more a/c questions
Thread Starter
Le Mans Master
Joined: Jul 2006
Posts: 8,117
Likes: 104
From: charlotte north carolina
more a/c questions
i'm rebuilding a 70 vert that didn't have a/c. i purchased an a/c system from a 76 from a forum member that is is reasonable condition.
is this an oriface system? the drier/receiver mounts on the evaporator housing and doesn't look like a poa valve. i would like to change to a new style compressor (r4 or sanden type). should i go r12 or r134? i've seen vir replacement kits mentioned in other posts, but i'm not sure exactly what the difference is between the poa, oriface, vir, and thermal expansion systems, or if they're the same. any and all help would be appreciated.
jeff
is this an oriface system? the drier/receiver mounts on the evaporator housing and doesn't look like a poa valve. i would like to change to a new style compressor (r4 or sanden type). should i go r12 or r134? i've seen vir replacement kits mentioned in other posts, but i'm not sure exactly what the difference is between the poa, oriface, vir, and thermal expansion systems, or if they're the same. any and all help would be appreciated.
jeff
Racer
Joined: Jun 2006
Posts: 316
Likes: 1
From: Southern California
If you come up short on any of the ducts or boxes for the inside, I may be able to help. I was about to do the same as you but decide to take a different route.
I have many parts for the inside duct work that I no longer need.
Art is correct on the other stuff.
I have many parts for the inside duct work that I no longer need.
Art is correct on the other stuff.
Melting Slicks
Joined: Dec 2005
Posts: 2,441
Likes: 0
The orifice system, a.k.a. CCOT or Constant Cycling Orifice Tube, is the most modern version of the three. It uses a low pressure switch to cycle the compressor on and off according to heat load. I converted mine to this system using 134a and the latest model evap unit.
Drifting
Joined: May 2005
Posts: 1,629
Likes: 4
From: Somers CT
The difference is in the amount of complexity, orifice being the simplest.
The orifice system, a.k.a. CCOT or Constant Cycling Orifice Tube, is the most modern version of the three. It uses a low pressure switch to cycle the compressor on and off according to heat load. I converted mine to this system using 134a and the latest model evap unit.
The orifice system, a.k.a. CCOT or Constant Cycling Orifice Tube, is the most modern version of the three. It uses a low pressure switch to cycle the compressor on and off according to heat load. I converted mine to this system using 134a and the latest model evap unit.
Melting Slicks
Joined: Dec 2005
Posts: 2,441
Likes: 0
I use the Sanden, it draws very little HP, the drop in RPM is not enough to make an impact on curb idle, cycling isn't noticable, saves about 20lbs in weight over the A6, works good.
If you've got a bigblock and decide to use one of these, get the one with the rear hose connections, my discharge fitting has hit the hood before.
If you've got a bigblock and decide to use one of these, get the one with the rear hose connections, my discharge fitting has hit the hood before.
Drifting
Joined: May 2005
Posts: 1,629
Likes: 4
From: Somers CT
I use the Sanden, it draws very little HP, the drop in RPM is not enough to make an impact on curb idle, cycling isn't noticable, saves about 20lbs in weight over the A6, works good.
If you've got a bigblock and decide to use one of these, get the one with the rear hose connections, my discharge fitting has hit the hood before.
If you've got a bigblock and decide to use one of these, get the one with the rear hose connections, my discharge fitting has hit the hood before.
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Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
The old Sanden 508 series compressors used from 2 to 8 hp depending on rpm.
The replacements for the 5 series, SD5H14 are all made in Singapore now if anyone cares and have a displacement of 8.4 cu in.
The SD7H15 series are US made and have a displacement of 9.5 cu in which is much closer to the original a6 10.2 cu in. It does make a difference in cooling performance.
Depending on the actual cabin heat load, you may find an ot system will cycle very little.
The replacements for the 5 series, SD5H14 are all made in Singapore now if anyone cares and have a displacement of 8.4 cu in.
The SD7H15 series are US made and have a displacement of 9.5 cu in which is much closer to the original a6 10.2 cu in. It does make a difference in cooling performance.
Depending on the actual cabin heat load, you may find an ot system will cycle very little.