[Samurai]

The Jeep was picked up at Friday afternoon, delivered back on Saturday night. That is how the AC got installed.



Like any of my mods, I try my best to understand the mod before going ahead with it. Now, AC is something I am not familiar with, so I studied it a bit before committing to the modification.

High Pressure Side

Originally Posted by http://www.howstuffworks.com/automotive-air-conditioning1.htm

Compressor: The compressor is a pump driven by a belt attached to the engine's crankshaft. When the refrigerant is drawn into the compressor, it is in a low-pressure gaseous form. Once the gas is inside the pump, the compressor lives up to its name. The belt drives the pump, which puts the gas under pressure and forces it out to the condenser. Compressors cannot compress liquids, only gasses. You'll see as we go through the system that there are other parts whose job it is to capture any water that accidentally makes into the AC loop.

Condenser: The condenser is basically a radiator, and it serves the same purpose as the one in your car: to radiate heat out of the system. The refrigerant enters the condenser as a pressurized gas from the compressor. The process of pressurizing the gas and moving it to the condenser creates heat, but air flowing around the twisting tubes of the condenser cool the refrigerant down until it forms a liquid again. Imagine steam cooling down and condensing back into water, and you've got the idea. The liquid refrigerant is now a high-pressure liquid and nearly ready to cool the car.

Receiver-Dryer: But first, the refrigerant needs to be prepped for the evaporator. As it moves out of the condenser, the liquid goes through a little reservoir installed in the line. This receiver-dryer contains desiccants, small granules that attract water. You've seen packets of desiccants in shoeboxes, where they do the same thing: attract water from the air to keep new shoes fresh and ready for your feet. (They're usually labeled "Do not eat.") In the receiver-dryer, they remove any water that has entered the system. If the water is allowed to remain and possibly form ice crystals, it can damage the air conditioning system.

Once the Jeep was back, I tried to understand the installation. The compressor part was easy, it is mounted on the engine using a clamp. It is Sanden 507, using R-134a refrigerant gas.



The compressed gas then moves on the condensor. When I referred it as another radiator, the mechanic was quick to correct me, saying it was condensor. But I was not wrong, condensor is nothing but a radiator. But I guess he is so used to thinking radiator as the water/coolant driven one that already exists.



The condensor is placed right in front of the stock radiator, behind the front grill. The electric fan is in-between the two radiators. I was a bit surprised about that, I was expecting the electric fan to be in front. He said it makes lot louder noise, also the direction of the air will be wrong.


This pic should explain the path of the refrigerant.



The big black pipe takes the compressed liquid from the compressor to the condensor in front. The smaller black pipe brings the high pressure liquid back from the condensor. In both cases, the pipe is not black, it is merely the wrapper over the metal pipe.

The high pressure liquid then enters that black container, which looks like a water bottle. The mechanic called it the filter. I assume that is the Receiver-Dryer mentioned in the HowStuffWorks article. I suppose it removes all the moisture from the high pressure liquid.



The Low-pressure Side

Originally Posted by http://auto.howstuffworks.com/automotive-air-conditioning2.htm

Thermal Expansion Valve (TXV): Here, the system changes from the high-pressure side to the low-pressure side. If you were to touch this part of the system, you'd feel it change from hot to cold.

The high-pressure liquid refrigerant flows from the receiver-dryer through the expansion valve, where it is allowed to expand. This expansion reduces the pressure on the refrigerant, so it can move into the evaporator. The valve senses pressure and regulates the flow of refrigerant, which allows the system to operate steadily, but the moving parts of the valve can wear out and sometimes require replacement.

Some vehicles have an orifice tube rather than an expansion valve, but it serves the same purpose in allowing the refrigerant to expand and the pressure to be lowered before the liquid enters the evaporator. The orifice tube allows refrigerant to flow at a constant rate and has no moving parts, but it can become clogged with debris over time. Systems with an orifice tube automatically turn the AC system on and off to regulate the flow of refrigerant to the evaporator.

Evaporator: This is where the magic happens. While all the other parts of the system are located in the engine compartment, this one is in the cabin, usually above the footwell on the passenger side. It also looks like a radiator, with its coil of tubes and fins, but its job is to absorb heat rather than dissipate it.

Refrigerant enters the evaporator coil as a cold, low-pressure liquid, ideally at 32 degrees Fahrenheit (0 degrees Celsius), which is why you don't want any water in the system. The refrigerant doesn't freeze at this temperature, but it does have a very low boiling point. The heat in the cabin of the car is enough to make the R-134a in the evaporator boil and become a gas again, just like water turning back to steam. In its gaseous form, refrigerant can absorb a lot of heat.

The gas moves out of the evaporator -- and out of the passenger compartment of the car, taking the heat with it. A fan blowing over the outside of the evaporator coil blows cool air into the passenger compartment. The refrigerant in gas form then enters the compressor, where it is pressurized and the whole process starts all over again.
If the system uses an orifice tube, there will be an accumulator between the evaporator and the compressor. An orifice tube sometimes lets too much refrigerant into the evaporator and it doesn't all boil. Since the compressor cannot compress liquid, only gas, the accumulator traps any excess liquid before it can get into the compressor.

