Mastermind
Work Saw Specialist
Does any of this really matter?
It does to me.......I wanna do the best job possible with the tools I have.
Popup vs Flat Top?
- Thread starter Mastermind
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It does to me.......I wanna do the best job possible with the tools I have.
Oh yeah it does!! I'll only feed square hay bales they are better for your cows. Round hay sucks.Does any of this really matter?
Doesn't the flow of the charge that washes across the piston crown happen way before then? I need to do some more studying on squish velocity and it's travel.
Mastermind
Work Saw Specialist
Time is different.......reason is the same.
Flat top pop up debate 
. I said flat top no I said pop up no I said flat top 
. I said flat top no I said pop up no I said flat top
Mastermind
Work Saw Specialist
Not saying popups won't work......they will increase compression.
I'm not OK when people say that they are actually better though.
There are too many easy to see reasons why they are inferior to stand by saying nothing when someone says that they are a better way to build a performance engine.
I said I wouldn't say anything bad about you Brad......and I plan to keep my word, but I read where you wrote that popups were not as good as a cut squish band.......then where you said they were as good.......now this morning you are saying they are better.
What do you really think? I'm confused by what you've written.
I'm not OK when people say that they are actually better though.
There are too many easy to see reasons why they are inferior to stand by saying nothing when someone says that they are a better way to build a performance engine.
I said I wouldn't say anything bad about you Brad......and I plan to keep my word, but I read where you wrote that popups were not as good as a cut squish band.......then where you said they were as good.......now this morning you are saying they are better.
What do you really think? I'm confused by what you've written.
Mastermind
Work Saw Specialist
I get it now........after reading my post.......I see.
I'm the one being trolled here.
Forget it.
Popups Rule
I'm the one being trolled here.
Forget it.
Popups Rule
Chris-PA
Where the Wild Things Are
Actually torque means nothing. Torque x rpm matters - that is the definition of power.
If you picture a perfectly symmetrical combustion chamber and a flat top piston as the gas is squished out of the band - it is all converging into the center. All of the mass is heading toward the center with equal velocity at the edge where it emerges from the squish band. At that edge it will begin to diverge upward into the combustion chamber, as a higher pressure builds at the center of the piston where the flow converges. How do we know if the pop-up actually changes that? I suspect the flow will turn up to follow the contour of the combustion chamber anyway, and that as long as the pop-up edge is not too close to the squish band edge it won't matter - but that is just my guess.
Say what? I'm confused. I don't think it makes a hill of beans difference in the real world. The only times I see it as an advantage is when you need to lower the exhaust port, not common IMHO, or you need more compression than can be had with a popup, again not common IMHO.I get it now........after reading my post.......I see.
I'm the one being trolled here.
Forget it.
Popups Rule
Pud
ArboristSite Operative
Hows the first graph i know 461's are a strong saw but i didnt think 660 strong
Subscribed. As long as this thread remains civil and no mud slinging starts, I think this could turn out to be a good thread. I for one, would love to see the dyno results of the same saw/same porting/etc. as Brad is suggesting needs to be performed. It's interesting that the Dan Henry 346xp is so highly regarded and it has a popup. Personally (nothing against Brad at all - I have alot of respect for that guy!) I prefer cut squish band just for simplicity in future piston changes. I say this because what if 10 years later, the porter of a saw (with a popup) is no longer in business, etc., and I need another piston. Then I've got to find someone to try and match the original, and they may not even want to mess with it since it wasn't their work to begin with.
Waylan
Waylan
The proper way to test flat top vs. popup isn't to have the engine ported to the exact same timing numbers etc. Shoot for the same compression, but port the engine so it makes best power in either configuration. Different engines get ported differently due to the design involved. Do the best porting for each setup at the same compression, see how the power compares. That will tell you which method works best. It's a whole method, not just piston vs. piston.
Nitroman
Addicted to ArboristSite
Do you really believe that? Would you take an old John Deere to a bank robbery, or an F1 car?
Flat top pop up debate
I just spent 20 minutes watching girl fights on youtube. It was glorious.
Mastermind
Work Saw Specialist
Welp........it can't be settled.
I'll stop saying cut squish is better if you stop saying it ain't.
Deal?
I'll stop saying cut squish is better if you stop saying it ain't.
Deal?
jughead500
Sasquatch
They sure was Installin some pop ups on each others heads.
Moparmyway
Its just a saw
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This is a great real world argument for cutting squish. As long as I can get a piston for the saw, I can get back to work. No waiting for a custom builder to have the time ( if they are still around) to fab a piston. I wonder how a saw built for a pop-up would run with a non- pop-up.
Nitroman
Addicted to ArboristSite
Okay, we have to hire someone who specializes in Schlieren photography to make a video of the gases leaving a port over a flat piston then a popped piston. This will expose the shock wave flow and all will see. So there. Now start looking in your Yellow Pages (if anyone knows how to use one of those anymore).
