Does valvesprings really make that much of a difference?
10-11-2005, 01:52 PM
#1
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Does valvesprings really make that much of a difference? Heres the story.
I have a set of LS1 heads that were ported and polished at Thunder Racing when Steve worked there. I had the heads machined to accept larger diameter Comp steel valvesprings, steel retainers like on the older V8's. I am being told that the valvesprings are making me lose roughly 10-15 RWHP and its causing me not to be able to rev as fast, and might even be causing me to break lifters cause so far I replaced one thats fallen apart and I have another one tapping.
I also run nitrous if that matters.
I have a set of LS1 heads that were ported and polished at Thunder Racing when Steve worked there. I had the heads machined to accept larger diameter Comp steel valvesprings, steel retainers like on the older V8's. I am being told that the valvesprings are making me lose roughly 10-15 RWHP and its causing me not to be able to rev as fast, and might even be causing me to break lifters cause so far I replaced one thats fallen apart and I have another one tapping.
I also run nitrous if that matters.
10-11-2005, 08:16 PM
#2
Valve springs have to keep the valve against the valvetrain. They should have a combination of stiffness, natural frequency, and damping to minimize bouncing on valve closing (Comp Cams makes a big thing of this with their beehive springs). If they are too stiff power is wasted openning and closing them.
They also have to be able to last for the application's duty cycle; which is different for street car, drag car, road race, endurance race, etc.
what is also needed is affected by the profile of the cam and the masses and rotational inertia of the valve train. Note that the spring itself and the retainer are part of the mass of the valvetrain.
As far as the lifters are concerned, other here will have more experience. However, unless you are way to stiff (or way to soft) I'm not sure how the valve spring could be breaking the lifter.
They also have to be able to last for the application's duty cycle; which is different for street car, drag car, road race, endurance race, etc.
what is also needed is affected by the profile of the cam and the masses and rotational inertia of the valve train. Note that the spring itself and the retainer are part of the mass of the valvetrain.
As far as the lifters are concerned, other here will have more experience. However, unless you are way to stiff (or way to soft) I'm not sure how the valve spring could be breaking the lifter.