The evaporator also takes humidity out of the air in the car, which helps you feel cool. Water in the air condenses on the evaporator coil, along with dirt and pollen and anything else floating around in the cabin. When you stop the car and see water dripping underneath, it's probably the water from the AC evaporator and nothing to worry about.

This is where things got a little hazy for me. Where is the Thermal Expansion Valve or orifice tube?



Anyway, in the above pic, you can see the refrigerant entering the evaporator that is inside the Superking II blower. There the cooled liquid flows thought a coil, and the fan in the blower will blow the air over the cooling coils and into the cabin through the vents. Thus the cabin will get cooled.



After absorbing the heat in the cabin, the liquid gets heated and turns back to gas. It flows back into the compressor, and the cycle repeats.

In the above pic, you can also discarded horns, they couldn't co-exist with the condensor behind the grill. Yes, that's right. I don't have a working horn right now. Need to find a place to re-install the horns ASAP.

The AC can be controlled using this switch.



I was hoping to do some 4x4 tests today, now that is dashed. I am unable to engage 4L since the blower is blocking the 4WD lever. Looks like I have to either shorten the lever or bend it into a L shaped lever.



While inspecting the AC installation, I also noticed that the clamp was touching the winch cable. Yesterday I noticed that the clamp gets pretty hot since it is mounted on the engine.



So I tied the wires to the filter mount and created a gap. That gap is wider than you see in the photo.



The AC installation has created some real estate problem in the engine bay. I see too many plastic ties. Not sure how reliable or safe it is...

[Rajith]

Dear sharath,
Does AC requirement for this vehicle was so much pressing??.

[jmvivek]

Originally Posted by Samurai

Looks like I will be doing Bangalore Annual OTR with the same Fuel tank.

Anyway, couple things I am getting done this week. The bull bar is not exactly located in the center, that kinda bothered me. So I am making it a little wider so that it will be centered. Also making a plate on the bull bar to mount the winch solenoid.

Just now the AC mechanic came and picked up the Jeep. His shop is 15kms away, so he is picking up and dropping after the installation. I am going with Sanden 507 compressor and superking blower. Says it will be back tomorrow evening.

Sharath,

I have the same stuff, I guess in my MM540. I am planning to change my tank and reposition the same to the front left passenger side . Do PM me your contact details. Can send this to you through TVS or some door to door service guy. Can send you a pic of the same, if you wish to see the same.

Regards,
Vivekj

[theMAG]

Congrats on the AC, Sharath.

1. How is the driveability with AC on?

2. Also, might be a good idea to replace some of those plastic ties - pretty sure plastic ties were not designed for an automotive usage originally. Here is what I could find on Wikipedia as alternatives:

Alternatives

Other methods of bundling cable together securely and semi-permanently include cable lacing, binding knots such as the surgeon's knot or constrictor knot, Velcro brand hook-and-loop strips, conveyor belt hooks, twist ties, Rapstrap fasteners, metal buckle clips or Cablox cable management.

3. Including the AC installation, what has been the total cost of the Jeep ?

[Samurai]

Originally Posted by Rajith

Dear sharath,
Does AC requirement for this vehicle was so much pressing??.

Oh, very. With the black top, it gets really hot under the sun. I plan to do travel to Bangalore OTR, that is a 400kms run. I have been pining for AC and HT for many years.

Originally Posted by jmvivek

I have the same stuff, I guess in my MM540. I am planning to change my tank and reposition the same to the front left passenger side . Do PM me your contact details. Can send this to you through TVS or some door to door service guy. Can send you a pic of the same, if you wish to see the same.

I'll PM you.

Originally Posted by theMAG

1. How is the driveability with AC on?

Not much of a difference since I keep the AC in low setting. But I see the engine temp at 90C instead of 80C. Need to check in longer runs.

Originally Posted by theMAG

2. Also, might be a good idea to replace some of those plastic ties - pretty sure plastic ties were not designed for an automotive usage originally.

Thanks, I'll need to look up for these alternative items.

Originally Posted by theMAG

3. Including the AC installation, what has been the total cost of the Jeep ?

The cost of AC is 29K. Total cost until now is not something I want to count.

[roji]

Dear Sharath,
Congrats, I have similar ac setup in my MM540 for almost 2 years now. Its working fine. Recently I faced a problem with adjusting the fuel pump, there is no room for doing it, hence I am planning to shift the compressor to the right side of the engine. Also it was difficult to replace the lower radiator hose.

