Have you heard? The old rules about cylinder-head flow are changing. It's not strictly about airflow anymore. If you're serious about making horsepower or at least knowing what the big dogs are doing to spin that horsepower meter, the new mantra is: get wet.
Wet-flow technology is where it's happening in the cylinder-head world. If you think about it for more than a moment, the concept makes perfect sense. Intake ports flow fuel along with air regardless of whether the engine is carbureted or fuel injected. The sharp cylinder-head designers have started looking at creating intake ports and combustion chambers that mix fuel more efficiently with air, and the results appear to be impressive.
Dart Machinery is the first company we're aware of to apply this wet-flow technology to off-the-shelf cylinder heads, starting with its Platinum line of iron small-block Chevy cylinder heads. After witnessing Dart Machinery's custom-built wet-flow test bench in action, we couldn't get back here fast enough to write about it. This is the future of cylinder-head development, and Dart is leading the way.
What is Wet Flow?
The concept is simple. If we're really going to make more power, we need to know what happens to the fuel once it is introduced into the cylinder head and especially what happens as that air/fuel mixture blasts past the intake valve on its way to the cylinder. Well over 20 years ago, high-performance automotive scribe Jim McFarland's tech stories began discussing the concept of the "quality" of airflow into an engine, emphasizing the importance of properly conditioning the fuel as it entered the combustion space.
A few years ago, Joe Mondello and his partner, Lloyd Creek, developed the first commercially available wet-flow bench using an industrial solvent similar to gasoline in specific gravity that could be used to trace fuel movement as it traveled past the intake valve and into the cylinder. Mondello's wet-flow bench adapter is designed to be used with the SuperFlow 600 flow bench. The guys at Dart Machinery used many of the Mondello concepts but built their own massive flow bench specifically to move air at much higher Pro Stock-style flow rates. While the SuperFlow 600 bench can achieve flow up to roughly 600 cfm with large ports at 28 inches of water test depression, Dart's new bench is capable of a massive 55 inches of test depression with even the largest of Pro Stock heads flowing at valve lifts in excess of 1 inch. Owner Dick Maskin is still heavily involved with NHRA Pro Stock engine development, and while this bench was originally intended to help in Pro Stock cylinder-head R&D, the eventual goal was also to use it to improve the power potential of Dart's own line of small- and big-block street and race cylinder heads.
There is no high-performance cylinder-head crystal ball, but this black light dance of air
This is the bench that Dart built. The guys spent more than a year building and developing
Dart also uses its SuperFlow 600 and the latest 1020 dry benches to develop intake and exh
Any bench that can pull 55 inches of water test depression at 0.600-inch valve lift on eve