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Mega HVAC and Cooling

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304-dude View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Jul/30/2019 at 8:40am
After another bout of rethinking block connector fittings and zero restrictions within the system, I have decided to clean up what is going on and why. Note... most of the details are from previous additions which are now removed, and recompiled for ease of understanding.

First the why... Due to the type of receiver and pressure switch combo I am using, I must make sure all #8 connections are true to form for proper function.

So far all block types and their hose fittings have some restrictions over their O-ring counter parts. I did not expect to have to go into forensic detail, on why such issues are as they are, but it seems tollarances are loosely made on some A/C block fitting manufacturing processes.

The oversized block that would not fit my condenser, from the Miata line, is about 1mm too big on its port OD, which seemed to be more than adequate for its factory intended use at the high side output, on the compressor. Though only 1/2 of the hole in the block was properly drilled, which pinched off the opening for full flow. I did a test by blowing through the hole and compared before and after redrilling. A noticable difference in free flowing pass-through. This would not have been seen unless one examines the hole once debrazing and removal of the tube from the block.

Another issue on the same block fitting, the tube end ID to the hose, was slightly smaller and would not pass a properly sized drill bit without force. I had to hand ream out the ID until the drill bit slid in and out with ease. So there was two issues on just a single block fitting, which was to be mounted to the compressor, and would allow more pressure internally within the compressor, than what may be read by a pressure switch further down in the system.

Some compressors have switches mounted at the output port, which are more accurate to the pressure within the compressor's operational specs.

As for the perfect block from the Elantra, it pinches under the hose and is unseen, until the hose is removed by cutting the crimp ferrule. Once the hose fitting us cut just before the reduced size, the flow is unrestricted.

As for the shorter end of the Elantra line, its restriction is at the O ring flare, which seems reduced by the process of creating the O ring nose at the end of the tube.

I assume the reasons for the restrictions on smaller hosed fittings are because most condensers have #8 input and #6 output, so the use of equivelent blocks are required. Just seems odd that the tube diameter is oversized for its fittings and hose type, which can throw off expections of capability by simple visual inspection.

As for the Elantra line... its fine and dandy, no issues with oem specs. Its just for my setup only, a mod must be done to replace the tube end to the hose for proper #8 size, since my setup requires #8 in, #8 out at the condenser.

On the Miata line, the block fitting seems out of spec for normal #8 fitting standards in flow capability, and must be inspected within the blocks port holes, and hose fitting ID at the end. While the #8 O-ring fitting end of the line is perfect, and does not need orfrice cleanup work done for any flow capability improvements.

To remedy my setup, I will attempt to modify the Miata block and its tube. I will remove the port end off the block and braze an #8 O-ring fitting end, and adding more angle, around a 90° bend. Since I have no lathe, its simpler to give brazing a try.

For the Elantra block fitting, I will braze a section of 1/2" ID aluminum tubing as a sleeve, over the removed bead lock section butted with a small section of 1/2" OD aluminum tubing. The other end of the 1/2" tubing will be brazed the same way to a #8 Male O-ring fitting for connection to the drier. Basically turning the block fitting into a hard line connection, for simplicity.

Added cost of $14.00 for the custom setup. If I had kept with the Range Rover receiver, or used an up stream pressure switch, this would not be much of an issue, as the restriction down stream would be part of the #8 to #6 conversion, before the drier, any way.


Edited by 304-dude - Jul/30/2019 at 1:05pm
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker
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304-dude View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Aug/02/2019 at 12:28pm
After locally sourcing aluminum tubing for A/C perposes, at advanceauto, the manager, who does buisiness with mom and pop shops, gave me info on a local shop owner that can create custom lines, very much like factory.

So, I will end up contacting the guy and see about having him crimp my #10 fittings for the low presure return line, and the single #8 fitting for the high pressure line.

From what I understand the guy can make up the hard lines in any style, but it seems simple enough to rebraze and create hard lines on my own.

I also looked into PAG oil. The Sanden compressor should be filled with 7 oz of PAG 100 or SP-20 (Sanden spec oil) to start with. Since I am at a larger capacity than stock, I estimate around 26 oz of refrigerant give or take an once. I will measure the capacity of my evaporator to calculate total volume to verify the amount of refrigerant required, as to make adjustment to PAG oil fill. 6 oz seems standard for oem usage for the Forester and others, but my drier and evaporator are larger, so the standard fill of 7 oz should fit for my needs. Note: Some compressors have 6 oz fill of PAG oil, so when doing your own A/C service be sure to verify the volume of oil within the compressor before its installation.

All this extra work, will make the cooling system efficient and help the running life of the compressor.
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker
Back to Top
304-dude View Drop Down
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Location: Central Illinoi
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Aug/03/2019 at 11:21am
Got the connectors done... though I am using OEM Honda or if one wants to use a metric 7.2mm equivelent terminal, this connector will work. I chose Honda, as i picked up an engine compartment fusebox a while back for repairs on our Honda. Note... these wires are for 50amp circuits, which are about double what each fan will ever pull. The main reason why I used them, is that terminals are high quality, and will work better than after market in the long run. You can pick up replacement pigtails from any auto manufacturer if you prefer.

The red rectangular water proof blocks are for separate fuses on each fan. This way the circuit is still functional even if a fan motor goes bad and shorts out.



Installed my cut out and rotated pressure relief vent. Once the glue dries, I will do the opposite side to fully seal the seam.



Will finish up wiring up the fan wiring to complete the fan assembly for installation and connection. Notice the ground wires are not in place... since I am using a 2 connection connector, and want to eliminate ground wires from inputs, i chose to make ground separate from the harness, to be directly connected at the upper support. Also i will be adding ground straps to the radiator since it is mounted on rubber isolators.

Edited by 304-dude - Aug/03/2019 at 4:35pm
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker
Back to Top
304-dude View Drop Down
AMC Addicted
AMC Addicted
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Joined: Sep/29/2008
Location: Central Illinoi
Status: Offline
Points: 9081
Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Aug/12/2019 at 7:12am
I will eventually get around to revising my fan circuit once more. After fiddling around with fan operation, the fan noise is almost the same between each other. So, I will set up the A/C fan to be switched on at A/C and over temp. A simple swaping of the connections is all that is needed to the circuit, for now.

Even though VW places the fuse current lower than Ford Contour fans, these blase air and draw a considerable amount of current when directly started from a stand still. The OEM VW soft start fan control modular really makes a difference.

Oddly enough, I wonder if the B body Dodge boys are interested, as the fan unit is a cheap and requires few light modification to fit, just i have gone a wee bonkers in not required mods.
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker
Back to Top
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