blower vs shop vac

[Sups]

really hate to start my membership with a question before i have the chance to look through all the threads. hopefully the answer will be fairly simple.

well first of all, i have a project to where i need to build a SAE formula one race car and as of right now my job is to figure out a way to test out air flow through the intake system (the rules adds a restrictor and so reduces air flow). the engine is powered by a yamaha fz6 engine (roughly 100hp, but with the restrictor it'll probably be near 60hp).

a teammate figured that we'll have an airflow of 0.13 kg/s (or 0.06 kg/s) and that was coverted to cfm. either they are off or 1 shop vac is not enough, but my professor did a rough calc to 240 cfm.

so far i havent seen any shop vacs nearing 200 cfm so i was thinking of using a blower instead

keeping cost in mind, my questions are:

1. anyone know if that conversion is even remotely close?

2. any shop vacs that can produce that air flow? and where can i buy it?

3. blower vs. shop vac: cost wise to produce the same cfm, which one will be cheaper

4. how many blowers would i need? any "super" blowers that can blow at that range? single or double blower setup doesnt matter, as long as it ends up cheaper.

5. if i am purchasing a blower, how should i search for that? one of the older threads had a person buying 4 blowers for like 80 bucks but not sure if there is a better keyword to use. also who makes some decent blowers that will fit my specifications?

i'm thinking that to test out the intake system we'll need to get the cfm to be as close to the actual as possible and so which setup would be the easiest to configure so that it does work at that range. will any be adjustable so that it is enough to get it as close to that number as possible? (ie like buying a larger blower and able to control the flow rate to near pin point accuracy). only reason i ask is that the few flowbenches i saw in this forum looked like there was only an on and off switch for each motor and the air flow rate was more on the idea of change of flow from any flow rate (like flow rate is not as important as long as it is there).

any help will be greatly appreciated!

[84-1074663779]

240 CFM yes, but at what working pressure differential ?

240 CFM is easy if there is no back pressure, a leaf blower will do it easily.

As soon as you start loading it up against some realistic test pressure, it starts needing some real horsepower, and the mains current can rapidly climb to frightening levels. In theory you just keep adding more vacuum cleaner motors until you run out of available mains power.

Once you have built and tested a suitable blower system, you can then start thinking about how the rest of the bench can be arranged around it.

It is no good building a bench first and then finding the blower is not up to your original expectations. Find out all that first before sawing up large expensive timber panels.

[Sups]

[2seater]

If you are looking for 240 cfm capability @ the standard test depression of 28" H2O, you will need three or possibly four common vacuum motors. The other alternative is to use a lower test depression, say 10" of water, and convert the results to any test depression desired. This will require less power and is reasonably accurate. The cheap vacuum motors I am using from Surplus Center (GS Electric) will flow between 80-90 cfm @ 28" of water, (some are better than others).

[Sups]

How can I tell the CFM ratings of a motor? will it be listed on the motor itself? Since you mentioned common vacuum motors, I was thinking of just going to a Vacuum repair shop and see what I can get from there. Also can the superposition law be used for CFMs (adding them up with neglible differences)?

So for a setup requiring multiple motors, is it safe to assume that using multiple Shop Vacs would be a bad choice?

Also by using shop vacs, are the ideas of an intake and exhaust test gone? Are there cheap Shop Vacs that can double as a blower as well?

Also, do all vacuum motors fuction the same? so like it can suck and blow X CFMs with neglible differences in the direction? I know air flows in one direction so just asking if the sucking end equals the blowing end. I would assume yes since the motor is displacing volume and not creating it. Just want to be sure

[larrycavan]

[Mouse]

Pushing power, I think, is usually less than pulling power with a typical vacuum motor or shop vac.

Ridgid shop vacs are pretty good. Even a 2hp for about $39.00 has almost the same air power as a 4hp Craftsman.

Most all shop vacs now come with a blower port, except for the really low power ones, less than 1.5hp.

John

[2seater]