I would think octane is octane; it is a measure of how combustible fuel is. I wonder if fuel economy is better with higher octane. I have tried using higher octane fuel (premium is 91-93 octane here) but did not notice a difference. Regular fuel here has an octane of 87. I think you can even buy octane boosters by the can to add to regular fuel. At some point you would think there would be potential for engine damage.

Does anyone know the details about this?

Octane rating is basically a measurement of the fuel's tolerance to spontaneous combustion. If you check the pump, you'll see RM2 after the rating. Root mean square. In other countries, they may use a different means for determining it. Lower octane fuel will pre-ignite within your combustion chamber due to many things. The most common two being carbon buildup that leaves "Hot spots" on the piston top or in the head around the valves, and high compression ratios. When you get past abut 9.5:1, or have a turbo or supercharger, it's possible for lower grade fuels to ignite before the spark plug fires. This pre-ignition is that knocking and pinging you hear when pushing a crappy old car up a hill with a load.

As far as too high, I think that's a matter of the higher octane fuels burning too hot. We use to run a mixture of 76 leaded (yummy!) and Avgas aviation fuel in our 1968 Camaro when we went racing. This was the cheaper version of 104+ octane boost. Not only do you get a more controlled burn, but since it's generating more power, you're getting much more heat. Is suppose if I wasn't on my way to work, I could provide a more detailed explanation, but I hope that helps.

By the way, unless the manufacturer calls for it, there's no benefit to running high octane fuel in a stock motor. Even a Corvette can run 87 on the freeway. Some engines have "Knock sensors" that will adjust the ignition timing to compensate for good or bad fuel quality.

[warning, no bike content]

Not only is there no benefit, in most cases it will actually lower your performance and gas mileage. To make more power, you need to cram more air into an engine. The more you compress the air, the hotter it gets. Higher octane fuel takes more heat to ignite (that it burns cleaner is a side benefit) than lower octane fuel hence why it's used in higher compression engines where the cylinder temperature is higher than a "normal" car. Without the necessary heat to ignite higher octane fuel, it won't burn completely and you'll have more emissions and less power.

[now back to bike talk]

Not so. You'll get the same economy, as it's the same air/fuel mixture being burned, but in most cases you'll be paying more for wasted potential energy. You're also a bit off target on the combustion process. You mention cylinder temperature, but you must mean combustion chamber temp. And the only thing that should ever ignite the mixture is a spark plug. But if you're only squeezing that mixture into 1/8th the space, rather than 1/10th, you don't need the extra resistance to spontaneous combustion. Higher octane fuel will burn just as fully as lower octane fuel, (we're talking pump gas here, right?) but it's like eating an energy bar and then going to bed alone.

Zürich, Switzerland:

My car uses 95 octane unleaded: 1.61 Swiss francs / litre
ie. US$7.86 per US Gallon (this is not a typo).

It was around CHF1.50/litre last year ...

You also get 93 octane [a few cents cheaper per litre] and recently also super 100, which costs quite a bit more.

Guru, any idea why you guys have the high octane stuff? Is it for turbos? Would it have anything to do with higher altitudes?

My car is a turbo, yes. But I think it's just recommended by the manucturers, whether to use 93 or 95 octane ...
The 100 octane is a new release (although we've had it in South Africa for a long time - although not as unleaded), and claims better performance.

I suspect that in Switzerland there are more high output, small displacement motors, and less cars with V8s.

Yep. Conspicuous by their absence are the large American Trucker types..
In fact, there was recently a big hoo-ha about the Monster Truck show coming to Zurich because of the callous abuse of fossil fuels required to operate these machines.

Still, there's no shortage of Ferrari, Lamborghini, Porsche, Maserati, Bentley, etc on the roads here.
But throughout Europe, most cars are on the more compact-side of design.

Just a hunch, but if you pulled up to a rest stop in Texas driving one of these:



you'd better be wearing your flame-proof undies...

I actually saw a Smart car in California several (5?) years ago, but the guys driving it spoke very little English. They were at a petrol station, something I'm sure they didn't do too often. Many European countries are embracing direct injection diesels, as they're clean burning, and produce a lot of power from a small engine. The exotics that you mention are probably still a small percentage of the vehicles on the road.

