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I know this sounds counter-intuitive, but is there any way my car would run hotter with a smaller water pump pulley designed to spin the pump faster at all rpms? It may be a coincidence, but after I replaced the stock pulley with the smaller diameter one and drained/replaced my coolant, the car now runs about 10 degrees hotter at idle and cruising speeds. I do have an Edlebrock high flow pump. Is it possible to move the water too fast and end up running hotter? Thanks, Evan
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Hi Evan,

My guess would be you still have air in the system... You cannot move the water too fast...

Since the speed varies with RPM, the current idle speed would be the same as the old minus approximately 80 rpm. For example, if the pulley speed was 800 before at idle, the new speed would be 880 approximately. Cavitation, if it were to occur, would happen at way higher speeds.

You have air still trapped in the system somewhere...

The idea that the coolant flow rate of the Pantera's cooling system is too slow (especially at low rpm) is not new. John Taphorn has been advancing this for at least a decade. I've seen very old articles in Pantera International News also advancing this idea. I've held this opinion since long before I purchased mine.

Odoardo Govoni raced a group 4 Pantera (chassis 2873) for 11 seasons (1974 to 1984). He won 3 Italian championships and one European championship. He claimed Bertocchi made one improvement to his group 4 Pantera's cooling system, i.e. installation of a smaller water pump pulley. This is where Scott and I got the idea for this mod. That pulley is a mod that the Pantera has needed for 40 years, and I applaud Scott for bringing it to market. I am not exaggerating when I say every Pantera needs this pulley.

If you own the De Tomaso Racing Book by Olczyk you can find a short 2004 interview with Govoni on page 102 where the pulley is mentioned.

Air collecting in the radiator is another problem, the only way to resolve this is to install a header tank and plumb an "air-bleed" from the radiator to the header tank.

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