I race a BN7. Revs generally kept between 4,500 and 6,000, with
occasional forays to 6,500. Engine on the dyno shows constant torque
from 2500 rpm to 6000 rpm. Big drop-off in torque and horsepower after
6000. I have Carrillo rods and stock crank. Rods cost $225 each (13
years ago). Rods have lasted 13 years. Broke two crankshafts before
going to an upgraded stock crank. Here's what the machinist did:
"radiused" all the journals, balanced, and nitrided. Current crank has
lasted about 6 years -- no problems.
Gary K. Black, AICP
Hexagon Transportation Consultants, Inc.
40 S. Market Street, Suite 600
San Jose, CA 95113