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Alstrup
Samba Member
Joined: July 12, 2007
Posts: 7207
Location: Videbaek Denmark
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 Posted: Mon Sep 17, 2012 5:30 am Post subject: Re: INTAKE PORT UPDATE 7-7-12 |
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| bvilletom wrote: |
The intake ports were a real learning lesson; the ports are very short in length with many sharp edges causing a turbulent, jumpy airflow. I generally don’t like to flow the head ports with the intake manifolds on because sometimes it is a crutch to get really good flow numbers. Everybody wants to say that their heads flow more than anyone else’s heads, what they really mean is my heads with manifold on will flow better than your heads. They don’t mention that the test was with the manifold versus without a manifold, so you don’t know if you’re comparing equal test components.
The Wolfsburg West intake ports are pretty good, I blended slightly and that was it. Then I started to play with different intake manifolds,
WOW!
This head was the most intake manifold dependent unit I have ever seen. You can gain or lose great amounts of CFM just by the manifold choice. Here are the flow figures for the head, intake port flows 54.9 CFM alone.
1. Put on an old Okrasa or a new Wolfsburg West manifolds; both had flows that varied from: .…………………………………………… 55.5 CFM to 57.9 CFM
2. Put on the handmade Brukrasa single port manifold, flow is…. 59 CFM
3. Put on a new SPEEDWELL manifold , flow goes to …………………….67 CFM
WOW!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
In summary, a manifold that is tapered and fairly long, gives the head's port a rush of a laminar flowing column of air which smoothes out most of the turbulent problems in the short head port. More drastic porting and shaping of ports could possibly make way more CFM. But look at this gain alone with stock valve and seat and practically no intake porting, a 12.1 CFM was accomplished just by bolting on a manifold!
By spending a couple more weeks time continuing the tests would result in more improvement in CFM, like value and seat shaping. However, the is not time for this additional work before the motor needs to be completed.
This is the first set of Wolfsburg West heads I have ever tested on my bench.
Bvilletom |
Hello.
I take it those #´s were at 25" ?
I have been studying those heads quite a bit, and have come to the conclusion that the ports have the wrong shape and size to the stock 33 mm valve. Going up to 35,5 mm intakes and it all sort of equals out and the port can be shaped much more correct (At least from my point of view) I have never gotten around to it but I´m sure that the port can be massaged to flow at least 100 cfm @ 25" at 0,475" valve lift without welding. With a 37,5 mm valve even more. So there is plenty of room to grow.
WRT the drastic increase in flow one manifold to the next. I think that the intake port shape has a good deal to do with that due to large area´s having air speed decrease tendencies. (The jumpy airflow you describe) That is also why I belive that the port will do so much better with a larger valve. But granted, the Speedwell manifolds are nice.
Out of curiosity, what flow bench do you have ?
I use an old Super Flow 600 with a PT electronics module (which I´m not that satisfied with. It is sensetive to the annoying and takes too long to get ready for a test)
T |
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splitpile
Samba's Worst Speller
Joined: May 03, 2000
Posts: 5927
Location: back to living where hell meets the suface
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| Posted: Mon Sep 17, 2012 8:22 am Post subject: Re: INTAKE PORT UPDATE 7-7-12 |
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| Alstrup wrote: |
| bvilletom wrote: |
The intake ports were a real learning lesson; the ports are very short in length with many sharp edges causing a turbulent, jumpy airflow. I generally don’t like to flow the head ports with the intake manifolds on because sometimes it is a crutch to get really good flow numbers. Everybody wants to say that their heads flow more than anyone else’s heads, what they really mean is my heads with manifold on will flow better than your heads. They don’t mention that the test was with the manifold versus without a manifold, so you don’t know if you’re comparing equal test components.
The Wolfsburg West intake ports are pretty good, I blended slightly and that was it. Then I started to play with different intake manifolds,
WOW!
This head was the most intake manifold dependent unit I have ever seen. You can gain or lose great amounts of CFM just by the manifold choice. Here are the flow figures for the head, intake port flows 54.9 CFM alone.
1. Put on an old Okrasa or a new Wolfsburg West manifolds; both had flows that varied from: .…………………………………………… 55.5 CFM to 57.9 CFM
2. Put on the handmade Brukrasa single port manifold, flow is…. 59 CFM
3. Put on a new SPEEDWELL manifold , flow goes to …………………….67 CFM
WOW!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
In summary, a manifold that is tapered and fairly long, gives the head's port a rush of a laminar flowing column of air which smoothes out most of the turbulent problems in the short head port. More drastic porting and shaping of ports could possibly make way more CFM. But look at this gain alone with stock valve and seat and practically no intake porting, a 12.1 CFM was accomplished just by bolting on a manifold!
