Finally, we ordered an oil filter housing lid from UUC Motorwerks to accommodate the oil temperature sender from the SPA gauge. With two 1/8" NPT (national pipe thread) taps, this lid can accommodate both oil temperature and oil pressure sensors, taking the guesswork out of how and where to install them.
Benchmark
With new parts in hand, we took the car to Modified by KC Performance for the installation and testing. Right away, the car was strapped to its 424x Dynojet dynamometer. Our goal was not only to see the affect on temperature of the new cooling products, but to also see if better performance would be a byproduct.
Our new gauge registered water and oil temps of 190F and 180F, respectively. We also recorded an intake air temp (IAT) of 95F from the shop's Snap On OBD2 scan tool. This established a baseline. From here, each pull would start with the same temps, and with 100% water in the cooling system to further limit skewing of the results.
To put more strain on the cooling system we also tested in fourth gear, and with the hood closed. Bear in mind, this wasn't an attempt to recreate what we'd see on the street, but to simply see the differences during the abuse in a more controlled setting.
After each 7000rpm pull, we took coolant readings exactly 30sec after, giving time for the heat to transfer into the cooling system. Our baseline pull started life at 190F, and 30sec later averaged 208F.
Testing
We got to work on the Stewart water pump, which was a straightforward install. After bringing the car back up to temp, we did another series of dyno pulls. Unfortunately, the coolant temp soared to 208F after 30sec again. This indicated we had another bottleneck in the system - it had to be the radiator.
Installing the radiator was fairly straightforward. And while some people reported the need to grind down the fan shroud for better clearance, ours dropped right in.
Our next test showed an improvement, thankfully. With a 190F start temp, the coolant averaged only 199F after 30sec.
To see if there would be a performance gain, we also performed a 30-150mph pull, using third, fourth and fifth gears, before and after the radiator installation. As it transpires, third and fourth gears didn't show any significant gains or losses. However, a long fifth gear pull seemed to heat things up sufficiently so that, in the 122-150mph portion alone, the PWR radiator was worth an average 3whp and a 0.15sec improvement in acceleration- every little bit counts!
Next time, we'll try a similar dyno test with our 80C (176F) thermostat and see how much the 14F difference in thermostat operation is worth. We'll also tackle a few basic suspension components to improve handling as well.
We'd like to congratulate BimmerWorld owner James Clay for winning his first Speed touring car race at Elkhart Lake recently. And thank MKC Performance for its assistance in both the testing and trouble-free installation.