I was filling up premium to my Volvo even when 20 cents price difference made 25%.
Driving often in the mountains I even used Premium in cars design for Regular. With premium struggling on steep slopes the car didn't have to downshift, giving not only much better performance but also fuel savings.
Kajtek1, you make an excellent point. Back when gas was $1.50 a gallon it arguably made more sense to try and "skimp/save" by running regular instead of premium since the percentage increase was roughly 13-14% of the bill. Now that gas is three times that much, the cost savings is minimal.
Indeed, for those with adaptive cars that can recognize and adapt to higher octane (but don't require it), the improvement in fuel economy might in reality make premium a smarter buy for such folks.
Another way to look at this: you save $3 on a tankful of gas, which equates to roughly 20 miles of driving. By watching how you drive and keeping your tires properly inflated (and your car otherwise maintained) you can save more than that through increased fuel economy.
Or you can cut out one latte a week.
Take care and enjoy the ride,
Greg
__________________ If the only prayer you say in your life is thank you, that would suffice. Meister Eckhart
When you learn from your own mistakes, that's experience.
When you learn from the mistakes of others, that's wisdom.
When you fail to learn from any mistakes, that's government.
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.
Quote:
Originally Posted by ozcan
So, in short we need to s t i c k to the recommended octane which is premium.
Our standard RON over here is 95 and costs $6.43 per us gallon . We can also get E 5 , 95 % petrol and 5% bio , it has a RON of 99 and costs the same about $6.43
You can find articles on anything, including "proof" that the CIA blew up the WTC towers.
It is almost always dangerous to apply general principles to specific situations.
You can do whatever you want to your car, but suggesting the same to others is foolhardy. You going to be paying for their repairs? Not a chance, and neither is the NYT or USA Today.
Here's the other half of the article that is left out: Why use regular gas when it WON'T do?
Here ya go (2). See a pattern ?
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On the one hand, we have our BW experts.
On the other, here is a relevant article from PopMech.
Besides having Premium and Regular we do have in US gasoline and the stuff they sell in California. I am not even talking about 98 octanes available in other countries. The watery stuff sold in California is one of the reasons why I decided to buy diesels.
At least I don't have the problems you guys do
Our only gasser -ML55AMG will be running on Premium. I think our son do the same in his ML320
The problem is that the knock sensor cannot handle everything.
Premium resists preignition, meaning that the edge gasses resist spontaneous combustion by pressure alone, before being hit by the flame front.
There are several ways that engines can reduce the pressure, but it does come down to lowering the power output.
If you reduce the pressure by delaying the spark (which used to be the only method), you increase the heat at your exhaust valves. A full-throttle run could cause you to lose a valve.
A better method would be to alter the camshaft timing to reduce the maximum cylinder pressure. But this will also result in reduced engine efficiency.
The best method would be to alter the combustion chamber size, directly affecting the compression ratio. I do not know of any modern engines with this capability.
Here ya go (2). See a pattern ?
---------------------------------
On the one hand, we have our BW experts.
On the other, here is a relevant article from PopMech.
Again, applying general principles to specifics is not always the best way to proceed.
And again, if you want to experiment with your own car, you can also buy really cheap oil (or never change it at all), buy your generic brake pads at Kragen and put in dot 3 brake fluid, all while never changing the AT fluid or coolant, either. And Pep boys is running their "buy three get one free" tire sale, too (load ratings are meaningless anyway). But...suggesting others follow such poor examples is really, really bad form.
The problem is that the knock sensor cannot handle everything.
Premium resists preignition, meaning that the edge gasses resist spontaneous combustion by pressure alone, before being hit by the flame front.
There are several ways that engines can reduce the pressure, but it does come down to lowering the power output.
If you reduce the pressure by delaying the spark (which used to be the only method), you increase the heat at your exhaust valves. A full-throttle run could cause you to lose a valve.
A better method would be to alter the camshaft timing to reduce the maximum cylinder pressure. But this will also result in reduced engine efficiency.
The best method would be to alter the combustion chamber size, directly affecting the compression ratio. I do not know of any modern engines with this capability.
Matt L, your comment about varying combustion chamber size reminded me of the old Honda CVCC engine with the (kind of) dual chamber setup. Worked really well -- until it didn't.
And actually, the real problem is not engine design, knock sensors or anything else related to the car. Rather, the real problem is human: some people will buy a silk purse and treat it like a sow's ear. Such nonsense is also referred to as penny-wise and pound foolish (or actually, perhaps it's just plain foolishness). There are lots of ways one can choose to save money, and not all of them require abusing your vehicle. So why people choose that one is beyond me.
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