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Discussion Starter #1
What does one have to gain from using them? Do they bring better air/fuel "swirl" properties into the combustion chamber, or is it possible to port out the valve...runners(?) for better flow all around?

Thanks, Kango
 

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Discussion Starter #3 (Edited)
I tried that, ya silly goose.

Hmmm, I found somethin' but not sure I'm getting my question answered. Let me get back to yaz.
 

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i guess it's a little like putting in a new cam with bigger lobes (not longer duration though). More air...
 
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It's my understanding that bigger valves add top end power but cost you the low end torque you need in a daily driver, Yes you will get more air but you'll lose bottom end power because when the exhaust valves open you allow more of that expanding air to escape faster then it could originally so you lose some push.

I think thats right but I just screwed up my new engine head so maybe you shouldn't listen to me...
 

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Bigger valves help you get more air into and out of the engine, but depending on the cam profile it can hurt your low-end torque (Long duration and high overlap increase top-end power, but hurt torque because its allowing expanding gasses to escape, but those help scavanging and assist drawing a new charge into the engine which helps top-end power)

There is such a thing as too large a valve though, since bore diameter, valve placement, etc can affect the pattern of charge flowing into the combustion chamber. In general though, bigger is better since you are essentially providing more "Place" for the mixture to enter, and combustion gasses to escape which helps things move faster, therefore filling and emptying the combustion chamber faster/more completely..

Oops.. I'm still a noob here.. Sorry if I'm overstepping my bounds..
 
J

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HAHA - we need more noobs who actually know something! Good post - keep it up
 

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Discussion Starter #10 (Edited)
Good info and all but thanks Lule.....

Lule said:
Bigger hole, more air in and out. The swirl is mostly defined by the shape of the valve.
that's all I wanted to know. Lol, just kiddin'. Lule answered my original question perfectly but all the other information was a nice added bonus. Ahh, the beauty of accumulated brain power.
 
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