Quiz time for anyone that can guess correctly without Googling - Name the country with the highest per-capita ownership of Ferrari's.

Luxembourg or Monaco?

My final answer: Luxembourg.

I'll go with my adoptive homeland
Switzerland.

I've never done any scientific tests to prove it but if you don't have enough heat to completely burn a fuel, then your economy should go down. By cylinder temperature, I'm referring to the same thing as you are with combustion chamber temperature (and I would have said the same thing had I been thinking more when I was typing ). I was talking about pump gas and thinking along the lines of running 93 octane in a car meant to take 87 octane (and not just one that can run on 87 with a knock sensor).

Maybe "completely burn" isn't the right way to look at it. When the piston is at it's top most point (or at whatever point the designer's set to have the spark plug fire), the engine was designed around the fuel being ignited and burning at that moment. With a cooler engine, I would think the fuel would at least burn slower than in a hotter engine. This slow burn would cause a loss in power.

Neither.

[edit] Oops. Not Luxemburg or Switzerland. And it seems to be Google-proof as well.

Veering way off topic here ... but still.
Google found: this
which states: "Switzerland is Ferraris’ fifth largest market after North America, Germany, the United Kingdom and Italy. Ferrari Switzerland is based in Nyon on Lake Geneva and is headed by the recently-appointed Giulio Zauner. With 250 cars delivered nationwide in 2004, Switzerland boasts the highest per-capita concentration of Ferraris of any country in the world."

I recall reading it elsewhere too, hence my stab in the dark.

There's never a shortage of heat when it comes to combustion chambers, with the exception of a car that hasn't warmed up to operating temperatures yet. Getting all the fuel mixture to burn is a function of design. You need the proper mixture from a carb or fuel injection system, and correct intake port length and size for optimum velocity. You also need correct valve lift and timing, along with correct ignition timing. That mixture has to be in the chamber with the valves closed at the right time for peak performance. I don't think pump gas can burn too slow in a production car. If you want to learn more about great designs, look at Ducati's Desmodromic valve system.

Errr.
Further googling shows this :
"New Zealand has the highest per-capita number of Ferraris".

The thlot pickens...

Guru, it appears my info is now outdated. Switzerland has surpassed New Zealand since I was there in 2002. I'm going to check with my source to make sure they're not still making the same claim.

I need to type quicker. I'll have to call it a tie, as I'm sure neither country will cop to the truth.

Last tank I paid $2.579/gallon for regular unleaded; and it was the cheapest one I saw around that area...

Well, if it was easy, anyone could do it. I would imagine a century or so ago, folks were sitting around a checkerboard in the general store discussing how those "new-fangled automobiles" were just a fad and would never replace a good old horse. Just look at us now.

As for the 80 hp Corvette, you're thinking along the lines of coverting the existing gasoline engine to burn hydrogen much in the same manner as the propane conversions you mentioned. I was thinking more along the line of something completely new...an engine designed to burn hydrogen effectively. This or something like it is a necessity, not only for cleaner air, but because of the finite amount of "petrol" available. As I've said before, it can't last forever, no matter how effiecent we make the engines.

And besides, wouldn't a 400 hp hydrogen powered Corvette be just too cool?

I wouldn't mind seeing the price of gasoline double and the price of diesel drop to < $2.00/gal (along with biodiesel becoming more common). Cheaper diesel means less money spent by the trucking companies on fuel so transporting goods won't cost as much.. Higher gasoline prices hopefully means people will drive less and seek alternate forms of transportation. Heck, make sure the gas price increase is mostly in taxes so it's not the oil companies that are making all the money off the price hike. It'll never happen, but it'd be neat to see.

Bc, designing an engine that burns hydrogen effectively has already been done. The problem is creating the hydrogen. I suppose the electricity needed could come from coal burning electrical plants...

Cryongenic, Raising fuel prices will only impact low income earners, it won't stop people from driving. Cigarettes are at least $10/pack here, and that hasn't deterred smokers.

Either way is fine by me... Those that are still able to drive are paying through the nose for it and a large portion of the money isn't going back to the oil companies. Those that can't afford to drive take alternate forms of transportation. I still fail to see a problem here

Or from geo-thermal wells. Iceland would then become the new UAE...