Stock 1.8 head flow numbers??
- craigvwdude
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- Wally
- Posts: 4562
- Joined: Mon Oct 28, 2002 12:01 am
Its probably very close to the 2 liter round port bus heads.
I think we actually everything 'you always wanted to know about stock type 4 head flow numbers'
I think we actually everything 'you always wanted to know about stock type 4 head flow numbers'
T4T: 2,4ltr Type 4 Turbo engine, 10.58 1/4 mi
www.apfelbeck.nl
"Mine isn't turbo'd to make a slow engine fast, but to make a fast engine insane" - Chip Birks
www.apfelbeck.nl
"Mine isn't turbo'd to make a slow engine fast, but to make a fast engine insane" - Chip Birks
-
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- Joined: Wed Jan 14, 2004 7:33 am
The sq. port #'s are the same as the 2.0 bus #'s and are posted below.
I no longer do any serious performance mods to sq port ex. They offer no advantage in terms of flow (I can actually get more flow from a oval port) and by the time you take them out as much as needed to balance a good flowing 44mm intake port the sq port runner is so damn thin I don't trust it any more. Add to that the old maxim about ex gas as it relates to ex port design "all the exhaust wants is out" and you see where I'm coming from.
0.0500 22.0 32.2 28.00 28.00
0.1000 40.1 57.8 28.00 28.00
0.1500 57.2 73.1 28.00 28.00
0.2000 72.0 89.4 28.00 28.00
0.2500 83.7 104.8 28.00 28.00
0.3000 91.5 118.3 28.00 28.00
0.3500 97.1 130.0 28.00 28.00
0.4000 101.4 139.0 28.00 28.00
0.4500 105.3 145.5 28.00 28.00
0.5000 107.7 149.3 28.00 28.00
0.5500 109.8 151.6 28.00 28.00
0.6000
I no longer do any serious performance mods to sq port ex. They offer no advantage in terms of flow (I can actually get more flow from a oval port) and by the time you take them out as much as needed to balance a good flowing 44mm intake port the sq port runner is so damn thin I don't trust it any more. Add to that the old maxim about ex gas as it relates to ex port design "all the exhaust wants is out" and you see where I'm coming from.
0.0500 22.0 32.2 28.00 28.00
0.1000 40.1 57.8 28.00 28.00
0.1500 57.2 73.1 28.00 28.00
0.2000 72.0 89.4 28.00 28.00
0.2500 83.7 104.8 28.00 28.00
0.3000 91.5 118.3 28.00 28.00
0.3500 97.1 130.0 28.00 28.00
0.4000 101.4 139.0 28.00 28.00
0.4500 105.3 145.5 28.00 28.00
0.5000 107.7 149.3 28.00 28.00
0.5500 109.8 151.6 28.00 28.00
0.6000
- LowLife
- Posts: 29
- Joined: Thu Aug 05, 2004 1:27 am
Hello,
I have some flow sheets from my newly ported heads.
Heads are 44x38 for 94mm cylinders ( bus heads).
050 27.0 24.6
100 53.6 46.0
150 79.7 61.4
200 102.8 76.2
250 126.9 89.8
300 144.2 99.2
350 153.8 106.9
400 161.9 112.8
450 167.6 116.5
500 172.3 122.6
550 175.1 125.0
These were flowed at 25" instead of 28", what is the difference ?
Also the flow seems to be close to original non ported heads and a lot lower than an original porsche head ? Are my heads not done well ??
Any input is highly appreaciated.
Engien will be 78x94
Mario
I have some flow sheets from my newly ported heads.
Heads are 44x38 for 94mm cylinders ( bus heads).
050 27.0 24.6
100 53.6 46.0
150 79.7 61.4
200 102.8 76.2
250 126.9 89.8
300 144.2 99.2
350 153.8 106.9
400 161.9 112.8
450 167.6 116.5
500 172.3 122.6
550 175.1 125.0
These were flowed at 25" instead of 28", what is the difference ?
Also the flow seems to be close to original non ported heads and a lot lower than an original porsche head ? Are my heads not done well ??
