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  #41  
Old 07-10-2020, 03:36 PM
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I was consifering using an Aisin AMR300 as a supercharger along with E85 for a gokart build. I have to keep my mind from wondering into crazy builds. Lol
Do it. You'll have a blown hemi.

https://i.imgur.com/Ln5yFHP.jpg
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  #42  
Old 07-10-2020, 04:09 PM
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I guess I should point out some of the terms that I have been and will be using concerning the ports and various parts of the head as well as intake and exhaust system.

So I am in the process of trying to figure out the actual cross-sectional area in various spots within the intake port. There are a few ways that I will try to accomplish this accurately. So there are a few cross-sectional port areas I am trying to get to. The smallest area just before the valve bowl (choke area), gasket entry and average port area. In addition I want to keep the taper to less than 7 degrees. Since there is about a .53" rise in the port floor the length of the ramp would have to about 4.5" or longer. Since the port so short the taper will have to continue into the runner. I have also calculated the best average runner cross-sectional area, exhaust port minimum/average/max gasket areas as well as 2 stage header areas. Also I have calculated the harmonics of the valve events at multiple rpms to determine the best lengths of intake runner and exhaust header to tune the pulses for best overall performance.

The smallest port cross-sectional area= 0.389" (287 FPS)
Average port cross-sectional area= 0.423" (262 FPS)
Intake gasket cross-sectional area at gasket (pre-port in runner)= 0.488" (228 FPS)

Method #1: Use an Inner Caliper device to determine the height and width of the ellipse and use those numbers in the ellipse formula to determine area.

Method #2: Use modeling clay and pack the port. Remove modeling clay, cut very thin slices at the needed areas, ball the clay up and place it in a measuring vile. Measure the displacement in mL. 1mL = 1cc. Convert cc to cubic inch.

Method #3: Average numbers from Methods 1 & 2.

Method #4: Eyeball it and wing it.

I think I will go with Method# 3.

The above numbers are calculated at about 95% Volumetric Efficiency. So they are at the small side of the scale to help me determine the smallest areas. If I stay above those numbers (bigger cross-sectional areas) and under the numbers chrunched for 85% VE then I should be good. With the right sized ports, proper intake and exhaust and all things designed to work for the specific engine cam and dynamics a peak VE of 100% or more is very possible with total averages above 93% being a reasonable goal. With the simplicity of a small single cylinder engine, short oversized ports and a hemispherical head design it is a good candidate for respectable VE numbers. So I will calculate the port cross-sectional areas and when I get them close to where the number crunching suggests I will put it on the flow bench and see how they flow. I am shooting for a max CFM between 45-49 CFM @ 28in H2O at near max lift. Due to the piston speeds during rotation the actual amount of decompression created varies dramatically to well over (up to 60+in H2O or more) atmospheric pressure (14.7psi is seen as 28 in H2O) to very little pressure as the piston slows it's withdrawal speed. So it's difficult to know just what a live running engine needs to flow based on a static pressure. I am building a dynamic flow bench to better simulate the actual dynamic sweep of the piston. It will have the ability to test at different static pressures for comparative results to other flow benches also.

If the higher velocity and design of the port allows the mixture to be better mixed then less max CFM is needed. So while the total CFM might drop a bit the overall efficiency can go up reducing the amount of air needed for the same amount of work to be produced. Also, if the velocity of the ports are more responsive then the A/F mixture begins to fill sooner, fills faster and more efficient than a bigger port so again the max CFM flow needed goes down. So the max flow numbers can actually vary and may not actually represent the perfect goal of what would be the most efficient numbers. Atleast I have reasonably close numbers to focus on. The true way to tell will be to put it on a dyno or on the cart and run it.
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  #43  
Old 07-12-2020, 07:14 AM
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Originally Posted by 65ShelbyClone View Post
Do it. You'll have a blown hemi.

https://i.imgur.com/Ln5yFHP.jpg
Yeah, I thought it would be sweet. I would invest in some better guts and such so it didn't become a blown hemi literally, but think the build would be pretty ok.
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  #44  
Old 07-13-2020, 01:53 PM
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The flowbench is getting close to being done. Just finalizing exact placement and implementation of a couple of gaskets/O-rings, where I'm going to put it and a couple bracing designs. It shouldn't be long. I just have to fit it between other things I have going on.
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Old 07-17-2020, 01:14 AM
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I am finalizing the flowbench and trying to figure out where to put it in my shop that has limited space. I am trying to make it so I can store it out of the way after I get done.

