100+ octane gas?

weister42 · #1 (**permalink**) 05-02-05, 06:06 PM

I seen a Shell gas station by my house that has some really expensive gas, something like "high proformance gasoline" and I remember it was either 110 or 105 octane and close to 6 dollars a gallon

. Anyone used such gas and what's so good about it?

N0DIH · #2 (**permalink**) 05-02-05, 06:14 PM

Other than high octane, it won't help your car much. But it often is higher specific gravity, which basically means the fuel is denser, so more molocules that explode or burn are contained in the mix. It takes more barrels of oil to make a gallon of that than 93 oct or 87.

It would likely benefit you slightly if you mixed 87 and 110 to make a higher octane like 93 then real 93. But I doubt the cost would warrant it.

weister42 · #3 (**permalink**) 05-02-05, 09:33 PM

I see, I thought high octane gas gives the same effect as nitrous but in a small manner

addison_ii · #4 (**permalink**) 05-02-05, 10:00 PM

Quote:

Originally Posted by weister42

I see, I thought high octane gas gives the same effect as nitrous but in a small manner

Oh, how do I wish that was true !!

BeelzeBob · #5 (**permalink**) 05-02-05, 11:05 PM

Higher octane fuel makes no more power than "regular" octane fuel...it is simply more resistent to detonation or spark knock so the engine can be modified with a higher compression ratio to make more power.

The fuel you see advertised is for highly modified engines with high compression ratio or turbo/supercharged cars running a lot of boost. Some hot rodders will run some very highly modified engines on the street and detune them by retarding the spark to be able to run them on normal pump premium fuel. This hurts the power out put of the engine considerably. The 110 octane fuel would allow even the highest compression ratio engine to run at optimum spark timing with no detonation.

Using fuel like that in a production engine is pointless as the high octane rating is not needed nor required. It will not give you any more power.

Octane rating has nothing to do with the fuel's burn rate, temperature or potential power output...it is just a rating of the fuel's ability to resist detonation or spark knock.

Even if the fuel had more "burnable molecules" in it those burnable molecules would require air molecules to burn with. Simply adding more fuel or more burnable molecules to the mix does not make any more power at all.

An engine is an air pump. The more air it can pump the more fuel it can burn and the more power it can make. The problem starts with pumping more air...not putting more fuel in or more "burnable molecules" into the engine. If the fuel contained more heat energy it would just make the engine run rich...not make any more power. To make more power you must do something to the engine to make it pump more air to support the additional combustion. No way around it. Higher octane fuel does nothing to aid in this.

**Ranger** · #6 (**permalink**) 05-02-05, 11:08 PM

The only benefit of that gas is to the gas station, by selling you something you don't need for a high price. Octane is nothing more than a fuels ability to resist knocking. MORE IS NOT BETTER. It provides NO increase in power, no matter what their marketing says. A Northstar will run perfectly fine on 87 octane due to the knock sensor. 93 is recommended but not necassary. Anything more is a waste of money. People that are buying that stuf are probably also buying the "Tornado", "Turbonator" and the fuel line magnets.

BeelzeBob · #7 (**permalink**) 05-02-05, 11:15 PM

Or they have a 13:1 CR rat motor in their street racer.....LOL LOL

Eric2203 · #8 (**permalink**) 05-03-05, 08:28 PM

So how come in Europe, unleaded is either 95 or 98 octane ? And even 100 in at least one country. Or so I was told. Are engines so different ? I mean some cars are sold both here and there, including Cadillacs. So what am I missing ?

addison_ii · #9 (**permalink**) 05-03-05, 08:42 PM

Quote:

Originally Posted by Eric2203

So how come in Europe, unleaded is either 95 or 98 octane ? And even 100 in at least one country. Or so I was told. Are engines so different ? I mean some cars are sold both here and there, including Cadillacs. So what am I missing ?

I think it's because different countries use different calculations to arrive at their octane rating.

**Ranger** · #10 (**permalink**) 05-03-05, 09:34 PM

probably similar to metric vs english

rnunez76 · #11 (**permalink**) 05-03-05, 10:58 PM

but doesn't your engine run a little rough when it has a lower octane? My caddy seems to like higher octane better than lower. Why?

**Ranger** · #12 (**permalink**) 05-03-05, 11:31 PM

No. Octane has no effect on running smooth or rough. Mine runs just as smooth on 87 as it does on 93. You said it "SEEMS to like higher octane better than lower". I suspect alot has to do with what you expect and want to see. The K&N air filter does nothing for the Northstar powerwise, yet people swear they can "feel" more power. It does make more noise. Between the "sound" of more power and the fact that they just spent $60 on an air filter and need to justify it, your subconcious is probably telling you what you want to hear.

BeelzeBob · #13 (**permalink**) 05-03-05, 11:55 PM

Quote:

Originally Posted by Eric2203

So how come in Europe, unleaded is either 95 or 98 octane ? And even 100 in at least one country. Or so I was told. Are engines so different ? I mean some cars are sold both here and there, including Cadillacs. So what am I missing ?

There are two methods of measuring/rating octane. Research and Motor. Research octane ratings are typically higher numbers.

European gasoline octane is typically rated per the Research method.

Gasoline octane in the US is typically rated as an average of the Research and Motoring numbers. That is why the gas pump will sometimes say R+M/2 on the pump. It means that the octane rating advertised is the average of the Research and Motoring numbers.

93 octane Premium in the US would probably be rated at 97/98 in Europe. Same gas. Same octane. Different rating methods.

turbojimmy · #14 (**permalink**) 05-04-05, 06:33 AM

Quote:

Originally Posted by bbob

Or they have a 13:1 CR rat motor in their street racer.....LOL LOL

Or need to run 25 PSI through their 3.8L V6.

Sunoco sells 2 versions of their Unleaded GT race fuel: 100 and 104 octane. I've never seen 104 at the pump. The local Sunoco sells 100 @ $4.50 a gallon. At the track I run a mix of unleaded 100 and leaded 110 (114 or 116 when I can get it) octane in the GN. Otherwise it's 'only' 100 octane and I have to turn the boost down. The difference between, say, 94 and 110 is amazing.

If you have a car with a knock sensor, and it's sensing knock with 87 octane fuel then the low octane fuel is affecting performance. The knock sensor will cause the timing to retard thus reducing performance. If you put 93 in it and the knock sensor does not have to intervene then you get more power. People that claim an increase in performance on 93 vs. 87 may actually be feeling the difference.

As bbob pointed out, 'octane' is a measurement of a fuel's resistance to ignition. You want spark to ignite the fuel, not compression or high cylinder temps. Otherwise you get pre-ignition and detonation.

I don't know what premium (93) vs. regular (87) does on my Northstar. I haven't put anything but 93 in it. I may be wasting my $$$ I guess.

Jim

Eric2203 · #15 (**permalink**) 05-04-05, 07:32 PM

Quote:

Originally Posted by bbob

There are two methods of measuring/rating octane. Research and Motor. Research octane ratings are typically higher numbers.

European gasoline octane is typically rated per the Research method.

Gasoline octane in the US is typically rated as an average of the Research and Motoring numbers. That is why the gas pump will sometimes say R+M/2 on the pump. It means that the octane rating advertised is the average of the Research and Motoring numbers.

93 octane Premium in the US would probably be rated at 97/98 in Europe. Same gas. Same octane. Different rating methods.

Thanks for the reply. I understand now.