C4 blower motor
Thread Starter
Safety Car
Joined: Dec 2012
Posts: 3,796
Likes: 1,706
From: Summerville SC
C4 blower motor
OK, I am starting to get my parts together to replace my '78 blower motor with one from a C4. Engine is out of the car,evaporator box & heater box are on the bench. I know I need to have a spacer, and that is under construction. So my question is will I need a resistor and a relay for a C4 or will a C3 work just as well. I am clueless about a lot of things, but really clueless about resistors. I also know I need to use a different plug for the electric and I will have a good size ground wire, heavier than stock. Thanks.
Drifting
Joined: Aug 2006
Posts: 1,727
Likes: 193
From: Scottsdale Arizona
I am in the middle of doing mine also, I have a 72 and I am using a 84 motor which you don't have to change the wiring at all just plug in. I am making my spacer out of black plastic so it will be less noticable. There was a forum thread that described the difference of the motors.
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
The C4 blower doesn't really have any advantages - it's the fan cage that is longer and has a steeper angle than the C3 cage.
I did this modification recently as well, made a spacer to use for it out of some black ABS plastic.
To get the full benefit, I've read in the past that people can get some better voltage to the unit by first improving the ground and then adding a bigger supply voltage (by means of a relay, typically).
With the two units off the car and hooked straight up to the battery, the C4 fan is a clear winner in air displacement.
I did this modification recently as well, made a spacer to use for it out of some black ABS plastic.
To get the full benefit, I've read in the past that people can get some better voltage to the unit by first improving the ground and then adding a bigger supply voltage (by means of a relay, typically).
With the two units off the car and hooked straight up to the battery, the C4 fan is a clear winner in air displacement.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
The C4 blower doesn't really have any advantages - it's the fan cage that is longer and has a steeper angle than the C3 cage.
I did this modification recently as well, made a spacer to use for it out of some black ABS plastic.
To get the full benefit, I've read in the past that people can get some better voltage to the unit by first improving the ground and then adding a bigger supply voltage (by means of a relay, typically).
With the two units off the car and hooked straight up to the battery, the C4 fan is a clear winner in air displacement.
I did this modification recently as well, made a spacer to use for it out of some black ABS plastic.
To get the full benefit, I've read in the past that people can get some better voltage to the unit by first improving the ground and then adding a bigger supply voltage (by means of a relay, typically).
With the two units off the car and hooked straight up to the battery, the C4 fan is a clear winner in air displacement.
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
FWIW, 4 Seasons lists the same SKU for 77-86 (obviously excluding 83
).I would not be even slightly surprised if the aftermarket 87-91 motor assemblies used the same motor as the earlier blower assembly. The 87+ is definitely a cleaner wiring setup with a single pigtail rather than the spade + spade/ring connector on one of the mounting bolts.
Of course, if the motor is original and the car is well-seasoned, going to a new motor should help with air-flow.
Last edited by Shark Racer; Jul 26, 2015 at 02:48 AM.
Team Owner
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From: Southbound
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Add it to the list of things to do 
Thread Starter
Safety Car
Joined: Dec 2012
Posts: 3,796
Likes: 1,706
From: Summerville SC
Thanks for ll the replies. I am in the middle of putting an 86 TPI engine in the car, so the wiring will be a combo of 78-C4 stuff. Not sure if there is a difference between the 78 & C4 blower motors-I got an 87 with the newer plug in it-and since I needed to upgrade the ground, I figured to just do the swap as close to 'C4 as I can. Just trying to make it easier for me to remember what year part is in the car later on down the road. Thanks.