What is the best way to cut down on port velocity percentages? To my knowledge, a percentage of less than 20 is good, and under 5 for competition. I am looking for under 10%
Which of these options would be better for lowest PV?
One 5" x 9.25" port
OR
Two 4" x 13.61" ports
IN A
2.56(ft^3) box
I cant find a formula or calculator online anywhere, so i hope someone can help.
Thanks, Daniel
Replies (13)
P0werLifter on 01/26/2005 02:33:48
To lower Port Velocity you need to have sufficient port surface area. Generally the more the better. With the 2 options you have listed, My suggestion to lower the PV is to go with Two 4x13.61 ports. It will take away more displacement for the internal cu ft but not a huge difference here.
I plugged in the ports and pumped out this graph. Notice the difference in PV between the 2.
The Green Line = 5x9.25
The Purple = (two) 4x13.61
Hope this helps
PL
danielm87 on 01/26/2005 08:53:22
It sure did help, thanks a bunch.
danielm87 on 01/26/2005 12:09:49
How much improvement should i expect with three 3" x 10.4" ports? I dont have room for more than 3 on the box, so if this is better, thats what i'm gonna do.
And, is there any way to translate the stats to percentages?
Thanks
P0werLifter on 01/26/2005 12:49:31
Your best bet is to go with (two) 4x13.61" ports. The vent volicity is much lower compared to (three) 3x10.4" ports.
If you have the room, Id suggest going with (two) 5 x 23.45" ports if your tuning to 39hz. This significantly lowers the PV to 65.1 Ft/sec @ 40hz compared to 98 and 120 of the others.
danielm87 on 01/26/2005 12:57:20
Wow, two 5s it is!
That'll be all,
Thanks a bunch.
danielm87 on 01/26/2005 13:11:39
umm, maybe it wont be all, now that i think of it, 5 inch PVC doesnt exist at lowes or home depot and 5" port tubes arent sold anywhere online, so what am i to do? What else is there to use in 5 inch?
uochronos on 01/26/2005 15:09:58
5" PVC does exist and both lowes and home depot sell it daniel.... infact i just bought some 5" and it was not the largest..... infact if you goto a place that specializes in that kind of stuff i think PVC can get really big hehe. but 5" pvx defiantly is at home depot... also they have many other types of plastic tubing too...
Chronos
danielm87 on 01/26/2005 15:16:12
......Ummm.....I KNEW THAT!
Well i did call Lowes and they said they only carry 4 and 6, no 5 inch.
Maybe they lied or maybe home depot is better....heh.....okay i'll drive to home depot and see what they've got!
Thanks Chronos
gearhead on 01/26/2005 15:39:10
Will this work?
http://www.defender.com
Then type this # in the search box
60694.
uochronos on 01/26/2005 15:50:18
hmm really well ares sells it maybe not all of them carry it but i know there warehouses must because i just went with a friend to buy parts for a potatoe gun and we bought 5" platic pipe and 2.5"..... maybes its because you asked for PVC they have other plastic pipe other then PVC....
Chronos
danielm87 on 01/26/2005 21:31:42
POTATOE GUNS ARE THE SHIZNIT!
A friend and i made one, we got the potatoe 275 yards.
Our secret: cheap hairspray, full of butane and alcohol, or cheap spray deodorant.
and the biggest flint snap lighter you can find!
P0werLifter on 01/27/2005 01:32:43
Also keep in mind, since the ports are 23.45" long they might need to be bent using a 90degree elbow depending on the depth of the enclosure.
MrBrownstone on 01/27/2005 02:22:41
23 inches...would that fit in your box..even bent up?
Which of these options would be better for lowest PV?
One 5" x 9.25" port
OR
Two 4" x 13.61" ports
IN A
2.56(ft^3) box
I cant find a formula or calculator online anywhere, so i hope someone can help.
Thanks, Daniel
Replies (13)
P0werLifter on 01/26/2005 02:33:48
To lower Port Velocity you need to have sufficient port surface area. Generally the more the better. With the 2 options you have listed, My suggestion to lower the PV is to go with Two 4x13.61 ports. It will take away more displacement for the internal cu ft but not a huge difference here.
I plugged in the ports and pumped out this graph. Notice the difference in PV between the 2.
The Green Line = 5x9.25
The Purple = (two) 4x13.61
Hope this helps
PL
danielm87 on 01/26/2005 08:53:22
It sure did help, thanks a bunch.
danielm87 on 01/26/2005 12:09:49
How much improvement should i expect with three 3" x 10.4" ports? I dont have room for more than 3 on the box, so if this is better, thats what i'm gonna do.
And, is there any way to translate the stats to percentages?
Thanks
P0werLifter on 01/26/2005 12:49:31
Your best bet is to go with (two) 4x13.61" ports. The vent volicity is much lower compared to (three) 3x10.4" ports.
If you have the room, Id suggest going with (two) 5 x 23.45" ports if your tuning to 39hz. This significantly lowers the PV to 65.1 Ft/sec @ 40hz compared to 98 and 120 of the others.
danielm87 on 01/26/2005 12:57:20
Wow, two 5s it is!
That'll be all,
Thanks a bunch.
danielm87 on 01/26/2005 13:11:39
umm, maybe it wont be all, now that i think of it, 5 inch PVC doesnt exist at lowes or home depot and 5" port tubes arent sold anywhere online, so what am i to do? What else is there to use in 5 inch?
uochronos on 01/26/2005 15:09:58
5" PVC does exist and both lowes and home depot sell it daniel.... infact i just bought some 5" and it was not the largest..... infact if you goto a place that specializes in that kind of stuff i think PVC can get really big hehe. but 5" pvx defiantly is at home depot... also they have many other types of plastic tubing too...
Chronos
danielm87 on 01/26/2005 15:16:12
......Ummm.....I KNEW THAT!
Well i did call Lowes and they said they only carry 4 and 6, no 5 inch.
Maybe they lied or maybe home depot is better....heh.....okay i'll drive to home depot and see what they've got!
Thanks Chronos
gearhead on 01/26/2005 15:39:10
Will this work?
http://www.defender.com
Then type this # in the search box
60694.
uochronos on 01/26/2005 15:50:18
hmm really well ares sells it maybe not all of them carry it but i know there warehouses must because i just went with a friend to buy parts for a potatoe gun and we bought 5" platic pipe and 2.5"..... maybes its because you asked for PVC they have other plastic pipe other then PVC....
Chronos
danielm87 on 01/26/2005 21:31:42
POTATOE GUNS ARE THE SHIZNIT!
A friend and i made one, we got the potatoe 275 yards.
Our secret: cheap hairspray, full of butane and alcohol, or cheap spray deodorant.
and the biggest flint snap lighter you can find!
P0werLifter on 01/27/2005 01:32:43
Also keep in mind, since the ports are 23.45" long they might need to be bent using a 90degree elbow depending on the depth of the enclosure.
MrBrownstone on 01/27/2005 02:22:41
23 inches...would that fit in your box..even bent up?
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