to fast over SSR

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PRH
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Re: to fast over SSR

Post by PRH » Wed Jul 25, 2018 9:40 am

Did you flow an ootb ex port?

With and without a tube?

I thought I saw an earlier post where the numbers were in the 160’s, and these last numbers were in the 140’s?
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Re: to fast over SSR

Post by steve cowan » Wed Jul 25, 2018 3:59 pm

PRH wrote:
Wed Jul 25, 2018 9:40 am
Did you flow an ootb ex port?

With and without a tube?

I thought I saw an earlier post where the numbers were in the 160’s, and these last numbers were in the 140’s?
Those # without pipe
I think 138@500" ootb
steve c

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Re: to fast over SSR

Post by PRH » Wed Jul 25, 2018 4:15 pm

This isn’t pertaining to your project per se, just some general observations/questions.....

It’s always interesting to see results from other benches.

I’m a firm believer in not comparing numbers gleaned from different benches as “apples to apples”.

I can tell that your bench and mine def wouldn’t agree at .100 lift.
Those numbers look much lower than what I’m used to seeing.

On a couple of your screen shots there’s a box for leakage..... and there are values of 30+.
30+ cfm of leakage? Is that what that means?

Does that bench pull 28”, or are you converting?
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Re: to fast over SSR

Post by PRH » Wed Jul 25, 2018 4:27 pm

I have a popping exhaust port at .2"-.3" lift. I can measure reverse flow going past the valve into the chamber along the center of the SSR at those lifts. It is worst at .2" I don't have a solution yet (just found it tonight), but I wonder if you might have the same phenomena.
Are you saying while you’re flowing the ex port in the “correct” direction, you can find air back flowing into the chamber?
Off the top of my head, at that kind of lift, I would be inclined to look at the valve job and chamber for something preventing good access to that side of the bowl.
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Re: to fast over SSR

Post by steve cowan » Thu Jul 26, 2018 6:31 am

PRH,
thanks for your reply,and questions.
from day one the bench has had leakage,i spent a bit of time isolating the problem as the bench.
my bench uses performance trends blackbox electronics and there are no water manometers,now i am only speculating but maybe the bench has a safety of some description for when everything is closed and in the instructions it is not recommended to to run the bench at 0 lift but leak has to be checked and accounted for,i have made the mistake before of checking for leak and not filling in the box.
the parameters on the software are 0 - 50 for leak.it is near always around 30.
I am assuming if leak is accounted for and the 0.00'' reading says 0 cfm after leak test it should be good to go,
It is pretty obvious that i have no clue as to what i am doing but i am trying to do my best,i am just a guy in the garage at home trying to learn this head porting deal and yes its a can of worms at the very least,i have been lucky enough there has been some really helpful guys on this forum including yourself PRH and i am grateful.
one thing that the software does is correct the cfm no matter what the depression is set to and i have tested up to 40'' depression,but i have a feeling after doing some reading tonight that maybe the velocity is also corrected but i have to do more research on that.
i sat the head on the bench tonight and put the bench in both modes and probed around the back of the guide with a flowball and i think the air sounds better,i will try and put some clay in there and recheck,with bench in the inlet mode the port sounded nice and smooth at all lifts and all depressions.
again thanks to everyone involved as i feel like i sound like a broken tape recorder at the moment.
steve c

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Re: to fast over SSR

Post by mag2555 » Thu Jul 26, 2018 6:57 am

Using clay to non distructively reshape a port and produce less or maybe even greater flow is a real fast lesson in regards to where the flow is going , and or where the flow wants to go!

Such reworking and there results are not cut in stone , but I do not think that any here who has serious porting time under there belt will dispute the fact that such results are reliable 75% of the time !

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Re: to fast over SSR

Post by PRH » Thu Jul 26, 2018 9:59 am

I think you should make an inquiry into that leakage setting.

Your exhaust numbers at .100 lift are so low (18cfm) that I have to believe that leakage correction is coming into play.

You should try flowing at really low lifts(like .010-.020, where the flow would be less than 30cfm but not zero) with the leakage set to zero to see if indeed there is some failsafe built into the system.
For example, if there were 10-20cfm worth of “flow area”(maybe search one of the flow bench sites and get a dimension for a 15cfm sharp edge test plate and make one), and you have the leakage set to zero, and read 50+/- cfm flow, then there is indeed a 30cfm leak.

IMO, if there is actually a 30cfm leak, that’s a problem.

I’m still unclear if the bench is actually pulling the 28” test pressure or converting to it.
Do you know how many vacuum motors it has?

