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Alstrup
Samba Member
Joined: July 12, 2007
Posts: 7851
Location: Videbaek Denmark
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 Posted: Sat Jul 19, 2025 5:58 am Post subject: Re: Endcastings flow? |
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| Rob Combs wrote: |
| earthquake wrote: |
Has any body ever used a set of short K-dog manifolds and made a nice flowing upper manifold that bolts to them? It might be a little tall.
eQ |
This just gave me an idea for what to do with my cracked race trim manifolds. A few pie cuts to make a sharper turn into a regular center section and back in business… |
K dog (Kadron) manifolds dont flow much better than a set of mildly massaged end castings unless they are heavily welded and modified. So not much idea in that.
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Brian_e 
Samba Member
Joined: July 28, 2009
Posts: 4027
Location: Rapid City, South Dakota
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| Posted: Fri Jul 18, 2025 5:43 pm Post subject: Re: Endcastings flow? |
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| BFB wrote: |
| Really seems flow numbers are another one of the marketing ploys that we've been taught to focus on |
Correct. Flow numbers are really irrelevant, and are a ways down on the list of important factors when choosing heads.
Average airspeed is FAR more important, and an easy way to determine how efficient a head really is.
Comparing two head flowed on different benches is also near worthless.
Flow numbers are just like comparing peak HP Dyno numbers. They really don’t tell much about the engine. Just like looking at average airspeed, a guy is much better off looking at the average torque numbers rather than peak numbers.
Brian
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BFB
Samba Member
Joined: November 03, 2014
Posts: 2723
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| Posted: Fri Jul 18, 2025 4:18 pm Post subject: Re: Endcastings flow? |
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so, im going to assume none of you know otherwise someone wouldve chimed in to educate me. But on further reading & research ( which btw is not easy to find ) , cfm ratings on intakes are not comparable to cylinder cfm ratings, in a similar way to carb cfm’s ratings being different, not only between 2 & 4bbl but between carbs, heads, and engine. Im not going to try to explain it because 1. I dont remember enough specifics ( although i did save what i found ) and 2 i spent too much time looking for what i found.
Also read a lot that stated making flow numbers of heads & intake your primary focus, is a huge mistake as it’s only one factor in several dozen. All the other points made a lot of sense. Really seems flow numbers are another one of the marketing ploys that weve been taught to focus on
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BFB
Samba Member
Joined: November 03, 2014
Posts: 2723
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| Posted: Fri Jul 18, 2025 3:47 pm Post subject: Re: Endcastings flow? |
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| earthquake wrote: |
Has any body ever used a set of short K-dog manifolds and made a nice flowing upper manifold that bolts to them? It might be a little tall.
eQ |
Pics?
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Rob Combs
Samba Member
Joined: December 30, 2020
Posts: 563
Location: South Bay LA, California
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| Posted: Fri Jul 18, 2025 2:38 pm Post subject: Re: Endcastings flow? |
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| earthquake wrote: |
Has any body ever used a set of short K-dog manifolds and made a nice flowing upper manifold that bolts to them? It might be a little tall.
eQ |
This just gave me an idea for what to do with my cracked race trim manifolds. A few pie cuts to make a sharper turn into a regular center section and back in business… |
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earthquake
Samba Member
Joined: January 10, 2008
Posts: 4001
Location: SANDY VALLEY, NEVADA
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| Posted: Fri Jul 18, 2025 2:17 pm Post subject: Re: Endcastings flow? |
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Has any body ever used a set of short K-dog manifolds and made a nice flowing upper manifold that bolts to them? It might be a little tall.
eQ
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modok
Samba Member
Joined: October 30, 2009
Posts: 27686
Location: Colorado Springs
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| Posted: Tue Jul 15, 2025 10:02 pm Post subject: Re: Endcastings flow? |
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I've looked into it, simulated putting a resonator anywhere I could think possibly make sense in the handlebar intake but so far found nothing useful.
The idea of small plenums on either side does not work well overall either. |
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Wreck
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Joined: July 19, 2014
Posts: 1315
Location: Brisbane
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| Posted: Tue Jul 15, 2025 9:10 pm Post subject: Re: Endcastings flow? |
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throwing this out there .