Any input is highly appreaciated.
Engien will be 78x94
Mario
- Type 4 Unleashed
- Moderator
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- Joined: Tue Nov 08, 2005 10:43 pm
Here are some more comparison flow #'s.
Jonas's 44x40 heads I believe were square port bus heads and I believe were extensively remolded on the exh.
The 48x38 heads are square port bus heads with the square port welded, then made into round ports. And the Int port have had some minor welding. These are Old School done back in the 80's
The New Heads 50x42, are 2.0 914 heads with a lot of welding done to the Int ports, the exh are just cleaned up with the guide & guide boss removed, and the valve guides were moved wider to make room for the larger valves. These are my handy work and are still a work in progress.
The Newest 48x38 are 1.8 ltr 914 heads, with spark plugs relocated to the 914 2.0 ltr location and the port & chamber work along with some welding were done by A.J. Simms for a big Type lV Turbo Project.
Jonas's 44x40 heads I believe were square port bus heads and I believe were extensively remolded on the exh.
The 48x38 heads are square port bus heads with the square port welded, then made into round ports. And the Int port have had some minor welding. These are Old School done back in the 80's
The New Heads 50x42, are 2.0 914 heads with a lot of welding done to the Int ports, the exh are just cleaned up with the guide & guide boss removed, and the valve guides were moved wider to make room for the larger valves. These are my handy work and are still a work in progress.
The Newest 48x38 are 1.8 ltr 914 heads, with spark plugs relocated to the 914 2.0 ltr location and the port & chamber work along with some welding were done by A.J. Simms for a big Type lV Turbo Project.
Code: Select all
1.8 Ltr 914 914 1.8 Ltr 914
Square Ports 2.0 Ltr Oval Ports 2.0 Ltr
Jonas's Heads 44x40 48x38 New Heads 50x42 Newest 48x38 Titanium 48x40.1
Lift Lift" INT EXH LIFT" INT EXH LIFT"INT EXH LIFT"INT EXH LIFT"INT EXH
2mm .078 40.1 39.1 .100 63 42 .100 60 54 .100 58.2 50 .100
4mm .157 78.7 61.4 .150 97 62 .150 84 77 .150 86 70 .150
6mm .236 110.8 83.5 .200 127 81 .200 110 95 .200 112 91 .200
.250 151 94 .250 131 111 .250 135 107 .250
8mm .315 143.6 103.7 .300 163 104 .300 152 122 .300 150 116 .300
.350 174 113 .350 166 130 .350 167 118 .350
10mm .394 167.9 119.7 .400 181 121 .400 181 136 .400 181 120 .400
12mm .472 180.3 132.7 .450 188 128 .450 194 141 .450 195 120 .450
.500 196 132 .500 209 144 .500 206 120 .500
14mm .551 190.4 140.6 .550 200 135 .550 216 145 .550 216 120 .550
16mm .630 196.4 146.6 .600 221 146 .600 224 120 .600
.650 226 147 .650 227 120 .650
.700 228 .700 227 120 .700
Last edited by Type 4 Unleashed on Sun Feb 15, 2009 9:05 pm, edited 8 times in total.
Richard
EMW
“Have you ever noticed how some people never
have the money to do it right, but can always
find the money to do it twice ?”
EMW
“Have you ever noticed how some people never
have the money to do it right, but can always
find the money to do it twice ?”
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If I remember correctly you multiply the 25" figures by 1.06 to get it at 28".LowLife wrote:Hello,
These were flowed at 25" instead of 28", what is the difference ?
Also the flow seems to be close to original non ported heads and a lot lower than an original porsche head ? Are my heads not done well ??
Mario
Your flow looks like this then:
50 28.6 26.1
100 56.8 48.8
150 84.5 65.1
200 109.0 80.8
250 134.5 95.2
300 152.9 105.2
350 163.0 113.3
400 171.6 119.6
450 177.7 123.5
500 182.6 130.0
550 185.6 132.5
So I'd say it's pretty close the Porsche 2litre, a little less. But significantly better than the VW 2litre.
