WILL 89 OCTANE CAUSE ANY PROBLEMS?

[Big Jim]

Quest, so much of what you have said is just plan wrong that I don't have the time or interest to try and set you straight.

This is the old "If you can't dazzle them with you brillance, baffle them with **".

Thanks for the interesting theories though.

 

[beanoil]

Big Jim,
Disagree if you will, but how about dazzling us with some of your brilliance? I believe the expression is "back it up or back it out". As a tuner, you know how to get an engine to run on a given fuel. Great... Now how about tuning the fuel to the engine for maximum performance, or fuel economy, or whatever your goal is. I'm with Quest on this one. Choosing the correct fuel will make a difference in HP output, torque curve, and in some cases, max RPM. I have seen and dyno proven 2 hp gains from fuel changes only on MX bikes turning 14,000 RPM's. Octane is like rungs on a ladder.. GENERALLY speaking, you need only climb as high as needed to ward off detonation, but Octane ratings and flame speeds are two totally different animals, and come from different components of the fuel. Maybe your local library has the book titled "High Performance Automotive Fuels and Fluids" for reference. Or call Dr. David M. Redszus at PAR. He is worth a discussion, and may have something you could use. http://www.precisionautoresearch.com

[ September 19, 2006, 01:39 AM: Message edited by: beanoil ]

 

[Big Jim]

Beanoil,
Sure, tuning to available fuel is critical in hard competition. I could tune for substantual more power with about 25% aviation fuel mixed with street fuel. To do so required a slightly richer mixture (as confirmed with CO2 exhaust readings) as well as increasing ignition timing at the appropriate rev levels.

What's the main difference between aviation fuel and street gas? Mostly it is leaving out the light ends that help a car easily start when the weather gets a little colder. The elevation changes in an airplane make it very undesirable to have as much vapor pressure as is desirable with a car. Airplanes compensate for the lack of the light ends in the fuel with fuel heaters.

Oh, buy the way, the light ends burn quicker.