Function of LSA; Duration; Lift
09-26-2003, 07:00 AM
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Function of LSA; Duration; Lift Correct me if I am wrong please. Besides the many other factors associated with grinding a cam, just the basics.
Duration = Where the hp/tq will start.
Lift = Determines the the hp/tq under the curve mostly
LSA = Determines the tq peak and shape of the tq curve
Duration = Where the hp/tq will start.
Lift = Determines the the hp/tq under the curve mostly
LSA = Determines the tq peak and shape of the tq curve
09-26-2003, 07:06 AM
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Re: Function of LSA; Duration; Lift It is not that cut and dry, they are all correlated. I am in by no means an expert so maybe a guru will chime in and help us out. I do know that the torque and horsepower peaks are a function of both duration AND lsa (LSA affects both torque peak and HP peak).
09-26-2003, 07:31 AM
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Re: Function of LSA; Duration; Lift Yes and No, I wish it was that simple then we all could be cam guru's but it's not.
Basically the duration and the LSA have a bigger part in what happens more than the lift does. Lift most just eats up valve springs, and gives you some extra HP.
A set duration and LSA along with the advance or retard that the cam is installed or ground at will give you the HP and TQ curves and the peaks.
In reality the duration, LSA and Advance/Retard are changing the valve opeing and closing events. The most important (IMO) being the intake valve closing point.
One thing to definately read is this:
http://www.compcams.com/Technical/TimingTutorial/
That page gets you the basics of it. As long as you understand that fully then you can really get into a discussion about camshafts.
Bret
Basically the duration and the LSA have a bigger part in what happens more than the lift does. Lift most just eats up valve springs, and gives you some extra HP.
A set duration and LSA along with the advance or retard that the cam is installed or ground at will give you the HP and TQ curves and the peaks.
In reality the duration, LSA and Advance/Retard are changing the valve opeing and closing events. The most important (IMO) being the intake valve closing point.
One thing to definately read is this:
http://www.compcams.com/Technical/TimingTutorial/
That page gets you the basics of it. As long as you understand that fully then you can really get into a discussion about camshafts.
Bret
09-27-2003, 05:46 AM
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Re: Function of LSA; Duration; Lift I was saying that the wide LSA of the OMC/GT2-3/LS6 will make them more of a topend cam and you must raise shift points to get max power from cam.
I was also stating that the TR220 will feel more bottom end on the street because of the 114LSA's lower torque peak and will also work well with stock shift points.
He was basically saying the opposite that the LS6/OMC/GT2-3 will feel more bottom end then the TR220 because of the lower duration numbers. We both had valid points and were pretty much argueing for now reason.
I was also stating that the TR220 will feel more bottom end on the street because of the 114LSA's lower torque peak and will also work well with stock shift points.
He was basically saying the opposite that the LS6/OMC/GT2-3 will feel more bottom end then the TR220 because of the lower duration numbers. We both had valid points and were pretty much argueing for now reason.
09-27-2003, 07:36 AM
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Re: Function of LSA; Duration; Lift
I was saying that the wide LSA of the OMC/GT2-3/LS6 will make them more of a topend cam and you must raise shift points to get max power from cam.
I was also stating that the TR220 will feel more bottom end on the street because of the 114LSA's lower torque peak and will also work well with stock shift points.
He was basically saying the opposite that the LS6/OMC/GT2-3 will feel more bottom end then the TR220 because of the lower duration numbers. We both had valid points and were pretty much argueing for now reason.
I was also stating that the TR220 will feel more bottom end on the street because of the 114LSA's lower torque peak and will also work well with stock shift points.
He was basically saying the opposite that the LS6/OMC/GT2-3 will feel more bottom end then the TR220 because of the lower duration numbers. We both had valid points and were pretty much argueing for now reason.
The more duration you have the higher you will have to spin the motor (with equal LSA) to take advantage of peak power. The more you drop the LSA the lower the peak will be (relative to duration), and normally with a lower LSA you will have more area under the curve.
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09-27-2003, 09:16 AM
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Re: Function of LSA; Duration; Lift ..also the tighter the lsa the more/quicker the curv will drop off after peak hp/tq. a tighter lsa and a moderate duration(224 IMO) is a good street cam providing you have the valve timing events where they need to be, i feel that you should find the timing events you want and build a cam around that, ie what kind of drivability will i have with this set of specs,and what diffrent specs can i get that will alow me close as possible to the timing events io need. if this doesnt make sense im sure some one smarter than me can explain further...