Len: I remember you, or Jake, said in another thread here at the Shop that the sq.ports had more potential than a oval, do I rember wrong or has new discoveries been made?
Edit: Found a conversion chart for head flow: http://image.highperformancepontiac.com ... 9_zoom.jpg
- Class 11 streeter
- Posts: 4083
- Joined: Sun Nov 11, 2001 12:01 am
In case Len does not get back to us soon, I remember something like that also but I think it was the square port head was a better blank canvas, or starting point, for modification with it's small ports rather than a better flowing head (than the oval).Rba wrote:Len: I remember you, or Jake, said in another thread here at the Shop that the sq.ports had more potential than a oval, do I rember wrong or has new discoveries been made?
So you think your project is taking forever eh? Well you've got nothing on me.....
- Piledriver
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...this flow data needs to be a sticky or added to a FAQ.Class 11 streeter wrote:In case Len does not get back to us soon, I remember something like that also but I think it was the square port head was a better blank canvas, or starting point, for modification with it's small ports rather than a better flowing head (than the oval).Rba wrote:Len: I remember you, or Jake, said in another thread here at the Shop that the sq.ports had more potential than a oval, do I rember wrong or has new discoveries been made?
IIRC Len later figured out the squareports (AMC) had serious casting core shift issues and were not really suited to do much with on a consistent basis... The stock heads are frequently cracked beyond economical repair, at least in North America, Vanagons are hard on heads.
I can also "visualize" the ex ports area running much hotter as there... is one, rather than basically only having a bowl dumping into a somewhat thermally isolated steel tube.
(The latter is pure, unadulterated speculation on my part)
I'm impressed the stock 1.7s flowed ~5 CFM of the 1.8s with itty bitty valves... I always figured they'd be equivalent to the bus heads, but the straight port shot must help a lot.
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
- Type 4 Unleashed
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Here is a pic of the 48x38 square port exh's welded then ground to a round port. The outside of the ports, the welding was limited because of the head studs. And think the flow #'s would of been better if the guide & boss was removed and if they would of had a 40mm valves.
Richard
EMW
“Have you ever noticed how some people never
have the money to do it right, but can always
find the money to do it twice ?”
EMW
“Have you ever noticed how some people never
have the money to do it right, but can always
find the money to do it twice ?”
- Class 11 streeter
- Posts: 4083
- Joined: Sun Nov 11, 2001 12:01 am
Done.......it's now listed in the "Interesting Reading..." stickey under "Some facts about head flow"!Piledriver wrote:...this flow data needs to be a sticky or added to a FAQ.
Len once told me in reply to my question that 1.7 heads could support a 2.0 motor if modest RPM's were expected, now I know why! The 1.7 heads are plucky for their size!I'm impressed the stock 1.7s flowed ~5 CFM of the 1.8s with itty bitty valves... I always figured they'd be equivalent to the bus heads, but the straight port shot must help a lot.
So you think your project is taking forever eh? Well you've got nothing on me.....
- fusername
- Posts: 6806
- Joined: Sun Jan 28, 2007 11:26 am
here they are
So I can only understand things visually, so I made this and found the numbers to be a bit surprising, with 2.0 bus flowing quite poorly.
give a man a watch and he'll allways know what time it is. give him two and he can never be sure again.
Things are rarely just crazy enough to work, but they're frequently just crazy enough to fail hilariously.
Things are rarely just crazy enough to work, but they're frequently just crazy enough to fail hilariously.
-
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For years I was pretty hot to do some sq. port R & D. I had a hunch that they had more potential than the oval ports. Very early efforts suggested I was on the right track. However, in back to back studies I found only a slight (and I do mean slight) improvement on valve sizes up to 36mm and no gains after that. And the big concern for me regarding the 38mm port was just how thin the port walls were downstream from the area that would normally be the oval port exit.
There were a couple of big lessons for me regarding the sq. ports. The most significant being that it is unwise to speak about R&D until we have results. The other was one that all designers learn early on, and one that I already had learned, which is that hunches are just that, and sometimes they don't pan out. I now hate to even look at sq. port heads. To much time spent trying to justify a hunch! I felt like an ideologue! I produced a few pairs that are fine heads, but in the end offered no distinct advantage over the sq. ports.
