Cooling-System Loopholes

Cooling Was Required. Constant Cooling Was Negotiable.

Dave Marcis wasn’t trying to run 500 miles during qualifying. He needed a couple of very fast laps, after which he could lift, bring the Dodge home and worry about engine temperature before expensive noises started.

That changes the engineering conversation. During the race, the radiator needed a steady supply of air. During qualifying, Hyde needed enough cooling to keep the engine healthy just long enough to get the number on the stopwatch.

So he put a movable flap in the radiator opening.

When cooling was important, the opening could admit air. When straight-line speed became more important, the flap could close and send that air around the car instead of through it.

Same Dodge. Same radiator. Less aerodynamic argument going through the nose.

From Hyde’s side of the garage, this was simply intelligent management of cooling air.

NASCAR had another description available.

The Inspectors Were Already Having a Fine Afternoon

The timing could hardly have been better if Hyde had deliberately scheduled his trick for maximum irritation.

A.J. Foyt had just produced the fastest qualifying speed. NASCAR inspected the car and found a hidden nitrous-oxide system. Darrell Waltrip had been second fastest, so his car received the same attention and produced another nitrous setup.

Two cars. Two bottles. Two reasons for the inspectors to quit assuming anything at Daytona was innocent.

➤ See Darrell Waltrip in Racing Legends

➤ See the 1976 Daytona nitrous affair in Racing Shenanigans

That left Dave Marcis third on the speed chart with Harry Hyde’s Dodge waiting for inspection. By then nobody was walking over to admire the paint or compliment the spark-plug wiring.

NASCAR started looking.

There was no nitrous bottle. Hyde had not bothered copying the trick they had just found twice.

He had brought his own entertainment.

Somebody Found a Door in the Radiator

The inspectors eventually reached the radiator opening and discovered a component radiators had managed without for quite a few years.

A door.

Hyde’s flap could close the opening during the qualifying run. Instead of ramming a wall of high-speed air through the grille and radiator, the Dodge could clean up its nose and leave more of that air outside where it caused considerably less trouble.

The mechanical logic was difficult to argue with. Unfortunately for Hyde, the aerodynamic logic was just as obvious.

Harry could point at the radiator and explain that it was still a radiator. NASCAR could point at the movable piece closing off the front of the car and ask why a cooling system had suddenly developed an interest in drag reduction.

Cooling systems are expected to move coolant, carry hoses, hold pressure and keep engines alive. Once one starts changing the shape of the nose according to what the stopwatch wants, technical inspectors tend to lose interest in what the part was originally called.

The radiator opening had acquired a second job.

NASCAR threw out Marcis’s qualifying time.

Harry Still Liked the Idea

Hyde never seemed particularly convinced that NASCAR had appreciated the engineering properly. From his side, he had found a way to stop wasting cooling air when the engine didn’t need it. From NASCAR’s side, he had built movable aerodynamic bodywork and hidden it behind the respectable occupation of cooling an engine.

Both descriptions involved exactly the same flap.

Only one was going to survive inspection.

That is what makes the trick so good. Hyde did not need another horsepower trick, a mysterious engine part or something buried where the inspectors couldn’t reach it. He looked at an ordinary radiator opening everybody else treated as permanent and asked a very dangerous racing question.

Why leave it open when you don’t need it?

The hole in the nose was there to let air in.

Harry Hyde gave it the good sense to know when not to.