Originally Posted by Epstein
SR20DET crank? Why can't you just use the QR20DE crank? ....of course I have no idea what the stroke is on a QR20.... hmmm
*edit* yeah, those sounds like some nasty cams! I hear a lot about that guy. Is he like the FWD god or something?
Yeah it lopes like crazy.
He's done a lot of pioneering w/ the B15 SE-R chassis, and the QR25DE.
The QR's stroke and rod length yields a 1.43 rod to stroke ratio, possibly the lowest of any engine on the market, definately the lowest of all Nissan engines. the high piston speed and short dwell time at TDC leave little time and room to fill the cylinder. (why the QR25 hyperventilates on the top end) The QR20DE crank is a direct fit in the QR25. The bore is the same as the QR25DE (89mm) but it uses an 80.3mm stroke producing a slower piston speed. Comparitively, the SR20 crank would produce a QR that is able to utilize it's high flow head efficiently and also yeild about 2150cc displacement. The shorter stroke and longer rod would be better for high rpm power, and take advantage of the tall deck height on the QR engine (no more hyperventilation) Basically you can get more displacement out of the SR crank, or more RPM's out of the QR crank.