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DIY Flowbench project


Roman
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Good point. 
This vac has quite a large internal chamber and a big grunty motor so I'm hoping it'll be fairly steady in that regard. 
Hopefully I will be able to pick that up with sensors if it's happening. 

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Why not use servomotors for the valve actuation? You probably don't even need a valve spring. Just 3d print a jig that can move from valve to valve and clamps on where the collet groove is. Just need to calibrate once with the dial gauge.

Could also use the map value to control the vacuum with pwm. The vacuum motor is probably a universal motor and would run fine on DC.

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I'm keen to see how this turns out. I'd love to make my flowbench less manually dependent.

I built my flow bench a couple of years ago. I based mine on this design.  http://dtec.net.au/Flowbench Design Guide.htm

But used a couple of cheap Ebay  digital manometers for measuring pressures. I downloaded a spreadsheet that had all calculations done for head flowing. I just had to enter the pressures in manually and I could print a graph from that. Very low tech.

I use 4 vacuum motors in mine which is just enough to flow my Ford 2.8 heads at 28" so I suspect you'll need a lot more than a single vacuum motor for your 1NZFE head.

My flowbench is ugly but works and is repeatable. Great tool and fun to build and learn from.

8 hours ago, Roman said:


If your test shows that the head flows way better than your manifold does. Then there's hardly any point being a fuss pot over the state of the head.

I've found that even with a low flowing inlet runner, improving the head flow usually gives an increase of flow at the valve with the manifold attached. It's just a smaller increase than the bare head. You will always get a decrease in flow to the valve with a inlet manifold attached, no matter how well the manifold flows.

20180421_183609.jpg

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Possibly could sponsor a differential pressure transmitter. 

4-20mA. I think I have a 10kpa one that is surplus. It has damaged thread on the cable entry so its certification is not valid.

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15 hours ago, Muncie said:

Could you use a centrifugal blower or even a roots supercharger and spin it with a briggs or something? Even a small one should move plenty of air for a single cylinder.

@Roman if you scope creep to include a roots blower driven by the old eco engine- I'll buy you dinner.

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Haha, that would be a laugh. 

Nah ive actually got 4-5 1500w vacuum cleaners here so theres room to upgrade if needed.

Thanks for your feedback @Stroker thats all very good to know. its handy to know right from the start that I will need multiple motors.

Ive been having some thoughts about just getting my ECU to log the data, and use megalog viewer to interpret and compare results. 

As I can send all of the flowbench data from the arduino to ecu over canbus. I just have to park the car near it and plug a cable in haha.

 

So the arduino would still control valve distance etc but just saves reinventing the wheel a bit with logging etc.

It also means I will have before/after engine logs in a compatible format with the bench data. So I can directly see how its changed things in real life (if at all)

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50 minutes ago, Roman said:

So the arduino would still control valve distance etc but just saves reinventing the wheel a bit with logging etc.

I was only here to pinch your methods for data-logging with the Arduino :grin:

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20 hours ago, anglia4 said:

I was only here to pinch your methods for data-logging with the Arduino :grin:

I've written some stuff before, for logging to my digidash. 

But it depends on what board you're using. 
If using Teensy 3 or 4 then its easy as you've got onboard eeprom or flash memory. 
But if using an arduino mega or something, need to write to SD. Which isnt too hard there's code for it. 

It becomes harder when you want to transfer the data to anything else though.
 

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On 21/06/2021 at 15:18, ajg193 said:

Why not use servomotors for the valve actuation? You probably don't even need a valve spring. Just 3d print a jig that can move from valve to valve and clamps on where the collet groove is. Just need to calibrate once with the dial gauge.

Could also use the map value to control the vacuum with pwm. The vacuum motor is probably a universal motor and would run fine on DC.

I've been thinking about this, and yeah servos could be a really good option. 

Only thought about not running a valve spring is that at low lift there can be a fairly grunty pressure differential on either side of the valve, trying to pull them open. So having a valve spring seems useful to make sure there arent tiny oscillations or whatever. 

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  • 1 month later...

This has been slow going, waiting for parts to turn up / other shit going on. 
But I managed to get my MAF in a pipe hooked up to my arduino nano.
So I could quantify how good/shit each of my vac cleaners are as a vac source.