Has anyone welded some helmholtz resonators to the end castings to even the intake volume per runner ,mainly to help with low rpm /idle quality and even AFR ? when using a larger duration cam . |
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modok
Samba Member
Joined: October 30, 2009
Posts: 27686
Location: Colorado Springs
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| Posted: Sat Jul 12, 2025 11:34 pm Post subject: Re: Endcastings flow? |
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| Not sure which ones you mean, but I'm pretty sure all the OEM EFi manifolds are significantly smaller diameter, under 30mm ID |
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BFB
Samba Member
Joined: November 03, 2014
Posts: 2723
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| Posted: Sat Jul 12, 2025 10:41 am Post subject: Re: Endcastings flow? |
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As far as end castings, what about the T1 efi ones that are split. Anyone compare their flow to the “normal” DP ones?
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"how am i supposed to torque the rear wheel nut to 250 ft lbs??? " - clonebug
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BFB
Samba Member
Joined: November 03, 2014
Posts: 2723
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| Posted: Sat Jul 12, 2025 10:26 am Post subject: Re: Endcastings flow? |
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| Alstrup wrote: |
| modok wrote: |
I have a set of four 48 IDAs for a small block ford, 40mm vents
What is the cfm rating of that, in caveman units?
around 1500 or so?
I know it's not enough to make "real" power by todays standards
but beyond 450hp/6000k is where the block starts to crack in half so it's perfect IMO |
On a V8 ? around 600 |
600 what ? CFM or HP?
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"how am i supposed to torque the rear wheel nut to 250 ft lbs??? " - clonebug
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Most experts aren't. |
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Alstrup
Samba Member
Joined: July 12, 2007
Posts: 7851
Location: Videbaek Denmark
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| Posted: Sat Jul 12, 2025 1:20 am Post subject: Re: Endcastings flow? |
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| modok wrote: |
I have a set of four 48 IDAs for a small block ford, 40mm vents
What is the cfm rating of that, in caveman units?
around 1500 or so?
I know it's not enough to make "real" power by todays standards
but beyond 450hp/6000k is where the block starts to crack in half so it's perfect IMO |
On a V8 ? around 600
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modok
Samba Member
Joined: October 30, 2009
Posts: 27686
Location: Colorado Springs
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| Posted: Fri Jul 11, 2025 7:05 pm Post subject: Re: Endcastings flow? |
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I have a set of four 48 IDAs for a small block ford, 40mm vents
What is the cfm rating of that, in caveman units?
around 1500 or so?
I know it's not enough to make "real" power by todays standards
but beyond 450hp/6000k is where the block starts to crack in half so it's perfect IMO |
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BFB
Samba Member
Joined: November 03, 2014
Posts: 2723
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| Posted: Thu Jul 10, 2025 6:05 pm Post subject: Re: Endcastings flow? |
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| Wreck wrote: |
Earlier you stated this
"According to my mathing, with he help of some online calculators , a N/A 2276 turning 5500 rpm at 100% VE flows 220 cfm. If your running a single center mount carb then you have 2 endcastings, each capable of flowing minimum of 110 CFM to as much as 130 CFM.
Even if you only counted the flow per cylinder at a time, each one only flows 55 CFM , which is half what the endcasting is capable of.
Tell me if im missing something here?
I am attempting to get you to visualise how low 55cfm is and that the flow numbers for the end castings is per throat , not both . So a stock head at 0.100" lift is in the ball park of 55cfm .
If I get a chance tonight , I'll plug a 2.3lt 4 cylinder etc into pipemax and 5500 at 55CFM and see what the VE is . |
Oh i know 55 cfm is low. Have you ever plugged in the numbers for what a 1600’s cfm is? It’s stupid low, like 120 cfm , which is why ppl have trouble with much bigger carbs ( single ) than a pict. hell, this is the same scenario even with bigger engines too and why theres so many post of having flat spots and needing to “roll on the throttle” vs being able to floor it.
I also didnt say anything about those flow numbers being for both throats, i was meaning the numbers for both end castings, so the whole flow for the engine ( by using two endcastings). But being totally honest i did not think about only one throat being flowed at a time until you mentioned it.
However, my point then was that that would raise the total flow capability of the end casting as a whole, maybe not doubling the number but still more than the single throat’s cfm.
As far as you pipemax, i think your not listening and still dwelling on the 100% VE. I dont give a shit about VE, never did. Please re-read what ive written.
I think your trying so hard to make me see your point that you’re not seeing mine
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"how am i supposed to torque the rear wheel nut to 250 ft lbs??? " - clonebug
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Most experts aren't. |
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Wreck
Samba Member
Joined: July 19, 2014
Posts: 1315
Location: Brisbane
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| Posted: Thu Jul 10, 2025 5:46 pm Post subject: Re: Endcastings flow? |
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Earlier you stated this
"According to my mathing, with he help of some online calculators , a N/A 2276 turning 5500 rpm at 100% VE flows 220 cfm. If your running a single center mount carb then you have 2 endcastings, each capable of flowing minimum of 110 CFM to as much as 130 CFM.
