Reduction in duct size will reduce air flow?

[Stealthy]

I'm sure it does but how much?

here's my example...hope it makes sense.


Say I want to go with an 8" inline fan to cool my four 1000 watters but two of my 1000 watters are built for 6" duct and the other two are made for 4" duct. Well I'll need all the power I can get to cool x4 big lights so I can't really go with a smaller size fan (4" or 6").
How would I go about hooking my 8" fan up and reducing it to 6" and then again to 4"? Wouldn't this be to much of a strain on the fan...even if it was not to much of a strain, would it reduce the airflow so much that it would not properly cool my lights?

I've grown with a couple of 1000 watters before using a 4" Dayton blower but I've never gone over 2000 watts and I've never reduced duct size as my hoods have always been built for 4" duct (never had to worry about reducing the duct size).

I'll attach a small, embarrassing sketch and you guys tell me if I need two separate size fans or can I make this setup work efficiently.
Again...sorry about the shitty pic. ~I'm no good with paintbrush~

 

[Guest]

With your current design, I would recommend converting the 4's to 6's.

If you need help with that, get us a pic of your hood & socket.

When you grew with the 4" dayton and 2000 watts were the lights daisy chained (in series)?

 

[billbob]

go 6" fan (or 8 with 6" reducer) to the 6" lights, then use 6" to 4" reducer and go out the 4" with 4" ducting to the desired location. Always go down. Do NOT go from 6 to 4 to 6 or 4 to 6

 

[humble1]

you have two options

I.........regulator......6"light...6"light.......I
fan(8"-6 reducer) exhaust
I........6"-4 reducer..4"light...4"light.......I

and then the flow regulator is optional.
Or

I..........6"light....6"-4reducer..4"light...I
fan(8-6) exhaust
I..........6"light....6"-4reducer..4"light...I

hope that makes sense

 

[MaxYield]

I would separate the 2 path.

I presume you already have a fan for the 4" 's. Keep that fan for those and buy a 6" fan for the 6" lights. With your schematic you'll lose lot of charge, with your separation than reduction. You want to be as straight as possible with as less as possible change in diameter, nor the more power you bring with a 8" fan will be lost in charge (or air flow).

You can use the same size for each fan, though the best would be to match the size of the ducting with the size of the fan...

 

[Harry Gypsna]

stick ne required reducers on ur hoods to make em all 8" and use that, squashing all ur airflow into a smaller duct is gonna make a bloody racket like you wouldnt believe

 

[humble1]

harry's got a point about the noise;
also in my schematic i meant dampener, not regulator.
thanks LIME!

 

[Stealthy]

Thanks guys. I appreciate your input on this.

With your current design, I would recommend converting the 4's to 6's.

If you need help with that, get us a pic of your hood & socket.

When you grew with the 4" dayton and 2000 watts were the lights daisy chained (in series)?

Yeah they were daisy chained and that's how I would like to do it this time... only double.

humble1,
Makes lot's of sense. Thanks bro!





MaxYield,
That's what I thought. I figured that I might as well go with a 6" fan cause by the time I reduce an 8" fan down to 6" I will have lost the extra power anyway.
I would still like to run the 4 lights off of one fan just for simplicity but I may have to go with the separate fan idea. Thanks for the input!!!


Harry Gypsna,
I was worried about that. I definitely don't want my neighbors to think I'm hiding a jetliner in my house!! SSSWWWWOOOOOOOOOOOOOOOOOOSSSSHHHHH.
LoL

 

[humble1]

so whadja do?