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Vintage Air Gen IV Mods for 1977.

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BankOfHell

Guest
I recently installed a Vintage Air Gen IV Kit in my '77. Here is I mod I made to their kit I call SuperMAX.

On a 95F day at idle, FAN at highest speed, duct temperatures cycle between 45F and 50F. Compressor operation is controlled by a thermister in the evaporator coil that cycles the coil temperature between 42F and 45F.

Normally this is plenty cold enough. VA has it set at those temperatures to ensure no ice forms on the coils in any condition; they had a problem with icing in the past so they have set the temps fairly conservatively.

However, on really hot days, I noticed the compressor still cycles fairly often. Meaning there's more cooling that can be squeezed out of the system.

So what I did was to install a second thermister and temperature control with an enable switch. This I have set to cycle between 28F and 34F.

With SuperMAX engaged, I now have duct temperatures that cycle between 31F and 37F. This very quickly will cool down the car even after baking in full sun in a parking lot. Once the car cools down, I disable SuperMAX and revert back to VA's thermister.

This mod really made a big difference to the functionality of the VA system.
 

Antz81

Well-known member
Joined
Dec 21, 2013
Messages
936
Location
Auckland, New Zealand
Corvette
1981 4 speed
Welcome to the CAC. :w

Since bank of hell's seems to be a guest he most likely won't respond.

I can give you some tips on how he would have done it though.
The thermistor that he installed in the coil would be connected in parallel with the existing thermistor.
He would also have connected a switch somewhere inside to disable supermax. This would need to be connected in series with the new thermistor. I'll draw up a quick diagram later to show it.
 

Antz81

Well-known member
Joined
Dec 21, 2013
Messages
936
Location
Auckland, New Zealand
Corvette
1981 4 speed
I've attach a couple of basic diagrams showing two different possibilities. the first would provide better control of the switching temperature and would be easier to set up. the second would be a cheaper option but would have some limitations in settings (would be trial and error for the correct setup).
one.png
output.png
 

jbburlison

New member
Joined
Jun 2, 2014
Messages
3
Location
Albuquerque, NM
Corvette
1976
Thanks

Thanks for those diagrams, I am definitely going to try to get the system cooler. Probably go with the simpler option for starters.

Unfortunately, recently discovered that my cam was worn out.....

Will get to the AC mod after the new roller cam goes in :happyanim:
 

Antz81

Well-known member
Joined
Dec 21, 2013
Messages
936
Location
Auckland, New Zealand
Corvette
1981 4 speed
Thanks for those diagrams, I am definitely going to try to get the system cooler. Probably go with the simpler option for starters.

Unfortunately, recently discovered that my cam was worn out.....

Will get to the AC mod after the new roller cam goes in :happyanim:

I would recommend going with the second temperature controller ( first diagram ). But before you go buying any parts have a look and make sure that you are comfortable with making the mod. It may look simple in the diagrams but it might be a bit more complicated than it looks. As I don't have a vintage air system myself I'm not sure what you'll find once you get into it.
Good luck with the cam and the mod
 

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