241 243 castings. CFM?
TECH Fanatic
Joined: Jun 2002
Posts: 1,979
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From: Upstate NY
This is getting interesting now.
I don't port heads, but I listen to some very successful guys who do. The ones who I know who do extremely successful LS endurance engines pretty much agree with what Cascazilla posted, which seems to disagree with what Schwanke posted.
My own opinion is that you design a cam to work with the rest of the engine, especially the ports, intake manifold, exhaust headers, etc...that stuff that moves the wind, rather than try to make the heads "fit" the cam. This applies to daily drivers, drag only, endurance. sprint or 'bout any engine. Heck, even if you race in a "lift rule" or "duration rule" cam class, this still applies. It just makes the cam guy's job a little more difficult.
FWIW, I am impressed by the numbers quoted above. I don't think everyone with a die grinder can get there. I certainly couldn't.
Jon
I don't port heads, but I listen to some very successful guys who do. The ones who I know who do extremely successful LS endurance engines pretty much agree with what Cascazilla posted, which seems to disagree with what Schwanke posted.
My own opinion is that you design a cam to work with the rest of the engine, especially the ports, intake manifold, exhaust headers, etc...that stuff that moves the wind, rather than try to make the heads "fit" the cam. This applies to daily drivers, drag only, endurance. sprint or 'bout any engine. Heck, even if you race in a "lift rule" or "duration rule" cam class, this still applies. It just makes the cam guy's job a little more difficult.
FWIW, I am impressed by the numbers quoted above. I don't think everyone with a die grinder can get there. I certainly couldn't.
Jon
i used to think it was all about low-mid lift flow nos...but i have seen in the last couple years that is not really what you want,at least for most applications..i don't understand exactly why,but the guys making the big HP go for flow in the higher lift range..
TECH Fanatic
Joined: Jun 2002
Posts: 1,979
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From: Upstate NY
is this because having more low lift flow will increase reversion at lower rpms?
i used to think it was all about low-mid lift flow nos...but i have seen in the last couple years that is not really what you want,at least for most applications..i don't understand exactly why,but the guys making the big HP go for flow in the higher lift range..
i used to think it was all about low-mid lift flow nos...but i have seen in the last couple years that is not really what you want,at least for most applications..i don't understand exactly why,but the guys making the big HP go for flow in the higher lift range..
Jon
The engine knows what it wants and that is what is important. Those folks who are making the power try to explain what works, but if their theories are wrong, they change theories and keep giving the engine what "she" wants. Unlike many other "shes", the engine tells you if what you gave it is what it wanted.
Jon
Jon
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Joined: Jun 2002
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From: Upstate NY
My guess is that those who have figured out what works and why it works aren't going to be too forthcoming with the details. IOW, you may not get a valid answer to your question here.
If I knew any of the details I wouldn't compromise my sources. I encourage folks to keep thinking about what happens in an engine and not parrot what they have read from internet "experts". Everything in the operating engine is interconnected which often makes it difficult to understand the "why".
If I knew any of the details I wouldn't compromise my sources. I encourage folks to keep thinking about what happens in an engine and not parrot what they have read from internet "experts". Everything in the operating engine is interconnected which often makes it difficult to understand the "why".
https://ls1tech.com/forums/generation-iii-internal-engine/832264-flow-bench-results-inside-ported-ls1-vs-ported-5-3-vs-ported-ls6.html
My guess is that those who have figured out what works and why it works aren't going to be too forthcoming with the details. IOW, you may not get a valid answer to your question here.
If I knew any of the details I wouldn't compromise my sources. I encourage folks to keep thinking about what happens in an engine and not parrot what they have read from internet "experts". Everything in the operating engine is interconnected which often makes it difficult to understand the "why".
If I knew any of the details I wouldn't compromise my sources. I encourage folks to keep thinking about what happens in an engine and not parrot what they have read from internet "experts". Everything in the operating engine is interconnected which often makes it difficult to understand the "why".
i used to parrot what some "experts" have said,and i've learned a lot from modding my cars,and had to change some of my "theories" about how an engine works over the past few yrs..i've also learned i how much i don't know as well,lol..
