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It does seem very likely that the flapper would end up sticking or wearing long before the normal service life of a normal valve and guide would be over. What lubricates them?
I would assume you would be correct, but the most miles that have been put on this new technology is 50k, and they came out basically looking like they did when they went in. Speaking of lubrication, the gasoline lubricates electric fuel pumps and injectors. It might be interesting to see if there was any wear on a 50k mile E-85 engine, where there is very little gasoline. Would there be lack of lubrication wear issues with the alcohol? I don't know the answer.
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It would be pointless to enhance low the low end torque of a high rpm cam at the expense of mid to high rpm power, just put in a smaller cam and be done with it. If the variable valves limit flow like it appears to me that they probably do, you likely end up with less overall for a bunch of trouble.
When the flapper is closed, the valve flows exactly the same as the 1-piece it replaces. The only time the flapper would be open (closing off the flow through the intake seat) is when there is more pressure in the cylinder than the intake port. In those instances, you really don't want flow anyways; which is why the Powre Valvz are beneficial. I don't have the charts, but from conversations with the inventor, peak torque and HP are usually within 2 HP of what it was with the 1-piece valves.
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The 327 chevy torque figures are way too low in the mid range for even a low compression two barrel with a stock cam on a conservative dyno. Has anyone flow tested these in any kind of head? If they limit flow they could only help below peak torque and would cut output from there on up.
I agree with the 327 numbers. I wonder if the seats weren't cleaned up and maybe the exhaust valves and seats refaced while it was apart. It just so happens that this chart is the only one I have at my disposal for the time being. Flow numbers on a flow bench would be 100% unchanged with the Valvz. On a flow bench, the flapper would always be tight against the valve and the flow wouldn't be altered.
The peak of the power band doesn't change with the Powre Valvz. It is the area below peak that improves, but not at the expense of the peak. Again, peak torque remains unchanged. Peak flow remains unchanged. The changes are when the valve overlap is too much for the rpm/load of the engine, and then the only change is that you aren't pumping exhaust gasses back into the intake charge. Being so incredibly different, I can understand how it might be difficult to visualize exactly how they work. If I haven't done an adequate job of explaining it, please offer me another chance.
Mike