Barnhart wrote:

Just remember that Ellison doesn't recommend using auto fuel through their TBI's.
http://www.ellison-fluid-systems.com/faqs/autofuel.htm

Barny

I wonder why?

Paul Lamar

A quote from Ellison's web site...
Use with Auto Fuel
The Ellison Throttle Body Injector has been designed specifically for aircraft use and has been thoroughly tested with aviation fuels. We do not recommend the use of auto fuel with the TBI. Several of our customers who have used auto fuel have had substantial damage to the rubber and metal parts of the TBI. When operated only on aviation fuel, we have never observed any deterioration of metal or rubber parts in the unit.
The EPA has required the oil companies to add oxygenates to auto fuel in in many parts of the country to reduce pollution in the winter months. In most areas this additive is alcohol which will damage aircraft fuel systems. In addition to possible chemical incompatibility, the high vapor pressure of auto fuel can be a problem when used in aircraft, as it is much more likely to boil that aviation fuel. Unlike aviation fuel, the formula of auto fuel is altered as the seasons change, so winter grade fuel is even more likely to form vapor.
Many of our customers have stated that they believe there is no chemical difference between aviation fuel and auto fuel. A dramatic difference can be demonstrated by pouring a sample of each into Styrofoam coffee cups. The aviation fuel will remain contained in the cup, but auto fuel will dissolve the cup and flow right through the bottom.

End of quote.

The last statement is assuming the auto fuel has alcohol in it.
Here in CA the pumps are marked when the fuel contains oxygenates.

Why does he not choose Viton, Teflon or Kalrez parts that are compatible with 
automotive fuel. Automotive gas does not destroy automotive fuel systems :-) duh!!

The vapor pressure issue does not apply with the electric fuel pump in the tank
or probably near the tank. Many aircraft carb engines have mechanical fuel pumps
located on the engine for low wing airplanes. My high wing C182 has no fuel pumps
at all and that is why most low compression engines in 182s and 172s will burn
auto fuel... no problems.

Most of this is nonsense for a modern EFI system like Tracy Crook's.

Paul Lamar
 
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