Edit: I just checked the FMA website....... I see you bought a 400, so you’re able to test at 28” and aren’t converting.
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Re: to fast over SSR

Post by steve cowan » Thu Jul 26, 2018 3:50 pm

mag2555 wrote:
Thu Jul 26, 2018 6:57 am
Using clay to non distructively reshape a port and produce less or maybe even greater flow is a real fast lesson in regards to where the flow is going , and or where the flow wants to go!

Such reworking and there results are not cut in stone , but I do not think that any here who has serious porting time under there belt will dispute the fact that such results are reliable 75% of the time !
Thanks mag,
I am seeing some things on the exhaust with clay and flow balls, I understand it's not about making the exhaust port bigger to fix it, more testing before modifications
Thanks for your input much appreciated
steve c

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Re: to fast over SSR

Post by steve cowan » Thu Jul 26, 2018 3:59 pm

PRH wrote:
Thu Jul 26, 2018 9:59 am
I think you should make an inquiry into that leakage setting.

Your exhaust numbers at .100 lift are so low (18cfm) that I have to believe that leakage correction is coming into play.

You should try flowing at really low lifts(like .010-.020, where the flow would be less than 30cfm but not zero) with the leakage set to zero to see if indeed there is some failsafe built into the system.
For example, if there were 10-20cfm worth of “flow area”(maybe search one of the flow bench sites and get a dimension for a 15cfm sharp edge test plate and make one), and you have the leakage set to zero, and read 50+/- cfm flow, then there is indeed a 30cfm leak.

IMO, if there is actually a 30cfm leak, that’s a problem.

I’m still unclear if the bench is actually pulling the 28” test pressure or converting to it.
Do you know how many vacuum motors it has?

Edit: I just checked the FMA website....... I see you bought a 400, so you’re able to test at 28” and aren’t converting.
You make some excellent points, I have a link from FMA to download and then warren can look at my computer from his end, in the meantime I still want to learn what I can
steve c

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Re: to fast over SSR

Post by steve cowan » Tue Aug 07, 2018 12:12 am

Ok guys,
Been working on sealing my flow bench up from suspected leak even though the software does compensate for leak in its parameters.
using rubber mat and clamping head to test fixture,sealing off intake and exhaust ports,the software is so sensitive it will give a reading at high depression.
parameters are 0 - 50 cfm for leak i am down to 12 - 17,i feel i am close.
i have spent late nights reading a lot of old posts from early speedtalk threads on cylinder heads,porting and looked at 100s of pictures on different shape ports,I have spent alot of time on the speedtalk search engine and its amazing,yes its information overload but real interesting reading early threads and posts from MADBILL,RANDY,RICK AND LARRY meaux who has contributed so much data it is mindblowing and i see CURTIS (cboggs) just to name a few from 2006 onwards anyway enough rambling.
i feel i made a important discovery today for myself about flowing an exhaust port with and without a pipe,now i am sure the head port and flow bench guys already know this but i have not seen it anywhere here before so here goes-
i bought a bare 190cc runner pro comp head as a test head last week just learn on,so i have found that flowing a cylinder head with no pipe nets no air on the floor of the port,i found this as well on my 165 dart cast heads so i am assuming that is fairly common(should not assume anything yeah i know) i bolt a pipe on and put pitot in end of a 10 inch pipe and air flows 290 ft/sec @ 28''so i am thinking the exhaust port really needs a pipe on it to develop the port correctly unless you really know what you are doing which i admit i do not and i am trying to learn.
so i drill 2 x holes in one of my test pipes AS PER PHOTOS one hole puts the pitot at the flange area and the other is further in around the guide boss area.
i put tape on the one not being used and my finger around to seal the pitot on outside of the pipe,so now i am checking velocity at 10'',25'',28'',35'' and find there is airflow at ALL AREAS of the exhaust port including the floor and air is way more stable out of the port flange.
sorry for the long rant but pretty excited just want some breadcrumbs to follow the path.
exhaust pitot 001.JPG
exhaust pitot 002.JPG
exhaust pitot 003.JPG
exhaust pitot 004.JPG
exhaust pitot 005.JPG
exhaust pitot 006.JPG
exhaust pitot 007.JPG
the 165cc head is ongoing and i am waiting for some more manley valves to arrive for testing and a friend is cutting a few valves for me to test with,back cuts,radius face and even a ditch cut in the exhaust valve just so can learn something,
any feed back or advice always appriciated.
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steve c

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Re: to fast over SSR

Post by mag2555 » Tue Aug 07, 2018 6:41 am

You will not find much with that ditch cut Exh valve unkess you reverse flow the Exh port. And in the normal flow direction you might see a low lift flow loss!
In a running motor with a ditch cut valve I have seen a very very small low rpm TQ gain, to deal with reversion the way to go is to have the Exh header be 1/16" larger then the Exh port outlet , and this shows flow gains as you have found out besides dealing with reversion!

