My '95 850 Turbo Wagon runs much better on 93 Octane than the lesser ones offered in my area (87 & 89). I try to buy only from Tier 1 stations and those that are always busy, helping assure me that the fuel is fresh.
As our economy has weakened, most people I have talked to are now purchasing lower octane fuel because of its lower cost per gallon.
So If I am the only person still purchasing higher octane gasoline, am I going to begin to get stale gas? If so, how can I tell and how will it affect my car?
I could purchase 87 octane and add octane booster but that would make my cost per gallon considerably higher.
Some high-performance cars do get better mileage on "HO" gas. My Civic EX gets 10% better mileage on midgrade, which is more than enough to offset the price difference. I'd suggest to the original poster that he try midgrade. And to answer his question: stale gas has a distinct odor, kind of like kerosene. You'll know it if you smell it.
My owner's manual calls for 91 octane. I don't know how much it would help my car if I used 89. I can not hear engine knocks with 89 but that doesn't mean they aren't happening. And I can't think that constantly retarding the spark of the engine is healthy.
At this point I will stick with 93 and keep a sharp nose on the odor.
I would be very surprised if your car ran much better on 93 octane than on 91, 89 or 87. If this is true then the knock sensor might be dead on your car.
I have no idea how well it runs on 91 octane, I have not seen it available in my area. But on the 93 octane that is available, it runs much better than on 89 or 87.
I understand that with a well tuned car one can eke out a small net cost benefit by switching to lower octane gas. The difference is not simply the difference in price per gallon however.
I doubt that you are the only person buying high octane gas.
Just continue to buy at busy stations. I've driven cars for over 45 years and have yet to buy a tank of bad gasoline.
I did buy bad gas at a Valero station when prices shot up last year. I was able to recognise the problem before damage was done to my wife's Saturn. It turns out that the propriator of the station was adding water to the underground tanks to streach his supply. He is not in business now.
Yes, you could do that. You should plug all the variables impacting the net cost of gasoline to you as a consumer into a spreadsheet and see what the real difference is.
I am more concerned with the health of my car than the price of fuel at least at this point. I'll stick with buying premium.
Lower octane will probably not hurt anything, there's a pretty significant safety margin, but I would stick with what the manufacture recommends. If the car was designed to take advantage of high octane fuel then I don't see much reason to skimp, even at the peak of high gas prices, it was only a few dollars more per tank than the low grade stuff, yet a lot of people blow the money they saved in gas on a single latte on the way to work.
Generally gas stations will order less of a grade that isn't moving as quickly so they don't get stuck with stale fuel. So long as you buy from a reputable station you shouldn't have a problem.
No, not all cars get better mileage on HO - it depends on their design and the driving conditions. Our '95 Camry gets better mileage on regular, as long as there aren't a lot of hills involved. So did my old Civic.
It should also be noted that "Midgrade" isn't a separate gasoline. It's actually a pump-blended mixture of Regular and Super, so as long as people are buying Midgrade, the Super is getting used up.
240 knock sensors - like the rest of the engine wiring - can stop working because of corroded connections, but as long as yours is working, 89 octane will work fine. In fact, if you are driving on more or less level ground and not racing Acuras, you're wasting your money on Premium.
You're right - it's an 850 turbo. I was confusing the thread with the one about the B200 engine. I still think that Midgrade would suffice for normal driving, though.
Yes, mid grade should be fine, it's a good compromise.
On a 240 Turbo I would recommend premium though, especially if you have turned up the boost beyond stock. Those have no knock sensor so your ears are the last line of defense.
FWIW, using HO gasoline provides me with better mileage, but only on the highway, about 10% better or slightly more. In the city, I barely see any difference, Of course, I see a difference when I accelerate in city/highway.
Cars used for tests were all non-turbo and 240s and a 740 and S90/960.
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