Racecar Project - Flex Fuel Vehicle
#17
Nordschleife Master
Thread Starter
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When racing the 90 minute enduros I found that I need 5 gallons of fuel during the mandatory 5 minute pit stop. This requires a funnel and careful pouring of the fuel to prevent spillage which might ignite on the hot brake rotors or other components. It takes about 1:45 to pour 5 gallons of fuel into the car. In at least 1 enduro, I ended up adding 10 gallons because I wasn't sure if I could make it to the end.
One option to solve this issue is to use a dry break system on the fuel cell. Normally, you see a double dry break which has one side for fuel and the other for a vent for the air in the cell displaced by the fuel. This type of setup is complicated for a simple club race car. I worked with Fuel Safe to design a single dry break system for my fuel cell. This contains a single port for fuel to enter and something called a Discriminator valve which "discriminates" between fuel and air. Through this valve, the air in the cell displaced by the incomming fuel is released and when the fuel reaches the top, the valve shuts off and prevents fuel from spilling. All of this requires a special fuel container with a dry break connector. This system will fill 5 gallons of fuel in approximately 10 seconds.
Since I am going to use E85 fuel, the engine will consume somewhere between 30 and 40% more fuel making refilling during an enduro that much more difficult. In addition, the fill plate was annodized so that the ethanol would not corrode the aluminum.
In the first picture, the left vent is the discriminator valve and the right is the fill. In the center is a hole for the electrical connection for the in tank fuel pumps.
![](http://www.racetek-engineering.com/images/Drybreak1.jpg)
![](http://www.racetek-engineering.com/images/Drybreak2.jpg)
One option to solve this issue is to use a dry break system on the fuel cell. Normally, you see a double dry break which has one side for fuel and the other for a vent for the air in the cell displaced by the fuel. This type of setup is complicated for a simple club race car. I worked with Fuel Safe to design a single dry break system for my fuel cell. This contains a single port for fuel to enter and something called a Discriminator valve which "discriminates" between fuel and air. Through this valve, the air in the cell displaced by the incomming fuel is released and when the fuel reaches the top, the valve shuts off and prevents fuel from spilling. All of this requires a special fuel container with a dry break connector. This system will fill 5 gallons of fuel in approximately 10 seconds.
Since I am going to use E85 fuel, the engine will consume somewhere between 30 and 40% more fuel making refilling during an enduro that much more difficult. In addition, the fill plate was annodized so that the ethanol would not corrode the aluminum.
In the first picture, the left vent is the discriminator valve and the right is the fill. In the center is a hole for the electrical connection for the in tank fuel pumps.
![](http://www.racetek-engineering.com/images/Drybreak1.jpg)
![](http://www.racetek-engineering.com/images/Drybreak2.jpg)
![](http://www.racetek-engineering.com/images/Drybreak3.jpg)
#18
Professor of Pending Projects
Rennlist Member
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This great Geoffrey. I don't think we can thank you enough for sharing all this with us. From the start of the build of the car to now making it greener... Pretty cool stuff.
#19
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Geoffrey, I wanted to pick this up with you again...
How is the e85 working out for you? What changes to fuel flow (injectors, pump etc) had to be made in order to handle the increased consumption? What HP increases did you get from re-mapping on the Motec? Any other thoughts?
TIA
How is the e85 working out for you? What changes to fuel flow (injectors, pump etc) had to be made in order to handle the increased consumption? What HP increases did you get from re-mapping on the Motec? Any other thoughts?
TIA