if any of the cars that you listed (other then the BMW 5-Series, which regardless of the engine it was equipped with, required Premium fuel) needed Premium fuel contrary to the Owner's manual to run smoothly, then there was something else wrong with the car. There can be many reasons why an older engine "seems" to require Premium, not the least of which is because the owner "thought" they were doing their engine a favor by using Premium fuel in the first place. All that will accomplish is to cause combustion chamber deposits to build up to the point where the car won't run well without it. It's sort of like a self fulfilling prophecy. Another reason older engines might seem to need premium is if the ignition timing is off a few degrees, which can be caused by worn timing chains or belts and/or bad or non existent service. The fact remains that if an engine was designed to run on a specific fuel and doesn't, then there are problems that need to be addressed. Using Premium fuel is essentially a "Band-Aid" and will only delay (but not eliminate) the point where said problems will need to be addressed. Sooner or later repairs will be necessary and when that point is finally reached, the cost of remediation is likely to be much higher than if the owner had just bitten the bullet in the first place and gotten the engine fixed when the problem first became evident. Now, if I had an old beater that I was planning to junk in the very near future, and it pinged heavily without Premium fuel, then I too might well be inclined to nurse it along with Premium fuel just long enough to get it to its appointment with the bone yard. By the way, what is a "1989 Nissan Sentra Coupe, "special" engine"? I can find no reference to it anywhere on the internet. Could said "special engine" been a custom modified mill? If so, then it comes as no surprise that it would require a higher octane fuel than was called for in the manual. Best Regards, Shipo |
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Replying to: kvngwynth (Jun 15, 2005 1:58 pm) But actually there could have been many explanations for the "change", from purely perceptual to other environmental or physical factors. As this relates to cars, for instance, your car will always run better on a rainy day or a colder day; also, if you are adding something for "power" you will unconsciously press harder on the gas. You may also change brands of gas while searching for the best price for your premium fuel. So there are four new causes and effect that have nothing to do with octane rating directly. If your engine isn't designed to use premium fuel it won't do it a bit of good. Automotive physics doesn't seem to care about our opinions, it just does what it does. However, having said all this, if one of your cars had a pinging problem, then adding premium certainly would help it, as the premium fuel burns more evenly, thereby alleviating the reason for pinging (the ragged flame front). But if your car wasn't pinging, then your knock sensor will set your timing for the type of fuel it was designed for. If the engineers built your car to run on 87 and didn't allow for timing advance, then premium fuel won't give you any difference in performance. But if say your engine were built to tolerate just a touch of knock at 87 octane, it may very well allow a timing bump when you put in 91 octane, and you'll notice an improvement.
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Replying to: Mr_Shiftright (Jun 15, 2005 3:40 pm) The Accord discussion has people who say that the factory states the V6 with variable valve timing will give increased horsepower on premium fuel. I don't want to start a battle here, but I'd also read and heard another mechanic state that the higher deposites are a problem. The first mechanic probably has mostly up-to-date, well-maintained motors, although some vehicles have higher mileage on them. I also wonder if his driving style is heavy to the metal and that helps keep the combustion chambers cleaned out... Myself my Buick 3800s have run well on regular and I occasionally mix in a fillup of plus and don't really notice any difference. I use brand name fuels only. I add Techron about every 20K and do note a difference when that's in the tank. |
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I have just found the wonderful forum, and I have gone back and read to '03. About 8 months ago and 8000 miles ago I added a fuel additive that was invented in '87 by a chemist in my town. It was given to me as a gift and the inventor said that my car would never ever be the same again. I tried it and the results were unbelievable! RIGHT AWAY, 20% better fuel savings and the car runs and sounds better. I know if I were reading this I would be rolling my eyes too! I was so convinced about the additive I have since talked 12 people in my circle of friends to try it. All are floored at the difference. The oil almost stays an "ale" color and doesn't get dark. My uncle tried it in his tractor trailor and is getting 14% better and putting on massive mileage. If anyone is interested reply and I will steer you to the guys phone number.
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| The mixture goes in your crank case not in your tank. The performance didn't seem to go back to it's old ways after i dropped the old oil, the engine is different. The guy is in talks with huge oil companys for doing testing so dont be so sure that you woin't be seeing it in your local wal-mart very soon. | |
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Replying to: russshp (Jun 15, 2005 11:19 pm) I'm continually amazed that folks think that by adding an oil additive to their car they can achieve a significant improvement in fuel economy. The fact remains that once an engine has been started and is up to normal operating temperatures, the engine runs with very near zero internal friction. If it didn't, it wouldn't last more than a few trips to the grocery store, much less the couple of hundred thousand miles most engines are capable of. Best Regards, Shipo
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Replying to: shipo (Jun 16, 2005 3:57 am)
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Replying to: russshp (Jun 16, 2005 6:35 am) Sorry, until I see some hard science, I ain't interested. Best Regards, Shipo |
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