Postby brad smith » Tue Jun 30, 2015 4:02 pm
last Sunday was my first event with everything in place. Radiators in parallel, electric booster pump wired to run off grid battery when engine off and the on-board battery when engine on. It was about 90 degrees, with 60% humidity (after a popup rain shower in the first heat that put about 1" of water down on the course, but I got dry runs by my heat)
anyway - my cheepo electric water temp gauge said I was starting each run around 110-120 and by the time I pulled into my grid spot it was around 140-150. I will say that I had some major issues up at spring nats with a co-driver, but that was before the electric water pump.
I've learned a bunch about cooling. It's important to have as much flow as possible - the turbulence in the coolant is important to keep lower temp coolant mixing with the higher temp coolant in the passages of the engine and keep localized hot spots from forming. It can not flow too fast - speed is good. (so is turbulence inside your radiator - if the flow is too laminar the energised water molecules won't shed their energy because they become trapped inside the other water molecules and it's like an insulated sleeve.)
Cavitation though, that's bad. Make sure you have all of the air out of your system. If you don't you won't get high enough pressure to resist cavitation at the water pump.
Also - when I switched my setup from series to parallel - it halved my flow rate through the radiators. It wasn't fast enough to cause the turbulence inside the radiators needed to shed the energy efficiently. I was better off in series - until i got the booster pump. Now it's flowing like crazy through my engine and rads, keeping everything nice and cold. And i'm down on total weight for the system. The old radiators were heavy - the new ones saved me almost 5 lbs total even with the electric water pump.
Is there a better way to cool the engine - definitely. In my case it would have required more body work changes than I had time to do. In a couple years I'll probably revisit it and drop in larger radiators to help in keeping the system as cold as possible.