While I am trying to figure out the best placement I started trying to figure out the best starting point as a full system (carb to intake runner, to intake port and exhaust port to exhaust manifold/header) since any one piece will affect the system as a whole and if one piece is off the whole system will suffer. The intake runner is my main focus as of now. Without a suitable intake runner design the rest of the system will not work properly. Since I am doing a tuned intake it will be of extended length in comparison to many normal intake runners.

The extended length can lead to some very nice benifits if done correctly. However if not done correctly it could lead to very poor performance. Since the runner length is of considerable length many factors that normal short runners never really have to worry about become very much a concern. Basically there are a few ways to get it to work but many ways to get it wrong. Some of the things you have to take into consideration are:

-Proper length to achieve the desired "RAM Effect"
-Correct diameter.
-Proper shape
-Proper taper
-Proper finish
-Correct angle

I have been crunching numbers, making grids, multiple 2-D graphs to combine to make a rough 3-D graph and I think I have enough to atleast start in the right ballpark. I can't go into details because it would take forever to try to explain and go over all of the different theories, formulas and different routes that I went through to try to come to a conclusion to a good starting point for the runner diameter, length, taper, shape and inside surface. I ended up back engineering publicly accessible research studies of similar compressionible liquids within walled chambers, various intake runner study results, etc and applied it to my own specifications... made my own charts, cross-referenced, re-worked the numbers, applied different formulas and data charting applications, learned to be much more specific on coping formulas (the difference between an "i" and a "j" had me trying to balance an equation wrong for 3hrs) and in the end I ended up with my own back engineered set of formulas... which are probably way wrong but they gave me numbers that seemed to be in a very close relationship to other applications that have been concluded that are proven to work very well. So I have changed my origional design some and feel that all the hard work will pay off. I don't think that my origional design would have worked well past 4,200rpm.

If your interested in some of the theories, formulas or sets of equations that I gather information from I will list some below as well as some terms that you might want to research to better understand some of the physics involved with the intake runner designing process. This is just a short list off the top of my head because I doubt many will ever have the desire to go down such a math-heavy rabbit hole. I almost regret all of the work. It's best to use much of this on a computer in a modeling program. Long handing these with a calculator, pencil and paper is NOT recommended! It takes FOREVER to correctly balance some of these equations and get plottable points. And you have to do small grids of plottable points to be accurate enough to obtain usable results to use in the next plottable point so that you can come to a decent representation of the *hopefully* pretty accurate outcome that you can use to determine if your application will be beneficial or suck eggs. I learned a lot but spent too much time on trying to get mathematical results when I could have just spent the time and resources to build a ton of different variations and dialed it in that way. Having a strong, very fast computer with a modeling program would be much more ideal. It still takes several hours on a moderately fast computer to run a full mapping with only one set of variables for some of the sets of formulas like the 7 formula 3-dimensional Reynolds Stress Model. The Reynolds-Averaged Navier-Stokes is a bit more computational friendly. The Navier-Stokes Equation isn't too bad. The problem is that none are completely accurate. Plus the variables have to be accurate to get it in the ballpark. Anyway, here are some things to consider:

-Reynolds Stress Model (There is a 5 equation model for 2 dimension and 7 equation for 3 dimension)
-Reynolds-Averaged Navier Stokes
-k-€ model-I don't have the right symbols to correctly name the models of some of these. It's the Turbulence Dissipation Rate Model
-k- Turbulent Kinetic Energy Equation
-Navier-Stokes Equation
-Mass Conservation Law
-Energy Conservation Equation
-Specific Heat Capacity
-Heat transfer Coefficient
-ko family
-Prandtl Mixing Lengths
-Boundry Conditions (layers)
-Slip Condition
-Dampening Layers
-Stress
-Viscosity

There is a whole study within hydrodynamics trying to figure out how to best depict how certain gasses/liquids/air-fluid mixes will travel in different pipe type configurations with attempts to figure out how to factor in all the specific variables involved in each application. It's insanely involved and while I feel that I have a pretty firm grasp on the majority of the principles involved I realize that my time would be better spent on trial and error, since the top universities are still trying to figure out how to create proper equations to accurately predict real life observations. I feel that I have enough knowledge to have an understanding of the principles at play to the point that I can create a better starting point as well as to have a better understanding of the results that I will get and how to make positive adjustments accordingly.

This thread isn't getting much attention any more so I will not go into any details. I will just write up my conclusions and a more brief description and call it good. Any terms that come up you can either look up or ask and I will explain. It's just way too complicated to explain, especially in a thread that isn't getting any attention (probably from writing too much) so I will the time doing other things.

