Lobe Seperation Angle

[93cobra1928]

I was reading up on this to find a good spec for a turbo cam and came across some conflicting info on calculating it.

Using my X-303 as an example, one way showed adding the intake center and the exhaust center and divide by 2. So 107+117/2= 112 LSA

The other way used an engine math calculator taking the advertised duration of 286 and the intake opening of 5* and the exhaust opening of 49* and it came up with 116 LSA

Why the difference?

[86GTPONY]

Ford Racing shows a 112 for the x-cam... sounds like the second method is off.

[coupe]

The first method is correct. You can get there with the durations and open/close events, but they have to be at the same lift measurement.