With the coolant passages all but eliminated after fortifying the cylinder block, Mark Luton relies on cool cylinder heads to maintain a comfortable engine temperature in the twin-turbo 351ci Mod motor that powers his Outlaw 10.5 car. To that end, he uses a Davies Craig EBP25 water pump to push coolant through the heads during the run.
“It’s like a fire hose coming out, as far as the flow,” says Luton.
The pump is mounted up front in the vehicle and close to an 1.75-gallon aluminum tank. Coolant is drawn from the tank, through the pump and fed to a Y-block that distributes the water to each cylinder head. Coolant is collected again through a Y-block behind the heads and returned to the tank.
“We have temperatures at the end of the run, and with no radiator, at 160 degrees on a 85- or 90-degree ambient day,” says Luton. “So it moves enough water to keep the engine cool.”
The Davies Craig EBP25, which stands for electric booster pump, features a brushless motor turning a centrifugal pump rated at 25 liters (6.6 gallons) per minute. The compact design weighs only 995 grams (less than 2.2 pounds), and the pump draws only 3.5 amps.
“We run it on a 16-volt battery system, so it’s probably putting out a little more than it would an average alternator car,” adds Luton.
Davies Craig rates the motor life at 15,000 hours and notes that the burst pressure is 36 psi minimum. It’s available as a stand-alone unit or in kit form with a wiring loom. Besides reducing heat in the engine, it’s also a leading choice for racers using air-to-water intercoolers. Additional water-circulation applications for this pump includes camping for outdoor showers or water taps, marine and irrigation. But Luton’s Modular Motorsport Racing team finds it’s a perfect tool for his cooling system.
“We’re basically using the cylinder heads as a heat sink to help draw heat out of the block,” says Luton. “The coolant temperature depends on the temperature at the truck. We can even fill the tank with ice to cool down the engine between rounds.”
The pump can be controlled with a Davies Craig digital controller or with thermal switches.