Here is some more info to throw at you guys. My turbo cam was spec'd by Kenny Duttweiler with a 242/242 dur @ .050 W/113 LSA.
Int opens @ 8 BTDC
Int closes @ 54 ABDC
Exh opens @ 54 BBDC
Exh closes @ 8 ATDC
With the above info, it looks like there is 16 degrees overlap. It also appears that the most that I should consider advancing this cam is 4 crank degrees with a resultant intake centerline of 109 degrees. This would put the exhaust closing event @ TDC.
Assuming that there is a 1:1 relationship between boost and exhaust backpressure, and also assuming that there will be no exhaust scavenging, what are your opinions on this cam ? Advance, Retard, start with a new grind ? Add more overlap ? This cam was installed straight up @ 113 intake centerline. My ultimate goal is to enhance turbo spoolup since I'm running a large turbo. My previous performance has been 9.86 @ 137 MPH in a 3700# car with a small 76 mm turbo. Engine pulled to 7500-8000 RPM so I have room to sacrifice some top end.
Allan G.