What were the specs on the peanut cam (305 LO3 cam) and how much better is this one.
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Junior Member
Joined: Nov 1999
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From: South Riding, VA
What were the specs on the peanut cam (305 LO3 cam) and how much better is this one.
I was wondering what the specs were on the 92 305 tbi cam were and how much better this cam is (this is the one in the car now). The specs on the Comp are Intake 206 and exhaust is 210- seperation is 112 with the intake at .3000 and exhaust at .3200. I also have no idea as what these numbers mean either. Thank You for your responses.
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Joined: Sep 1999
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From: Philly, PA
Not really sure of the peanut cam specs but I know they were really mild- like under 180* intake duration at .050", not a lot of lift, either. So the cam you mentioned is a fair bit hotter, but totally streetable, smooth idle, good mileage, etc. You won't have a lumpy idle at all with that one.
Duration is how many crankshaft degrees the valve is off its seat (open). The numbers you gave are most likely for duration "at .050"- how many crankshaft degrees the valve is at or above .050" of lift. The "advertised" duration is going to be higher since it is usually measured at only .002"-.006" of valve lift and the spec varies from manufacturer to manufacturer. .050 lift specs are easier to compre between different cams since it is pretty much an industry accepted standard.
The lift spec is just the maximum height the cam will lift the valve. The numbers you quote are most likely lift AT THE CAM LOBE and need to be multiplied by 1.5 to get the actual lift at the valve. If you plan on using "1.6" rockers then you multiply that number by 1.6 instead. Stock rockers are 1.5:1 ratio.
Lobe separation is the number of degrees the intake and exhaust lobes of the cam are spread apart as measured from their respective lobe "centerlines" (which is not the same as the point of maximum lift). It is a spec designed into the cam and can not be changed. Lots of confusion around what the "best" lobe separation is and way too much to try to cover here but generally for a street car with a mild performance cam 112* is about what you want, although it is generally accepted that TPI engines like a little more- like 114-116 lobe separation.
------------------
94 Firebird Formula M6- No options but Z rated tires. No mods over $10. 13.5@105.
79 Malibu "beater" w/junkyard 400 SBC, tweaked QJet 4bbl, finally a decent set of heads, a few other tricks. A maddening 13.000001 @ 108 on the motor with little traction. No nitrous runs with the new heads yet.
Grandma's old 78 Malibu (33K miles!) soon to have the powertrain from the 79 put in it.
"One of the last remaining QJet tuners on Planet Earth!"
[This message has been edited by Damon (edited October 05, 2000).]
Duration is how many crankshaft degrees the valve is off its seat (open). The numbers you gave are most likely for duration "at .050"- how many crankshaft degrees the valve is at or above .050" of lift. The "advertised" duration is going to be higher since it is usually measured at only .002"-.006" of valve lift and the spec varies from manufacturer to manufacturer. .050 lift specs are easier to compre between different cams since it is pretty much an industry accepted standard.
The lift spec is just the maximum height the cam will lift the valve. The numbers you quote are most likely lift AT THE CAM LOBE and need to be multiplied by 1.5 to get the actual lift at the valve. If you plan on using "1.6" rockers then you multiply that number by 1.6 instead. Stock rockers are 1.5:1 ratio.
Lobe separation is the number of degrees the intake and exhaust lobes of the cam are spread apart as measured from their respective lobe "centerlines" (which is not the same as the point of maximum lift). It is a spec designed into the cam and can not be changed. Lots of confusion around what the "best" lobe separation is and way too much to try to cover here but generally for a street car with a mild performance cam 112* is about what you want, although it is generally accepted that TPI engines like a little more- like 114-116 lobe separation.
------------------
94 Firebird Formula M6- No options but Z rated tires. No mods over $10. 13.5@105.
79 Malibu "beater" w/junkyard 400 SBC, tweaked QJet 4bbl, finally a decent set of heads, a few other tricks. A maddening 13.000001 @ 108 on the motor with little traction. No nitrous runs with the new heads yet.
Grandma's old 78 Malibu (33K miles!) soon to have the powertrain from the 79 put in it.
"One of the last remaining QJet tuners on Planet Earth!"
[This message has been edited by Damon (edited October 05, 2000).]
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