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CorvetteforumC3 CorvettesI managed to get some REAL air flow out of my vents |

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phoenix
Senior Member

1897 posts [100%]
Framingham MA

I managed to get some REAL air flow out of my vents | 5:15 AM 7/23/2002 |

In the process of rebuilding the AC system, I replaced the heater core, sealed everything up, replaced all vacuum lines, new AC hoses/VIR/Evaporator etc...
I bought the AC book from Ecklers and actually learned a couple of things.
1. Seal everything
2. Check all lines and verify that the flappers open and close with appropriate vacuum
3. Since I never want fresh air at any heater or AC speed, I connected the fresh air and recirculating vacuum lines to the source line. This will close the fresh air door and open the recirc door at all times.
4. Check the voltage at blower (on max I was only getting 9volts) so I temporarily removed the resistor. Now I get only max 12v
5. New blower motor
NEW INFO
First I just replaced the original motor with a replacement and used the same impeller. I put everything back together, duct taped the joints, foam sealed everything and still only had a little air flow. I then bought a blower and impeller from Autozone for a 1995 Vette. ($45) The impeller is bigger, more blades, steeper angle and they are slightly twisted.
I had to fabricate a spacer for the new impeller to fit into the housing because is is about 1.5 inches longer. The motor mounts the same. I made two rings of pressboard, glued them together, sealed them and painted them black. I then sealed them to the housing and mounted the motor to them.
When I got everything back together, I tested the air flow and put vacuum to the source and holy cow I have real air flow. It actually blew the papers off the seats.
I still haven't hooked up the AC yet, but my first goal was to get air flow. Now I can concentrate on getting it cold.
I'll get some photos when I get a chance.
Thanks to everyone that helped with the vacuum lines.
I'd also definitely recommend that AC book if you are struggling like I was to get the air moving.

[Modified by phoenix, 8:16 AM 7/23/2002]

Fleetwood
Senior Member

365 posts [100%]
Perth,Western Australia,Australia

Re: I managed to get some REAL air flow out of my vents (phoenix) | 5:24 AM 7/23/2002 |

Glad to hear you have success,I have heard that vette air flow sucks...well at least does not blow very well.Definately post pics of the motor fan mods.
_______

Neil,Perth Western Australia.1979 red coupe,L82 auto,glass T tops,A/C,P/S,E/W,C/L.Presently undergoing restoration.

VettePower
Senior Member

351 posts [100%]
Conroe TX

Re: I managed to get some REAL air flow out of my vents (Fleetwood) | 5:33 AM 7/23/2002 |

Sounds like great engineering!! Need pics!!!
_______

1977 L-82 with 3:70 and TH400. Still in Primer stage. Update. Just out of the Paint Shop. Now the fun starts putting on all the new stuff!!!

Stevo
Senior Member

307 posts [100%]
Petaluma ca

Re: I managed to get some REAL air flow out of my vents (phoenix) | 6:17 AM 7/23/2002 |

You, sir, are a steely- eyed Vette man. Being 6'-1", anything under the dash is tough for me. Now is it time for the Chiropractor?

gtr1999
Senior Member

2788 posts [100%]
CT

Re: I managed to get some REAL air flow out of my vents (phoenix) | 7:12 AM 7/23/2002 |

Good job Mike. How did the spacer look when you were done? I have a Gm replacement motor and,likewise, it's longer. I have all the a/c system out of the car still too
Gary
_______

GTR
'69 350,M-20 4 spd,3:73's conv.
'72 350,TH400,3:08 coupe.

70Shark
Senior Member

293 posts [100%]
Plano, Texas TX

Re: I managed to get some REAL air flow out of my vents (gtr1999) | 8:55 AM 7/23/2002 |

Oh man,
you have Got to get pics of that up online!!
Those of us in Texas could really use that kind of power on our blowers...

_______

Steven Helms http://www.corvetteforum.net/c4/stevenhelms/
Currently Own:
1982 Bright Blue
Previously owned :
1970 Bridgehampton Blue Convertable
1988 Medium Blue Metalic Coupe

Daves_rusty_75
Senior Member

135 posts [100%]
Brookline NH

Re: I managed to get some REAL air flow out of my vents (70Shark) | 9:10 AM 7/23/2002 |

This sounds like a great fix. You folks down south gotta give it up for
Phoenix.
Why never fresh air intake ?
Sounds like it will blow all the mouse crap out of my system !!

phoenix
Senior Member

1897 posts [100%]
Framingham MA

Re: I managed to get some REAL air flow out of my vents (Daves_rusty_75) | 9:27 AM 7/23/2002 |

quote:
This sounds like a great fix. You folks down south gotta give it up for
Phoenix.
Why never fresh air intake ?
Sounds like it will blow all the mouse crap out of my system !!

Why no fresh air intake??? because that's what windows and the T-tops are for Seriously, when using the AC or heater, why try to cool or heat outside air constantly. Why not cool the air or heat the air more each time. That's why Max cool recirculates the air. It is more efficient than starting from scratch constantly.
I can't ever think of a time that I would want the vent on and not the AC or heater. If I did, I'd open the window.
I'll get some pics tonight.

