difference between 87 and 91 unleaded
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From: LA, CA
difference between 87 and 91 unleaded
does it matter if you use 87 or 91 on the E class or C class and do you notice the difference in performance? I drive 2 cars so I spend about $50+ a week on gas and gas in Ca is very expensive lately.
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Which model year cars do you have? If your cars do not have knock sensors and are not able to adjust to lower octane fuels, you could damage your engines.
Is there a difference in performance? Well, in my experience when I'm able to travel outside local areas that have only 91 octane, I find that 93 octane fuel provides noticeable better fuel economy and better performance.
I just spoke to my brother-in-law who has a Ford mini-van and he told me he gets better performance and fuel economy with 89 octane fuel over 87 octane fuel. This is with a vehicle which is supposed to use regular fuel.
I don't know what model year Mercedes are able to adjust to lower octane fuels but I'd say it's newer than 1992.
Is there a difference in performance? Well, in my experience when I'm able to travel outside local areas that have only 91 octane, I find that 93 octane fuel provides noticeable better fuel economy and better performance.
I just spoke to my brother-in-law who has a Ford mini-van and he told me he gets better performance and fuel economy with 89 octane fuel over 87 octane fuel. This is with a vehicle which is supposed to use regular fuel.
I don't know what model year Mercedes are able to adjust to lower octane fuels but I'd say it's newer than 1992.
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From: Boston
'05 A4 1.8TQM6
Answer is yes and no to harming your engine.
Yes, being if your car is older and has no knock sensors and computer programming to handle the lower fuel.
No, if your MB is more recent (92-93+?). There are computer systems inside the car now that automatically adjust to what type of fuel you put in, so no worries about damaging the car. The only difference in performance is that it may lose a few HP which you will not notice. An MB spokes person said "if you do not use premium in our cars, you will not achieve the car's listed performance figures".
There was an article on USA Today about fuel and the differences. If your car was made for regular and you put premium, you may actually do more damage to the car than good because there is no performance gain on that car by using premium and it is harder to ignite than regular fuel. They also pointed out that cars now have computers that adjust/compensate for the lower grade fuel and automatically adjusts to the fuel that you put in for timing and detonation. So no damage will be done.
I know gas can be expensive...I wouldn't go so low as regular (87), but 89 (middle grade --> "special" as most stations call it) or 91 will be fine for your car. I think 87 is too low, so it's either 89 or 91.
Yes, being if your car is older and has no knock sensors and computer programming to handle the lower fuel.
No, if your MB is more recent (92-93+?). There are computer systems inside the car now that automatically adjust to what type of fuel you put in, so no worries about damaging the car. The only difference in performance is that it may lose a few HP which you will not notice. An MB spokes person said "if you do not use premium in our cars, you will not achieve the car's listed performance figures".
There was an article on USA Today about fuel and the differences. If your car was made for regular and you put premium, you may actually do more damage to the car than good because there is no performance gain on that car by using premium and it is harder to ignite than regular fuel. They also pointed out that cars now have computers that adjust/compensate for the lower grade fuel and automatically adjusts to the fuel that you put in for timing and detonation. So no damage will be done.
I know gas can be expensive...I wouldn't go so low as regular (87), but 89 (middle grade --> "special" as most stations call it) or 91 will be fine for your car. I think 87 is too low, so it's either 89 or 91.
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More modern Mercedes sold in the US are designed for a minimum octane rating of 91. It can use higher octane w/o a problem.
There is another thing that people don't talk about and that is additives. When I drove BMW's, they told me to use Amoco premium because it had additives that would keep the valve train clean. I was also told that the lower octane versions of Amoco did not have the amount of additives that the premium fuels had.
I know that American and some Japanese car manufacturer's approve of using 87 octane fuel but all you have to do is hang around a gas station in one of our Arizona summers to hear these cars ping like the devil.
Stick with 91 octane fuel. The additional cost of higher octane fuel is peanuts compared to having to buy a new car or even to repair your old one.