I've already got a MAF scaling for this pipe size, from my engine tune. So I can just refer to this for voltage to airflow conversion:

image.png.79a59469191546e46edef86a60545c38.png


So with my big industrial shop vac, it reached 2.68 volts on the MAF. 
so this is about 40 grams/sec of airflow. 
Which is about 60hp worth of air. 

I tested the other vacs that I've got, and they were worse than this.
Using the best two running at once, I could get the MAF up to 3.0 volts. So around 70 grams per sec / 84 horsepower worth of air. 

So is that enough to simulate a single runner? 
84hp x 4 runners = 336hp 

Which sounds good but unless you have a 720 deg intake cam, this is not representing anything close to the peak or average airspeed at all.
268 deg cams out of a 720 deg stroke = 37% of the time it's breathing in air. And then much of this time is spent at less than full lift obviously.

So to truly simulate the airfow through a single port on a 4 cyl 150hp motor I'm thinking I'll need at least 100-120 grams per second capability.
So I will look at getting some vac motors all of the same and wiring them up. Maybe 4 to start with. It's a better situation if all of the motors are identical rather than mix and match. 
But I can rule out the idea of running just a single vac to get meaningful results anyway, even if its a grunty one.

On my previous search I only found more expensive ones, but 2kw vac motors are $50ish each delivered from aliexpress so might start wth 4 of these, and hope that it's overkill! 
https://www.aliexpress.com/item/32966020456.html?spm=a2g0o.productlist.0.0.7e675d6fuVKTf7&algo_pvid=8dca2d00-4acb-4a6d-b88a-a9401a618dcd&algo_exp_id=8dca2d00-4acb-4a6d-b88a-a9401a618dcd-3

 

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So I've just got my intake pipe with MAF in it, attached to throttle body, attached to intake manifold. 
Then everything on the manifold blocked off. 
Then printed an adapter so I can shove a vac hose into an intake runner.
To test two, or more, I unblocked off the other runners and jammed more vacs in. 
But also tested them one by one in a single port. 
The worst had about half the flow capability of the industrial one. 
The other two somehwere in between. 
 
 @h4nd do you have any good thoughts about wiring up 4x 240v motors? 

I've been looking at some 240v speed controllers, one I saw had 4000w capability. 
So could potentially run 2 motors full blast (or just on/off) then vary the other two at the same time to reach a goal flow amount
240v wiring makes me nervous!

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rather than airflow, what static vacuum can you achieve with those fans?

I get the feeling you may struggle to generate the vaccuum and subsequent flow required without serious spending 

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3 hours ago, Roman said:

wiring up 4x 240v motors? 

 

3 hours ago, Roman said:

240v speed controllers

Light dimmer style? Probably OK, best ask a tame sparky. @UTERUS etc?

Chuck'em in parallel, use sensible fuses, make sure chassis are securely grounded. Insulate them for another layer of safety.

4kW is getting pretty heavy, you're gonna maybe melt your plugs / sockets / wires in the wall / set the suburb on fire / raise the CO2. Maybe get a (safe) current meter so you know how reckless you're being?

I think @NickJ comment may be worth considering. Pneumatic engineer, I ain't :)

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Just for reference, my vacuum unit uses 4 x 1200w vacuum motors that I have in parallel, wired in 2 x pairs. That way I only run the single pair when testing low valve lifts. With 4 going it's just enough on a hot day to achieve 28in vacuum on my 2.8 v6 heads at peak lift. Something else to be aware of is heat, the vacuum motors usually require airflow over them for cooling. So in vacuum they tend to get hot quite quickly. That's one reason I use a air bypass setup to adjust my test pressure, that way it increases the airflow for the vac motors.

Also my flowbench flows a max of 247cfm@10in.

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20 hours ago, h4nd said:

 

Light dimmer style? Probably OK, best ask a tame sparky. @UTERUS etc?

Chuck'em in parallel, use sensible fuses, make sure chassis are securely grounded. Insulate them for another layer of safety.

4kW is getting pretty heavy, you're gonna maybe melt your plugs / sockets / wires in the wall / set the suburb on fire / raise the CO2. Maybe get a (safe) current meter so you know how reckless you're being?

I think @NickJ comment may be worth considering. Pneumatic engineer, I ain't :)

I'm running 4000w of heater off a multi plug in our garage- doesn't even get warm :-) 

Edit. The heaters get warm... the plug/socket does not.

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