Here are the flow #'s for our LE-200 CNC heads. 44 x 36mm valves. They are so named (as all of the LE heads are) by the minimum intake flow at .500" lift.
BTW I have flowed heads prepped for 48 mm valves by a popular West coast guy that didn't match our 44valve heads! The ports weren't welded. No O.E. T4 heads will support a 48mm valves potential without welding to allow for larger ports. 46mm is pushing it on the 2.0 914 and 1.8's and even there some welding is beneficial. So remember, bigger is not often better when it comes to valves.
0.0500 29.9 34.3 28.00 28.00
0.1000 51.4 62.0 28.00 28.00
0.1500 70.0 88.4 28.00 28.00
0.2000 87.6 115.8 28.00 28.00
0.2500 102.8 143.3 28.00 28.00
0.3000 113.8 164.0 28.00 28.00
0.3500 122.6 180.4 28.00 28.00
0.4000 129.6 189.5 28.00 28.00
0.4500 135.5 195.8 28.00 28.00
0.5000 139.6 200.3 28.00 28.00
0.5500 142.4 205.4 28.00 28.00
0.6000
Those #'s are from an early intake port shape. We have actually increased the flow by a few cfm since then, but I don't have those files stored on this computor so these will have to do. BTW these are the heads that Jake uses on his 2270 and 2316 engines.
This statement is absolutely spot on. I would much rather direct the hot gasses through a steel tube than a thin wall aluminum port that is liekly to eventurally crack. The effectiveness of the ex port is determined by the shape at the bend, not downstream. The sq. port is restrictive in this downstream area on the 38mm and larger valves unless it is opened up scary thin.I can also "visualize" the ex ports area running much hotter as there... is one, rather than basically only having a bowl dumping into a somewhat thermally isolated steel tube.
(The latter is pure, unadulterated speculation on my part)
There were a couple of big lessons for me regarding the sq. ports. The most significant being that it is unwise to speak about R&D until we have results. The other was one that all designers learn early on, and one that I already had learned, which is that hunches are just that, and sometimes they don't pan out. I now hate to even look at sq. port heads. To much time spent trying to justify a hunch! I felt like an ideologue! I produced a few pairs that are fine heads, but in the end offered no distinct advantage over the sq. ports.
Here are the flow #'s for our LE-200 CNC heads. 44 x 36mm valves. They are so named (as all of the LE heads are) by the minimum intake flow at .500" lift.
BTW I have flowed heads prepped for 48 mm valves by a popular West coast guy that didn't match our 44valve heads! The ports weren't welded. No O.E. T4 heads will support a 48mm valves potential without welding to allow for larger ports. 46mm is pushing it on the 2.0 914 and 1.8's and even there some welding is beneficial. So remember, bigger is not often better when it comes to valves.
0.0500 29.9 34.3 28.00 28.00
0.1000 51.4 62.0 28.00 28.00
0.1500 70.0 88.4 28.00 28.00
0.2000 87.6 115.8 28.00 28.00
0.2500 102.8 143.3 28.00 28.00
0.3000 113.8 164.0 28.00 28.00
0.3500 122.6 180.4 28.00 28.00
0.4000 129.6 189.5 28.00 28.00
0.4500 135.5 195.8 28.00 28.00
0.5000 139.6 200.3 28.00 28.00
0.5500 142.4 205.4 28.00 28.00
0.6000
Those #'s are from an early intake port shape. We have actually increased the flow by a few cfm since then, but I don't have those files stored on this computor so these will have to do. BTW these are the heads that Jake uses on his 2270 and 2316 engines.
- typ4
- Posts: 551
- Joined: Sat Mar 01, 2008 9:46 pm
Len, thanks for the great info, I do lots of vw heads and most are stock rebuilds, I cant buy anything on the west coast that lasts, some of the rebuilds I take off of engines are just plain scary.
Maybe I am too picky.
Anyway, I fully agree with the 48mm intake info I built a pair for myself ,they look nice but not welded, and they pretty much suck on my engine.
