Electricity and the modern nitro car

By Sam Logan, June 02, 2014

Goosein71HW-FCcockpitThere aren’t many people you can engage in conversation about the old days of drag racing like Mongoose McEwen. Though drag racing brought him to prominence, McEwen is defined as much as anything by his selfless behavior—a kindly man with none of the racer’s avid self-absorption—his upbeat humor and his remarkable memory.

“In the old days, at least up till 1952,” he explains, “we acquired our engines from junk yards. Flat-head Ford V8s or Oldsmobile Over Head Valve V8s were often the favorites. But when Chrysler, Plymouth and DeSoto introduced the Hemi we switched.

“We used to tune using the spark plug’s heat range. We’d start the engines on Powertips, which featured an electrode and porcelain that protruded from the tip. Then we’d change to a cooler plug when the engine warmed. One night at Orange County we forgot to change them and were amazed at how well the engine ran. So we figured in future we’d run with the hotter Powertips, and increase the fuel volume.

“At that time Top Fuel and Funny Cars operated with fuel pumps that delivered 10 or 11 gallons of fuel per minute; today Top Fuel cars deliver 120gpm. Can you imagine filling two 55-gallon drums in a minute? The trick is to put a lot of fuel in the cylinders, generate huge cylinder pressures, and ignite it—that’s where the power comes from: lots of fuel, lots of compression, lots of electricity.

“Our Fuel cars used 8 spark plugs; today they have 16—two per cylinder. We ran single ignition that didn’t have 10amps. Now they have twin MSD ignition systems each generating 44 amps. If you grabbed hold of them and stood in a puddle of water they would electrocute you!

“People have no idea how much cylinder pressure there is to ignite. If it doesn’t ignite it, it floods the bore and as a consequence the engine often “drops a cylinder”. You can see this on TV where it blows the fuel out the pipe—it floods the motor and substantially damages it. Boosted to around 30psi by a 1471 supercharger, which consumes 1,200hp to drive it, nitro-methane engines used to be rated at 8,000hp; now they have revised that to between 11,000 and 13,000hp. One cylinder of a Top Fuel car makes more horsepower than all 8 cylinders of a NASCAR Cup car.”

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