How much do you gain with hollow stem valves?
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How much do you gain with hollow stem valves?
I see that there are a few people that used the hollow stem valves on their heads including "Chris1313". I don't know if they are all using the LS3 valves. Anyone know what kind of gains they are getting? I have tfs235s. Thanks
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See. I didn't read everything right. I thought you were saying that the LS3 valves were heavy and he'd gain from that. You were saying the TFS valves were heavy. My bad
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A lighter valve will not add any power by itself, It could possibly help the engine to rev a slight bit higher if the springs are not up to par. If the valve springs are in good shape and properly matched with the cam, the difference in the valves should never be a factor.
Turning down the stem will lighten the valve, but it is also done to increase flow.
Turning down the stem will lighten the valve, but it is also done to increase flow.
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Wouldn't saving grams of weight on each valve allow the motor to rev quicker and be more stable? Isn't weight savings a good thing to have in a valve train? Or a crank or any other light weight part in the engine? I would think so, or am i incorrect?
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Saving weight in most engine parts is always a plus and never a bad thing, I don't think that you would ever see an engine rev quicker because the valves are a few grams lighter. A couple of things to keep in mind. The valves in a LS engine are not that heavy to begin with, many engines use much heavier valves and run good. Secondly the valve weight will never be a factor on how quickly the engine will rev under a load.
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I would have to disagree. The valvetrain should be considered in its entirety in order to get it to work correctly and efficiently. The valvesprings shouldn't be matched to the cam, it needs to be matched to the entire system. When you get into the more aggressive lobes and RPM ranges, you will definitely see the difference 30-40g does when taken away from or added to the valve side of the rocker arm.
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I would have to disagree. The valvetrain should be considered in its entirety in order to get it to work correctly and efficiently. The valvesprings shouldn't be matched to the cam, it needs to be matched to the entire system. When you get into the more aggressive lobes and RPM ranges, you will definitely see the difference 30-40g does when taken away from or added to the valve side of the rocker arm.
For reference...
http://www.youtube.com/watch?v=019Jyn9oB5k&feature=youtube_gdata_player
You can easily see, even with the dual valve spring, the valve is bouncing off it's seat when it closes. A lighter valve can help combat that.
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I would have to disagree. The valvetrain should be considered in its entirety in order to get it to work correctly and efficiently. The valvesprings shouldn't be matched to the cam, it needs to be matched to the entire system. When you get into the more aggressive lobes and RPM ranges, you will definitely see the difference 30-40g does when taken away from or added to the valve side of the rocker arm.
In a all out racing engine where one is trying to get every last HP and rpm from an engine, for sure run the lightest componets that you can safely get away with, for the guy wanting to hop up his street car or mild street/strip car, sourcing out light weight valves should not be on the top of the list.
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My post was short in an effort to keep my explaination simple, and I was trying to keep it relative to the OP's question and following replys. Yes the valve train is considered in its entirety, and using all light componets never hurts. Yes valve springs have ALWAYS been matched to the cam, the cam pretty much set the baseline for the usable rpm range of the engine.
In a all out racing engine where one is trying to get every last HP and rpm from an engine, for sure run the lightest componets that you can safely get away with, for the guy wanting to hop up his street car or mild street/strip car, sourcing out light weight valves should not be on the top of the list.
In a all out racing engine where one is trying to get every last HP and rpm from an engine, for sure run the lightest componets that you can safely get away with, for the guy wanting to hop up his street car or mild street/strip car, sourcing out light weight valves should not be on the top of the list.
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If a guy is running around on the street with a street car and they are floating the valves. Two things come to mind, the valve springs are not up to the job and the engine will be short lived.