There is another thing that people don't talk about and that is additives. When I drove BMW's, they told me to use Amoco premium because it had additives that would keep the valve train clean. I was also told that the lower octane versions of Amoco did not have the amount of additives that the premium fuels had.
I know that American and some Japanese car manufacturer's approve of using 87 octane fuel but all you have to do is hang around a gas station in one of our Arizona summers to hear these cars ping like the devil.
Stick with 91 octane fuel. The additional cost of higher octane fuel is peanuts compared to having to buy a new car or even to repair your old one.
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From: Chicago Western Burbs
'06 SL65
As mentioned above....lower octane can cause Pinging and KR (Knock Retard). I had pinging/KR in my other car after engine work as it wasn't fully tuned so I would always put racing gas every other fill up.
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From: Boston
'05 A4 1.8TQM6
This is a discussion that is never gonna end with one winner :p
everyone has their own views on octane/fuel for their car. Really, do what you'd like and don't take what you see on the boards as "must do" but as a possible reasoning or thought.
I usually fill up with 91 (93 here in MA), but 89 will not harm the engine.
everyone has their own views on octane/fuel for their car. Really, do what you'd like and don't take what you see on the boards as "must do" but as a possible reasoning or thought.
I usually fill up with 91 (93 here in MA), but 89 will not harm the engine.
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From: WOT somewhere in the Bay Area
1951 Caterpiller D6
Originally posted by GDawgC220
There was an article on USA Today about fuel and the differences. If your car was made for regular and you put premium, you may actually do more damage to the car than good because there is no performance gain on that car by using premium and it is harder to ignite than regular fuel. They also pointed out that cars now have computers that adjust/compensate for the lower grade fuel and automatically adjusts to the fuel that you put in for timing and detonation. So no damage will be done.
There was an article on USA Today about fuel and the differences. If your car was made for regular and you put premium, you may actually do more damage to the car than good because there is no performance gain on that car by using premium and it is harder to ignite than regular fuel. They also pointed out that cars now have computers that adjust/compensate for the lower grade fuel and automatically adjusts to the fuel that you put in for timing and detonation. So no damage will be done.
The first part of this statement is 100% false. 91 octane is no harder to ignite than 87 and will not cause engine damage. In fact, the opposite is usually true since higher octane fuel usually contains more volitile aromatics to get the higher rating.
The second part is unclear at the very least. If your late model computer controlled car is designed to achieve maximum performance with 91 octane, there will be no benefit from running 94. If you choose to run 87, the computer will automatically adjust engine parameters to compensate for the lower grade fuel. Does this mean that no engine damamge can occur? Not exactly. Under extreme conditions such as high heat and load, the engine may not be able to compensate enough and destructive detonation can still be present.
Ho can you tell what grade of fuel is optimum? The one that gives you the best fuel mileage.
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I think the current BMW V8's are designed to run on 97 octane (or something like that) but can accomodate octane ratings down to 91. My '91 300E cannot adapt to engine knock so I use premium fuel.
Here in Arizona, the difference in price between 91 and 89 octane is $.20. If you drive 10,000 miles a year at an average of 18 miles per gallon, you'll save $111. You pays your money and you take your choice.
Now then if you look at the overall cost of car ownership, there are two things that overwhelm all other costs...depreciation and the cost of money. What that means is that the longer you can drive a car, the more money you save. Just the difference in the cost of annual license plates here in Arizona between my current car and a new E-Class is $700. That'll pay for a lot of premium gasoline and synthetic oil
Here in Arizona, the difference in price between 91 and 89 octane is $.20. If you drive 10,000 miles a year at an average of 18 miles per gallon, you'll save $111. You pays your money and you take your choice.
Now then if you look at the overall cost of car ownership, there are two things that overwhelm all other costs...depreciation and the cost of money. What that means is that the longer you can drive a car, the more money you save. Just the difference in the cost of annual license plates here in Arizona between my current car and a new E-Class is $700. That'll pay for a lot of premium gasoline and synthetic oil
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