Low cost digital readout of velocity and flow

[106-1194218389]

[bruce]

This is probably about all the pictures you will see on the PTS bench build:



All the info in the plans comes from this forum, the plans are my way of making some $$$'s for the efforts of keeping this forum free of charge (not many websites give you this kind of info for free anymore). You could spend hours searching this site to find the info in the plans. So if you value your time the price of the plans saves you that time searching. Once you purchase a set of plans you gain access to the PTS Flowbench plans area which has more indepth discussion and detailed pictures of my personal build using simple hand tools.

::ok here comes Bruce's rant mode again::

The plans came out of watching people purchase a set of other plans sold on the net and then coming here to find out how to make them work accurately! You're buying a set of plans for $50 that allows you to build something that costs thousands to buy commercially? My plans work, they can be modified to meet your specific needs, you don't have to go to someone else's flowbench forum to find out how to make them work. What more do you want me to say?

I'm not going to go into what was discussed with other product suppliers. One of them I have a relationship/worked with before he even had a product to market. I could show you "concept" email traffic discussing the products being sold now. I also understand why the other one is reluctant to come on-board due to other people he works with in the industry.

Yes, it makes me wonder sometimes, you help other people along the way and then when you ask for help they say "nope not interested but thanks for helping me" . . . it is a "funny world", I'll say that much . . .

::rant mode off::



Edited By bruce on 1209612174

[Tony]

[MMack]

Let me first say that I have not bought the plans, I found the plans that Mercdog sells in the form of the original article about the MSD flow bench. I think I even read that when it was current. I started building an MSD bench and Bruce saw a post I made about it on another forum not in any way related to flow benches. He invited me over and I would not have the bench I have today if it were not for what I learned on this forum. I can also say that if his plans were out back then, I wouldn't have the bench I have today. I would have a much better one, using his plans. Some examples of what I learned on here:
1. I spent a ton of time scavenging vac motors. When they started dieing, I had learned on here about the suplus center motors, now I have more airflow potential than I need and three spare motors on top of the bench for down the road.
2. I would have been very disappointed with my bench if I had not learned the trick of putting the addition on the top to stabilize the air to keep from "ram-airing" the orifice.
3. I was at the point of trying to make that darn fool orifice disk when I learned about port holes and made my plates removable.
4. I learned on here how long the cylinder section needs to be to get good numbers.
5. I have parts to make a swirl meter and know what to do with it!
6. I should have a J-bend pitot tube and a calibrated plate to really know what I have and how to make it better soon from what my wife ordered for my birthday.
7. Based on what I learned here and what I learned standing in front of my bench, I have a head for my go kart that flows 120% more than stock. And I know that my carb maxes at about the same point, so going farther will not help. And I didn't enlarge the port at all, just short side work, port to bowl, valve size, unshrouding in the chamber.
8. I added several reinforcing plates, stay rods, and stiffeners based on other contributors failures with similar builds. And I started with painting my MDF so I have a leak free bench.
9. Since I am very low budget, and built my own water gauges, I learned on here to put reseviors top and bottom for ease in zeroing and ease of recovery when you mess up, and you will!

You can count on what is posted here as the real deal. You won't find better, I have looked, and so have many others. And you have folks with tons of experience to help you along if you are inexperienced as I am.

Mike

[49-1183904562]

This may help in the concept of a cheep digital monometer, all these parts are available from Jameco, digikey etc. cheep and even the code is here.

You can get samples if you are realy frugal from the manufacturers.

I have been MIA for a while (Down and OUT) looks like i'm facing the big D after 18 years at it, so I have had little time to think about Flow bench stuff (it Sucks).

Love this thread and new section, i also think the ADC section will be great.

Rick

[R Thompson]

Flow bench plans from this forum looks like a great idea. I am glad you mentioned the companies above because it got me asking questions. I was thinking ther may be a reason they were not interested (your words). I contacted both of them. Performance trends said they don't recall ever saying no, and flow performance said they have not received any specific details about the project and have not made any commitment at this time. These plans just don't seem like such a good idea to me anymore, after spending the estimate 600 dollars and how many hours of time to build it.

[Tony]

Very interesting Rick. I recall a rather similar project in one of the engineering magazines from many years ago. A guy decided to build a digital altimeter for his hang glider. It read out in feet altitude instead of pressure. The biggest problem he had was temperature drift of the sensor.

There would be two possible ways to convert pressure signals to flow or velocity (or altitude), either direct number crunching, which is going to be difficult with a very basic microcontroller, or a far more simple and straightforward lookup table. Every possible digital pressure output number 0,1,2.......253, 254, 255 points to a previously calculated result, which is then displayed.

The biggest limitation with most of these microcontrollers is that the analog to digital converter has only eight bit resolution, which only allows 256 different pressure levels to be measured. So you can only have 256 different output values to display.

