I mentioned a few entries ago that the updated Challenger II is using dry block engines that don’t require radiators or a water system. All the necessary cooling is provided by the large amount of fuel being fed to the engines. We estimate a consumption rate of approximately 20 gallons per minute, which works out to about 0.083 miles per gallon. The Brown & Miller fuel line is constructed out of braided stainless steel and has an unusually large diameter at 1.25 inches. It snakes through the streamliner’s superstructure in order to feed both engines.
Our fuel system utilizes four injectors per cylinder. One of the four is only used to start and warm the engines. A simple two gallon gravity tank sits on top of the body work and feeds pure methanol through the system while the beast gets up to temperature. When it’s suitably hot, Frank Hanerhan will radio me to turn on the internal pumps and we’ll switch over to the onboard nitro blend.
Given the car’s profile, the actual process of fuel injection is a real challenge. I sit in a semi-reclined position and look through a 7 inch curved windscreen. There’s almost 13 feet of body work in front of me, so keeping the manifolds and injectors low is essential. The intake manifold is only 5.875 inches above the top of block, and the throttle body is actually situated in front of it rather than in the apex position. All of this is duplicated in the rear engine for the sake of consistency. If something goes wrong, we don’t want to have to think about how to fix it.
All of this is being handled by the extremely talented Jerry Darien, who’s somehow managed to design a system that meets our extremely compact packaging requirements. How he’s managed to fit in the barrel valves, metering blocks, return lines, bypass systems and all the other component infrastructure is a little bit mind boggling to me.
Now, here’s the money question. If the engines are cooled by fuel, what happens to them if I let up on the gas pedal during the run? The simple answer is that they’ll probably blow up. There’s not really much room for compromise with this setup, so if I feel like something is going wrong, there is a good chance that I’ll cut the engines immediately. Finger’s crossed!
Thanks for following along. See you next week.