PV vs. Non-PV

[wildman326]

Is there any discussion already written somewhere else?

I'm looking for information. Considering getting a Lamey and want to know if it's worth the extra $$ for the PV.

I'm planning on going with a 5mm stroker, flat top, big-bore.

How much HP is gained by going with the PV?

 

[Matt_E]

Here are some cons:
- more expensive (both the block and accessories like headpipe and valves themselves)
- more maintenance

I think on the pro-side, you'll definetely have the best of both worlds (race & freestyle) - killer bottom end and killer mid and top

 

[T-bone]

valves dont nessassaraly make more HP, but they allow you to make a motor with a bigger exhaust port and then vary the timming of that exhaust port, so in the real world you get more low end and more top end.

 

[Mile9c1]

I personally would opt not for them, not in a freestyle ski anyway.

 

[freestylegeek]

From what Paul has told me, the powervalve engines make more power, however, they are smoother.
I passed up a PV cylinder for my non-PV cylinder because I wanted the motor to 'hit'.

The nice thing is that the 3rd generation cylinder already has the boss' on them. So any time I want to add powervalves I can machine the slots and I'm good to go. I doubt I ever would because I really like the power delivery the way it is.

 

[wildman326]

Geek,

How much porting (read how much $$) was done to your non-pv cylinder?

 

[Mile9c1]

I'd get the porting that Smitty has, his engine was sweet. Geeks isn't a stroker.

 

[wildman326]

Well I could get a non-pv now that's uncut. It's 3rd gen, so I could opt for the pv later.

How much do the stock lameys need to be cut? In the uncut pics I've seen it looks pretty hogged out.

Geek, did you mean that it doesn't make more power, but it's smoother?

 

[Mile9c1]

Dan Lamey said in an old post that they make the same power above 5500 RPM weather or not they have exhaust valves. I might be misquoting 5500 RPM but you get the idea. You should be able to adjust the tension on the valves to tune when they open.

I think the powervalves take out the "hit" because there is a smaller jump in power around 5500 RPM when the valves are there, because they increase the power in the lower RPM's to match the power coming on when the valves open. Did that make any sense? It should really hit harder with valves, since the horsepower is higher down low, but overall it will be a smoother powerband if tuned correctly. That's the way I see it anyway.

 

[freestylegeek]

Geek,

How much porting (read how much $$) was done to your non-pv cylinder?

I got the Honda/Lenzi porting.
It was part of my whole package, so I'm not sure of the exact dollar amount.
I think it's around $400-$500.
This is the spec from last years Lenzi motor (basically)

Mile9 is correct about my motor not being a stroker, but it is the same porting as smitty, Pdiddy, and a few others have.

 

[freestylegeek]

...
Geek, did you mean that it doesn't make more power, but it's smoother?

Here's what a graph might look like:

 

[wildman326]

Well, the pv does seem to offer more over all. I can do a majority of the necessary mods to the pipe, so it's not quite as much . . .

Just gotta see how much the initial $$ hit will be.