By spending a couple more weeks time continuing the tests would result in more improvement in CFM, like value and seat shaping. However, the is not time for this additional work before the motor needs to be completed.
This is the first set of Wolfsburg West heads I have ever tested on my bench.
Bvilletom |
Hello.
I take it those #´s were at 25" ?
I have been studying those heads quite a bit, and have come to the conclusion that the ports have the wrong shape and size to the stock 33 mm valve. Going up to 35,5 mm intakes and it all sort of equals out and the port can be shaped much more correct (At least from my point of view) I have never gotten around to it but I´m sure that the port can be massaged to flow at least 100 cfm @ 25" at 0,475" valve lift without welding. With a 37,5 mm valve even more. So there is plenty of room to grow.
WRT the drastic increase in flow one manifold to the next. I think that the intake port shape has a good deal to do with that due to large area´s having air speed decrease tendencies. (The jumpy airflow you describe) That is also why I belive that the port will do so much better with a larger valve. But granted, the Speedwell manifolds are nice.
Out of curiosity, what flow bench do you have ?
I use an old Super Flow 600 with a PT electronics module (which I´m not that satisfied with. It is sensetive to the annoying and takes too long to get ready for a test)
T |
I'm pulling down my first WW head engine soon (last years Bonneville engine 1192cc). I'm going to flow the heads to compare numbers with Tom's (he knows how to port heads, thats for sure). I now have the WW manifolds on it and the heads were ported by OLLIES Machine shop. I will flow them with the WW manifolds the with the SPEEDWELLS as thats whats going on it now with some 1.25 rockers
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bvilletom
Samba Member
Joined: January 22, 2006
Posts: 95
Location: cedar rapids iowa usa
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| Posted: Tue Sep 18, 2012 8:15 am Post subject: Airflow |
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Reply to Ronnie & Alstrup:
All of my flow tests are at 10" H2O. If you want them at 25" H2O, just multiply by 1.581 and your 10" flow number will then be 25" number. For example: the 10" number 67 CFM on the speedwell manifold will be calculated as follows: 67 x 1.581=105.927 which will become 25" flow number. That is pretty good for that small port.
My flow bench is a Super Flow 110 with manual controls. I love the bench and the repeatability is excellent. I have used it for many years & have created a lot of adapters.
Reply to Alstrup:
I agree with you, there is something wrong with the intake port or the valve head shape. It was really jumpy until I put on ANY manifold, then it smooths out. It was the first Wolfsburg West (WW) heads I have ever worked on and I think I could get in the 125 CFM range @ 25" H2O. I was able to get 88.5 CFM @ 25" with .400 lift without an intake manifold from my unwelded VW singleport Brukrasa heads but there is so much more potential in the WW head castings. I wanted to see what I could get out of them with stock valves and seats. The exhaust ports are very good. Let me know how you do with them?
I plan to post the before & after flow numbers of the WW heads if there is any interest. I still have to make the sheets easier to read & I ran out of time before Bonneville.
Bvilletom
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bvilletom
36hp Challenge record holder New Age 126.236mph
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splitpile
Samba's Worst Speller
Joined: May 03, 2000
Posts: 5927
Location: back to living where hell meets the suface
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| Posted: Tue Sep 18, 2012 8:48 am Post subject: Re: Airflow |
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| bvilletom wrote: |
Reply to Ronnie & Alstrup:
All of my flow tests are at 10" H2O. If you want them at 25" H2O, just multiply by 1.581 and your 10" flow number will then be 25" number. For example: the 10" number 67 CFM on the speedwell manifold will be calculated as follows: 67 x 1.581=105.927 which will become 25" flow number. That is pretty good for that small port.
My flow bench is a Super Flow 110 with manual controls. I love the bench and the repeatability is excellent. I have used it for many years & have created a lot of adapters.
Reply to Alstrup:
I agree with you, there is something wrong with the intake port or the valve head shape. It was really jumpy until I put on ANY manifold, then it smooths out. It was the first Wolfsburg West (WW) heads I have ever worked on and I think I could get in the 125 CFM range @ 25" H2O. I was able to get 88.5 CFM @ 25" with .400 lift without an intake manifold from my unwelded VW singleport Brukrasa heads but there is so much more potential in the WW head castings. I wanted to see what I could get out of them with stock valves and seats. The exhaust ports are very good. Let me know how you do with them?
