Vintage Pontiac Cooling System Upgrade

Testing
Since the basis of the dyno session was to determine any power gains that could be attributed to a reduction in parasitic accessory drag associated with the factory water pump and 7-blade clutch fan, both the original OEM-style setup and the upgraded components had to be tested. To ensure comparable results, both configurations were tested at the same session.

Because the Tempest's upgraded cooling system was already installed, it would have been easier to test it first, then convert back to the OEM-style setup once testing concluded. Rather than test in this order, we instead converted the car back to the stock-type system and had all components of the new system ready to install at the conclusion of the baseline pulls.

The cooling system consists of a new custom-aluminum two-core radiator (retail $415) from Performance Rod and Custom (PRC). Other than a few spacers to raise the height of the radiator and some minor trimming of the radiator hold-down bracket, the high-performance unit was almost a direct-fit into the Tempest.	Rather than utilizing a belt-driven water pump, coolant exchange functions fell to a Meziere heavy-duty electric water pump (PN WP103BHD, retail $315) that fits '69-and-up timing covers. Available in multiple colors, the pump is rated for continuous street use and flows more than 40 gpm.	Replacing the factory 7-blade fan and clutch fan is a SPAL 16-inch electric puller fan (PN 30102047, retail $157.95), a 185-degree thermo switch, and a wiring harness (PN 185FH, retail $55.95). Once the fan and electronics were installed, the fan engaged automatically when the coolant temperatures reached 185 degrees, then cycled off when temps dropped to 175.
The use of a Meziere electric water pump required a Butler Performance Alternator relocation kit (PN TRP-ALT1, retail $85) as shown for the driver side, or mounted on the passenger side of the engine compartment (PN TRP-ALT2, retail $85), as utilized on this application. In addition to detailed instructions, both kits come with all of the necessary brackets, bolts and a belt for installation. A passenger-side kit is intended for applications without A/C, while a driver-side kit only fits cars with manual steering.	The OEM-style system and the PRC aluminum radiator are installed and ready to be tested on the dyno.	From beginning to end, the installation and dyno testing of the upgraded components took two hours. Included in the time was at least 15 minutes to allow the hot coolant to drain so that Floyd Hand and Marty Parker could complete the mechanical tasks devoid of hot fluids. Once complete, the system not only looked attractive, but added 19 rear-wheel horsepower to the already potent Poncho.

To be sure no false readings occurred attributable to differences in the cooling capabilities of the radiators, the new PRC radiator was left in place (minus the factory shroud).

This also provided a force function to ensure that none of the components of the stock system were left behind or went missing. An added bonus was that a stopwatch could be used to time how long it took to swap over the parts without unnecessary delay, such as having to slow down for step-by-step photographs. Since Meziere advertises that its water pump can be "changed in the pits," the challenge was on!

Dyno Results
Tests were conducted on a Dynojet 248 chassis dynamometer equipped with a wide-band O2 sensor. All horsepower and torque readings were converted back to SAE. Average horsepower and torque were taken from 3,900-5,900 rpm. In both the baseline- and dyno-tuned configurations, the peak horsepower and torque numbers were recorded at the same rpm levels. Peak horsepower occurred at 5,850 rpm, while peak torque registered at 3,950 rpm. Since the Tempest was equipped with a Turbo 400 automatic transmission and a 3,200 stall tight 10-inch Continental torque converter (Jim Hand Special), the car was pulled in Third gear. Rather than simply romping on it, which caused the car to downshift into Second (and invalidate the dyno pull), the throttle was eased down until just over 3,200 rpm, then mashed to the gunwales.