I have included a couple quick pages of notes that I have used. I can't include all of the notes or work... there is a couple of notebooks and tons of graph pages. And I am only moderately convinced that all of my math is correct because of so many variables and the complexity. So it's best to do your own research. They are just some notes to get you started and going towards the right areas of intrest.

The other 2 pics are from "Intake Manifold Design using Computational Fluid Dynamics" by Matthew A. Porter from University of New South Wales at the Australian Defence Force Academy. They give you an idea of how the boundry layer, viscosity, sheer, stress, etc effect how the flow and velocity are effected in a "tube" type or infinite walled channel. Basically a crappy designed runner will cause the friction of the fluid to cling to the wall and slow the velocity and restrict the total amount of flow. Again, it's way more involved but that's a quick tidbit of some of the things going on that you have to factor in when designing such channels for compressionible fluid transportation.
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  #46  
Old 07-17-2020, 10:56 AM
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You gonna make the flowbench wet-capable so you can see where the fuel is going? Something else to research at 3:30am.

Have you run across an old thesis paper yet about determining intake tuned length based on directly measuring pressure in a dead cylinder spun at running speed? I though about doing the same, but the typical sensors alone cost about a grand, not to mention the daq needed to log it at high res. What would be nice is that it could be used to evaluate head flow on an engine as well as intake effects at running speed. It would have the shortcoming of not being able to show effects of exhaust blowdown on overlap, although maybe there would be enough inertia from pumping that a correlation could be made.
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  #47  
Old 07-17-2020, 01:09 PM
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Originally Posted by 65ShelbyClone View Post
You gonna make the flowbench wet-capable so you can see where the fuel is going? Something else to research at 3:30am.

Have you run across an old thesis paper yet about determining intake tuned length based on directly measuring pressure in a dead cylinder spun at running speed? I though about doing the same, but the typical sensors alone cost about a grand, not to mention the daq needed to log it at high res. What would be nice is that it could be used to evaluate head flow on an engine as well as intake effects at running speed. It would have the shortcoming of not being able to show effects of exhaust blowdown on overlap, although maybe there would be enough inertia from pumping that a correlation could be made.
Quote:
You gonna make the flowbench wet-capable so you can see where the fuel is going? Something else to research at 3:30am.
Yes, in fact I am! And here I thought I was going to be soooo clever and figure out something to do that hasn't been done before. I guess my research isn't so great. I was trying to determine what non-volatile fluid best behaves like gasoline, put some blacklight reactive substance in it, run a holding tank piped to the carb, put the intake on, have a plexiglass cylinder tube and side panel with a blacklight and run it that way to witness the wet flow characteristics. I built the main flowbox with plexiglas viewing windows and a 70mm ID tube for the cylinder chamber just for this purpose as well to run smoke. I have everything to go wet-flow but I want to be sure that the fluid combo I use has the proper surface tension, weight, viscosity, etc as fuel to get the best actual results. I didn't even think to research wet-flow capable flowbench designs. I bet they have already figured out a suitable fluid to use. I certainly dont think it's a very good idea to run actual fuel! Water seems like it would have too high of surface tension. Do you know what they use? Is the blacklight idea new to you or has that been done also?

Quote:
Have you run across an old thesis paper yet about determining intake tuned length based on directly measuring pressure in a dead cylinder spun at running speed?
No I haven't read that, but again, I was thinking of using the block with an electric motor spinning the crank to try to obtain actual readings. I am much more behind the curve than I thought. I thought I would be breaking new ground with these ideas. Turns out I am not as clever as I thought.

Quote:
I though about doing the same, but the typical sensors alone cost about a grand, not to mention the daq needed to log it at high res. What would be nice is that it could be used to evaluate head flow on an engine as well as intake effects at running speed. It would have the shortcoming of not being able to show effects of exhaust blowdown on overlap, although maybe there would be enough inertia from pumping that a correlation could be made.
I was going to use an Arduino-type SBC that has plenty of digital and analog I/o with differential pressure sensor breakout boards as well as the tiny sensors they have now-a-days and run them with tiny wires. They would still affect the flow some but not nearly as much as any pitot tubes they have. Speaking of pitot tubes (since I'm learning that all of my grand new ideas are probably not new at all) I have ordered stock replacement valves and am going to (or pay a machine shop to do it) drill a hole down the center of the stem and then a hole out to the lip of the valve so that I can spin it to get more accurate velocity readings 360 degrees around the valve curtain area.