Even if you only counted the flow per cylinder at a time, each one only flows 55 CFM , which is half what the endcasting is capable of.
Tell me if im missing something here?
I am attempting to get you to visualise how low 55cfm is and that the flow numbers for the end castings is per throat , not both . So a stock head at 0.100" lift is in the ball park of 55cfm .
If I get a chance tonight , I'll plug a 2.3lt 4 cylinder etc into pipemax and 5500 at 55CFM and see what the VE is . |
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BFB
Samba Member
Joined: November 03, 2014
Posts: 2723
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| Posted: Thu Jul 10, 2025 5:36 pm Post subject: Re: Endcastings flow? |
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| Wreck wrote: |
If you look at the chart on this
thread https://www.thesamba.com/vw/forum/viewtopic.php?t=573099
look for stock 1600 twin port flow numbers at 0.100" That is what they flow per port at the measured depression.
At the beginning you said that a 2.3lt needed 220cfm at 5500 to be at 100VE
That is just a theorised program that doesn't take into account port design and efficiency . It is a tool to work out what your intake needs to flow per cylinder to get 100% cylinder filling at that rpm .
I was pointing out that those numbers are per cylinder. People think you put twin twin throat carbs/itbs to get more air into the engine , that is not correct , it is to separate the reversion pulses and get the engine to run smoother at lower rpm . and more ability to fine tune it. |
Ok.
That link needs edited, the “thread” is part of it, i changed it in the quote.
I get what you’re saying about the dual carb thing. And on that note, i think thats one of the coolest things ever that the carbs run so well in that set up and also very cool to see the fuel mist vapor above the carbs.
My point about the 2.3 wasnt what it “needed to be at 100% VE”, the 100% VE wasnt to point nor the goal, it was that i plugged that engine in at 100% VE to come to 220cfm. I did that because 100%VE gives a higher cfm than what is probably accurate as i doubt many 2276’s running around are that efficient. Probably more like 80%, right? I was going for overkill on the cfm by using 100%VE.
Why are we reading the flow at .100 lift? Whats the point with looking at it there in regards to what we’re talking about? ( i dont mean that to sound like a jackass, serious question)
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"how am i supposed to torque the rear wheel nut to 250 ft lbs??? " - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
Most experts aren't. |
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BFB
Samba Member
Joined: November 03, 2014
Posts: 2723
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| Posted: Thu Jul 10, 2025 5:20 pm Post subject: Re: Endcastings flow? |
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| EVfun wrote: |
| BFB wrote: |
if im missing something on this then educate me, because maybe I am. but it seems pretty cut & dry to me, an engine that pumps 220 cfm doesn't pump 220 cfm per cylinder. if its a 220cfm 4 cylinder then you divide 220 by 4 to get per cylinder cfm, if its a 600 cfm V8 you divide 600 by 8. and we all know theres more factors involved in the complexity of the entire system and that the end castings are a paired runner so its not just as simple as " the end castings flow 110- 130 cfm", all that is a given.
but to say that opening a stock valve .080 as an equivalent of one cylinder flowing 55 cfm ( the 220 / 4 ) is just trying to be an ass about it vs just explaining how that conclusion was come to.
a single cylinder measuring 94mm w/ 82 mm stroke is 569cc or 34.7 Ci , we'll just call it 35. plug those numbers into the equation or an online calculator and you get the same results, 55cfm @ 100% VE, 85% VE is like 47 cfm. I have no idea why Wreck would think this same cylinder moves 220 cfm.
I havent boosted as many engines as I have by mis-calculating engine cfm and referencing a turbo maps to match things up. so I can't be off by much... not by 660 cfm...
but again, show me, if im wrong then im wrong. |
I think you might be missing the point that each cylinder only draws for about 1/4 the time, so per minute run time that intake port is only flowing 15 seconds.
I ran the numbers for your theoretical 1 cylinder engine at 5500 rpm (2750 intake pulses per minute) and get a overall flow of 55 cfm at 100% VE. However, it needs to flow that 55 cfm in about 15 seconds of that minute so you would want a port capable of flowing 220 cfm (then reduced by the VE being less than 100%).
