Behind the Technology
Many hours of research have gone into developing our performance technology. To help you better understand the theory behind our technology - the how and why - we have included a brief summary below.
Based on our extensive study of airflow we have developed our MPG Port Plates. These port plates dramatically increase the amount of engine torque and horsepower.
Our studies have disproved many long-held assumptions regarding cylinder head porting. The shape of the port, not the size, determines the airflow through any port. Depending on their shape, smaller ports can flow more air than larger ones. This is why many of the new sophisticated race heads have significantly smaller ports than previous high-performance heads. When more air volume flows through a smaller cross-section, the air speed or velocity increases.
Airspeed in cylinder heads is important because it allows cam profiles with later intake valve closing points. Closing the intake valve later, in conjunction with very efficient (High-Velocity) intake ports, increases the volumetric efficiency (VE). This is commonly known as inertia supercharging. Using ports plates, and custom cam profiles can generate VE's in the 105% to 108% range.
Many people think that port plates restrict airflow, but actually port plates allow more air volume to flow through a smaller port. Additionally, they do not require machine work to install.
351C / Boss 302
Intake: On the street, or where midrange torque is important, the Cleveland ports are not effective. At midrange air velocity slows and the vacuum signals pulsing through the ports become confused because of the volume. Due to the slow air speed, fuel drops out of suspension, mixture distribution becomes a lottery, and throttle response is poor. The Cleveland heads need smaller ports, exactly what MPG Head Service delivers with our port plates. Our port plates force airflow into the naturally higher velocity section of the port and produce beneficial effects on throttle response and mixture distribution.Exhaust: When the exhaust valve opens on a Cleveland or Boss 4-valve engine, the expanding airflow path wants to follow the roof of the port. However, the floor of the port falls off dramatically at the header/exhaust manifold junction, causing the column of air to expand. Whenever a column of air expands, it stops flowing or stalls.
The port plates raise the exhaust port floor approximately 1.5 inches. When the engine RPM is low, the column of exhaust gas wants to reenter the exhaust port (because of 14.7 inches of atmospheric pressure in the exhaust system). This phenomenon is known as reversion and it hurts low RPM torque by diluting the quality of intake mixture in the cylinder. The port plate creates a wall that when the air column tries to turn and reenter the port. The air column strikes the plate and stays captured in the header pipe, where it belongs.
Dove Heads
On Dove Heads the exhaust ports quit flowing above .500 valve lift, limiting the torque and horsepower of the engine. We recommend removing the ERG boss in the roof of the port and performing the usual bowl blending etc. We also recommend that there be no grinding of the port floor because its already too low from the factory. Like the 351C, bolting MPG Port Plates onto the exhaust side, is an instant way to solve the exhaust port flow problems. The plate will help any C8, C9, DOVE head ported or not, and gives you the same anti-reversion qualities. as in the 351C/Boss 302.Return to Port Plate Details
On a performance motor, the crankshaft's counter weight speed routinely exceeds 100 mph. A spinning 3.0" stroke does this at only 5,000 rpm. Without a well-designed oil control system, the crankshaft must spin through large drops and sheets of oil. The result of the oil's "interference" with the spinning crankshaft is lost horsepower or "windage." Efficient oil control systems quickly return the oil to the pan and help keep the crankshaft free of unwanted oil, thereby restoring the horsepower that would have otherwise been lost to windage.
Over the years our technicians at MPG Head Service have studied the effects of windage in Ford engines and have tested about every type of windage tray on the market. We went as far as fabricating an oil pan with a Plexiglas window just to see what goes on inside the pan during full throttle, high rpm dyno pulls. The best way to describe the chaos that the crankshaft creates is to liken it to a trailer tire with no fender going through a never-ending puddle of water. Oil fans out 360 degrees. In our tests we found that the full wrap designs worked pretty well but there was room for improvement. Fabricating and installing a simple 35-degree "J" style scraper made a significant difference, but at higher rpm it was clear that oil was stacking up under the scraper. To solve this problem, we pulled the outer edge of the tray back toward the center of the crankshaft, creating a half wrap. This allows oil to be thrown free of the crankshaft and captured under the tray.
Today our MPG Windage Tray Kits are the most efficient designs available anywhere, and we continue to update them as we learn more.
The use of the MPG Windage Tray Kit allows the engine to achieve maximum horsepower by quickly dispersing oil, leaving the connecting rods and main bearing areas clear so the large drops of oil do not bounce off the interior of the oil pan back onto the spinning crankshaft.