Aviation Fuel

[Zrush]

Whats anybodys opinion on running aviation fuel in their Z. The local airport (not a major airport) has fuel with a 110-112 octane rating. Would you mix half with pump gas (93 octane) or would you run a tank full of 110 octane every once in a while. I've always heard that you should run the highest octane available from the pump in our Z cars.

[MikeW]

Octane is a measure of how easily the fuel ignites. It's not a measure of how much power is in the fuel. Higher octane is needed as the compression ratio goes up to prevent pre-detonation (or pinging). Cars that require premium fuel do so because of higher compression ratios. If your car is not pinging on 89 octane then 93 octane isn't going to do you a bit of good. You're just wasting your money. It may be that the premium fuel has other benefits (like better additives, etc) but don't buy more octane that you need.

My understanding is also that AvGas contains some lead which can certainly be harmful to newer cars (but probably not our old Z cars since they were designed for leaded fuels).

[Bambikiller240]

An Aviation Mechanic friend has mentioned that these AvGas products are sometimes colored so that when burned they leave a tell-tale color in your exhasust pipe. Since these fuels are not sold with the Road Use Taxes included in the price, it is illegal to run them in vehicle used on public roads. I don't know how much chance there is of getting busted, but if your luck is like my luck you'd get nailed at the first stop light as you left the airport.

[PrOxLaMuS©]

aviation fuel is CHEAP.. and would never be a waste of money.

For some reason.. the way they process it is crappier than automtotive fuel... i think because of the high altitudes and thin air the airplanes fly in.

But either way when an airplane fuels up.. they need LOTS of fuel... and it's cheaper for an unknown reason.

I only fear.. carbon build up... or crap built up inside the engine and exhuast pipe.

But.. it's good fuel... none the less

[Chino 240Z]

Av-gas is probably as expensive as racing gas. I am probably burning money too, but I use the Union 76 Cool Blue gas for track days. It is 100 octane, looks, smells and evaporates different than pump gas. Some 76 stations may sell it in 5 gal. throw away containers, but where I buy it, it's sold from the pump. It's about $4 to $5 frog skins a gallon, so ya, it ain't cheap. I like the results you get from this type of gas for reading the plugs and tailpipe, you can easily see different coloring (rich vs. lean) on the plugs compaired to standard pump gas.

Good grade pump gas would probably be fine for daily driver, but for those times you want to smell different, perhaps gain a few extra ponies and play with your plugs? this 100 octane fuel is something to try.

[Bambikiller240]

Originally posted by PrOxLaMuS©

aviation fuel is CHEAP.. and would never be a waste of money.

For some reason.. the way they process it is crappier than automtotive fuel... i think because of the high altitudes and thin air the airplanes fly in. But either way when an airplane fuels up.. they need LOTS of fuel... and it's cheaper for an unknown reason.

Wrong, wrong, wrong.

IF anything it is refined and filtered to a higher standard than automotive gas. Aeroplanes cannot afford to have fuel related problems IN FLIGHT. The Public Road Use taxes are not added into the price of said fuels and these fuels are STILL of a far higher cost than fuel sold for road going (automotive) engines.

[frank13]

The extra cost of Aviation fuel is passed on to the consumer who buy's the plane ticket. Every time the oil companies raise the cost of a barrel of crude oil the cost of ALL fuels GOES UP! Using a higher than needed Octane fuel can also have adverse effects on computer controlled OBD II cars from the OEM's. Older non-computer controlled Z's like the 240Z will just run slower. As mentioned by MikeW high octane race fuel is used when the increase in Compression Ratio is leading to DETONATION (or pressure increased due to the build up of carbon deposits, which can also lead to PREIGNITION due to hot carbon deposits igniting the fuel/air charge before the spark ignition). The increase in the Octane rating is a measure of the rate at which the fuel will burn. Higher Octane fuel has a sort of higher flashpoint, for lack of a better example. The consistency of the fuel is better and will burn at a more uniform rate than lower octane fuels. But is Only needed in high performance engines. That have high compression ratios. That's why race fuels are always high rated octanes, such as the 76 race fuels, Trick, etc. Using High octane 92/93 or race gas 100+) in stock motors can lead to damage to internal parts (e.g. crank, rods, piston ring lands) on tight tolerence computer controlled modern engines. And fouled plugs on the cars that can not ignite the entire fuel/air charge. The slower burn will also decrease accelaration. You should only use the highest rated octane gas that your engine requires. If it pings with 87 and you want to keep that dizzy advanced those extra 3 degrees(legal 3 degrees +or- in Cali from OEM spec) move up to 89. If pinging still occures move up to 91,92, or 93 what ever they got in your neck of the woods. That is what high octane fuels are for. High Compression Ratio, high working pressure engines. My 2cents:devious: :devious:

[frank13]

Damn Chino 240Z you gots way to much free money burning holes in your & your wife's driving suits!

What about the scented additives? Your race gas exhaust can smell as sweat as strawberrys or Vanilla!!! . Guess I shouldn't laugh I have non existent hatch seals, hum strawberrys????

:devious:

[280zx Fever]

Originally posted by MikeW

Octane is a measure of how easily the fuel ignites. It's not a measure of how much power is in the fuel. Higher octane is needed as the compression ratio goes up to prevent pre-detonation (or pinging). Cars that require premium fuel do so because of higher compression ratios. If your car is not pinging on 89 octane then 93 octane isn't going to do you a bit of good. You're just wasting your money. It may be that the premium fuel has other benefits (like better additives, etc) but don't buy more octane that you need.

My understanding is also that AvGas contains some lead which can certainly be harmful to newer cars (but probably not our old Z cars since they were designed for leaded fuels).

I disagree.. bigger bang hence more power..

On a stock engine you would see no benefits if anything a little loss of power..

But if you advancd the timming and ran AvGas there you go your taking full advantage of it..

In Australia the highest octance we can get off the pump is 98. That is perfect for cars running up too 11:1 ratio any higher you will need avgas as said earlier they ping..

AvGas is also good for high performance turbo engines with alot of boost as the combustion chamber tempretures increase and the center of the pistons create hot spot which cause the fuel to pre ignite..

[ZmeFly]

Av Gas isnt meant for your car, never was, never will be.

Nuff said on that.

[frank13]

By advancing the ignition timming and adding Aviation fuel to your menu, you in no way will get a "Bigger Bang". Advancing the dizzy only helps bring on what you already got in a more timely manner. Which leads to the pinging. Which leads to using mid grade fuel instead of the cheapo 87. High octane fuel does not have any added HORSE POWER in it to release magical as it burns. It only allows you to make the horspower that you have built your monster motor to make WITH OUT MELTING, shatter, or otherwise damage pistons and cranks, head, valves, head gaskets. If Any body who thinks Aviation gas is going to make more power in thier Zed, Try some Nice JET Fuel! Real Nice stuff, burns real quick! See how long your pistons and bearing last in a wash of refined kerosene. Sound good? Hey if it works for Jet linners, it's gotta put a Z in the low 9's right??? NO! :devious:

[Alan Pugh]

Hi everyone,

I am an aircraft engine technician and I can tell you frank13 and ZmeFly are 100% correct.