Back to the daq... You can put a cheap sensor on the crank to gather degree angle, cam timing, rpm, etc and as long as you degree in the valve events properly a simple set of formulas will keep track of all of the engine events and be able to plot them with the sensor readings. From there it is a simple task to set up real-time write code to a screen as well as to memory. Later you can convert the gathered code to graphs. You could even write the code to build a graph in real-time if you wanted. The technology is there for a person with a very modest budget to do incredible things these days. The whole system would cost less than $300. Even less if you don't want to be as elaborate.

I have already gone too far on this "simple" diy build and need to cut myself off and just finish it up. I might add more things later on but so far I am building this for a stupid stock yard kart motor and it has already gotten out of hand! Lmao

Thanks for the insight though! Now I have to read up on what has already been done to short-cut some of my final touches. I spend too much time figuring everything out for myself when I could just copy what's already been done. I guess the raw knowledge and understanding comes in handy so I suppose it's not a complete waste of time. I'm feeling that I have to incorporate the practice of KISS a little more on this build.
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Old 07-20-2020, 10:40 PM
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I'm making progress on the flowbench. I got the hole cut for the 70mm ID acrylic tube to portray the cylinder and routed out a ring for the o-ring gasket for between the acrylic adapter plate and flowbench. Just waiting on some medium density acrylic glue to chemically weld the tube to the adapter plate. The main system is bought and temporarily put together to size it up in the workspace to determine where I will put it. I am getting closer.

I did some research on actual hp numbers of some of the Hemi 212's from dyno pulls I could find on the internet in various stages of build but with stock porting. Then I made a theoretical CFM/HP chart and plotted all of the results against theoretical CFM flow #'s. I factored in 50%-85% Volumetric Efficiencies to see where the different engines with different mods might be with CFM and Volumetric Efficiency.

The data seems to suggest that the ports can support in excess of 25 CFM with about 68% VE and produce up to 16 ft/lb and just over 12hp. There are other claims of more power being made with stock ports but the alterations like cam, timing, rod length and rocker arm ratios were too far from stock for me to include since they are so far from stock, although the ports provided enough CFM for them to make more TQ and HP so I know the volume of the ports aren't much of a weak link. The Volumetric Efficiency in all of the engines are below 70% of a theoretical 100% amount of CFM needed for the engine and the rpm where the engines make peak TQ and peak HP suggests that all of the engines have pretty inefficient intake and exhaust systems.

From what I can guesstimate these engines with a normal little gasket-matched runner and a 22mm Makuni type carb and fatty 3-stage header pipe still has a VE around 50-60%, which is pretty crappy. Most general Non-performance based modernish car engine have a VE of about 70% or a little better. A single cylinder engine should be much easier to get high VE since there are no other cylinders attached to the intake and exhaust system upstream/downstream to have a negative affects on the efficiency. So with almost no restrictions left in the system VE peaks at about 65%. That just leaves turbulence, bad A/F mixture, and low velocity to blame for the most part. We know that the ports can flow enough volume well above stock rpm and hp and the power curve stays about the same. I really think a more efficient (well designed port) with less volume will be beneficial.

So in a perfect system with 100% efficiency you should be able to make 6.5hp with 4.5-5 CFM. Ofcorse that is not going to happen so we figure in a percentage of loss due to inefficiencies within the system and engine design. It seems like the typical 70% VE is too generous for this engine and a more accurate 55% should be used. With the 70mm (2.756") piston with a 2.165" stroke at 5,300rpm the maximum average CFM needed to flow through the intake system is:

Displacement x rpm ÷ 3,456

12.93 x 5,300 ÷ 3,456 = 19.83 CFM

At 70%VE you would need to flow about 28.4 CFM. (28.4 × .7 = 19.88)

Theoretically 19.88 CFM should be able to produce 28.63hp.

If you take the hp you make to calculate the CFM used in a properly tuned engine a 6.5hp engine uses 4.51 CFM. Somewhere there is a huge loss of efficiency in the Hemi even with realistic expectations in mind. We should see a little more efficiency. I think there is a decent amount of gains left on the table in stock form and in my opinion the data suggests that we are loosing too much velocity which is ruining the Volumetric Efficiency that we could be enjoying. I am even more confident now that a well designed intake and exhaust system incorporating a smaller cross-sectional runners, ports and exhaust would not only make more efficient power at low and mid rpm but quite possibly gain maximum overall tq and hp numbers.