While I have absolutely everything right here to begin a project like this myself, it really goes way beyond a do it yourself project for most of the other Forum members. Not everyone has access to a suitable programmer for the microcontroller chip, or the knowledge of assembly language programming to write and modify a suitable program to get it all working.

Far more practical for a group Forum project, would be to connect up a pressure transducer (and suitable amplifier) to a commercial serial interface, to then plug into an ordinary PC. Then use a spread sheet program to do the transducer scaling and any number crunching or unit conversions.

That would be vastly simpler, cheaper, easier to copy, and a much more flexible solution.

[86rocco1]

Hey Tony, how do you feel about 10 bit ADC? There are a number of low cost microcontrollers in the Atmel AVR family, with 10 bit ADC, some as small as 8 pin dips.

[Tony]

[bruce]

Pssssst . . . we already have Larry's FPExcel spreadsheet to work with :;):

Larry . . . hey Larry, what do we need to make a DAQ setup work with your FPExcel?



Edited By bruce on 1210115694

[Tony]

I agree Bruce, a spreadsheet is the only way to fly.

But discussions about pressure transducers, amplifiers, analog to digital converters and other hardware required to get the pressure data INTO a spreadsheet are still relevant.

Raw pressure data may also require some smoothing and averaging.
We have all seen bouncing manometers at various times, and bouncing unstable pressure readings entered into a spreadsheet can be fairly problematic.

These presure transducers respond so rapidly they are often used as microphones that extend beyond the upper limits of human hearing, I am not kidding !! So any buffeting, air roar, or surging in pressure will give scrambled pressure readings, unless something is done. It is not difficult, but there are certainly traps for the unwary.

[Moriniman]

This is a slightly stange place to step in and introduce myself, but never mind.

I'm a self taught electronics engineer working in scientific research and I design instrumentation and dataloggers.

Skimming through the thread, I looks like you need an analogue multiplier to generate the square function. I've used the Analogue Devices AD633 in another application

If I can find the time, I'll take a propper look at the problem and see if I can whip up a PCB to condition the signal from a sensor (I'm looking at the Honewell 26PCBFA6D ) and output a linear voltage.

I'm going to build a basic bench first, but I would like to step up to an automated one later and will probably do my own black box and software.

The flow-bench requirement has come about for two reasons. Firstly becuase I've been asked to help prepare a 1962 Morini Corsaro 150 for racing. The aim is to be competative against the 160 Ducatis and that should be a realistic aim, but very little tuning knowledge or parts remain these days. Secondly, there is no longer anyone in the UK who specialises in porting Morini V-twin heads. One company closed following the death of the owner and the other lost it's expert to a better paid job. They're tricky heads to do right due to the unusual deign and the difficulty of getting tools down the exhaust port.



A full article on the engine can be found here;

[bruce]

[115-1172523331]

Welcome aboard indeed! I couldn't help a Google as I had never heard of a Moto Morini Corsaro. Is this the bike? The layout also had a "9-1/2" which I translated as a 160, then saw in the article you referenced the 3-1/2 was a 350. Does that make the 9-1/2 a 950? This one looked a bit big for a 160, but "What a sweet ride!". Pics would be welcome! -- Doug

I now see that this a 1200cc. That makes more sense! Pics are still welcome!

[Scotts]

R Thompson,

I usually fish at the lake.....
-
I think both FP and Perf. Trends gave an appropriate response to you, a potential customer, did you expect anything different?
I don't have a set of Bruce's plans, but I have been a lurking regular(daily) since the old forum and already have built a few benches solely from the knowledge gained on this forum.
Most of the people who frequent here have limited budget resources,are fairly handy and want to learn the whys and hows of a flowbench and the comradery(sp) is great as well.
There are people here with every kind/style of commercial and homebuilt bench imagineable and I have yet to see a person turned away.
I would venture to guess that Bruce's bench could be built for less by someone that is resourceful and shops around for parts.
As far as support,besides Bruce, there are at least 20 well respected people on this forum that are willing to walk you through any problem you may encounter during the build and would be suprised if your questions werent addressed within and hour by someone regardless of the time posted.
This flow bench building stuff ain't for everyone, if you have a stack of customers Benz heads piled to the rafters waiting for flow testing, then you may be better off ponying up the money for a commercial flowbench or a Smoketron it all depends on your needs, wants and budget.
Many of us own FP1's and Perf. Trends products and they each come with excellent support in my opinion.
I am closely following this particular thread because of my interest in Data Acqusition, but yet I own an FP1 and have no need for anything else.
In my opinion, Bruces dealings with either company are not of concern to anyone on Bruce's forum and nobody is telling people not to support either of the companies.
What ever way you decide to go,what ever product you decide to buy, you can be rest assured that the people of this forum will show interest and help out......


Scotts/Scott/RRBD