I plan to post the before & after flow numbers of the WW heads if there is any interest. I still have to make the sheets easier to read & I ran out of time before Bonneville.
Bvilletom |
Thanks Tom, I would like a copy of the flow chart. We also will be using a superflow 110 (Ray Stephens )
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Alstrup
Samba Member
Joined: July 12, 2007
Posts: 7207
Location: Videbaek Denmark
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| Posted: Tue Sep 18, 2012 10:28 am Post subject: |
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Hello again.
OK with the flow #´s. Now it begins to make sense.
We´ll see who makes it to the counter first  I have about 6 engines to complete before I can begin thinking of those again.
T |
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Beetspeed
Samba Member
Joined: July 30, 2004
Posts: 429
Location: The Netherlands
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| Posted: Wed Sep 19, 2012 12:12 am Post subject: |
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I believe indeed you could make good flowing ports with the WW heads, but then that air needs to:
- mix with fuel well and
- combust efficiently.
Those two events will eventually determine how much torque/power will be made.
That semi-hemi-like combustion room shape with that far out of center spark plug location of the Okrasa/WW heads however is still horrible imo.
So, maybe it would help if the focus is not just fully put on max flowing of the ports but also towards the combustion area?
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splitpile
Samba's Worst Speller
Joined: May 03, 2000
Posts: 5927
Location: back to living where hell meets the suface
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| Posted: Wed Sep 19, 2012 12:22 am Post subject: |
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| Beetspeed wrote: |
I believe indeed you could make good flowing ports with the WW heads, but then that air needs to:
- mix with fuel well and
- combust efficiently.
Those two events will eventually determine how much torque/power will be made.
That semi-hemi-like combustion room shape with that far out of center spark plug location of the Okrasa/WW heads however is still horrible imo.
So, maybe it would help if the focus is not just fully put on max flowing of the ports but also towards the combustion area? |
We do rework the combustion chamber with out welding it up, flycut for higher combustion, angle port the exhuast port and rework the intake. I have 3 pair of ported heads, each a little different, guess it's time to put them all on the flow bench. We have put a ton of work into the WW heads and am trying to come up with a inexpensive way to improve them,
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Alstrup
Samba Member
Joined: July 12, 2007
Posts: 7207
Location: Videbaek Denmark
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| Posted: Wed Sep 19, 2012 10:10 am Post subject: |
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I agree, the plug location is not optimum. But the semi hemi chamber shape helps equal it out to some extend. The relatively small bore also aids in decreasing the downside.
I have filled the chamber up on the far plug side on a few occasions on stock heads, to gain better quench and more CR and of course a more efficient burn. The far plug side becomes "3" shaped. I have yet to figure out what the optimum distance between the valve and the chamber wall is, but I have worked out from 5 mm. which doesnt seem to slow anything down compared to an all stock head.
T |
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vintage fiberglass
Samba Member
Joined: January 23, 2006
Posts: 485
Location: Reading, Pa
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| Posted: Tue Feb 26, 2013 7:23 pm Post subject: wild 36hp engine |
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Guys,
I had talked to Mr. Motorhead about possibly building this Denzel engine for me. I have to wait for more money first. Then I read tom's amazing stuff?? I even had a wild thought about someone helping me build it in exchange for trying to run it on the speed challenge. But got real scared thinking it could blow up. Cost to much to blow up. Here is a pic of my Denzel 1500S heads with super rare brass valve keepers to keep the valves from any side to side play at high RPM's with Solex 40 P 11 carbs and Porsche 550 spyder stacks.
What crank are you guys using? and rods? 74mm? Tim |
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Roadcow
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Joined: November 14, 2003
Posts: 1012
Location: Stockton, Ca. area
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| Posted: Tue Feb 26, 2013 8:09 pm Post subject: |
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Are you planning on using the stock Denzel Aluminum rods?
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Beetspeed
Samba Member
Joined: July 30, 2004
Posts: 429
Location: The Netherlands
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| Posted: Wed Feb 27, 2013 1:14 am Post subject: Re: wild 36hp engine |
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| vintage fiberglass wrote: |
Here is a pic of my Denzel 1500S heads with super rare brass valve keepers to keep the valves from any side to side play at high RPM's with Solex 40 P 11 carbs and Porsche 550 spyder stacks.
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Tim,
That picture is soooooo awesome! Those Denzel heads are really something.
Could you pls make more close-up pictures of just the heads? Intake and exhaust and such? As I've never seen good actual pics of them other then some very small advertising pics.
Thanks!
