I just found an old article that I wrote decades ago. I haven't proofread it. But it is what

I THINK! Ollie

Tuning tips for hot weather

A race engine is a lot like the human body.  Working outside on a hot, humid day, it is hard to breathe.  By contrast it's much easier to accomplish the same task on a cool day.  There are several products on the market that can keep your engine and the fuel going into it cooler.  Let's examine some of them with tuning tips that will keep your car running strong in hot weather.

In order to cool down your engine and fuel you must think in terms of removing heat. The task of the radiator is to cool the engine.  The most efficient models, from a weight standpoint are made of aluminum and plastic.  Some came as original equipment on foreign cars, but it’s better to buy one made specifically for drag racing.  Former Pro Stock racer Paul Blevins has been researching the effects of detonation.  Tests have shown that greater radiator efficiency may be gained by employing the radiator constructed of two rows of 1/4" tubing with 16 fins per inch versus four rows of 3/4" tubing.  The ability of a radiator to cool an engine is affected by the rate that the coolant flows through it, and the amount of air that passes over it.

Common sense is usually the best ally when figuring ways to improve airflow to the radiator.

If you examine road race and circle track cars you can glean ideas on how to route the air in such a way that cooling is optimized without destroying aerodynamics.  In the heat of the summer grille openings that may have been taped over to make the body smoother, could be uncovered to allow the engine to run cooler. Electric fans affixed to the radiator ensure airflow through the core even when the car is stationary.

According to prevailing conditions you may be able to just use the fan before or after the race, reducing the car and drain on the battery, which must also power the ignition.  If the fans are thermostatically controlled, you may want to activate it at a lower temperature during the summer months so that the fan is capable of keeping the temperature under control.

There are several options open to drag racers.  Stock water pumps have given way to aluminum castings which obviously reduced weight, but some models also contain low drag impellers, and flow capacity tailored for high RPM racing engines.  Contact the manufacturer and carefully read all specifications and features.  Even with low drag impellers, engine driven pumps use horsepower that could be moving the car down the track. 

One solution is to use an electric motor which drives a standard water pump.  It can be switched on and off as needed and will handle most cooling chores.  Drawbacks are size and weight in the number of nuts bolts, washers and brackets required.  The latest device on the market has moved drag racing cooling systems to the next plateau.

 Moroso performance has developed the pump and motor combination for small block and big block Chevrolets.  It bolts to the front of the block where the stock pump originally was and is only less than 5 inches deep.  Inside the aluminum housing is a built-in 12 V electric motor capable of pumping 16 gallons of water per minute and is 8 3/4 pounds lighter than the water pump and drive kit normally used by drag racers. 

When between rounds cooling is needed an ordinary garden style pump sprayer filled with cold water can be sprayed on the radiator core while the electric pump circulates coolant.  This combination makes short work of virtually any cooling problem.

Midsummer heat, it’s not unusual for the gasoline in the carburetor or fuel line to change from a liquid to a paper.  The facts of this cause the engine to be down on power, to vapor lock and to be unable to start, as a worst-case scenario.  Be aware of where your fuel lines are routed and how you store racing fuel.  It's best-kept in sealed containers in a cool dark place.  Once you pour it into the fuel tank try to keep it out of the direct rays of the sun.

Several years ago, ingenious drag racers coiled aluminum tubing around the inside of coffee cans and filled them with ice, making the first cool cans.  Several manufacturers have improved on the originals by lining the cans with cork and sealing them with a tight-fitting lid to make the ice last longer.

 Moroso has another idea.  Their container has a polyethylene outer shell and a foam plastic inner wall which combine to provide better insulation for keeping ice solid.  A cast aluminum heat exchanger inside the can has 30% more surface area which means a 20% reduction in temperature over the coiled tube design.  The 3/8-inch NPT female inlet and outlet simplify the connection of either braided line or rubber hose.

Whichever cool can you choose, consider where and how it is mounted.  The most common location has been in the front of the car, close to the carburetor.  Shielded from any excessive heat source, where it is easily accessible for checking and adding ice and draining excess water.  Insulate the fuel lines in some way.  Several types of the cheap shield material are commercially available, but many racers use aluminum foil with satisfying results. 

One Pro Stock team taking advantage of the increased efficiency of the cool can in the trunk recirculating all of the fuel in the fuel cell between rounds thus insuring the coolest densest fuel charge possible.

With fuel moving through the carburetor in a relatively cool liquid state, the next encounter is the actual temperature of the car.  As heat rises from the engine and automatically transfers to the carburetor this is called heat soaked.  Fuel becomes hot enough to boil in the bowls.  Several manufacturers offer carb spacers that shield the carb from the engine heat. The most popular materials for these spacers have been plastics including phenolic base sheets.  These are very effective in comparison to an aluminum spacer. They drastically lower the temperature of the carburetor body. 

 NASCAR legends like Smokey Yunick, and Junior Johnson used these carburetor spacers 30 years ago.  They are light weight and capable of transferring heat.  In addition to being excellent heat shields.

Now let's try some tuning adjustments that will help cope with the dog days at the track.  These tips are based on practical experience and will get you headed in the right direction.  If it's in your budget, tuning for the dragsters entered the computer age.  Nova computers offers several hardware and software combinations.  One program can predict to three decimal places next round ET at mile per hour based on changes in the weather.  The company can also provide a weather calculation program to compute relative humidity corrected altitude vapor pressure. without a computer you can study the following examples to achieve the same results.