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Changing C3 blower to C4 blower (Read 8855 times)
Aug 4th, 2012 at 5:24am

Karlw61   Offline
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vette first!!!!
Williamsville, IL.

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Hey Guys!  I've been reading a lot about putting a C4 blower motor in, in place of the C3 blower motor.  How hard is it to change this over?  Is the wiring different and do you need different relays or anything?  Thanks!

Karl
 
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Reply #1 - Aug 4th, 2012 at 5:53am

wnmech   Offline
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Grand Prairie Texas

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Karl
I did that mod to my 77 and it definately made a differance in the volume of air to the vents.  I bought the motor along with the squirrel cage from a 90's C-4 along with a new connector at autozone for I think around $30 dollars.  I purchased a small piece of 3/4in plywood at Lowes and removed the squirrel cage from the new blower motor and drilled the center hole and laid it over and traced a template and cut it out and you will have to lay the squirrel cage over the cut out piece and cut it out.  I then drilled all the holes in the template and used silicone sealant and adheared it to the firewall with screws and next day Isealed and attached the new motor to the firewall.  You will need screws atleast 3/4th inch longer to compensate for the spacer. I changed my blower motor ground to a 10G wire due to the bigger motor.  It's not a hard job it just involves some technique to get the blower motor out and in because it is tight.  There are several posts over on the corvette forum about folks that have done it.
Rick
 
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Reply #2 - Aug 4th, 2012 at 12:34pm

Redwingvette   Offline
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Waterford, Michigan

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I also did this to my 73. Not hard at all, just a little time because of the tight area you are working in.
 

Brian
73 Coupe, Performer RPM Heads & intake
Holley carb
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Reply #3 - Aug 4th, 2012 at 12:59pm

Karlw61   Offline
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Life is short, drive a
vette first!!!!
Williamsville, IL.

Gender: male
Posts: 112
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Thanks guys!!  I do have one advantage, I'm rebuilding the car so at this point I have PLENTY of room...it's on my workbench!!!  Lol!  I'll see what I can come up with. Thanks again!!
 
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Reply #4 - Aug 8th, 2012 at 7:35pm
blue 77   Ex Member

 
Karl, just one of the advantages of having your vette all apart. Grin Grin Grin

Dale
 
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Reply #5 - Aug 9th, 2012 at 6:01am
TX 73 stock   Ex Member

 
it's on the to do list for mine too this year.

Charlie
 
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Reply #6 - Aug 9th, 2012 at 6:09pm

77vette   Offline
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Sioux Falls, S.D

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I found a template online for the conversion. If interested will send it to you, going to wait until this winter to give it a try.

Ron
 

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Reply #7 - Aug 10th, 2012 at 11:02am
TX 73 stock   Ex Member

 
I'd like that Ron. can you send it to charlie@corvettec3.com ?

Thanks
Charlie
 
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Reply #8 - Aug 10th, 2012 at 1:45pm

Artsvettes   Offline
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New Jersey

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Really dosen't have to be a c4 blower. I used one out of a 95 and up S10 in my 73.................jack
 

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Reply #9 - Aug 10th, 2012 at 7:24pm

77vette   Offline
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Sioux Falls, S.D

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Charlie-sent you an email with the PDF attachment. Hope it works out.
Jack-I agree, I guess what we need to know which one would be the best bang for the time spent. I have read post that said the 94 works well in some cases, others said it didn't improve the air flow that much and wasn't worth the effort. I guess it all depends on what you are hoping to gain out of it. More air flow is what I think people are after.

Ron
 

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Reply #10 - Jul 15th, 2014 at 6:34am

737fixer   Offline
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Houston

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I'm doing this mod right now.  My 75 has a very low volume of airflow, I'm hoping this mod will help out.  I've made the spacer out of 3/4" plywood, epoxied it and painted it, I believe it will fit well.
Here's my question... I need to get a connector to match the new motor, when cutting and splicing in the new connector do I need to worry about hot and ground or will it run either way?  Also on the original fan motor wiring, there is what looks like a resistor on the positive (hot) wire a few inches from the end connector, do I keep or remove it for the newer style motor?  All help is appreciated!

John (trying to stay cool in Houston Cry)
 

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Reply #11 - Jul 16th, 2014 at 8:46am

Artsvettes   Offline
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New Jersey

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If you wire it backwards it will run backwards. The cap was for noise suppression coming from the radio, You can toss it or wire it back into the system...............jack
 

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Reply #12 - Jul 18th, 2014 at 7:58am

737fixer   Offline
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Houston

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I just finished the install, it wasn't too hard and it made a difference, not a tornado in the cockpit, but I can feel the air blowing on me now.  I'd say a 50-75% increase in volume of airflow.  The old fan really didn't do much at all.  I ordered the new fan for a 1994 corvette from Advance auto parts online and used the 30% coupon so it was about $25 and the new screws where about $1.50 so the whole mod was $26.50 and well worth it.
Thanks Jack (artsvettes) for the info.  I left the noise suppression cap in the circuit.  As for a plug, I made two jumpers from some extra wire I had, put a female and male on each and just plugged them into their respective slots.  I might get the correct plug in the future.  Also Jack's right, if you wire it backwards it spins backwards...  Should have known that Embarrassed
John
 

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