| FAQ |
| Members List |
| Social Groups |
| Calendar |
| Search |
| Today's Posts |
|
#1
01-23-2001, 02:32 PM
|
||||
|
||||
came across a cam with a 105 deg. lobe separation (100 int./110 ex.)
what would one guess as to the characteristics this cam may exhibit in a 455 with say 11:1 comp.? just curious because i have never seen this lobe separation stated for any pontiac cams i have come across. [This message has been edited by Larry Navarro (edited 01-23-2001).]
__________________
Home of WFO Hyperformance Shaker induction. |
|
#2
01-23-2001, 02:32 PM
|
||||
|
||||
|
came across a cam with a 105 deg. lobe separation (100 int./110 ex.)
what would one guess as to the characteristics this cam may exhibit in a 455 with say 11:1 comp.? just curious because i have never seen this lobe separation stated for any pontiac cams i have come across. [This message has been edited by Larry Navarro (edited 01-23-2001).]
__________________
Home of WFO Hyperformance Shaker induction. |
|
#3
01-24-2001, 01:52 AM
|
||||
|
||||
|
Larry , Tight lobe sep make lumpier idle and a "peakier" torque curve due to more overlap. Good for an open header 5 speed car that can keep the rpm all in one range. More like a SBC cam.
__________________
Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
|
#4
01-24-2001, 10:41 AM
|
|||
|
|||
|
Not so odd at all. Half Inch Stud runs all 104 cams.
------------------ "I open my front door and I hear my back door slam...."--Robert Plant |
|
#5
01-24-2001, 02:52 PM
|
||||
|
||||
|
so....this would basically mean that the 105 lobe separation already has an "as-built" design that someone would achieve as if they took a 108 lobe separtion cam and installed it 3 degrees advanced...right?
__________________
Home of WFO Hyperformance Shaker induction. |
|
#6
01-24-2001, 07:48 PM
|
||||
|
||||
|
Larry - No. The LSA is a physical dimension that is independent of how you install it. You can place the lobe center at different places. So the cams you mentioned are three degrees different in LSA. The 105 would be pretty radical. I have a 108 LSA on my street car (flat tappet hydraulic) and a 106 LSA on my racecar (solid roller). Both are installed about 2 degrees advanced.
------------------ Jim |
|
#7
01-24-2001, 09:18 PM
|
|||
|
|||
|
Lobe Separation Angle (LSA) is the distance between the centerlines of the intake and exhaust lobes. It is a physical characteristic of the cam as it is ground and cannot be altered by any reasonable means short of regrinding the cam.
The Intake CenterLine (ICL) can be set at any position desired, usually it's advanced some. If a cam has a 108 lobe separation, and the intake is put in at 104, then it would be said that this cam is installed 4 degrees advanced. If the cam had a 110 lobe separation and the intake was installed at 110 degrees, then it would be said to be "straight up." The smartass answer to your question is that a 105 lobe separation angle cam would behave somewhere between 104 and 106 LSA cams... That's a pretty tight LSA and will have a lumpy idle and peaky powerband as Skip already mentioned. Hope that clarifies things some.
__________________
---------------------------- '72 Formula 400 Lucerne Blue, Blue Deluxe interior - My first car! '73 Firebird 350/4-speed Black on Black, mix & match. |
| Reply |
|
|
The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.
Linear Mode
