what fuel octane
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toddr124
Hagerstown, MD
How do you rate octane in New Zealand?
In the US we use the average of RON and MON (R+M)/2 for pump octane. In Australia and most of Europe they just use the RON.
This means 93 in the US is 99 in most of the world. 87 in the US is 91 in most of the world.
With this in mind, the octane level you need depends on your compression ratio. Higher octane only helps with higher compression. I run 89 (R+M)/2 in my X1/9, This is about 95 RON. I get no knocking or pinging from the engine.
In the US we use the average of RON and MON (R+M)/2 for pump octane. In Australia and most of Europe they just use the RON.
This means 93 in the US is 99 in most of the world. 87 in the US is 91 in most of the world.
With this in mind, the octane level you need depends on your compression ratio. Higher octane only helps with higher compression. I run 89 (R+M)/2 in my X1/9, This is about 95 RON. I get no knocking or pinging from the engine.
Black-Tooth
Tony Natoli
As Todd said...
The best we have in SoCal is 91 octane unless we go to exotic fuels (Rockett Brand Racing Fuels) and I use it because of the high desert heat here. BTW... knocking or ping in these engines is the weirded noise I've ever heard! HA!
As for MPG from your carbed 79... it would depend on what carb you have... but my BEST on the highway has been about 32... and around 26 - 28 around town with the carb I'm using.
I do indeed get better mileage with the 91 octane versus the 87 but the increase cost of the fuel makes it all about even, from a monetary standpoint. So for the performance and range... I use the best I can find.
The best we have in SoCal is 91 octane unless we go to exotic fuels (Rockett Brand Racing Fuels) and I use it because of the high desert heat here. BTW... knocking or ping in these engines is the weirded noise I've ever heard! HA!
As for MPG from your carbed 79... it would depend on what carb you have... but my BEST on the highway has been about 32... and around 26 - 28 around town with the carb I'm using.
I do indeed get better mileage with the 91 octane versus the 87 but the increase cost of the fuel makes it all about even, from a monetary standpoint. So for the performance and range... I use the best I can find.
size does matter
Hi newzealand uses UK measurements for gallons but in theory we are metric and ment to use litres.
Our fuel is ment to be rated at 91 and 95 octane unleaded with a little bit of 98 in the major cities. avgas is availible for racing.
will let you know tomorrow what standard is used to rate octane,
Hi newzealand uses UK measurements for gallons but in theory we are metric and ment to use litres.
Our fuel is ment to be rated at 91 and 95 octane unleaded with a little bit of 98 in the major cities. avgas is availible for racing.
will let you know tomorrow what standard is used to rate octane,
toddr124
Hagerstown, MD
You use Research Octane Number (RON) to rate gasoline. Therefore US 86=NZ91 US90=NZ95 US93=NZ98. Avgas is 100LL, the LL stands for low lead. I make octane analyzers for a living.:wink2:
toddr124
Hagerstown, MD
AVGAS
AVgas is 100LL in the US. This does not mean the same as 93 octane in motor gasoline. 100LL requires the MON to be a minimum of 100 rating. The RON also has a minimum rating of 100, but is normally higher around 108. AVGas raises the MON that high by adding Tetraethyl lead to the fuel.
Summary; 100LL will be between 100 (R+M)/2 and about 104 (R+M)/2 depending on the additives.
AVgas is 100LL in the US. This does not mean the same as 93 octane in motor gasoline. 100LL requires the MON to be a minimum of 100 rating. The RON also has a minimum rating of 100, but is normally higher around 108. AVGas raises the MON that high by adding Tetraethyl lead to the fuel.
Summary; 100LL will be between 100 (R+M)/2 and about 104 (R+M)/2 depending on the additives.
toddr124
Hagerstown, MD
To much octane can be bad
If you raise your compression high enough, there are advantages. On a normal X1/9 your can do more damage than good.
Octane is not real. It is a rating scale of how much compression you get have without preignition. The higher the octane the more you can compress the gas vapors before they self ignite. To much octane normally just is a waste of money. The spark plug will still ignite the fuel at the normal time if the octane is 93 on a car that runs fine on 87. The problem comes in when octane gets real high.
I had to get rid of 130 leaded race fuel at the office. My 72 Fiat spider can legally run leaded gas. pour in 6 gallons of race fuel into a empty tank. Started the car and you could hear the engine fire with the exhaust valves already open. The high octane had retarded the ignition until after the exhaust valves started to open.
