Hello all:

I was wondering if anyone has used High Octane instead of Regular gas. If so, did you notice any increase in mileage?

 

I tried it in an HCH-I and found no noticable, repeatable increase. Also tried acetone - no noticable increase.

 

Unless otherwise noted in the logs, I fill exclusively with 89. The only reason for that is one of the 'perks' my employer provides is on-site gas pumps with payroll deduction, priced at wholesale. I haven't noticed any difference between my daily driving and the times when I've filled with 87 during a long trip.

 

You should do a search here... this topic has been discussed to death.

The conclusion has been and will be... running anything other than the recommended octane rating is a waste and will probably make your FE go down.

The engine was designed with a lower octane rating in mind (87). Everything else is just a waste, and do not equate higher octane gas as better gas. That is total b.s.

 

That's a nice perk! I have always wondered what 'wholesale' pricing for fuel would be; is it about 15-20 cents less per gallon, or more?

You don't work for an Oil Company, do you?

 

Like livvie said, many long threads on this. Bottom line is this: Octane is only needed to ensure the gas/air mixture does not ignite prematurely when compressed. Engines with high compression ratios need higher octane for this reason - to prevent combustion. Octane does not add any performance into the gas itself. Typically, higher performance engines have higher compression ratios, thus needing higher octane gas. Because all these high-end performance cars need high octane gas, people generally assume the gas itself is "high performance gas". It's not. Go with what the manufacturer recommends. Running 91 octane in a car that requres 87 does more harm than anything.

 

When I filled up yesterday, our pumps were set to $2.620, about $0.10 cheaper than average for the city where I work, and $0.25 cheaper than the midgrade at the Marathon I pass by on my daily commute. Our pumps tend to lag on price changes, sometimes significantly. When the price goes up, (I'm guessing) management runs the tanks nearly empty before calling in a refill. This was great last summer immediately after Katrina, as we were, at one point, nearly $0.50 cheaper than other stations. Of course, this also means we're slower on the downside, this past spring, there was about a week where it was cheaper to go down the street.

And no, I don't work for an oil company (they'd probably shoot me if they saw the HCHii). The founder of my company lived through the 70's oil embargo, and put the pumps there to make sure his employees could always get gas. So despite being without him for 20+ years now, his idea has remained

 

There is somehow a misunderstand of the concept of Octane. It's NOT a rating of how much energy is in the gas - it is a measure of RELUCTANCE to combustion. In other words, the higher the octane rating, the more difficult it is to ignite. High compresion engines require high octane to prevent "pinking" - pinking being the remature ignition of the gas/air mixture. Thus many high performance engines requires high octane gas or gas additive cal "octane booster"

So, unless the engine is designed to require hi-octane gas, it's a waste of money. Even some engines that "recommend" high octance will run perfectly great with regulars - modern engines are all computer controlled, especially the ignition timing and can retard it if it senses pinking or premature ignition if you use low octane gas - and with no harm to the engine. My Infiniti Q45 (8-cyl high compression) recommend 91 octane. But in the life of the car I've always used 89 and the computer seem to adjust to it. I tried 87 but it seem to be out of the range of it's adjustment and pinks a little. I own the car for 10 years and when I sold it to get my HCH, it was in prestine condition and the engine purrs like a kitten. btw, I can oil every 10,000 miles - all done by the dealer - much to their disgust who continually badger me to change oil every 3K miles.

Bottom line - high octane gas do not give you better mileage.

 

Don't waste your money. Octane is a measure of the fuel's resistance to knocking or pinging. Only high-compression engines (think sports cars) need the stuff. The folks who wrote the owner's manual know what they're doing; if they say regular is OK, then regular is OK!!

I recently read somewhere that only ~5% of all cars in the US need premium gas. IMHO, if that number drops much further we'll see premium phased out, as there won't be enough demand to make it profitable. Those who still drive high-compression cars will then have to put an octane-boosting additive in each tank.

 

Why use high octane? There's LESS power in a gallon of it, less gas in it, etc. More additive to SLOW combustion (to prevent pinging in hi-compression engines). It's retarded to waste money for less performance