On average from what I could find the average hp of an ungoverned Hemi engine makes 7.5 -8.1hp if you help unrestrict the intake and exhaust and tune it properly. So let's just shoot for a solid 9hp. If I can produce an intake and port that would flow enough CFM to support 9hp with 70% Volumetric Efficiency at atmospheric pressure (here it is about 14.2psia) so -28inH2O on the flow bench at 80% valve lift then the port and intake system should be plenty sufficient.

So 9hp takes about 6.25 CFM of average flow. 9.5 CFM at 70% VE would provide over 6.5 CFM. As long as the improvements in the intake and port can flow an actual 20CFM at 10inH2O or so I think that the alterations will at the very least not make less hp. As long as the intake system can flow the total needed CFM then there is no need to have them any larger or else you are just reducing velocity for for zero gain, and more likely loosing power because of it.

So I have my flownumber figures figured out that I will be aiming for. I will be aiming for a total max CFM of 23 CFM or so with a solid ability to flow 9.5 CFM at lower inH2O (around 10 inH2O) and at lower valve lifts. Then I will test at dynamic ranges at low valve lift to tweek low valve lift flow rates during overlap. Then I will try to match the performance characteristics of the exhaust in relation to what the intake flows with corrections factored in for the exhaust temps and characteristics in an attempt to provide not only a good exhaust flow and speed but also strong scavenging to provide a strong pre-pulse tug on the intake to get it moving before the piston starts to have an effect to make use of as much of the valve open event time as possible.

Well that's my thinking so far. Does anyone have any ideas or see any problems with my logic? What are your thoughts?
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  #49  
Old 07-21-2020, 11:06 AM
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12.93 x 5,300 ÷ 3,456 = 19.83 CFM

At 70%VE you would need to flow about 28.4 CFM. (28.4 × .7 = 19.88)
You divided 19.8 by 0.70 instead of multiplying. 19.8 × 0.7 = 13.9cfm.

Quote:
Theoretically 19.88 CFM should be able to produce 28.63hp.
I think the same thing has happened here. CFM per HP is usually estimated at 1.25-1.50; you're using 0.69. Flip the fraction and 0.69⁻¹ becomes 1.44.

13.9cfm ÷ 1.44 ≈ 9.7hp which is realistic for an ungoverned stock 212.
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  #50  
Old 07-21-2020, 02:32 PM
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You divided 19.8 by 0.70 instead of multiplying. 19.8 × 0.7 = 13.9cfm.



I think the same thing has happened here. CFM per HP is usually estimated at 1.25-1.50; you're using 0.69. Flip the fraction and 0.69⁻¹ becomes 1.44.

13.9cfm ÷ 1.44 ≈ 9.7hp which is realistic for an ungoverned stock 212.
Thanks for the response! The general "Rule of Thumb" that usually works quite well to find the bhp or whp for anengine with average BSFC and VE estimates that you need about 1.44 CFM to produce each HP.

Just to be clear I will explain my reasoning a bit more and then we will see if I sh!t the bed on my calculations, which is possible since I get turned around and screw up sometimes, especially when I'm tired.

In order to find the amount of air/fuel to fill the cylinder at maximum rpm you take the area of the cylinder and multiply it by the stroke and then multiply that by the rpm. Then you divide by 3,456 to get your average Cubic Flow per Minute that your intake would have to be able to flow to fill the cylinder at the calculated rpm at 100% efficiency. There are better, more involved formulas but this is a decent rough estimate to get started.

The CFM needed at 5,300rpm is 19.83. To give a little comfort room I want the intake to be able to flow the desired maximum CFM of 19.83 but include a buffer for inefficiencies within the pumping process so I calculate a target goal that would provide 19.88 CFM even with a 70% efficiency. So if you can flow 28.4 CFM at 70% efficiency you should be able to still get 19.88 CFM. So that's where I got that number and what I was trying for.

As far as the expected hp from 28.4 CFM, yes I screwed that up. Thank you for catching that. I just multiplied it and wrote the number down and didn't think about it. My initial research led me to 19.72hp. And I basically chit the bed on this when trying to re-calculate my numbers with only my end note figures where I crunching numbers for different engines to see how accurate the math was. Then I tried to figure out things as I wrote.

So 19.88 CFM should produce 9.64hp.

Going back to my big pages of figures my actual figures the target goals I wrote down are:
.050" to .200" sweep at 15 CFM @ 28inH2O
.100"-12 CFM @28inH2O to dynamic
.264"-28.4 CFM dynamic
.264"-21.83 CFM @ 28 inH2O
.264"-19.83 CFM @10 inH2O

Those are some numbers that I will be looking to get with the tightened ports with the intake and carb in place with the carb slide held open and air filter on.

