Updated Velocity Calculations Helper - Corrected Error

[106-1194218389]

JMR, what version of Port Flow Analyzer do you have? I have helped Kevin at Performance Trends beta test quite often and I have all of his software and in the latest versions. My PFA I use is V3.5 A.031 I also port map all my tests and checked my report in PFA against Larry C's velocity calculator and they agree. When I used yours there is quite a difference. I will list my test below: all test start top of port to bottom and left side is pushrod area and right side is divider wall.

#1 #2 #3
#4 #5 #6
#7 #8 #9

Pushrod SSR
PFA Larry's JMR's PFA Larry's JMR's
#1 364 365 357 319 320 335
#2 350 350 350 303 303 326
#3 319 320 335 286 286 317
#4 370 370 360 293 293 320
#5 329 329 340 303 303 326
#6 319 320 335 313 313 331
#7 329 329 340 416 417 382
#8 303 303 326 429 429 388
#9 286 286 317 378 378 364

JMR I would check your version of PFA. Kevin has done many updates to make it better since I have started using it.

John



Edited By larrycavan on 1207402806

[larrycavan]

Jfholm,

Am I ever glad you have that software! Could you please download the latest worksheet a couple of posts up and compare it to your PFA results. Get back to me ASAP ...PLEASE. I want to know if the last one I posted is absolutely reading everything correct.

[larrycavan]

Once the final verdict is in on the spreadsheet, this thread will be deleted and the worksheet reposted. I can't just delete the spreadsheet. The management interface won't let me do that....

If Jfholm reports that everything my spreadsheet yields coincides with the latest PFA, I'm calling it good to go and that's the end of it as far as I'm concerned....too many other things going on to advance free spreadsheets right now. I'm glad it's useful. I want it to be dead accurate! I don't have an advanced degree in math.....HS grad...period end of story...

JMR,

Nice web page you put together. Here's how I approach port averaging in my FPexcel application.

I use 3 distinct port sections. Entrance - Mid Point - SSR.

There are 9 mapping points for each section. Each section get's averaged individually, then the 3 sections get averaged for an overall port average.

I do that because if you just took 27 map points and averaged them all together, you could get a distorted picture of the profile. Eg. a too slow port entrance combined with a too fast SSR might average out to be acceptable in terms of FPS overall. That wouldn't be useful.

[106-1194218389]

[106-1194218389]

[larrycavan]

John,

THANK YOU SIR! I really appreciate that work! Anything you need that I can do for you, just holler. If you'd like a copy of FPexcel for free, PM me with your email address and it will be on the way. No fancy color velocity graphs, just numbers for that I'm afraid.

I will leave things as they are for a day or so with this thread, then wack it and repost the latest Velocity Calculations Helper Spreadsheet so there won't be any mistake about which one to grab.

Again, my most sincere thank you for proving the worksheet. My stomach got all knotted over it. I like my stuff right.....

Larry C



Edited By larrycavan on 1207284356

[JMR]

Larry, John

Looks like I jumped the gun with my calculator - there's definitely something wrong somewhere ???

I find it converts from test pressures lower than 28" OK and the resulting 'AVG Velocity' agrees within 1fps with PFA but entering readings with test pressure set to 28" throws it all off, as per jfholm's post.

[edit] see post below [/edit]

Should have tested it more thoroughly before posting it.

I'll post some PFA/JMR/Larry comparison figures later.

[JMR]

I've checked Larry's latest spreadsheet against my copy of PFA (v3.0) and I'm with jfholm.... they both agree within 1fps!

With my 28" Port Velocity Converter I was using Larry's earlier calcs to arrive at Converted Pitot Pressure. I notice the calculated conversion fps numbers are the same in the latest spreadsheet as the earlier version - it's just the converted pitot numbers that have changed (lower in the latest version). That'll explain why I was finding a discrepancy between PFA's fps and Larry's - PFA carries out its own fps calcs based on entered pitot readings.

Looks like Larry's got it nailed :;):

Didn't mean to cause any confusion. I guess that means my previously calculated port velocities weren't as high as I thought

I've reworked my to use the new pitot pressure calcs used in Larry's latest spreadsheet.

Suppose I should add a couple more motors so I can pull 28" for all flow tests!

[larrycavan]

[JMR]

[larrycavan]

[106-1194218389]

If I can put my 2 cents worth in, I like the versions that you can download so if my internet is down you can still work. I guess you could save the other one as a webpage on your computer, I have not tried that yet. But I want to make sure I can work if the internet is down or crowded.

John

[JMR]

[106-1194218389]

Hey I like that - not too shabby - I really do like having it downloaded, thanks

John

[larrycavan]

I just checked it out...NICE JOB!:D