Use the recommend octane fuel in your cars unless you have modified the engine.
If you raise your compression high enough, there are advantages. On a normal X1/9 your can do more damage than good.
Octane is not real. It is a rating scale of how much compression you get have without preignition. The higher the octane the more you can compress the gas vapors before they self ignite. To much octane normally just is a waste of money. The spark plug will still ignite the fuel at the normal time if the octane is 93 on a car that runs fine on 87. The problem comes in when octane gets real high.
I had to get rid of 130 leaded race fuel at the office. My 72 Fiat spider can legally run leaded gas. pour in 6 gallons of race fuel into a empty tank. Started the car and you could hear the engine fire with the exhaust valves already open. The high octane had retarded the ignition until after the exhaust valves started to open.
Use the recommend octane fuel in your cars unless you have modified the engine.
Things I noticed about Avgas
Running straight AvGas in a car that used regular gasoline causes problems in the seals. I had an issue (not in my X, BTW) where a mechanical fuel pump started leaking at the seals after using straight AvGas. It seems this stuff dissolves the gum that normal gas leaves behind. Regular Gas seems to swell the seals while AvGas does not. Makes a great injector cleaner too.
So I tried an experiment... I took a glass plate of regular gas, and the same with AvGas and let them evaporate outside. The result with the regular gas was a gummy brown-colored film substance. With the AvGas, there was a light blue haze, not gummy. I'm assuming the blue color is the dye used in the fuel.
I don't know the process to produce AvGas, but I'm sure it's quite different than regular gas. The odor of each is very different. You can smell regular gasoline a mile away, whereas AvGas leaves no odor behind at all it seems.
Which is why I use AvGas as a de-greaser. Works very well if you don't smoke. Ha!
Running straight AvGas in a car that used regular gasoline causes problems in the seals. I had an issue (not in my X, BTW) where a mechanical fuel pump started leaking at the seals after using straight AvGas. It seems this stuff dissolves the gum that normal gas leaves behind. Regular Gas seems to swell the seals while AvGas does not. Makes a great injector cleaner too.
So I tried an experiment... I took a glass plate of regular gas, and the same with AvGas and let them evaporate outside. The result with the regular gas was a gummy brown-colored film substance. With the AvGas, there was a light blue haze, not gummy. I'm assuming the blue color is the dye used in the fuel.
I don't know the process to produce AvGas, but I'm sure it's quite different than regular gas. The odor of each is very different. You can smell regular gasoline a mile away, whereas AvGas leaves no odor behind at all it seems.
Which is why I use AvGas as a de-greaser. Works very well if you don't smoke. Ha!
Not really recommended as a degreaser...
Fuels usually contain all manner of additives not meant for non-combustion use. And they can be harmful to organic organisms as well. One the fuel base is evaporated off the additives can be readily inhaled or absorbed into your skin.
You'd be better and healthier using mineral spirits or some other low-evaporation rate solvent.
I'm sure you know this though...:nod:
Fuels usually contain all manner of additives not meant for non-combustion use. And they can be harmful to organic organisms as well. One the fuel base is evaporated off the additives can be readily inhaled or absorbed into your skin.
You'd be better and healthier using mineral spirits or some other low-evaporation rate solvent.
I'm sure you know this though...:nod:
Xmember
True Classic
AV? as in aviation fuel? I once new of an older gentleman who was a retired airline pilot. He bought new a late 70's VW rabbit diesel, and all he would ever run in his car since new was aviation fuel. He said that the air lines and his plane would waste more fuel doing the pre-flight fuel tests then it took to fill his car, so he would use that fuel in his Rabbit. Said the car ran super clean and really well.
I had a Ski Nautique with
a 351W engine I completely rebuilt from the block out, bumped the compression up to 10:1 and used all new aluminum edelbrock components to gain 425HP and ran nothing but AvGas in it from the start.
I pulled the heads the first 2 years of running to see how things looked, and all that was present was a light tan haze of deposit on the pistons and valve heads. I was really impressed how well this engine ran and how clean it stayed inside. It would rip through the water when I hit the throttle....
a 351W engine I completely rebuilt from the block out, bumped the compression up to 10:1 and used all new aluminum edelbrock components to gain 425HP and ran nothing but AvGas in it from the start.