They work but not efficiently.
I have a question though. What size valves would you recommend for my current turbo 2840cc 10 lbs of boost?
Thanks again for all the info.
Maybe I am too picky.
Anyway, I fully agree with the 48mm intake info I built a pair for myself ,they look nice but not welded, and they pretty much suck on my engine.
They work but not efficiently.
I have a question though. What size valves would you recommend for my current turbo 2840cc 10 lbs of boost?
Thanks again for all the info.
2840 type4, turboed and injected with my GM conversion. runs great and still needs fine tuning.
-
- Posts: 591
- Joined: Wed Jan 14, 2004 7:33 am
That's a difficult question to answer. First there is the consideration that must be made for the breathing requirements (you didn't mention the revs you want) of that large engine. Next are the considerations that must be made regarding the relative weakness of the T4 castings in the combustion chamber in the area that is directly over the ex. port. It is a common problem on NA engines with over 11.0:1 compression ratios to push this area of chamber out toward the port. In essence the chamber droops into the port. You can't see this with the naked eye, but it becomes obvious when you attempt to cut the ex seats. (If someone can tell me how to post a photo I'll post a picture of a seat suffering from this condition) What we find is that the seat is no longer concentric to the guide. This is because when the casting droops it takes the seat with it. We have never seen a failure from this, but we do see some very high leakdown #'s around the ex valves. Thank goodness the high leakdown #'s don't hurt power, (we've proved this on the dyno and the track), otherwise we would have a tough time making 914's competitive in E and F-Prod SCCA competition.I have a question though. What size valves would you recommend for my current turbo 2840cc 10 lbs of boost?
Thanks again for all the info.
Now with a turbo which really loves high egt's (which really intensify the droop issues) we have to be very carefull as we select our valve sizes. Turbos want a relatively high I/E flow ratio. Generally in the neighborhood of 85%. To get that kind of ratio with a 42mm intake valve we have to run a 38mm exhaust valve and really work on the ex port. Push the intakes to 44 mm and the ex valve must move up to 40mm. Installing valve seats large enough for even a 38mm ex valve removes an extra 1.5mm of material in the radius from the ex seat counterbore as compared to a 36mm valve. I know that doesn't sound like much, but in relative terms it is because this area is already thin. Go up to a 40mm ex valve and you remove another .75mm for the appropriate valve seat.
I was recently asked my recommedations for a turbo engine. Here's what I came up with. 91mm bore and as much stroke as the customer could afford. He settled on 71mm (he couldn't afford much stroke!) I like the smaller bore for a couple of reasons, the biggest being the extra meat it leaves in the chamber. Plus when coupled with a long stroke the combo doesn't want/need as much breathing as the set-up lends itself to lowend torque. For the heads I recommended 1.7 castings fitted with 40 x 36 mm valves. This will allow for the 85% I/E flow ratio without weakening the head to much. The smaller intakes ports will also make the engine more responsive at low speeds which will help spool the turbo up faster.
Jake is developing a cam and pistons for this guy. We'll know soon how well the combo does. I think that this bore with a 78mm stroke would make a fabulous 2.0 powerplant for the street.
I'm really not a fan of turbocharging T4 engines (especially big ones) because of the problems I've seen with chamber droop. Heat and pressure are a bitchy combo! Aluminum melts at around 1400* and it gets damn soft at 1250*, which happens to be where NA engines make peak power. If a 1.8 producing 186HP with a 34mm ex valve and the smallish ex seat can't handle 1250* without drooping, what do you think is going to happen when you throw boost at it? If you want to go that route, don't freak out when the ex valves develop high leakdown #'s (I routinely race with 30%) It's just something you will have to accept.
Now back to your question, I don't think that the large T4 engine will ever be able to run the valve sizes that would be optimum for a turbo. Naturally it will make power with just about anything (that's why we love turbos!) But I would think 44 x 40 woulld be as big as you would want to go. Don't forget that the boost reaks havoc on intake valve control. You should see the carnage I've seen! And at revs that are no real challenge for a NA engine. [/img]