Aftermarket AC Condenser Install

[jonn6464]

Hey FABO,

I'm looking for some advice about installing an aftermarket AC system.

Car is a 70 Duster.

I have an AC system that came with a 12" electric fan for the condenser. The condenser fits, with no trouble, in front of (towards the grill) the radiator.
The radiator is also aftermarket with electric fan.

Is the condenser fan absolutely necessary, or will the rad fan and the position of the condenser on front of the rad be enough cooling?

With the fan and condenser, it extends into the space for the radiator about 2".

Alternately, I guess I can make 2" spacer brackets for the radiator mount to push it back. But I don't have the engine in yet so I can't check for clearance.

Thanks for any replies.

 

[67Dart273]

Not trying to be "smart." You are asking something we can not possibly know. Don't know if the present fan has any "overhead." It was common for AC cars to use larger mechanical fans on AC vs no AC, so "I'd say" "a crap shoot."

Also some fans can actually RESTRICT air at highways speeds.

 

[jbc426]

Hey FABO,

I'm looking for some advice about installing an aftermarket AC system.

Car is a 70 Duster.

I have an AC system that came with a 12" electric fan for the condenser. The condenser fits, with no trouble, in front of (towards the grill) the radiator.
The radiator is also aftermarket with electric fan.

Is the condenser fan absolutely necessary, or will the rad fan and the position of the condenser on front of the rad be enough cooling?

With the fan and condenser, it extends into the space for the radiator about 2".

Alternately, I guess I can make 2" spacer brackets for the radiator mount to push it back. But I don't have the engine in yet so I can't check for clearance.

Thanks for any replies.

I used to run a twin Spal electric fan set-up with their fan controller. It worked very well, but it required 2 relays and had a soft start fan controller function to reduce the 40 amp current draw those fans have at start up.

Obviously, I had to upgrade my electrical system to feed the fans and all the rest of my added electrical load. Unless you have a very good quality electrical fan on your car, it won't likely cool your car properly.

Generally, the amp requirements of many electric fans exceed factory alternator's ability to feed it, especially at low idle. The factory wiring also needs to have some of it's limitations addressed by taking into consideration the connections, routing and wire gauge size.

Later, I switched back to the factory HD shroud and thermal clutch fan. It worked even better.

Another thing you can do is block the air from being able to go around the radiator and condenser, so more air is forced to pass through the condenser and radiator.

 

[j par]

Usually your clearance between the engine and the radiator in an a body isn't an extreme amount. Like a truck or something... I have The Pusher fan on my condenser on my truck and my Duster.. the thing to do is to not install it get everything done and finished and run your AC... If everything works great then you're great but if the AC isn't cooling like you like try pouring a little water over the condenser and see if it cools the AC down which is basically cooling off the condenser... If that works and makes the AC More palatable then it's time to go ahead and install that fan that's triggered by the dryer which is also triggering the compressor clutch so it comes on when the compressor comes on...
In other words you can leave it out until you find it necessary...

 

[jonn6464]

Ok, thanks for the replies.

Just for clarification, there not a single factory wire or connection left in the car. It's all been replaced and upgraded in spots. 110A alternator is what I'm running, so I'm hoping to have enough juice for the AC, stereo, door poppers, etc.

 

[mgoblue9798]

Hey FABO,

I'm looking for some advice about installing an aftermarket AC system.

Car is a 70 Duster.

I have an AC system that came with a 12" electric fan for the condenser. The condenser fits, with no trouble, in front of (towards the grill) the radiator.
The radiator is also aftermarket with electric fan.

Is the condenser fan absolutely necessary, or will the rad fan and the position of the condenser on front of the rad be enough cooling?

With the fan and condenser, it extends into the space for the radiator about 2".

Alternately, I guess I can make 2" spacer brackets for the radiator mount to push it back. But I don't have the engine in yet so I can't check for clearance.

Thanks for any replies.

Can't tell you for sure about your particular set up, but here are a couple general points.

One, the pusher fan (front mount) is not as efficient as a puller ( rear mount).

It is entirely possible to run only the pull rear mount style fan provided it has enough CFM of air flow. You can reduce CFM requirement by making sure the fan shroud seals well against the radiator, and that the radiator to core support opening is sealed in some way as well.

I have used Dodge Intrepid dual fans on several set ups with good results. Fit 26" radiators like they were made for it. Used old trunk weather strip to seal against the radiator.

If you are going to run r134 for freon, make sure your condenser is a modern design with increased cooling capacity to make sure your AC will cool well at idle or sitting in traffic.

I would only run the front mount fan if you cannot get the cfm air flow you need from rear mount fans due to space issues.

Also that 110 amp alt should be plenty to handle the system provided you set up the fans on a relay.

 

[67Dart273]

One, the pusher fan (front mount) is not as efficient as a puller ( rear mount).I

This is not true in the absolute sense of the word. ANY pump / fan / blower that is at the "push" end, properly designed and installed, is much more efficient than "suction."

It may well be that a fan in this application is less efficient "typically" but only because it is improperly designed and installed WITH NO SHROUD or proper spacing, etc.

 

[mgoblue9798]

This is not true in the absolute sense of the word. ANY pump / fan / blower that is at the "push" end, properly designed and installed, is much more efficient than "suction."

It may well be that a fan in this application is less efficient "typically" but only because it is improperly designed and installed WITH NO SHROUD or proper spacing, etc.

It is the radiator/condensor combo it has to push/pull through that changes the equation. All else being equal, the same fan will work better pulling from behind than it will pushing through the combo. Just my experience and two cents.

 

[Ichillu]

It is the radiator/condensor combo it has to push/pull through that changes the equation. All else being equal, the same fan will work better pulling from behind than it will pushing through the combo. Just my experience and two cents.

Well, let the "fun begin"...
I have worked in the "Fans & Airflow Engineering" field for more than 40 years...
Both of you have made comments that could be correct... The real issue is that "Prop Style" fans do not produce a large amount of static pressure - with or without proper shrouding - but with a shroud will make any prop fan much more capable when properly set up... and depending on the pressure drop across the Condenser + Radiator arrangement - pushing or pulling effectively can be a real challenge... a "properly shrouded" prop fan would do a better job pushing through than pulling through depending on how much space exists... If I compare this issue to what I have seen in the past - My 2000 Dakota P/U had an electric fan and a mechanical fan installed from the factory to ensure the A/C condenser / rad had sufficient airflow when the compressor engaged... if you can fit a "pusher" and a "puller" fan arrangement in the car... this would be the best setup... but you may not need it other than on a very hot day and idling the engine with the A/C on.
My 70 Swinger 340 has air and only a mechanical 8 blade (aftermarket) fan installed and works fine.