Not the Mercdog again

[Hotz]

Nice job...I love it

I second that That is sweet!

Sorry Larry did not understand your affirmation, please explain ... (I remind you that the translation most often makes me crazy).
Really think I have to shut my mouth here ...

[Old Grey]

300 cfm PAP with the bench flat out.

Grey, Try the same test with like a 600 CFM internal orifice and see what you get.

Rick

I was hoping I would save some work by not having to set up the 3.33" square edge internal orifice, but you sparked my curiosity so I calibrated it up (0.63 cd) and gave it a shot.

I'm now getting this with 6 motors, 8 motors over pressures the 40" sensor in the FP1


This is what I get with 8 motors
36.9 351.4 352.3 9302 0.3
38.8 358.4 359.4 9488 0.3
39.9 362.7 363.7 9601 0.3
PS1 OVER RANGE!

You're going to have to explain this one to me.

It took 15 minutes of cogs whirring but I think I know.

The larger orifice has less restriction so the motors aren't taxed as much - 28" + 16" = 44", were as now it's 28" + some lesser value like 10" so the total load is now only 38" -

[Brucepts]

If I recall the FP DM has 40" sensors on each range? So on a max range on a specific plate you are working with 28" + 40" = 68" Unless I'm missing something?

Also running the sensor up to it's max or over it's max will over time damage the sensor.

[1960FL]

Grey,

I am glad the experiment worked out favorably, thought it would i had talked to Bruce about this phenomenon a couple a month ago; He gave me the crooked eye stare then he happened upon it himself and we surmised that when you are pushing the internal plate to high 85-95% the motors start to work against each other. So it does prove we have to have specific ranges to get good efficiency from the bench with good numbers on the flow. I am thinking for what i do and i want to run some current draw tests on my bench that i can probably get away with doing everything i want and not strain the bench with a 425 internal plate.

Rick

[Old Grey]

So if I'm running 28" in the top chamber and I have an internal orifice so big that the lower chamber only adds lets say 5", my total load on the motors would only be 33", This should increase the benches flow capacity if the motors are in a more efficient area.

Imagine running 60" dep and only adding 5", this could be a way to maximise limited motor power. Your modern PTS DM shouldn't have a problem reading small stuff, but it now makes multiple orifices much more than just flow range changing.

[Brucepts]

What we know is this: We built a design that will get you to 600cfm@28" and do it repeatably and is more than enough capacity for the average person who is building this design.

After stumbling into something last week doing some testing on a much larger internal orifice I found out I don't really know the total capacity and scope of the design of my products and I think there is alot more we don't know and need to findout.

More testing is required . . . and this will only enhance the PTS Design further, or leave us scratching our heads in total confusion.

[larrycavan]

One of the main reasons for having digital measurement and the thing I liked most about it was to NOT have to be frequently changing ranges. The digital units provided that function where the water gauges simply couldn't.

My bench....same thing you're working with but I installed a baffle and raised top section like the SF600 has. I included several SF benches for comparison.

Round Robin Test Resuts Plate 1 CFM % of Ford Plate 2 CFM % of Ford Plate 3 CFM % of Ford Avg of 3 Type Guage
Reher Morrison SF600 Range 4 98.20 100.1% 191.50 98.3% 286.40 96.5% 99.2% Orifice Manom
Reher Morrison SF600 Range 5 99.10 101.0% 199.70 102.5% 296.90 100.0% 101.7% Orifice Manom
Reher Morrison SF600 Range 6 97.10 99.0% 196.70 100.9% 288.10 97.0% 99.9% Orifice Manom
Dave [SF1020] Range 3 99.40 101.3% 190.10 97.5% 282.10 95.0% 99.4% Orifice FlowCom
Larry C 100.50 102.4% 191.50 98.3% 281.00 94.6% 98.4% Orifice FP1
Larry M SF600 w/FP1 98.56 100.4% 193.59 99.3% 289.62 97.5% 99.9% Orifice FP1
Larry M SF600-w/Dwyer Inclined 98.47 100.3% 193.31 99.2% 289.79 97.6% 99.8% Orifice Manom
Dave F. SF600 99.90 101.8% 195.80 100.5% 294.10 99.0% 101.1% Orifice Manom
Curtis SF110 103.50 105.5% 208.50 107.0% 306.30 103.2% 106.2% Orifice Manom

Now.... don't hand me any fluff that the FP1 is inaccurate, outdated, inadequate, etc. etc. etc.
Don't hand me any fluff that the MSD bench design is crap either....
Don't hand me any fluff that you need all sorts of ranges to get the job done....look at Range 5 on the RM bench???