With only having to worry about the pulses from a single cylinderI think that an average 80+% VE should be pretty feasible with peak VE during a targeted tuned rpm range about 93%. It is entirely capable to get over 100% VE if a tuned system is functioning properly so that ofcorse is my ultimate goal. About 113% VE in the "Sweet Spot" with a large band with about 90% VE and minimal VE of about 83%. With this being a single cylinder little stroker motor and hemi head I think it is possible.

I should not post while tired and without my proper notes to copy from.

Thanks 65ShelbyClone for catching my screw-up!

I am expecting to be able to attain the upper lift max CFM flow numbers pretty easily but I am thinking to get the biggest benifits during overlap and low to mid lift I will have to work on the valve seat area. I have a cheap set of valve seat cutters. I hope they will be ok enough if I use them very cautiously and patiently. The pilot/guide is not tapered and there is a tiny bit of play... Which could lead to disaster. The quality ones are twice the cost that I have into the engine and flowbench. I doubt that I will use them enough to validate the purchase. And if I did buy them I know that I would end up taking apart all of my engines just to cut the valve seats to get the most out of my purchase and make it worth it lol

Does anybody have experience with the cheap Taiwan valve cutter kits that had decent results? Any tips to get good results??
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Old 07-31-2020, 12:08 AM
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I should have the last of the parts to finish up the flowbench soon. The stalling shipping times are making this build way longer than it needs to be. Most of the parts are not things that are sticked on shelves locally where I could just go and buy so I am at the mercy of the wait times we have these days. But everything is coming together nicely now so it shouldn't be too much longer.



While I have been waiting I have been contemplating building a small engine dyno as well. Stay tuned since it will more than likely be the next side project. That way I can have actual results, good or bad, about the alterations I make as well as a good way to brake in the engine and be able to vary the load while doing so.
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Old 08-01-2020, 11:17 AM
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I feel for the logistics companies having prolonged Christmas-level workloads, but the surprise loser for me and those I know has been UPS. Most of it has been delayed from a few days to a week or more. I had an intake manifold supposedly on the truck for delivery yesterday. I even passed the usual truck and driver a few miles away. Now my intake is back at the distribution center.

Aaaanyway.....

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but I am thinking to get the biggest benifits during overlap
I think you'll find that the stock cam doesn't have any. Well, it probably has some, but it's mostly going to be across the lobe lash ramps. I doubt there's much if any ~0.050".

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I have a cheap set of valve seat cutters. I hope they will be ok enough if I use them very cautiously and patiently. The pilot/guide is not tapered and there is a tiny bit of play... Which could lead to disaster. The quality ones are twice the cost that I have into the engine and flowbench. I doubt that I will use them enough to validate the purchase. And if I did buy them I know that I would end up taking apart all of my engines just to cut the valve seats to get the most out of my purchase and make it worth it lol

Does anybody have experience with the cheap Taiwan valve cutter kits that had decent results? Any tips to get good results??
Are they actually cutters or are they the stone abrasive type? I rarely have to cut seats and either use a boring head or Neways, so no experience with the inexpensive ones.
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Old 08-01-2020, 07:13 PM
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With everything being stock I think the most "band for the cut" with cutting the 3 angles will be improved depression during what ever overlap there is and low lift. Any time you can get the air moving sooner at low valve lift the better and so if there is ANY scavenging improvement during overlap and low-lift then it has exponentially better benifits over any other improvements at the valve seat area at any larger valve lifts. Improvements at the lift during max piston speed and just after is a close second but if you have bad flow at low-lift then the only effective depression is being done then. If you can get the air pre-charged, meaning the air effectively starts to move before (or more) the pistion has an effect on it then you see a gain throughout the valve lift range. Hopefully I can cut the seats and improve atomization at the same time. I think the better bet is that I will experience a lesson in humility more so thanmaking tons of improvements in all of these areas lol But hopes are high that a decent improvement can be made throughout the entire range... Eventually.


The kit is a live pilot cutter set. Simple 30,45, 60 angle kit.
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Old 08-06-2020, 09:49 AM
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I should have the last of the parts to finish up the flowbench soon. The stalling shipping times are making this build way longer than it needs to be. Most of the parts are not things that are sticked on shelves locally where I could just go and buy so I am at the mercy of the wait times we have these days. But everything is coming together nicely now so it shouldn't be too much longer.



