PTS Flowbench Forum

olympiadis wrote:What do the plans cost?

http://www.flowbenchtech.com/store/inde ... ex&cPath=3

Doing this on the cheap is entirely possible. Many of us have started out that way.
You will need some vacuum cleaner motors, either brand new, or "for free" secondhand salvaged ones.
A means to control motor speed, which can be done with a low cost Chinese router speed control module to control two motors, and toggle switches to control all the rest.

And you could build your own water manometers and orifice plates, although Bruce's plates are so low cost this hardly seems worthwhile.
This would give you a completely functional flow bench at absolute minimal initial cost.

Once you have the bench built, it is entirely possible to then upgrade it in several ways.
Fit more motors, upgrade the motor speed control to control all the motors together.
Replace the water manometers with the PTS digital manometer and a lap top computer.
Fit fully automatic closed loop test pressure control.
All this can be done bit by bit over time as finances allow.

Mine has cost just under $3000, that's buying all the important gear from Bruce, which includes orifice plates, motor speed control, pressure pickups, contactor, transformer, pitot tubes and the plans. Plus I bought 8 new vac motors locally. Then the rest of the materials, I believe I have built mine to a professional level of finish and is all new so $3000 is great value in my opinion. Some things that worked to my advantage is that I'm a sparky so the electrical supply was cheap for me to do and I have a full workshop of tools to complete all aspects of the job including cabinet making, painting etc etc. I would allow $4000 in total if you have to hire a sparky to put the electrical supply in that a decent bench will require.
Hope that gives you some idea
Cheers
Sean

I forgot to mention that I already had a laptop to use so that is not in the cost

Stumper, what is the flow capacity of your machine?
If I'm going to do this then I want to make it worth the effort by building for about twice the capacity of a
SF600 so I can test at higher pressure drop, and larger objects like mufflers and full exhaust systems.

I'm thinking that just requires more motors and maybe a pair of 220v 60amp lines.
I have the stuff and ability to run the 220v connections, and a shop full of tools.
I would go for something like the orifice plate and the computer conversion software, but probably not the
closed-loop pressure adjuster.
I already have to use router controls (dimmers) for my die grinders, but I can see needing something more substantial to adjust the voltage on a big bench.
Doing toggles & controls is not a problem at all.
If I build with lots of motors I'd naturally want to be able to run only a few of them as needed, so I would probably wire them in pairs off of toggles.

Do you have a panel-mounted volt-meter in yours?

I just saw that the PTS plans are not for a high depression bench, so I won't be using that.
This thing has to be worth the effort in the end, so that's just how I think when it comes to stuff like this.
For low capacity I'd probably just buy a used SF, or do the shop-vac thing.

I want to be able to flow large carbs and whole exhaust systems when i want.
I'm short on shop space and I know this is going to be large, but the ability will be worth it to me.
It will make it worth the effort to build the thing.

Do you guys get the motors from Grainger? or is there a better source?

I can pull 35 inches of depression on a Dart 14* spreadport big block chevy head on my bench. It's the eight motor PTS version. If you want more you may want to build the 12 motor version. Buy the high capacity motors to start with. I got two motors from Grainger but got the other six from Ward at http://www.centralvacuummotor.com/flowbench.htm. Saved a few dollars over Grainger's price.

Ray

coulterracn wrote:I can pull 35 inches of depression on a Dart 14* spreadport big block chevy head on my bench. It's the eight motor PTS version. If you want more you may want to build the 12 motor version. Buy the high capacity motors to start with. I got two motors from Grainger but got the other six from Ward at http://www.centralvacuummotor.com/flowbench.htm. Saved a few dollars over Grainger's price.

Ray

Thank you, that's excellent.
If I'm not mistaken the SF600 has the 8-motors, so I might want to plan for 16 motors
in order to get high depression on large objects like exhaust systems.
It's my understanding that most automotive parts see much higher pressure drops than 28" while
in operation, so it seems overkill would have some advantages.
The motor controller can control up to 8 motors?
I'd have to get two of those controllers and run two 220v 60amp lines, - is that correct?
Or, could I just wire motors in series and run all 16 at once with the same 60 amps, just at reduced capacity?

Otherwise I may also have to physically separate each set of 8 motors.

::insert liability clause here:: The small 8 motor PTS Flowbench can be built in a home shop or garage with simple hand tools, it's rated for 28" as I have no idea of the skills of the builder.

Having built my personal PTS Flowbench using the same tools as someone in their garage or shop I know it works at 28" pressure.

More skilled individuals have under taken modifications to the original design and made it capable of with standing higher depression. This info is detailed in the PTS Plans area of this forum of which members who purchase plans get access. I do have a set of plans that feature 12 motors and a few members have even gone to 16. This no longer becomes a DIY in a garage/shop project for the average person.

The current solid state relay setup I am selling is rated for 125a at 240v, I was offering a 75a one but my supply is out on those so the 125's are selling in place of those with no cost increase. This is over-kill for the 8 motor flowbench.

olympiadis wrote:
Do you have a panel-mounted volt-meter in yours?

A voltmeter is not really of much practical benefit.

Basically you wind up the big power knob until you reach your desired test pressure.
An amp meter can be handy though, if you have enough motors capable of popping the main fuse or circuit breaker, experience will quickly tell you what max current you can draw.

If you are looking at maybe 40+ horsepower worth of motors, a supercharger or large industrial pressure blower fed from a VFD driving a three phase motor may be worth considering.
It would be simpler, much quieter, and probably more long term reliable.

My bench will pull 600cfm at 28in. If you want to flow test carbs then you will need a wetflow bench to map fuel curves and such and a bench that will pull more than 2000cfm for the larger carbs, I was under the impression from your first post you were after a flow bench for cylinder heads and intakes. I have spoken to a bloke here in Aus about flow testing carbs as he does this for a living with building custom race carbs and he said you need twice the flow potential of the carb rating to get meaningful and accurate results as well as it being a wetflow design. If you need info on this Zoran from Zok Race Carbs is well worth talking to.
No I don't use a volt meter as mentioned above the motor control is adjusted by looking at the test depression on the screen, I would think that what you are looking to build would have to be a steel construction bench with a large blower of some kind. I hope you find what you are looking for.
Cheers
Sean