In instances where engines are designed for use with a dry sump system from the ground up, they can be built with lower tension oil rings. “With a dry sump oiling system, since there isn’t nearly as much oil in the bottom end, the rings don’t have to scrape as much oil off the cylinder walls. This lets you get away with running half as much ring tension as in a wet sump engine without burning any oil, which dramatically reduces friction,” explains Erik Koenig of HKE. “In fact, with the heads removed you can turn over a race motor by hand with as little as 5 lb-ft of torque with low-tension rings, whereas a street/strip engine with standard tension rings might require 35 lb-ft. That 30 lb-ft–reduction in drag at high rpm equates to a big increase in horsepower. In an engine with a 1/16-, 1/16-, 3/16-inch ring package, the combination of a crankcase vacuum, improved ring seal, and low-tension rings can net a 30-40hp increase. Since the pressure in a dry sump system is adjustable, they also let you pump the minimum volume of oil necessary to lubricate the motor, which further reduces drag and parasitic power loss.”

In race setups that utilize a separate vacuum pump, a dry sump oiling system allows cranking up the vacuum without fear of compromising oil flow. When a vacuum pump is bolted to an engine with a wet sump oiling system, it creates a tug-of-war in which increasing vacuum reduces oil pressure. That’s because there’s less air pressure inside the crankcase to help push oil through the oil pump. In many instances, trying to pull more than 16 inches of vacuum will negatively impact oil pressure. On the other hand, since a dry sump system stores oil in an external tank — where 14.7 psi of ambient air pressure is always pushing down on the oil regardless of crankcase vacuum — engine builders can pull as much vacuum as desired without adversely affecting oil pressure and potentially burning up the bearings. As Erik asserts, however, on a well-sorted engine combo, it isn’t always necessary to run both a dry sump oil pump and a vacuum pump. “If a motor is sealed up well with good pistons, rings and straight bores, you can make a lot of vacuum with just a dry sump pump,” he says. “With big power adder motors that get a lot of blow-by, you might run a vacuum pump in addition to dry sump oil pump. That said, with most all-out race motors, just having a dry sump oil system will generate enough vacuum to control oil flow and seal up the rings.”

Item Part Number Price
Pan 1005M $814
Pump 3255S $1,484
Remote filter 4010 $163
Oil tank 7030 $475
Tank vent 7100 $93
Lines/fittings N/A $392
Total: $3,421

SOURCE
HK Enterprises
Houston
TX
713-722-7000
www.hkracingengines.com
Armstrong Race Engineering
916-652-5282
www.drysump.com