I pulled the heads the first 2 years of running to see how things looked, and all that was present was a light tan haze of deposit on the pistons and valve heads. I was really impressed how well this engine ran and how clean it stayed inside. It would rip through the water when I hit the throttle....
quattrorules
Michael. 84X
Jet fuel, not avgas
I don't think that avgas would do a diesel engine any good, but jet fuel, which is about the same as kerosene, would work. BTW, the high octane av gas is getting hard to find, because of the reduced demand, as the big old piston engined planes die off. Small planes with piston engines don't have high tech motors and don't need the really high octane of the old supercharged or turbocharged engines.
I don't think that avgas would do a diesel engine any good, but jet fuel, which is about the same as kerosene, would work. BTW, the high octane av gas is getting hard to find, because of the reduced demand, as the big old piston engined planes die off. Small planes with piston engines don't have high tech motors and don't need the really high octane of the old supercharged or turbocharged engines.
Xmember
True Classic
so avgas is aviation gas or just another term for racing gas? I know aviation fuel is basically super high octane diesel fuel and wont work on a regular engine, but whats avgas? its really bugging me that I dont know what it is, but feel I should, so share the secret with me :help:
The difference...
AvGas is generally for small prop aircraft. Basically like gasoline but more refined and with a low lead additive. You can get it at most small airports for around $5 or $6 a gallon. (last I checked) It's light blue in color and could be easily confused with window washer fluid. (if you store it in a like container) Folks occasionally use it as an inexpensive racing fuel or octane boost.
Jet fuel is quite different. It's more like kerosene, but (again) more refined to a much tighter spec. There's a significant oil content to jet fuel.
The two fuels are really nothing alike. Confusing the two would produce instant negative results, kinda like pouring gas into your oil fill. :confuse2:
AvGas is generally for small prop aircraft. Basically like gasoline but more refined and with a low lead additive. You can get it at most small airports for around $5 or $6 a gallon. (last I checked) It's light blue in color and could be easily confused with window washer fluid. (if you store it in a like container) Folks occasionally use it as an inexpensive racing fuel or octane boost.
Jet fuel is quite different. It's more like kerosene, but (again) more refined to a much tighter spec. There's a significant oil content to jet fuel.
The two fuels are really nothing alike. Confusing the two would produce instant negative results, kinda like pouring gas into your oil fill. :confuse2:
wannabfast
Thai with a 78 in MN
well ive ran regular 87 octane gas and 93 octane gas, i personally cannot tell the difference with the x, however this was before i upgraded my camshaft and carbs.. so i really want to play with different gas
You won't notice any difference...
If the engine isn't pinging with 87, then 93 won't make any difference as there is no need for further detonation resistance. Stuff like freshness of the gas in the station's tank, winter/summer formulations, amount of water and crud in the station tank will make a bigger difference from fillup to fillup.
If you're running a modern engine control system with knock detection, then it's a different story - the ECS can advance the timing to take advantage of the increased detonation resistance of the higher ocrane fule.
If the engine isn't pinging with 87, then 93 won't make any difference as there is no need for further detonation resistance. Stuff like freshness of the gas in the station's tank, winter/summer formulations, amount of water and crud in the station tank will make a bigger difference from fillup to fillup.
If you're running a modern engine control system with knock detection, then it's a different story - the ECS can advance the timing to take advantage of the increased detonation resistance of the higher ocrane fule.
Wow, finally something
I know a little bit about.
AVGAS, 100ll, dyed blue to identify it from 80 octane avgas, which was dyed red. I say was, as I haven't seen it in years.
100ll is great for piston powered airplanes, and 2 stroke engines.
Not good for any engine with a Catalytic converter.
I have run 100ll in my weedeater, chainsaw, and tiller for years.
Cleanest spark plugs you have ever seen. 50:1 mix, no problem.
JetA, jet fuel. Basicly one step above kerosene in the refining process. Works in diesels too, but may make them run a little hot.
Works fantastic in salamader heaters, and the like.
Jim
I know a little bit about.
AVGAS, 100ll, dyed blue to identify it from 80 octane avgas, which was dyed red. I say was, as I haven't seen it in years.
100ll is great for piston powered airplanes, and 2 stroke engines.
Not good for any engine with a Catalytic converter.
I have run 100ll in my weedeater, chainsaw, and tiller for years.
Cleanest spark plugs you have ever seen. 50:1 mix, no problem.
JetA, jet fuel. Basicly one step above kerosene in the refining process. Works in diesels too, but may make them run a little hot.
Works fantastic in salamader heaters, and the like.
Jim