Explain cam basics please
Thread Starter
Le Mans Master
Joined: Oct 2000
Posts: 6,209
Likes: 33
From: Texas-out west
Explain cam basics please
Can someone tell me why you would want or need lift that is dual pattern, example 540intake and 560 exhaust. What is the advantage or disadvantage to single or staggered lift and duration? How do you decide which is the best way to go?
Race Director
Joined: Nov 2000
Posts: 16,416
Likes: 1
From: NC,USA
Re: Explain cam basics please (LT1driver)
Duration = the amount of time the valves are open
lift = how high the valves are opened
ramp = the steepness (how fast) the valves are openend
More duration and less lift means high horsepower and low torque (high rpm cam)
Less duration and more lift is more torque less horspower and better off for the street (low rpm cam)
Overlap = how long the valves are open at the same time (ie how much compression/ torque is lost) the ones with more over lap are for high rpm and give a nice idle the ones with less overlap give more torque
hope this helps
ZD
lift = how high the valves are opened
ramp = the steepness (how fast) the valves are openend
More duration and less lift means high horsepower and low torque (high rpm cam)
Less duration and more lift is more torque less horspower and better off for the street (low rpm cam)
Overlap = how long the valves are open at the same time (ie how much compression/ torque is lost) the ones with more over lap are for high rpm and give a nice idle the ones with less overlap give more torque
hope this helps
ZD
Le Mans Master
Joined: Mar 1999
Posts: 6,744
Likes: 1
From: delmont pa
Cruise-In I Veteran
Cruise-In II Veteran
Re: Explain cam basics please (LT1driver)
go to http://www.newcovenant.com/speedcrafter/ more info than you want to know. :chevy
Drifting
Joined: Sep 2000
Posts: 1,616
Likes: 2
From: Round Rock, Texas, USA Texas
Re: Explain cam basics please (LT1driver)
If you are trying to pick the "right" cam for a specific application - check the power range the cam is rated for i.e. 1500RPM to 5000RPM good for street used probably with or without headers. A cam rated for 3000 to 6500 would very sledom run in the RPM range on the street -- unless you have a very heavy foot and big wallet (to cover all those speeding tickets:D ). Once you read a few of these numbers you and with an idea of what range you'll be drving in you should be able to pick a good cam - with cams bigger is notalways better.
I just bought an Edelbrock Street Tunnel Ram (intake) rated at 3000 to 6500 RPM so when I build the bracket race motor (gonna take my now 10 year old racing in a few years) I'll pick a cam for 2500 to 6500.
good luck
I just bought an Edelbrock Street Tunnel Ram (intake) rated at 3000 to 6500 RPM so when I build the bracket race motor (gonna take my now 10 year old racing in a few years) I'll pick a cam for 2500 to 6500.
good luck
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
Re: Explain cam basics please (rrent)
The reason for a dual pattern is if the intake and exhaust flow do not match. If your intake is more restrictive than exhaust then you need more intake dur. and lift. On a nitrous cam you will need more exhaust because of the dense intake charge and you need more exhaust to get rid of the bigger intake. The same is true for a blower or turbo cam. If you have restictive exhaust then you will also need more exhaust dur and lift to get rid of it all. It is all a matter of flow and trying to get it in and out quickly with as dense a charge as can be