While I have been waiting I have been contemplating building a small engine dyno as well. Stay tuned since it will more than likely be the next side project. That way I can have actual results, good or bad, about the alterations I make as well as a good way to brake in the engine and be able to vary the load while doing so.
Care to share a little on on the flow bench your building? What style? Did you use plans? How much is the flow bench costing you to build?

I have plans to build my own (been dragging *** on it for a couple years) has i have been using a buddies SuperFlow. I really need to get mine done instead of relying on him. He is getting up there in age and has a few health problems and I fear one day my access to his will be gone.
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Old 08-06-2020, 10:47 AM
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Maybe he'd sell it to you...
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Old 08-06-2020, 11:09 AM
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Care to share a little on on the flow bench your building? What style? Did you use plans? How much is the flow bench costing you to build?

I have plans to build my own (been dragging *** on it for a couple years) has i have been using a buddies SuperFlow. I really need to get mine done instead of relying on him. He is getting up there in age and has a few health problems and I fear one day my access to his will be gone.

Sure. I read a ton of other builds but mine is not directly from a particular plan. I went with a 4" schedule 40 PVC pipe design for the main pipe, double anti-turbulence/air straightener (one ahead and one behind of the anemometer) made from groupings of 10" plastic jumbo straws, digital anemometer for flow readings, digital manometer for depression readings, 12" cubed main flow box with 4" flow hole and 2 6"×6"×1/2" acrylic windows and a 6"×6" acrylic adapter plate with 70mm×6" acrylic tube for faux cylinder chamber. For depression control I have a 4" tube with 30 degree 2" split connector just in front of the vacuum and before the first air straightener. The 2" offshoot is piped up to a 21mm Maikuni carb. I have the throttle cable going to a servo/servo tester. You could use any mechanical device for this that serves the purpose and can hold it where you want it. As I turn the knob it will open and close the slide to allow suction of air through tge carb and not as much through the system thereby allowing you to reduce the depression in the main flow box chamber... plus it helps smooth out the air flow to make it more consistent. For further depression beyond the maximum full opening of the carb I have a SRT controller to reduce the power going to the 6 peak hp shop vac that provides the suction. Since the shop vac is a universal motor you can reduce suction successfully by reduching voltage/current.



The Anemometer reads out the actual CFM number in real time and the manometer will read out the current depression in -#inH2O to set your depression in real time. Pretty simple setup but it should work well for my needs.


If it seems like something you want to build I can draw up the plans and give you a parts list.

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Originally Posted by vpd66 View Post
Care to share a little on on the flow bench your building? What style? Did you use plans? How much is the flow bench costing you to build?

I have plans to build my own (been dragging *** on it for a couple years) has i have been using a buddies SuperFlow. I really need to get mine done instead of relying on him. He is getting up there in age and has a few health problems and I fear one day my access to his will be gone.

Sure. I read a ton of other builds but mine is not directly from a particular plan. I went with a 4" schedule 40 PVC pipe design for the main pipe, double anti-turbulence/air straightener (one ahead and one behind of the anemometer) made from groupings of 10" plastic jumbo straws, digital anemometer for flow readings, digital manometer for depression readings, 12" cubed main flow box with 4" flow hole and 2 6"×6"×1/2" acrylic windows and a 6"×6" acrylic adapter plate with 70mm×6" acrylic tube for faux cylinder chamber. For depression control I have a 4" tube with 30 degree 2" split connector just in front of the vacuum and before the first air straightener. The 2" offshoot is piped up to a 21mm Maikuni carb. I have the throttle cable going to a servo/servo tester. You could use any mechanical device for this that serves the purpose and can hold it where you want it. As I turn the knob it will open and close the slide to allow suction of air through tge carb and not as much through the system thereby allowing you to reduce the depression in the main flow box chamber... plus it helps smooth out the air flow to make it more consistent. For further depression beyond the maximum full opening of the carb I have a 15A fan controller to reduce the power going to the 6 peak hp shop vac that provides the suction. Since the shop vac is a universal motor you can reduce suction successfully by reduching voltage/current.



The Anemometer reads out the actual CFM number in real time and the manometer will read out the current depression in -#inH2O to set your depression in real time. Pretty simple setup but it should work well for my needs.


If it seems like something you want to build I can draw up the plans and give you a parts list.

