To further improve the 20V's flow capabilities, the stems of both the intake and exhaust valve stems were reduced in diameter from 6MM to 5.5MM and were further undercut behind the head of the valve. This not only helped improve flow through the intake and exhaust ports, but also reduced valvetrain mass to improve the already badass high, RPM stability of the SR20VE VVL cylinder head's shaft mounted rocker system.
The longer valves and unique long reach spark plug design of the SR20VE 20V cylinder head is evidence of another one of Nissan's improvements over the previous SR20DET, SR20VE, and SR16VE cylinder heads. Nissan opened up the cooling passages inside the cylinder head to help address one of the Achilles heels of the SR engine family, poor coolant flow.
So this is the basic DNA of the record breaking engine that we've dubbed the SR15VET 20V. In the next article, we'll meet the “23 doctor”, Nick Hunter of 5523 Motorsports, who was responsible for bringing this unconventional idea to life. Stay tuned, for an even more intimate look into the heart of our record breaker.