| I believe most of the major piston manufacturers are changing their forgings to reduce the width of the pin boss and skirts to lighten them and increase rigidity. This is a good example of F1/NASCAR/NHRA technology trickling down. JE calls their forging "FSR" (Forged Side Relief), note the scalloped areas outside of the pin boss that remove unnecessary weight along with the angular gussets that project from the pin boss to support the top of the piston and ring package. Also the inner bracing is moved inboard to the pin bosses and supports the skirts and piston crown better with less material. These are 87.5mm, 9.0:1 and JE's website lists their weight at 314g but my scale measured 320g. The pins pictured here are JE's standard 0.150" wall pin (98g) and an upgraded 0.230" wall pin (131.5g) for higher load capability. These pins are 0.250" shorter than the pins used in previous piston forgings and the 0.230" wall weighs the same as an old Wiseco "upgrade" 2.500" long x 0.197" wall pin... more strength and no weight penalty, not a bad trade in my opinion. For comparison to Wiseco and CP old-school forgings, here's a post from EPR, roughly a year ago. 
|
New piston forging for VGs from JE - 
