Originally Posted by
Joshy
am i reading this wrong?
so a longer rod gives an unrelated, but similar effect to increasing CR?
I.e. allows you to build power (torque)in high and low RPM ranges by increasing cylinder pressures earlier?
(ignition timing and detenation supression dependent of course..)
Hence with the fuels that ford were running in the above example meant they could increase cylinder pressures off boost closer to det at lower RPM's without having to increase the CR or advancing the timing?
Yes a longer rod is a similar effect to more CR, but ONLY at top dead centre, the effect is shorter lived than compression.
So the rod will have a big effect at 0 degrees of crank rotation, but at say 15 degrees (where most performance engines tend to make peak cylinder pressures) the effect is less but for an increase in CR its still marked.