Use the bench you have. Work with the numbers you get. You either gain, don't gain or loose flow when you port heads. The tool you measure it with is arbitrary after you reach a certain point....

Darin Morgan made the comment that he most definitely prefers the SF600 to the SF1020 bench with all it's automated bells and whistles..... Do you think he knows a thing or two about how to use a flowbench for more than looking at CFM numbers???? I personally don't like automatic depression control myself. It masks things you really want to see but hey...that's just me

This isn't to slam the PTS products in any way, shape or form.

[Old Grey]

What we know is this: We built a design that will get you to 600cfm@28" and do it repeatably and is more than enough capacity for the average person who is building this design.

This seams an artefact from the old water manometer days, like "640K of RAM ought to be enough for anybody" was ok back then but not now. Now it looks like DM has changed the rules and maybe flowbench design has to change.

It seams now that you design the lower chamber for working pressure of the motors and distribute the dep and internal orifice resistance in combinations that could be more advantageous.

After stumbling into something last week doing some testing on a much larger internal orifice I found out I don't really know the total capacity and scope of the design of my products and I think there is alot more we don't know and need to findout.

More testing is required . . . and this will only enhance the PTS Design further, or leave us scratching our heads in total confusion.

Bruce's bench has all the same motors, so all he needs a vacuum motor compressor map , pick the best motors dep number to be run in the lower chamber, and try combinations of higher testing dep with lower internal orifice restriction, and see what happens.

Based on this the pressure sensor looses some of it's razor precision under 1" - still adequate though -. So as long as the orifice is designed to run above that, it's still going to be super accurate.


In theory we could all have 38" benches for free by using the next biggest orifice, but the above puts multiple orifice back into play for accuracy.

I was toying around in my head last week to go back to a simple multiple orifice disk for this bench(10, 350, 600cfm). I was thinking about getting 2 large 6mm Alum disks and putting a large shallow recess on the bottom of the top disk for a 0.040" or 0.060" SS disk, and another recess on the bottom of the lower disk, so it's not directly screwed to a warped orifice board that my impart a bend in to it, and run a floating shaft and a disk position locater like the POS bench.

The FP1 has the ability to store 6 - I wish it had more - orifice diameters with their accompanying cd's which can be quickly recalled with a few keystrokes in configuration(M (UC) flowed by the pre-set orifice letter A to F), an advantage with the FP1.
The PTS can do it also, just not as easily - I don't have a manual so I don't know how easy it's to change in config -, based on this
http://www.flowbenchtech.com/forum/view ... f=6&t=1033.

[Old Grey]

Based on this the pressure sensor looses some of it's razor precision under 1" - still adequate though -. So as long as the orifice is designed to run above that, it's still going to be super accurate.

Actually it's probably not the sensor, because the graph for the sensor in the FP1 shows it's more accurate at low pressure reading, so this must be a phenomena of the orifice.

If you run the PAP plate on top of the bench while in exh and feel the air column, for visual representation, maybe the air column goes from tear drop to flame shape at a certain velocity, and that's when it becomes truly stable. This is one of the tests I was going to run on the POS bench, trying to find a more stable orifice design.

[Old Grey]

Any of you Pros want to decipher these motor specs, do you go for the dep at max air watts.

http://www.alliedelec.com/Images/Produc ... 259287.pdf

This is the Domel motor sheet I cobbled up in 2007 as a rough guide.
http://www.tractorsport.com/forum/viewt ... 3&start=30
It has every Domel at the time with the SF Ametek #115923 and the readily available over here Ametek #119655-00 at the bottom.