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Joined: Jun 2002
Posts: 1,979
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From: Upstate NY
Restricted User
Joined: May 2006
Posts: 132
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From: virginia
Hey OLD SStroker.... probably a good thing your kids not allowed on here anymore huh? Probably would give old Schwanke a lesson on Blair's teachings. I have a funny feeling that you could probably too but choose not to for some reason ;-)
As for numbers.... what do they mean anyways? Flow benches seem to lie worse than hookers do about the size of a guys member.
As for numbers.... what do they mean anyways? Flow benches seem to lie worse than hookers do about the size of a guys member.
Hey OLD SStroker.... probably a good thing your kids not allowed on here anymore huh? Probably would give old Schwanke a lesson on Blair's teachings. I have a funny feeling that you could probably too but choose not to for some reason ;-)
As for numbers.... what do they mean anyways? Flow benches seem to lie worse than hookers do about the size of a guys member.
As for numbers.... what do they mean anyways? Flow benches seem to lie worse than hookers do about the size of a guys member.
Restricted User
Joined: May 2006
Posts: 132
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From: virginia
https://ls1tech.com/forums/showthrea...t=#post8715823
Wow and infinte wisdom coming out of your pie hole here.... sounds like you can regurgitate what every other moron on the boards "thinks" is good. I highly doubt YOU have ever touched a ET or All Pro head let alone ran one on the dyno against something else or even come close to making 1000hp in a LS2 block.
Oh yeah you READ about it on a internet forum. I forgot
Thank god I'm actually screwing someone who knows something. Knowledge thru injecton!
Jess
I'm guessing "someone" has "lied" to you before, poor boys. Someone = Hooker
Wow and infinte wisdom coming out of your pie hole here.... sounds like you can regurgitate what every other moron on the boards "thinks" is good. I highly doubt YOU have ever touched a ET or All Pro head let alone ran one on the dyno against something else or even come close to making 1000hp in a LS2 block.
Oh yeah you READ about it on a internet forum. I forgot
Thank god I'm actually screwing someone who knows something. Knowledge thru injecton!
Jess
I'm guessing "someone" has "lied" to you before, poor boys. Someone = Hooker
Well actually, not that I need quantify anything to you, I have been around failed LSX blocks from 1500+hp as of late, several all pro heads, and different options of LS2 setups with 95mm/F1R setups around 1K hp. When someone asks a simple and straight forward question, you give a simple answer. Point of the matter, I have an o-ringed all pro/LS2 block being put together right now. So keep screwing and get back when you have something neat to put out there.
I would never change a head to fit a camshaft for an engine. I would do it the other way around.
As for the average flow versus peak flow, on LS6 headed small displacement engines with .590 lift the engines really only respond to increses in flow over .400 lift, and especially .500-.600 for the largest increase in power. Having lots of low lift hurts power substantially on the bottom end and has a small benefit of helping to carry power a little better after peak. Average power suffers when you use "Internet Logic" to port heads.
Most of the time, on an LS6 head, if you do something to increase the .500-.600 flow it will hurt the low numbers if you are doing it with the valve job.
Making peak flow just before peak velocity sounds like it makes sense. I used to actually think that too. It is easy to believe because it's logical in a basic sense. In reality, it absolutely won't work and can't be made to happen anyways.
As for the average flow versus peak flow, on LS6 headed small displacement engines with .590 lift the engines really only respond to increses in flow over .400 lift, and especially .500-.600 for the largest increase in power. Having lots of low lift hurts power substantially on the bottom end and has a small benefit of helping to carry power a little better after peak. Average power suffers when you use "Internet Logic" to port heads.
Most of the time, on an LS6 head, if you do something to increase the .500-.600 flow it will hurt the low numbers if you are doing it with the valve job.
Making peak flow just before peak velocity sounds like it makes sense. I used to actually think that too. It is easy to believe because it's logical in a basic sense. In reality, it absolutely won't work and can't be made to happen anyways.
Teching In
Joined: Sep 2007
Posts: 28
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The same thing applies to both, exept the exhaust is much more area sensitive. I changed the valve job on an SB2 head on the exhaust and it picked up 12 cfm, along with 48 hp@8200. It was the area that mattered. We flow exhaust ports at 1 psi. Exhaust ports have much higher pressure differentials than that. There is no way to accurately quantify results of an exhaust port exept on the dyno. Intake ports are much easier to predict what the change will do.
