Originally Posted by
maxflo777
Thats exactly what I'm talking about.
When an all-out racing engine is what you have in mind a cam will give you more.
Just look at the angle that the air way has in that rotary valve and only that gives back a chance to the poppet valve, and at the end you see the gears moving the shafts that rotate the rotary valves, there's the linearity that will kill it when you put it again side by side with a poppet valve race engine.
They say +14,000rpm, ok, but a hot bike will also do that all day, and a racing 1.6L-2.0L Honda is pretty close too, not to mention F1! and our little 4 strokes!, and way more importantly a poppet valve engine will probably have more power up there because of the timming available with the design. Whats good to be able to spin 20,000rpms if your torque curve is scrapping the floor?
X
Umm dude do some reading on the Coates design, it absolutely smokes a poppet valve engine in performance....not just beats it, smokes it....they did several v-8 engines and the results were absolutely stellar....
heres a test by popular hotrodding on a Coates conversion on a Ford 302
Where the CSRV really shines is in its airflow potential compared to a poppet valve Bench-marking a 5.0 L engine from a Lincoln, the stock Ford casting (when tested at 28 inches of H2O) flowed approximately 180 cfm on the intake port at static. The rotary valve for the engine in comparison flowed a whopping 319-cfm at the same test pressure. Equipped with the poppet valve head, the Lincoln engine dynoed at 260 hp and 249 lb.-ft of torque. When equipped with the CSRV head at the same 5,500 rpm test protocol, it made 475 hp and 454 lb.-ft of torque, with no changes to the block or rotating assembly: The higher power was a result of diminished frictional and pumping losses, but the inherent airflow benefit of the spherical valve was the major contributor. With a conventional poppet valve, it can take 34 degrees of crankshaft rotation or more to reach a fully open position, wasting energy and limiting volumetric efficiency. With the CSRV, a comparable port area is exposed in only 2 degrees of crank rotation. The CSRV allows for superior surface flow coefficients from its spherical shape. With the standard 4-inch Ford bore, the factory poppet valve covers only 15.8 percent of the total bore area, while the rotary valve is measured at 20.5 percent.