View Full Version : Flow Benches
woollymoof
07-23-2003, 04:28 PM
For those out there that have a commercial / production bench, what brand is it and how much did it cost? The only brand I've heard of is a SuperFlow.
For those out there who have built their own, did you get plans from somewhere, if so where? Or did you design it yourself?
Cheers,
Kirk Veitch
Swinburne University of Technology
woollymoof
07-23-2003, 04:28 PM
For those out there that have a commercial / production bench, what brand is it and how much did it cost? The only brand I've heard of is a SuperFlow.
For those out there who have built their own, did you get plans from somewhere, if so where? Or did you design it yourself?
Cheers,
Kirk Veitch
Swinburne University of Technology
Frank
07-24-2003, 05:06 PM
easy flow bench
i only test airfilter, throttle, restrictor
basically you mimic steady state flow into the plenum
use a industrial vaccuum cleaner (which should pull 10" water test pressure)
then use a PITOT probe to measure/calculate dynamic pressure.. (or 2 probes.. one static, one dynamic)
keep the air speed about 50 - 60 ms^-1 at the probes (for increased accuracy).. use barometric compensation
use a big plenum volume on the test bed.. use LONG tubes, effectively damping any pulses YES pulses.. diffusers in transitory stall cause the test pressure to fluctuate
use cloured water with condese crystals (available at chemist)
use a long tube before pitot probes to ensure consistantly "fully developed flow"
expect about 75 CFM at 10" test pressure
you cant "choke" the restrictor using a shop vaccuum
a superflow SF600 flow bench can JUST do it at 38-43 inches test pressure... watch the operator at your local speed shop "spin out" when the thing chokes
to be honest.. it's more sensitive to exit diameter than anything else
use a 45mm exit diameter AT LEAST
i believe 7deg outlet is FINE (and cheaper)
regards
Frank
ps have posted previously about this matter
http://fsae.com/eve/forums?a=tpc&s=763607348&f=648600998&m=3886005121&r=6346007242#6346007242
Frank
07-25-2003, 02:09 AM
just one more thing for swinbourne...
im sure you realise that a restrictor like this
http://www.users.bigpond.net.au/franko/swin.jpg
on a supercharged car..will only make slightly more power than a restrictor that is only 3 inches long...
it will serve to (slightly) reduce inlet temperature, and reduce the power consumption and hence size and weight of the blower, but I'd only expect a fraction of a horsepower more..
the choked flow rate (choked flow only being achievable on a supercharged car) is the same regardless of diffuser geometry
again i iterate, naturally aspirated cars WILL NOT CHOKE the restrictor, until they have lost a considerable amount of power; at a higher rpm than their at peak output.. of interest is the static pressure in the plenum when the engine is making maximum power..
it is this static pressure that you should use to conduct "flow bench testing" of the restrictor (if you test without the cylinder head or runners)
regards
Frank
Frank
07-25-2003, 02:33 PM
"emphasize" not "iterate"
my god I've forgotten what words mean
http://fsae.com/groupee_common/emoticons/icon_frown.gif
Daves
07-26-2003, 09:30 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>just one more thing for swinbourne...
im sure you realise that a restrictor like this
http://www.users.bigpond.net.au/franko/swin.jpg
on a supercharged car..will only make slightly more power than a restrictor that is only 3 inches long...<HR></BLOCKQUOTE>
I like the electrical tape holding the restrictor tube to the supercharger elbow. Also,the swiss cheese chain guard and supercharger belt guard add a nice touch.
woollymoof
07-27-2003, 03:27 PM
That car was two years ago and is something that most at Swinny would like to forget. Anyway, thanks for your replies.
Cheers,
Kirk Veitch
Swinburne University of Technology
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