Lobe Seperation Angle

93cobra1928 · 02-21-2010, 06:43 PM

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 · 02-22-2010, 07:06 AM

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

coupe · 02-22-2010, 08:43 AM

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.

02-21-2010, 06:43 PM	#1
93cobra1928 Dazed and Confused Join Date: Mar 2009 Location: Northport, Al Posts: 778	Lobe Seperation Angle 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? __________________ Proud owner of 93 Cobra #1928 306ci Forged flat tops, Windsor Sr iron heads, FMS X-303 cam, OE Cobra upper and lower, 65mm tb, 70mm maf, 24lb injectors, BBK shorties, Summit H-pipe and Flo-bastards

02-22-2010, 07:06 AM	#2
86GTPONY Gone but not forgotten Join Date: May 2008 Location: 4/08/2013. Went to the man upstairs. RIP Posts: 955	Ford Racing shows a 112 for the x-cam... sounds like the second method is off. __________________ *-Don* 86GT (sleeping in the garage for now) 87 T-bird Turbo Coupe (daily driver) 87 Ranger ($100 work truck) Meat is murder!... Tasty, tasty murder.

02-22-2010, 08:43 AM	#3
coupe Super Moderator Join Date: Dec 2004 Posts: 6,313	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.