SPANKY LS1

iTrader: (24)

I *think* it is a common assumption that 114 lsa cams have more P to V clearance than 112 lsa cams (assuming same specs and degrees of advance if applicable) right? Now, assume a 230/230 cam. If you are comparing a 230/230 112+2 to a 230/230 114+4 (both installed on a 110 ICL), would they both have the same P to V clearance, or would the 114 still have more clearance? I *think* it is generally accepted that 114lsa cams have more P to V clearance than 112lsa cams, but is this assuming that they both have equal amounts advance ground into them, IE 112+2/114+2?

Thanks, Shawn

KYSpeedFreak

Im interested in this as well...

Damian

iTrader: (89)

Shawn, your Duration & ICL figures are the most crucial for figuring in P/V clearance. LSA is just that, lobe seperation. Raising & lowering your ICL increases or decreases your intake closing point, which will increase or decrease compression as well. This also has an effect on cylinder pressure, bleedoff, and cranking compression. A motor running a 110 ICL cam will make much more cylinder pressure than a 114 ICL motor. On high compression motors, I recommend not running anything lower than a 110 ICL and thats provided the cam has plenty of overlap for bleedoff. My motor detonated so bad it almost blew up w/ 110 ICL and 11.4:1 compression.....hence my 114+0 (114 ICL) cam.

Lobes will also have a GREAT effect on P/V issues. Thats one reason FMS camshafts need more PV when going bigger, their lobes are much more aggresive...

Giving that both cams are an exact copy, one being a 112+4 and 114+4 equalling a 110 ICL, they will both have very similar PV clearances..


josh