Originally Posted by phimosis

ok... Math class. Current technology with forged crank, pistons and rods is only stable to around 5,000 feet per minute of piston velocity (with ideal stroke vs. Rod length).

Example: Fastest spinning engine on market is yamaha r6 and has 44.5 mm stroke. Advertised redline is 17,500 rpm, but test equipment shows yamaha lied on tacho readings and real redline is 16,200 rpm. This equates to 4517.7 feet per minute.

Example: Corvette z06 with forged internals has 101.6 mm stroke and spins 7,000 rpm. This equates to 4666.6 fpm.

Example: Ferrari f60 car used in 2009 forumula 1 racing has 2398cc displacment, 98mm bore. Doing a little math equates to 39.74 mm stroke. At 18,000 rpm regulation redline, this equates to 4693 fps. In 2007 before they limited rpm, it was rumored they were able to get the engines to 20,000 rpm, which would be 5215 fpm.


In the case of the 370z with 86mm stroke, 10,000 rpm would equate to 5,643 fpm = fail.
Based on current technology, the 5,000 fpm ceiling would occur at 8,860 rpm. Seeing estimates of power from tuned 370z's in the range of 380 engine hp at 7500 rpm, this gives you 266 foot pounds of torque at your peak hp with stock head flow characteristics. Shifting that curve upward by valve timing could give you up to 445 hp at 8,800 rpm (based on 266 lb/ft torque). With a bump from 11.3 to 14.0 compression would yield approximately 5.48% more power (power increase or decrease (%) = [ (1 - 1/ crnew(.4)) / (1 - 1/ crorig(.4)) ] -1 x 100). This yields a theoretical maximum of 470 hp if you could work out the vvel timing, spark and fuel maps and if the flow characteristics of the heads are not maxed out.