[svsantosh]

^ Exactly my concern too... a FIP job will be expensive and complicated now samu... why was the right side of the engine difficult to fit in? (expensive bcoz AC Gas would need to be drained and refilled when removing compressor, etc etc)

My AG...
http://www.team-bhp.com/forum/4x4-ve...and-4wd-6.html

[Samurai]

Originally Posted by svsantosh

^ Exactly my concern too... a FIP job will be expensive and complicated now samu... why was the right side of the engine difficult to fit in? (expensive bcoz AC Gas would need to be drained and refilled when removing compressor, etc etc)

I know, but I didn't have space on the other side thanks to the air filter. Unless I do some major rearranging around the engine bay, no space on the other side. I just have few days before driving to Bangalore, so I had to go with the space I had.

[svsantosh]

PS 2 more points to my prev post

1) Electric fan between 2 radiators is like the AG, OE setup... but the point of flow being reversed if kept outside is not 100% true, just reverse the leads of wires accordingly

2) dont cut/bend small lever for now, remove the holder-ball and use a rag cloth for time being and see if a smaller ball can do the trick... (from CJ days)

[Samurai]

Originally Posted by roji

Recently I faced a problem with adjusting the fuel pump, there is no room for doing it, hence I am planning to shift the compressor to the right side of the engine. Also it was difficult to replace the lower radiator hose.

Originally Posted by svsantosh

^ Exactly my concern too... a FIP job will be expensive and complicated now samu... why was the right side of the engine difficult to fit in?

Unfortunately, I didn't think about this before the installation. Thanks to the sudden decision to attend Bangalore OTR (decided on Jan 6th), I had to prep the Jeep in a hurry. I guess eventually I will relocate it, but will be an expensive affair. Hope I don't have to touch the FIP for a while.

Originally Posted by svsantosh

1) Electric fan between 2 radiators is like the AG, OE setup... but the point of flow being reversed if kept outside is not 100% true, just reverse the leads of wires accordingly

I did think the same when he said that. Unless there is a diode in the circuit blocking the reversal of polarity.

Originally Posted by svsantosh

2) dont cut/bend small lever for now, remove the holder-ball and use a rag cloth for time being and see if a smaller ball can do the trick... (from CJ days)

If I remove the ball, it almost makes it. But I want a permanent solution, so we are bending it.

Just left the Jeep back in the workshop with the following list:

Free wheeling hub is slipping.
Install bull bar with new holes.
Install horns
Bend the 4WD lever
Re-route winch/fog wires through the grill
Secure rear differential breather
Clean self-starter
Upgrade headlights to 100W bulb with relay (if missing)

Advantage of our Udupi mechanic (Prakash Poojary) is that he takes care of all the problems. He will take it to the auto electrician for electrical work, to the engineering shop for the drills of holes, etc. Over years, he has also learned the needs of offroading Jeeps, and the kind of care and maintenance they require. Without such mechanics, people like me won't be Jeepers.

[DHABHAR.BEHRAM]

Dear Sharath - please do not bend the transfer case lever, shift may get affected. You may move the evaporator a little to the left. I wonder why the compressor is not like Armada NGCS AC. The layout is exactly same in your Jeep. The alternator with the vacuum pump comes on the intake manifold, with the compressor going in place of the alternator. You could have used all the parts off the existing Armada BOM. As you have gone for the aftermarket LHS high mounted compressor, as the center to center distance between the crankshaft pulley and the compressor pulley is large, the belt will whip within the operating speed range of the engine, belt life will be less, belt will make noise, drive efficiency will be poor and if the belt breaks, it can affect reliability of hoses, please be careful.

Best regards,

Behram Dhabhar

[Samurai]

Thanks Behram, it is clear that this setup is not optimal. I am going to move it to the other side some day, can't have the FIP blocked forever. But I have to live with this for a while.

[Jaggu]

Congratz Samu san, the install looks quite clean. Minor touch up here and there like you planned and you should be fine. Price also is very reasonable. AC gas refilling is no big deal, will cost you 1.5k max since these days gas is recycled using machines.

[headers]

@Samurai:

just my 2 paisa!!

You can shorten the 4wd lever - just take an inch off and weld the lever back to get a short 4wd lever This would not interfere with any operations.


You could also go in for the bolero type air box {air filter with box } compared to the one in your jeep, it would help breathe better.

See you in BAOTR2013!
cheers

[Samurai]

Ah, the blistering barnacles!

I was supposed to do offroad testing last Friday. But the AC guy took it away and returned only on Saturday night. Sunday we took it for a proper offroad testing, found that the FWH was incorrectly installed. Also, 4L couldn't be engaged since the AC blower was blocking it. Yesterday night got it back from the workshop.



Today I took it offroad, in 4L. It climbed the first obstacles cleanly in 1st gear 4L. Then when I engaged 3rd gear, engine just revved. The 4WD lever had snapped back from 4L to N. Tried it a few more times, the 4WD lever snaps back to N within 2-3 minutes, every time. Once even while climbing, stranding me right there.

In fact, it doesn't stay there even when I engage 4L. It stays in between, ready to snap back. I had noticed that yesterday, but didn't think it will slip back to N while driving.

http://www.youtube.com/watch?v=fkKWdXxAr1Y

What is the cause of this? Can this be fixed fast? I have only a day to fix it.