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If you hear a vehicle knock and ping and generally run rough, it is usually due to the a/f being detonated by compression forces, not by the spark plug firing. Basically the engine starts firing out of whack.
If you hear knocking and pinging- you can try a move up to a higher octane rating to see if it eliminates it. Better yet- if you own a modern car and you hear knocking and pinging AND have been using the recommended octane rating of fuel in your car- it's best to have a mechanic check you car, specifically the knock detector system (if so equipped). This system should retard the timing of the vehicle to eliminate the problem.
If you think that using a higher octane fuel is going to get you better mileage- well your plain wrong. If you claim your vehicle DOES get better mileage from higher octane fuel, maybe you should switch BRANDS of fuel and stick to your recommended octane rating. Chances are your vehicle may not like the additives in a certain brands fuel mix.
If your car is designed to run on regular gas, buying higher octane gas won't increase your mileage because the car will not adjust its timing to take advantage of that higher octane.
Regardless of brand, my Porsche gets better mileage on higher octane gas.
So the answer continues to be, it depends upon your car.
Everyone has already covered the correct answer. If you're car is rated to take a grade then stick to it, anything else could potentially be an issue. I drive a vehicle that requires premium gas, that of course will differ station to station. Some stations consider 91 Octane as Premium, while some will have 93 Octane. I prefer the 93, but do not notice a difference between 91. I have never used anything other than premium in my car.
I have driven my 97 Nissan pathfinder (owners manual says to use 87 octane fuel) from my PA house to my Florida keys house quite a few times. It's 1292 miles each way the route I travel. I know that using 92 octane makes the engine run slightly quieter upon acceleration. it doesn't knock and ping like it does with the 87 octane. My mechanic buddy told me using 92 octane would get me better mileage. driving around town i did not notice a difference. on a hunch I decided to test this out on a long trip.I used regular 87 octane gas on the way down to my my fl keys house. I purposely filled up a the exact same gas stations starting out and also along the route and also at the end. I followed the same route and stop at the same stops and do all of the drive with cruise control set at 4 mph over the speed limit. I made sure to leave at times to avoid the Washington DC traffic. I pack my own food so I only stop at the gas stations for gas and bathroom breaks to make the run as quick as possible. The drive home was exactly 1.1 miles and 32 minutes longer then the drive down due to a traffic detour on the way home. I had maybe 100 less pounds of weight in the vehicle on the ride home. I checked the air multiple times throughout the trip with no negligible difference in pressure between when i left and arrived back in PA. I was amazed to after adding up my gas receipts that I used 3.77 less gallons of fuel on the way home then I did on the way down. In the case of my pathfinder on a long haul highway trip it definitely gets better gas mileage using 92 octane. Overall it cost me more for the 92 octane gas on the way home even though I used less so i will stick with 87 octane and deal with the knock and pinging at acceleration only cause it save me money in long haul.
In My Humble Opinion, If your vehicle uses 87 and you are pining, you have a potential vehicle issue. Pinging isn't good, depending on how bad it is can damage your valves/pistons/block. So if higher octane gas fixes it, it is probably cheaper over the long haul than rebuilding the motor... Granted I have driven motors with a slight ping for tens of thousands of miles without an issue - pinging also robs you of power, which is probably why the higher octane, non-pinging fuel, gives you better mileage, if effect, your vehicle now "requires" or is "recommended" that you use higher octane fuel.
If your car is designed to run on regular gas, buying higher octane gas won't increase your mileage because the car will not adjust its timing to take advantage of that higher octane.
Regardless of brand, my Porsche gets better mileage on higher octane gas.
So the answer continues to be, it depends upon your car.
no, the answer is no. If you lose lower octane than the recommended grade, you get LOWER mileage. There is a difference. If octane increased fuel economy why don't we all load our cars up with 100 octane?
no, the answer is no. If you lose lower octane than the recommended grade, you get LOWER mileage. There is a difference. If octane increased fuel economy why don't we all load our cars up with 100 octane?
Would that give me better mileage? Nope.
where can you buy 100 octane? I want some!! I am positive my nissan pathfinder would get moderately better mileage than with good ole 87 octane on a long haul highway run.
no, the answer is no. If you lose lower octane than the recommended grade, you get LOWER mileage. There is a difference. If octane increased fuel economy why don't we all load our cars up with 100 octane?
Would that give me better mileage? Nope.
So you're saying using lower octane gas in my Porsche lowers my mileage. But you don't want to say increasing the octane back up causes the opposite effect. I'm not sure what you think happens to my mileage when I move from mid-grade to premium. The mpg on my car computer moves in the positive direction about 3 mpg.
It's like saying you get lower when you walk downhill, but not higher when you walk uphill. You must live in a different universe than I do.
The reason "we" don't all get a benefit from increasing the octane is that most cars lack the sophisticated computer control system to retune the engine on the fly. As I've been saying from the beginning, "It depends upon the car."
In My Humble Opinion, If your vehicle uses 87 and you are pining, you have a potential vehicle issue. Pinging isn't good, depending on how bad it is can damage your valves/pistons/block. So if higher octane gas fixes it, it is probably cheaper over the long haul than rebuilding the motor... Granted I have driven motors with a slight ping for tens of thousands of miles without an issue - pinging also robs you of power, which is probably why the higher octane, non-pinging fuel, gives you better mileage, if effect, your vehicle now "requires" or is "recommended" that you use higher octane fuel.
You are correct. If your car pings you either have some bad gas or the car needs attention.
where can you buy 100 octane? I want some!! I am positive my nissan pathfinder would get moderately better mileage than with good ole 87 octane on a long haul highway run.
Aviation gas is typically 100 octane. It's not legal to use it in a car as it has lead in it and will ruin your catalytic converter.
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