Jim Martley2
Senior Member

1021 posts [100%]
Slingerlands, N.Y. New York

Re: I managed to get some REAL air flow out of my vents (phoenix) | 9:38 AM 7/23/2002 |

I was told by an "old time mechanic" years ago that the reason for the two different air inlets for a/c was for noise control & to "filter out" offensive odors. Max Air (recirculating) exposes the driver & passanger to more blower motor noise but cuts the amount of outside smells induced into the interior.
_______

Jim
Slingerlands(Albany),N.Y.
Red on Red 82
Bright Aqua on White 93 Convertible(Wifes)
Joined the Forum April 1999

74-Roadster
Senior Member

916 posts [100%]
Fort Worth TX

Re: I managed to get some REAL air flow out of my vents (phoenix) | 1:36 PM 7/23/2002 |

Very good information . . . I'm going to be heading down your path soon and already decided I'd try other fans, now the research has been done.
THANK YOU!!!!!!!!!!
_______

I just love Hooters

1974 two top car, L48, AC, PS/PB, TT & some temporary wheels, lots to come . . . Stay tuned!!
We can customize her, we have the technology. . .

shoptek
Senior Member

398 posts [100%]
Hollywood Florida

Re: I managed to get some REAL air flow out of my vents (phoenix) | 2:04 PM 7/23/2002 |

Great job!!
Please post the Auto Zone part number for the motor.
Also, can you explain point 2 again????? I'm not too sure I understand about where to connect vacuum and where not to for the recirc. mode.
Thanks
_______

Marc and Lisa
1971 White with T-tops, 350 .030 over, Edelbrock Performer manifold, 600 CFM Performer carb, Comp Cams 268H camshaft, Pertronix ignition, T-400 auto, 3.36 gears, A/C, P/S, P/B, P/W, numbers matching engine

phoenix
Senior Member

1897 posts [100%]
Framingham MA

Re: I managed to get some REAL air flow out of my vents (shoptek) | 3:55 PM 7/23/2002 |

OK, here are a couple of photos of the setup. I am going to take it off again and make it look better. This was the first test, just to see how things fit and how the flow was.
This is the original blower motor and impeller. The new one has the same size motor, but higher RPM (14,000 vs. 10,500) and a larger impeller (by 1 1/4 inches), more blades, steeper angle and they are twisted (the impeller is white) I didn't take photos of the new one off the car, but I will.

New blower motor with test wires on.

View from the top. I am going to sand down the spacers, seal them and then matte black paint them so that they fit in better. But, you get the idea.

As far as the vacuum lines.
There are two that go through the firewall. The black one is the source line. This goes straight to the control in the shifter plate. This is where the vacuum gets distributed.
The second line is a green one. This one goes from the control in the shifter out through the firewall and to the vacuum actuator in the right corner of the windshield. Vacuum to this actuator closes the fresh air intake.
Inside the car, behind the dash, the green line has a "T" that also sends vacuum to the vacuum actuator in the passenger side kick panel. This is the recirculating air intake. Vacuum to this line, rotates the flapper allowing recirculated air to be taken into the fan housing and then blown back in through the AC evaporator or heater core.
So turning the vacuum on to the green line (which normally only occurs when the AC is on Max) both closes the fresh air line and also opens the recirculating duct.
What I did, since I only want the recirculating air option... was instead of connecting the green line to the control under the shifter, I "T'd" the green line off the source. Now there is constant vacuum to those lines and I will always get recirculated air.
I replaced all the vacuum lines, connectors etc... lubed the controller and checked the seals on all ducting and actuators while I was at it. It works well, but isn't stock.
Hope that helps.

Armstrong
Senior Member

386 posts [100%]
Savannah Ga

Re: I managed to get some REAL air flow out of my vents (phoenix) | 5:08 PM 7/23/2002 |

Now THATS using the ole noggin for something besides a hatrack. Great Job!!! When I get to redoing my a/c I'll definitely be replacing my motor and adding spacers as you did for the ole wind tunnel effect. Thanx for the post and the pics. They'll definitely come in handy.
_______

PROSOUTH
Senior Member

327 posts [100%]
MANCHESTER TN

Re: I managed to get some REAL air flow out of my vents (Armstrong) | 5:30 PM 7/23/2002 |

Now to make it cold try one of these hi-capacity condensors, I haven't measured mine yet but I think this one will fit. It has a 33% higher rating than the old std. ones. It is also recomended for converting to R-134
as a necessity.
http://www.ackits.com/
Universal Parallel Flow Condensers
R134a compatible
1/3 more efficient than standard condensers, a must when converting to R134a.
Can also be used with R-12 and alternative refrigerants.
12-0511A 19 x 30.5 (Condenser straps included) $ 139.31 plus freight

Arizona Mobile Air Inc.
3601 West Clarendon Ave.
Phoenix, Arizona 85019
(800) 648-4475 or (602) 233-0090
Fax: (602) 233-0389
Good information, I have looked at this before. I will be using this Hi-Perf blower also. Thanks JIM
_______

My little candle is only one of many,
And I am only one, but I am one.
I cannot do everything, but I can do
something. What I can do I should,
And with the help of God, I WILL !
United we make one Helluva Flame !

" LET'S ROLL! " JIM O'NEAL [

gb4622
Senior Member

94 posts [100%]
Keyport NJ

Re: I managed to get some REAL air flow out of my vents (phoenix) | 6:39 PM 7/23/2002 |

I like the idea of the faster rpm blower motor.
Would the old C3 impeller fit the 1995 blower motor and thus wouldn't need to deal with the spacers.
Clever thinking and thanks for sharing the info with us.
_______

1973 Coupe
Rebuild/restoration (on frame) in progress since 11/1999.
All thats left is the body and paint. Can't wait!

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