Bill00Formula

iTrader: (4)

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

Tainted

iTrader: (9)

Those are pretty heavy valves in those heads, you can pick up maybe 10 or so hp..?

The biggest thing you gain is valvetrain stability and peace of mind.

KCS

iTrader: (20)

The valves themselves probably won't make you any more power unless you're having trouble controlling your valvetrain already. They will however allow you to run a more aggressive lobe or turn more RPM, either of which can make you more power.

mypoorLS1

iTrader: (4)

Explain how heavier valves would gain anything. Or did I read ur post wrong?

mypoorLS1

iTrader: (4)

This is correct.

Bill00Formula

iTrader: (4)

I was thinking that Chris said that he had gained some in GM Hightech magazine. His car is an over achiever, much quicker than the parts would suggest.

Tainted

iTrader: (9)

With lighter valves (if his valvetrain is already having trouble with the heavy solid valve) he could free up some power. Also lighter is better, it would be more stable and like was said, he could get different cam lobes and pick up some more power.

96capricemgr

iTrader: (1)

depends on the valvetrain package. If they do gain you much it would be an indication things were out of control before.

gMAG

iTrader: (1)

Lighter valves require a different level of spring control.

mypoorLS1

iTrader: (4)

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

Tainted

iTrader: (9)

When I was considering the tfs 235s from TEA I believe they said a turned down LS3 (hollow stem) valve was 83/84 grams whereas the solid stem from trickflow was over 110

TurboMonte100

iTrader: (1)

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.

FAD2BLK93

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?

TurboMonte100

iTrader: (1)

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.

KCS

iTrader: (20)

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.

farmington

iTrader: (14)

Technically, a lighter valve could allow you to use a lighter (pressure) spring which would free up some horsepower that would normally be lost to friction. that would be the only way you could gain from a lighter valve.

bww3588

iTrader: (49)

Yes. The average person would not think it would make that much difference, but it does. Even a properly setup heavy solid stem valvetrain would gain from a lighter valve.

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.

TurboMonte100

iTrader: (1)

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.

Tainted

iTrader: (9)

I dunno man LIL SS is hoping to pick up 10hp on his street car switching out solid stem valves for turned down ls3 valves. Granted you can clearly see the valve float on his dyno graph. But either way he should have more power, higher revs, and a smoother powerband to me thats worth it!

TurboMonte100

iTrader: (1)

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.