The electric water pump passed the test. I had two days of racing in 100 degrees and it worked perfectly. The first day of racing I would hook up a spare battery to the car and let the water pump/fan run in between runs. There would be a 15 minute gap between runs and the car would cool down by 20 degrees. The temps never went higher than 180. The cooling system got a real test at the second race. At that race, there was no cool-down time. There was only 5 minutes between runs. Not enough time to even shut the motor down. The coolant side of the cooling system worked great and the coolant temp never went past 190. Now the oil temp was another story. After about the 7th run, the low oil pressure light would come on at idle. For the last three runs I had to keep the rpms up to keep the pressure high enough so the light wouldn't come on.
So after getting it home I put the car on a lift so I could give it the post-race inspection and oil change. I switched to a 10/30 for the upcoming fall/winter racing. I might go with an even thicker oil for next summer. I also inspected the cooling system and discovered that the placement of the electric water pump was not ideal. Air pockets were collecting inside it and that would affect performance and lifespan. The radiator and water pump needed to be moved into a different position. The water pump needs to be lower than the radiator. At first I tried working with the single boxster radiator but I decided if I have to re engineer it, I might as well go with a bigger radiator. I went to the local pick-n-pull with a tape measure. I measured a bunch of radiators but most were too wide. Like Jon, I ended up using a 2001 toyota corolla radiator and cooling fans. It fits perfectly and looks like it holds as much coolant as a single radiator but has a much larger cooling surface. I grabbed the mounting brackets off the corolla and fabricated my own radiator mount.
I also found a set of wheels off a 996 with brand new winter tires on craigslist for $500. That was a rare find here in Texas! Most people use winter tires for racing rallycross if they can't afford real rally tires.
