I'm looking to set up a ducted collection system (not rolling from tool to tool) in my 16x24 shop. I'm comparing a couple single stage collectors to which I will add a Thein-style separator and 6"ducting.

http://www.grizzly.com/products/2HP-...llector/G0548Z
2hp, 1700 CFM, Max. Static Pressure 10in, 1 micron canister

vs.

http://www.grizzly.com/products/3-HP...peller/G1030Z2
3hp, 2300 CFM, Max. Static Pressure 16.7, 2.5 micron bags

Looking deeper into the specs, though, it's the exact same impeller rotating at the exact same speed - 12 3/4 @3450 rpm. Is the CFM and SP improvement simply because of the 7" vs. 6" inlet and/or less SP loss from 2.5 micron dual bags vs. the canister?

Keep in mind that these machines essentially the same price (separated by $20) and I can vent the blower outside. I'd like to save the space by getting the single-bag canister version but I wonder if the 3hp motor is the better way to go if I plan to make some modifications.

Looking at the machine setup, it appears I could take either motor and eliminate the rigid pipe between the motor and the collection bag, rotating the motor 90-degrees and pointing the intake straight down. I'd raise the entire assembly up and put the separator underneath, running duct out of the separator's side inlet and to the machines - no 90-degree up angle to the ceiling.

My questions are these:

Is the 3hp, dual-bag setup overkill? I don't want to take up too much valuable real-estate in the shop so I would likely try to use a single collection bag, connecting the blower directly to that bag and venting outside. If I do that, I'm essentially creating the exact same setup as the 2hp version, just using a larger motor.

Are there downsides to using this large a motor with less than half the SP loss (one bag vs. two, vent outside vs. 2.5 micron bags)? Should I be worried about sucking the collection bag shut or simply blowing *everything* outside?

If I get the 2hp canister, should I expect decent dust collection (not just chip collection, which I assume will be acceptable) with the stock setup on 6" pipe runs of less than 20-25 feet with 3-4 90 degree turns?

If I vent outside, what reasonable increase can I expect in my max. static pressure? Enough to offset the Thein separator?

Has anyone tried to move one of these blowers up to the collection baffle (removing the rigid duct that connects them)? Will it fit and can I rotate it 90-degrees to point the intake downward? That makes a straight, rigid connection to the separator which seems like the most efficient setup possible. This is the only way I could justify the 3hp unit - it's simply too large to use in its stock configuration.

I've asked Grizzly most of these questions and all they'll tell me is that they can't recommend altering their stock setup - so they're no help.

I know this has been long-winded but I would really appreciate some specific dust-collection advice regarding these collectors. My budget simply doesn't allow for a cyclone so I want to make sure I don't get an undersized setup to start out and then have to upgrade in 6 months.

Thanks in advance,
Steve