Im not sure why it double posted that. I can't edit my post for some reason. Anyhow I made up a quick list of expenses and it came up to a little over $200. I could have cut expenses in several areas to save money but I think I have a good setup for my purposes. I won't have to calculate numbers to figure out CFM or have to worry about water shooting out when running dynamic flow tests. Also I can take it all down to store it in about 10 minutes or less. I don't have to try to read depression marks on a water namometer or need the room for the water metering tubes. I have everything to run and see smoke runs as well as wet flow. It should be a nice little setup.
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Old 08-07-2020, 11:16 AM
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It sounds like a good plan. Let us know how it works. I have the PTS plans and i have a lot of the parts gathered to build it. I researched the simple flow benches but there seem to be accuracy and repeatability problems with most of the simple cheap flow benches. I'm sure you have found the PTS flow bench forum. It covers a lot ideas, troubleshooting, and work arounds of building and running a flow bench. I choose the PTS one to build because it was built and designed right on the forum. They only sell plans and no one is trying to make a living off it. It is also a proven design with support through the forum. I didn't want to spent too much time debugging a homemade flow bench but rather just build it and use it.
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Old 08-07-2020, 11:54 AM
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It sounds like a good plan. Let us know how it works. I have the PTS plans and i have a lot of the parts gathered to build it. I researched the simple flow benches but there seem to be accuracy and repeatability problems with most of the simple cheap flow benches. I'm sure you have found the PTS flow bench forum. It covers a lot ideas, troubleshooting, and work arounds of building and running a flow bench. I choose the PTS one to build because it was built and designed right on the forum. They only sell plans and no one is trying to make a living off it. It is also a proven design with support through the forum. I didn't want to spent too much time debugging a homemade flow bench but rather just build it and use it.

Yes I ran across that forum. Lots of good stuff there. For my purposes I just need to know whether the head that I modified for high velocity ports will have enough cross-sectional area to flow what it needs at the engine's highest demand... which is about 20CFM. Stock ports flow between 38-44 CFM stock. It seemed to me that I could tighten the ports up, raise the short turn radius floor for a less abrupt angle to the valve seat and possibly gain some power and efficiency. So just needing to make sure it will flow what the engine needs and then run smoke to see how well the air moves around the valve seat is what I needed to begin with. I build a wet-flow attachment to visualize how the fuel behaves.



As far as accuracy the manometer has a temp sensor to calculate accurate depression. The humidity isn't a huge factor since it needs about 40% difference to change the accuracy by just 1%. That's not enough for me to hassle with water tubes since I will be pulling over 120inH2O on dynamic runs. That would require a 5ft tall U -tube. The anemometer also has atemp sensor and does all the calculations in real time and reads out current CFM flow. As long as it doesn't fluctuate too much I think it will be all I need and plenty accurate.



The other designs are a bit more accurate but I think this one is sufficient weighing out the compromises. I like that I can set it up or take it down and store it pretty quickly.
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Old 08-08-2020, 08:17 AM
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Keep us posted on how it works. At your small amount of CFMs you will be testing at it just might work. I have different applications then you and need a large flow bench that can flow 600 CFM with consistant and accurate results. I work with a lot of circle track racers so I need a bench that can flow anything from a Preditor engine to a Big Block Chevy (which takes a lot of CFMs). Also only one other person that I know of in my area has a flow bench and once the word gets out that I have one I see an opportunity to pay for mine and possibly make a little profit with it.
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Old 08-08-2020, 01:22 PM
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Keep us posted on how it works. At your small amount of CFMs you will be testing at it just might work. I have different applications then you and need a large flow bench that can flow 600 CFM with consistant and accurate results. I work with a lot of circle track racers so I need a bench that can flow anything from a Preditor engine to a Big Block Chevy (which takes a lot of CFMs). Also only one other person that I know of in my area has a flow bench and once the word gets out that I have one I see an opportunity to pay for mine and possibly make a little profit with it.

I will. Yes, it should be plenty for my needs. All I would have to do is upgrade to a vacuum box with more vacuum power. I can test up to 100k CFM and 82.7 -inH2O. So you really don't need but about 85 CFM worth of flow and most don't think to flow over 28-inH2O so you really don't need that much power. 600CFM between 8 cylinders is only 75CFM to test per cylinder. I guess you could go for more but when your limited by a 600CFM carb why would you give away velocity for wasted total flow. With multiple cylinders operating in overlap, even big block Chevy's, it's important to keep the velocity up when your limited to a 600 CFM carb anyway. Unless your circle track racers can run big carbs. Oh well. I hope your flowbench comes along well for you. There are plenty of knowledgeable folks over there with some very solid plans.


It's great that there is only one other guy who has a flowbench in your area. If you can build one and utilize it properly there's no reason why you couldn't make your money back once word spreads that you can make them more HP. Hopefully when you get yours done you can share a sneak peak with us. Happy building.
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