Walter
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AirCooledClassics
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Alstrup
Samba Member
Joined: July 12, 2007
Posts: 7207
Location: Videbaek Denmark
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| Posted: Thu Jan 01, 2015 4:54 am Post subject: |
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Hello
Fast forward till today. 
Tom, did you ever get around to modify the WW heads ? I am just on the edge of beginning a 1644 cc engine with these heads. And I plan on increasing valve sizes to 35 x 30 or 32 mm. to get an intake air flow at around 125 cfm @ ,475"
Also, does anyone know where to source a set of Okrasa manifolds for 36 NDIX carbs ?
Thanks
Torben |
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tobiasax
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Joined: May 07, 2004
Posts: 202
Location: Sweden
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| Posted: Thu Jan 01, 2015 7:36 am Post subject: |
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If the boltpatern is the same as 32 NDIX I guess StefiG's intakes should work. He use to advertise here on thesamba.
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Alstrup
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Joined: July 12, 2007
Posts: 7207
Location: Videbaek Denmark
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| Posted: Thu Jan 01, 2015 11:26 am Post subject: |
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Gotcha.
- Did a couple of searches on this site with no luck. Do you happen to have a link to one of his ads maybe ?
T
Edit. Found him. Its Stefi.G |
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JeeWee
Samba Member
Joined: February 05, 2011
Posts: 120
Location: Garijp, the Netherlands
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| Posted: Sun May 05, 2019 1:23 am Post subject: Re: Motor Build for 1602cc 36 HP |
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I also run these steffi G and they have quite some material for porting them. I advise to match port them to your heads. I have modified them to get it running on 38 NDIX zenith carbs.
Anyhow I was wondering if after a couple of years there are some experiences to share how to further increase the flow of the WW okrasa heads, as I really like what has been written so far in this topic.
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Alstrup
Samba Member
Joined: July 12, 2007
Posts: 7207
Location: Videbaek Denmark
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| Posted: Mon May 06, 2019 5:17 am Post subject: Re: Motor Build for 1602cc 36 HP |
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Hello.
Wrt to modified WW heads. I came as far as gettint the heads welded for peanut shaped chamber, relocated the spark plug (further centered) to be able to flycut the heads more and also for better flame propagandation. After the heat treat I got 37,5 x 32 mm valve seats installed and used some Honda valves for testing. Then the heads sat on my shelf for a year and a half. when I finally got around to work with them again it turned out the the heads have cracks all over them  I think the aluminum we aadded is too different from the actual head material. Bummer! But then I could at least use them for testing.
- Even with a heavily reshaped intake port the port alone still acts up, but as soon as you install manifolds, in my case Speedwell IDF manifolds, the port flow really wakes up.
My first attempt was´nt worth writing home about. The second attempt was significantly better without being great. Third try, now things begin to look interesting. As said before, the intake port is VERY sensetive to the intake manifold and type/shape. At this point I had to leave it for a while again. Not so long ago I picked it up and looked at it again. Made a few small changes and tried again. Now I got 145 cfm @ 0,550" and 111 cfm @ 0,450" on the exhaust at 25" depression. These are pretty good numbers, - but - this port type is for racing, not street sinc ethe port volume is on the large side and the port velocity is on the slow side which means that the engine needs both displacement and rpm to pull good hp.
This was with a head cut for 83 mm bore.
Just for shiats & giggles I tried the heads with a WW manifold for the 32 mm Solex. That killed the flow completely and threw the package back to 1960. It would barely flow 85 cfm.
- I learned from testing some PCI manifolds a while back that the bowl under the carb most likely was on the small side, so I enlarged the bowl 10 mm downwards by taking some of the divider out and closing the holes I made in the walls with JB Weld. Made a nice throat into each port in the manifold and tried agin. This little stunt gave me an immediate 5 cfm increase. If you use 34 mm Solex carbs on these manifolds this mod is definitely interesting. The 32´s will most likely not flow enough to really make a difference, but you could gain some mid rpm torque I think.
I have not tried to flow a modified stock port w stock 33 mm valves, but Bvilletom´s claim at about 105 cfm @ 25 sounds about right. |
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gimmesomeshelter
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Joined: May 08, 2004
Posts: 1468
Location: San Carlos, CA
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| Posted: Wed Aug 07, 2019 3:12 pm Post subject: Re: Motor Build for 1602cc 36 HP |
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Has anyone tried using the manifolds sold by Stefi.g to see how they compare to Speedwells? The fit and finish looks good, but I'm more interested in how they flow.
https://www.thesamba.com/vw/classifieds/detail.php?id=2057650
Cheers,
Paul
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