EB03Z

had an opportunity to get some fuel they use in the Nascar Winston/Nextel cup cars. With the high octane rating, would that hurt, help, or make no difference if I put it in the 03 Z? I would never buy it at over 5 dollars a gallon but I have an opportunity to get a tank a week if need be.

Shylor

Just because high octane is recommended doesn't mean "more" octane is better. Only use what the engine is designed for. Racing fuel is designed for engines with a much higher compression than the Z06.

AU N EGL

NASCAR race fuel is Leaded. Sunoco 110-112 Octane Leaded

There are a few places where you can find 100 Octane unleaded. No real difference in performance.

and 5 bucks is now cheap / gallon

LTC Z06

Don't forget, the lead will kill your cats and O2 sensors. You don't need it.

barondw

I don't know where you guys live but in the Northeast you can buy 100 octane unlead race fuel at tracks and at special Sunoco Stations listed on their website.

The fuel is good for DEs and other types of racing. It takes a while for the computer to "learn" that the gas you have is higher octane.

LTC Z06

Higher octane fuel can not extract more HP from an engine, once an engine gets the minimum octane needed to prevent detonation you are done with needing to worry about octane.

Chris@East Coast Supercharging

more octane then needed will hurt performance. An engine needs just enough octane to prevent detonation, nothing more. Besides, you cant run leaded fuel in a car with 02 sensors and cats.

Ranger

I run sometimes at Maryland International Raceway (MIR), the nearest IHRA dragstrip. The lowest octane unleaded fuel they have on-site is 100.

A couple times after getting a "low fuel" light while making passes, I've added a few gallons of 100. Each time my car has lost one-two tenths in the quarter. Enough evidence for me that excess octane will adversely affect performance.

Ranger

LTC Z06

It surely can, higher octane burns more slowly than a lower number, it's that slow burning that can actually cause a HP loss!

FRISKY

"Burn rate" and "ignition rate", two entirely different issues.

“Burn rate” is how fast or slow the fuel will complete combustion once it has been ignited. Typically this process will be completed within 20-degrees of crankshaft rotation from TDC, and that is a very small amount of downward motion of the piston in the bore.

“Ignition rate” is how quickly the fuel can be ignited and is a product of octane. The higher the octane number, the more heat and pressure will need to be generated in the combustion chamber before the fuel can ignite.

Chemicals added to gasoline to increase the resistance to pre-ignition/spark knock/detonation also decrease the amount of BTUs available per pound of fuel. That is why you should use the lowest octane fuel possible that won’t cause the computer to pull timing or “pinging”.

Popular Hot Rodding Magazine, January 1998
By Scott Parkhurst

"The burn rate of a fuel is a measurement of the time required for complete combustion of the air/fuel mixture. The notion that octane ratings affect the burn rate of fuel is about 180-degrees from reality. Burn rate is a function of several variables, and the two are completely independent, although there is generally a correlation between higher octane ratings and faster burn rates.

To give you a good example of this, we contacted Jim Wurth from Sunoco Race Fuels. He explains, "A perfect example is Sunoco Maximal, which is our fastest burning fuel, and coincidentally one of Sunoco's highest octane fuels at 116 (R+M) / 2. A lot of Pro Stock teams rely on Maximal for those sub-seven second runs. When they are turning 9,000 rpm or more, the fuel has to burn pretty quickly to achieve complete combustion".

If you chose to try some of the 101-octane fuel, make sure it is unleaded. Leaded racing fuel and Aviation gas will cause problems with your catalytic converters and oxygen sensors.

EB03Z

Thanks guys. I will stay away from prospective problems and stick with the Chevron 93 (if it ain't broke, don't fix it)

95jersey

100 Octane fuel can work very well in a LS1/LS6. But your computer has to be tuned for the fuel. 100 Octane will allow you to run a lot more timing without getting detonation. The T1 race cars use stock motors with 100 Octane, and with slower burning properties of the fuel, they can significantly advance the timing and easily gain 25rwhp with nothing added to the car. Unless you run advanced timing, 100+ Octane is a waste.

SMFCPACFP

Gasoline is composed of hydrogen and carbon atoms. Octane is gasoline composed of 8 carbon atoms per molecule. The octane rating, traditionally, was a measure of what percentage of gasoline is composed of octane molecules. 90 octane gas is composed of 90% octane gasoline molecules and 10% heptane gasoline molecules and other additives. There are several ways to measure octane which is why you can have gas with an octane rating of over 100.

Octane, amongst the gasoline molecules (heptane, octane, nenane, decane) has the desirable characteristic that it can be compressed quite a lot before it spontaneously combusts. It also burns slower. A 4 cycle car engine doesn't count on spontaneous combustion. Instead it assumes that combustion will occur when the spark plug fires. If the gasoline combusts before the spark plug fires (beginning of power stroke), the engine will not make maximum power and can be damaged

The compression ratio of the engine determines the amount of octane you need in gasoline. The higher the compression ratio, the higher the octane percentage.

Here is the key thing. Your car's performance is a function of how many BTU's of energy it can process in a given period of time. Does higher octane gasoline possess more BTU's per gallon than lower octane gasoline - emphatically NO (octane and heptane have the SAME BTU rating)!! Thus using gasoline with more octane than required to control pre detonation, gives no added value, and may cause unburned gasses to pass directly to the catalytic converter unburned, shortening its life. As far as I know neither of the two molecules of gasoline used in the gasoline you buy has superior cleaning ability.

If you want really high energy fuel, try nitroglycerine.

LTC Z06

[QUOTE=FRISKY]"Burn rate" and "ignition rate", two entirely different issues.

“Burn rate” is how fast or slow the fuel will complete combustion once it has been ignited. Typically this process will be completed within 20-degrees of crankshaft rotation from TDC, and that is a very small amount of downward motion of the piston in the bore.

“Ignition rate” is how quickly the fuel can be ignited and is a product of octane. The higher the octane number, the more heat and pressure will need to be generated in the combustion chamber before the fuel can ignite.

[QUOTE]
Lot's of good info.

#001 2001 Z06

Without doing an extensive written work here.

No, do not use 110, 114 or 117. It will eat your O2's, Gaskets and cats.

Use Chervon 91/93 mixed with four/five gallons of 100. This is only if have very extensive F/I mods or are planning to race. The race gas gives you nothing except resistance to detonation. There are some additives in the race gas that may boost power by 3-5%.

See you at the track.

#001 2001 Z06