Of course, I could easily be wrong too. I'm no engine expert. |
Now something like that i could see. And i have read that when flow numbers are generated on a bench that they are done so with a constant fan which isnt quite the same as being on an engine and its “pulsating “ flow.
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"how am i supposed to torque the rear wheel nut to 250 ft lbs??? " - clonebug
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Most experts aren't. |
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Wreck
Samba Member
Joined: July 19, 2014
Posts: 1315
Location: Brisbane
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| Posted: Thu Jul 10, 2025 3:04 pm Post subject: Re: Endcastings flow? |
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If you look at the chart on this
threadhttps://www.thesamba.com/vw/forum/viewtopic.php?t=573099
look for stock 1600 twin port flow numbers at 0.100" That is what they flow per port at the measured depression.
At the beginning you said that a 2.3lt needed 220cfm at 5500 to be at 100VE
That is just a theorised program that doesn't take into account port design and efficiency . It is a tool to work out what your intake needs to flow per cylinder to get 100% cylinder filling at that rpm .
I was pointing out that those numbers are per cylinder. People think you put twin twin throat carbs/itbs to get more air into the engine , that is not correct , it is to separate the reversion pulses and get the engine to run smoother at lower rpm . and more ability to fine tune it. |
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EVfun
Samba Member
Joined: April 01, 2012
Posts: 6198
Location: Seattle
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| Posted: Thu Jul 10, 2025 12:39 pm Post subject: Re: Endcastings flow? |
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| BFB wrote: |
if im missing something on this then educate me, because maybe I am. but it seems pretty cut & dry to me, an engine that pumps 220 cfm doesn't pump 220 cfm per cylinder. if its a 220cfm 4 cylinder then you divide 220 by 4 to get per cylinder cfm, if its a 600 cfm V8 you divide 600 by 8. and we all know theres more factors involved in the complexity of the entire system and that the end castings are a paired runner so its not just as simple as " the end castings flow 110- 130 cfm", all that is a given.
but to say that opening a stock valve .080 as an equivalent of one cylinder flowing 55 cfm ( the 220 / 4 ) is just trying to be an ass about it vs just explaining how that conclusion was come to.
a single cylinder measuring 94mm w/ 82 mm stroke is 569cc or 34.7 Ci , we'll just call it 35. plug those numbers into the equation or an online calculator and you get the same results, 55cfm @ 100% VE, 85% VE is like 47 cfm. I have no idea why Wreck would think this same cylinder moves 220 cfm.
I havent boosted as many engines as I have by mis-calculating engine cfm and referencing a turbo maps to match things up. so I can't be off by much... not by 660 cfm...
but again, show me, if im wrong then im wrong. |
I think you might be missing the point that each cylinder only draws for about 1/4 the time, so per minute run time that intake port is only flowing 15 seconds.
I ran the numbers for your theoretical 1 cylinder engine at 5500 rpm (2750 intake pulses per minute) and get a overall flow of 55 cfm at 100% VE. However, it needs to flow that 55 cfm in about 15 seconds of that minute so you would want a port capable of flowing 220 cfm (then reduced by the VE being less than 100%).
Of course, I could easily be wrong too. I'm no engine expert.
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BFB
Samba Member
Joined: November 03, 2014
Posts: 2723
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| Posted: Thu Jul 10, 2025 11:27 am Post subject: Re: Endcastings flow? |
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if im missing something on this then educate me, because maybe I am. but it seems pretty cut & dry to me, an engine that pumps 220 cfm doesn't pump 220 cfm per cylinder. if its a 220cfm 4 cylinder then you divide 220 by 4 to get per cylinder cfm, if its a 600 cfm V8 you divide 600 by 8. and we all know theres more factors involved in the complexity of the entire system and that the end castings are a paired runner so its not just as simple as " the end castings flow 110- 130 cfm", all that is a given.
but to say that opening a stock valve .080 as an equivalent of one cylinder flowing 55 cfm ( the 220 / 4 ) is just trying to be an ass about it vs just explaining how that conclusion was come to.
a single cylinder measuring 94mm w/ 82 mm stroke is 569cc or 34.7 Ci , we'll just call it 35. plug those numbers into the equation or an online calculator and you get the same results, 55cfm @ 100% VE, 85% VE is like 47 cfm. I have no idea why Wreck would think this same cylinder moves 220 cfm.
I havent boosted as many engines as I have by mis-calculating engine cfm and referencing a turbo maps to match things up. so I can't be off by much... not by 660 cfm...
but again, show me, if im wrong then im wrong.
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