How many of these??????

[gavinator68]

HELP..................

How many of these



would I need to pull 250-300 cfm@28"?

Thanks guys

[ThomasVaught]

For a few bucks more, this is a much better motor:



Same motor as the Blue Bench Guys use.

Tom V.

[gavinator68]

Thanks Tom,

Are they so much better eventhough I can get 6 of mine for the price of one of those you mentioned.

[bruce]

Spend sometime reading these spreadsheets:



I did not see any reference to the 116757-13 in them though.

[86rocco]

For technical information on any current Ametek blower, go to , search the part# of the blower you're interested in. I've poured over a few dozen Ametek pdf spec sheets and I've concluded the 115923 blower that Tom suggested is, for flow bench purposes, as efficient a 120v blower as Ametek makes. Also, Ametek motors are very commonly used in central vac systems etc. so check the prices at a few local vacuum cleaner repair places, I was able to order some 115923's locally for considerably less than Grainger charges.

[gavinator68]

So............if the tech sheet indicates 122 cfm with a 2 inch orifice then do I just multiply that number until I get the CFM's that I need?

My work I am doing is on VW heads that do not flow more than 250 cfm max and really more in the 100-175 range. If I never intend on doing any other work and I would prefer working with a 28" wc, can I get good repeatable numbers from .050 valve lift thru .600 with a single 2 inch pilot tube element type system? Or would I be better off with something different?

Cheers,

David

[86rocco]

Not quite, if you look at the chart more closely, you'll notice that you only get 5.6" of vacuum with a single motor and a 2" orifice. Realistically, for an orifice type flow bench, you'd need about 40" to test at the standard 28" WC, on the chart, that corresponds roughly to a 1" orifice and 84 cfm.

[gavinator68]

Ok ................. my better half and I were talking about this today and she suggested we try the motor and fan from the dust collector we have in the wood shop. It pulls 1100 cfm through a 4" orifice @ 11.5" wc and 3450 rpm.

If I did use that on a 2" PVC pilot tube element would I be able to achieve the 28" test pressure @ 250-300 cfm? Or would I just get a large volume of air @ a very low pressure?

I have to appologize for all the silly ??????'s but I am VERY NEW to this flow bench stuff and just trying to get started as affordable as possible while still maintaining accuracy and repeatablity.

Cheers,

David

[bruce]

[gavinator68]

Thank You Bruce................. I guess it is time to go with the motors you AND others have recommended. I will get back in the morning.

Cheers,

David

[gavinator68]

Has anyone used or built the pitot type bench in the mopar tech article.

Bruce what do you think of that one?

[bruce]

Not sure I know what Mopar plans you are referring to?

I personally think that a set of plans are really not needed with all the info you can find on the forum. Someone can develop an excellent bench just following along with what others have found and done. Most of the plans that are on the net have had to be modified to work accurately and repeatable and have been discussed in alot of detail here on the forum.

Like I said in my earlier post I am currently working on a set of plans and plan to offer them for sale to help support the forum. This set of plans will be based cabinet size wise close to a SF1020 bench not flow wise and use a pitot setup for both intake and exhaust flow. You will be able to use 2-8 blowers depending on your flow requirements and electrical power. I'm also looking at making the same plans work with some changes to the cabinet for an orifice style setup.

Will these plans work for everyone? Probably not, some might want a smaller cabinet, some might want a larger work space. There really is no right or wrong way to build your bench, by doing it yourself though you can make it fit your needs, space and $$$ requirements, which following a set of plans will not let you do.

I'd like to finish up my large blower project first but it seems the need for plans right now is more of a priority . . . so it might move to the front of the line. I spent the past few days searching the forum, calling friends and laying out on the CAD program what I would like to see (since I was recovering from surgery the past 2 weeks I had time) but I need to prove my design in wood and pvc before anything is final and that might take a few weeks before that will happen.

Sorry for not being able to answer your question in this post . . .

[gavinator68]

I finally found the article I was talking about on the net.



Has anyone built this bench or have any input based on what you see in the article? It is a little toward the bottom of the gallery.

Cheers,

David

[ThomasVaught]

Looks like some of the other Pitot type plans
that have been posted here BUT this is the first time I have seen THAT article.

Tom V

[gavinator68]

Has anyone built it yet. How well does it work?

David