Increasing a/c vent air flow

[cjohnson6772]

I am trying to find a way to increase the air flow from my vents. I've put in an aftermarket a/c system and the fan motor sounds like a jet engine, but it's hard to even feel the air flow without putting your hand up to the vent. I was thinking that I maybe don't have the vent hose stretched tight enough and the ribs are creating a turbulent flow. Would a smooth pipe wall (like PVC) giving a laminar flow increase the vent flow much? Any other suggestions? I know that stretching the hose tighter would help, but I think I have it pretty short now. Hoping for some wisdom out there.

[cjohnson6772]

Nobody has any advice?
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[Andy4639]

There are a couple of things to check. Make sure the hoses are not torn and letting air out under the dash. Also check for the right flapper to be open on the unit itself. If the fan motor is blowing strong the hoses want have much of effect on it other than coming loose are holes in them.

I have factory blower and I can feel mine good.

[ChevLoRay]

I understand your question, and I also agree with Andy. If your hoses don't have any holes and your clamps are all tight, then that's good. Are there any locations within the system where air can be diverted? What about your fan speed? Do you have full voltage to the fan? Is the fan working properly? Is it tight on the shaft of the motor? Is there a seal where the motor fits to the blower housing?

Have you corresponded with the manufacturer about your concerns? If they're reputable, they should be willing to help and offer suggestions. Surely, you're not the first person to ever have such issues with their products.

[MrSchaeferPants]

Ya like all stated above, you shouldn't need anything special for good air flow. If you can't feel it you have something wrong. Check all connections, and dont forget to look for crud/nests in your air box on the engine firewall side restricting flow by the blower.
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[cjohnson6772]

I've looked and everything seems in order to me. The entire system is brand new (aftermarket). The flapper doors seem to be sealing off good, but the air just doesn't feel that strong.

I'm going to try contacting the manufacturer this week and hopefully they'll have some advice.
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[barraza]

Some well advertised aftermarket units are really not that great.

Something to check that I have seen before; a squirrel cage fan will move air very slowly if it is wired backwards. Check to see it is rotating in the proper direction.

[leddzepp]

Make sure you have the recirculating door open or your air volume will be poor. I do not know how they work on an aftermarket system, but on a factory sytem it is the passenger side vent on the kick panel.

[hayhauler71]

Originally Posted by barraza

Some well advertised aftermarket units are really not that great.

Something to check that I have seen before; a squirrel cage fan will move air very slowly if it is wired backwards. Check to see it is rotating in the proper direction.

I have seen this more than a few times make sure the fan is wired correctly and turning the right way

[Andy4639]

Originally Posted by leddzepp

Make sure you have the recirculating door open or your air volume will be poor. I do not know how they work on an aftermarket system, but on a factory sytem it is the passenger side vent on the kick panel.

I don't know if this would effect a aftermarket unit but it's worth a try also along with the fan being wired right.
It makes a world of differance in my factory air.

[ole dollor]

cjohnson6772: 1 more thing you can check, i have seen this a lot....check your a/c evaperator , it could be stopped up with dog hair,plastic bags, anything from the floor boards over the years.... it's inside the black box and not easy to feel inside of, you may have to drop it out and see whats inside the box...also does your heater blow ok out of its vents, if not then inside the box is where the problem could be....if all of your tubing is not leaking, gm does build fan motors that turn different directions and squirrel cages that turn different directions , the fan motor will sound like it humming....but nothing comes out. something to double check....have seen this several times also....