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Re: to fast over SSR

Post by steve cowan » Tue Aug 07, 2018 7:01 am

mag2555 wrote:
Tue Aug 07, 2018 6:41 am
You will not find much with that ditch cut Exh valve unkess you reverse flow the Exh port. And in the normal flow direction you might see a low lift flow loss!
In a running motor with a ditch cut valve I have seen a very very small low rpm TQ gain, to deal with reversion the way to go is to have the Exh header be 1/16" larger then the Exh port outlet , and this shows flow gains as you have found out besides dealing with reversion!
hey Mag,
i hear what you are saying,i read about the ditch cut on an old post that Mad bill had put up years ago and reread in my GRUMPY book,as you know its about me learning something or anything at this stage.
am i on to something with the pitot in the pipe deal,am i getting warm or out to lunch :D
steve c

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Re: to fast over SSR

Post by randy331 » Tue Aug 07, 2018 10:59 am

Steve, it certainly doesn't hurt to do the type of things your doing. Learning the shapes that flow well, cfm/speed etc.
I remember when I got my first flow bench. I thought I would find all the answers with it, boy was I wrong.

But at some point you'll need to start relating things to the running engine. That's the hard part.


On lower rpm stuff (say less than 7000 rpm ish) I don't worry much about speeds in the port. I've seen stuff with much higher local ST speeds beat up on heads with less speed. As rpm goes up I think that changes some.


Take the head your working on and measure in 1" from the gasket flange and make a mark all the way around the inside of the port, measure in one more inch and do the same etc. Then seal off the intake side and fill the port with water till the first inch is full. (move the head around till the water matches the mark you made. Then continue filling it till you are to the next mark etc. You can use the CC of each section to come up with a CSA for each section. It will help you see how fast the port changes CSA.
You don't want the port to be big-small-big-small. It may help you make better CSA changes within the port.
I use this method on intakes too.

Randy

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Re: to fast over SSR

Post by CGT » Tue Aug 07, 2018 1:18 pm

mag2555 wrote:
Tue Aug 07, 2018 6:41 am
You will not find much with that ditch cut Exh valve unkess you reverse flow the Exh port. And in the normal flow direction you might see a low lift flow loss!
In a running motor with a ditch cut valve I have seen a very very small low rpm TQ gain,
What did you machine the ditch with, how deep? And how much power did it make or lose? Dyno test? Butt dyno?
"How or Y do you think I get all this $hit, I read all of you all builds and desktop dyno them with all the correct info and I've got your build."

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Re: to fast over SSR

Post by steve cowan » Tue Aug 07, 2018 5:41 pm

randy331 wrote:
Tue Aug 07, 2018 10:59 am
Steve, it certainly doesn't hurt to do the type of things your doing. Learning the shapes that flow well, cfm/speed etc.
I remember when I got my first flow bench. I thought I would find all the answers with it, boy was I wrong.

But at some point you'll need to start relating things to the running engine. That's the hard part.


On lower rpm stuff (say less than 7000 rpm ish) I don't worry much about speeds in the port. I've seen stuff with much higher local ST speeds beat up on heads with less speed. As rpm goes up I think that changes some.


Take the head your working on and measure in 1" from the gasket flange and make a mark all the way around the inside of the port, measure in one more inch and do the same etc. Then seal off the intake side and fill the port with water till the first inch is full. (move the head around till the water matches the mark you made. Then continue filling it till you are to the next mark etc. You can use the CC of each section to come up with a CSA for each section. It will help you see how fast the port changes CSA.
You don't want the port to be big-small-big-small. It may help you make better CSA changes within the port.
I use this method on intakes too.

Randy
hi Randy and thanks for your input its much appriciated
last week i poured a mould of the cast dart intake runner i want to run,its 178cc and then i cut it 8 sections and put it on graph paper and worked out CSA including corner radius,this is very time consuming but with it in front of me it is easier for me to understand(sort of).
i like your idea with using the burette,on intakes is a great idea.
i agree i am probably looking at velocity way to much at this stage,and at my level will get out of my depth pretty fast,my interpretation is a intake is BIG at the port opening,SMALL at the pinch,BIG past the pinch up to the short turn,and then SMALL as it goes through the throat area is this a fair assessment?
here is an example of the dart cast-area in sq/in
intake opening- 1.92''
pinch - 1.46''
runner up to and over SSR - 1.67''-1.71''-1.70''-1.77''
shrink down to throat area - 1.70'' after taking off valve stem
1.94'' valve.
i can take a photo of graph page if you like but i understand if you dont want to get wrapped up in this as i know you are busy.
just confirm for me- did you go 10.1 @ 130mph in your nova back in 2007 with a 355sbc with 292 cylinder heads done by yourself :shock:
steve c

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