Coolant Chronicles
What you pour into a radiator is also an important decision if you want to protect all those expensive aluminum engine components. Straight water is the most thermally efficient coolant, but anticorrosion issues and cold weather demand antifreeze. According to Jay Ross at Applied Chemical Specialties, the best water to use is soft water. Distilled water is not a good idea because distillation strips ions from the water. When it is introduced into the cooling system, the natural chemical-balance process will pull the ions from light metals such as aluminum or magnesium that are exposed to the water. This ion transfer greatly enhances the corrosion process called electrolysis. Soft water is treated with sodium chloride that replaces the lost ions and minimizes the electrolysis process. If soft water is not available, then bottled water or tap water is the next best solution. If you insist on distilled water, Ross says mixing it 50/50 with antifreeze will pull ions from the antifreeze rather than from your cooling system itself.
Purple Ice and No-Rosion are...
Purple Ice and No-Rosion are excellent anticorrosion additives that can be used with either straight tap water or mixed with antifreeze to reduce the formulation of corrosion and scaling in the cooling system, which can reduce the performance of your cooling system.
If you are a drag racer who is required to use straight water, a high-quality anticorrosion additive is essential. We've found the No-Rosion additive from Applied Chemical works very well. A pint of this additive applies a thin anticorrosion layer to the cooling system to fight deposits and limit the effect of electrolysis, yet it does not hurt heat transfer. Royal Purple's Purple Ice is another anticorrosion product that uses additional additives called dispersants to help reduce the formation of steam pockets in the cooling system, which can reduce heat transfer from the combustion chamber, causing detonation and boilover. Additives such as Red Line's Water Wetter and Purple Ice address this by reducing the size of these steam pockets. When steam pockets form, they act as insulators, preventing heat transfer out of the combustion chamber. While it may seem obvious, it's worth noting that these additives will not help a car with problems such as an undersized radiator or insufficient water or airflow. These additives are not a mechanic in a can.
The Electric Side of Cool
What most car crafters rarely consider is that the early '60s and '70s vintage alternators rated at 60 to 70 amps were not designed to crank out maximum amperage at idle. Late-model alternators or high-performance alternators rewired by companies such as Powermaster are designed to generate greater amperage at idle. These more efficient alternators are capable of delivering the 40 amps or more required of dual fans running at full boogie along with a big electric fuel pump, lights, and maybe a thumpin' stereo. Add the draw from a pair of headlights and perhaps a defroster or A/C fan, and a load of 50 to 60 amps from the alternator at idle is not unusual. This will also require large 8- or 10-gauge wiring from the alternator to the underhood power source for your fans and multiple solid-ground circuits between the engine and the chassis. A good ground also means the ground wires should be of equal size as the power leads. The biggest electric fan won't run at anywhere near peak efficiency if the ground circuit suffers from resistance. A simple voltage drop test will tell you if the wiring circuit is the culprit.
 Did you know that a bad ground...  Did you know that a bad ground could cause electrolysis in your engine's electrical system? Use a digital voltmeter capable of measuring millivolts and attach the ground probe to the radiator. With the engine running, dip the positive test lead in the coolant not touching the radiator. If the reading is more than 150 millivolts, the coolant may be excessively acidic. If it reads anywhere near 300 millivolts, try adding a good ground from the chassis back to the battery. |  Spal makes this slick pulse-width...  Spal makes this slick pulse-width modulating fan controller, which is programmable to control either single or dual electric-fan speeds. The first level will spin the fan at half-speed. At the second trigger point, the fan will spin at 100 percent. It can also control two fans with the second on when the A/C is activated. This is done with simple dipswitches on the side of the controller. |  A 70- to 100-amp-output alternator...  A 70- to 100-amp-output alternator capable of delivering at least 50 amps at idle should be a part of the design package for any electric-fan cooling system. Make sure the wiring can handle this additional current flow without melting the connections. |