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Discussion Starter #62
And the debate will likely continue. I'll just continue to kick back and giggle at the debate while I enjoy my maintained performance and mileage.

They kind of remind me of the typical talk jock that will babble for hours about random topics and have no real world experience about it. Have they actually performed the experiments? Have they seen what gas diluted acetone will do to an injector or a handfull or o-rings? Have they ever passed a chemistry class in their life? Do they even know the chemical break down of acetone or can draw for you the bonds between molecules?

Most likely their answer will be no in every situation.

Anyway, I don't have definitive results as to how much MPG increase you should expect by doing this AC insulation mod. But what I can tell you, it that you'll be more comfortable during those hot summer months...which was the original intent of my investigation. :4:
 

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Actually yes, experiments under controlled environments to normalize all variables were performed, and failed to show any significant impact for using this additive. I will trust methodical science over anecdotal evidence anyday, but thats just me.
 

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Discussion Starter #64
Yep... :)

What can you do but do the best you can right?

At least I'll be more comfortable in my MO's cabin during the summer months now. I hope others will as well. :D
 

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Mr Warhammer,
I just wrapped my ac lines like you did and somehow I do not feel any difference. I had a 45 min drive one time and did not really felt any quickness in getting cold or ac getting colder than before. Maybe its just the vegas 100 degree temp that really kills it. I just used the 1/2" wall rubber pipe insulation and even covered all the way to the dip stick. (end of the rubber hose.)
How noticeable is the difference? Can you really feel it right off the bat? Or need to observe much closer. I will monitor it a bit more. My wife can't tell the difference either. You did not add more freon or anything like that did you?
Thanks.

nitely
 

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My guess is that while the idea sounds good, in practice one would be hard pressed to tell the difference in AC performance. I believe some WRX owners (don't have the link) did the same on their vehicles, and actually measured AC performance to find it only made the slightest different for getting the AC to cold after a short parked heat soak. If you are starting the AC after parking the car all day or overnight, no difference - the temperature for the rest of the system would have equilibrated anyways. My AC gets cold pretty quickly (within seconds) even after a heat soak.

It is possible that the OP's experience was also due to low refridgerant levels, so the wrap made more of a difference than it would normally.
 

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Yeah. Had my doubts too, but I was hoping... I figured that if those pipes needed insulation, or insulating it will yield added cooling to the system then the manufacturer would have placed it there. I guess its not significant enough, if any, to warrant insulation .
O well... salute to american cars ac system it gets colder!--faster! than the murano. Drove a new chevy malibu couple of times and I can tell the difference. My SE does get cold its just not as nippy. Leather seats does not help either.
 

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I was actually looking at articles/diagrams on how auto ac system works just now and I think that the line that I insulated is actually the return line (low pressure side) going back to the compressor. Thus insulating it will not make any difference. Its the end part of the process. Should have read some before I did this project. O well...

link:http://skyjuiceiswater.blogspot.com/2008/01/repairing-car-air-conditioning-part-1.html
 

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Discussion Starter #69
So if the insulation doesn't make a bit of difference at all, then why do other auto companies insulate their low PSI lines? Why do refrigerated air systems in the home insulate their low PSI lines?

There is a big possibility that I'm a bit more sensitive to AC performance considering I lived in Alaska before moving down to New Mexico. I like a good working AC system. :D

It's a known fact in the AC industry that you should insulate the low PSI line in order to increase the efficiency of the system. This is done in the home cooling market and should also be done or at least be made a standard practice in the automotive market.

My hypothesis and expectations on increased system performance comes from Google searches, personal knowledge of automotive mechanics, and from Honeywell's AC specialist technician. Honeywell's technician has been at it for almost 30 years and has worked on all types of AC systems.

The wording after the diagram explains overall system functionality very well. But the one thing it's missing is what the compressor goes through.

According to industry studies, one should always insulate the low PSI side of the system in order to keep the compressor from becoming too hot. By keeping the back end of the compressor as cool as possible by insulating the low PSI line, less heat is generated in the compression stage thus reducing the temperature on the whole system. This will in turn allow the liquid freon to enter the condenser at a cooler temperature and in turn reduce the delta temperature between the input and the output of the expansion valve.

What I haven't done yet or didn't include in my experiment; mostly due to time, was measure the before and after temperatures of the air being blown into the cabin. Plus before and after temperatures of the output and input of the compressor.

The only thing I can say is that I can feel a difference in both my MO and my wife's Sentra. Last time I checked, both systems had the appropriate amount of freon.

The only thing I can think of is maybe my thread title and explanations lead people to believe that you're fingers will get numb and fall of or something. :) Hind sight being 20/20, I can definitely say that the system is definitely more balanced and the temperature from the vents is more consistent. I also remember never asking myself why my arms were getting uncomfortable when I set the system to its lowest temperature. I do remember that before insulating the lines, the compressor would turn off and the vent air would increase in temperature a little bit. Plus, it would take longer than my previous domestic vehicle to get down to temperature. I don't notice that any more.
 

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Make sense man. I'm with you, thats why I did the project. Every bit helps. Thinking that when temp is about 75 outside and you turn the ac on, you find the cabin to cool much faster and colder, As compared to a 100 degree outside temp. So cooling anything around the system must help.

The reason I said "will not make any difference" is because of this explanation:

http://www.automedia.com/How_Air_Conditioning_Works/ccr20020501ah/1

When the compressor converts the low pressure freon to high pressure freon it also raises its temp at the same time. Much higher than the ambient temp. So it that sense it sounded like a wash.

Here is another explanation regarding insulation of the low pressure line:

http://answers.yahoo.com/question/index?qid=20070709154747AAsfxj1

Here is the vibe forum folks who did the same thing:

http://forums.genvibe.com/zerothread?id=38431

And the guy that did it before him saying it does not work:

http://forums.genvibe.com/zerothread?id=29064


So far, for me, I see no difference in ac performance after the wrap.

nitely
 

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Discussion Starter #71
The only thing I can say is that the guy in the other posts and I believe you used a different kind of insulation than I did. The insulation I picked up from the pro AC shop is very dense. The stuff from Home Depot or Lowe's is very bubbley and light weight.

Maybe this kind of thing will be just like the acetone debate. Some swear by it while others think otherwise... :8:
 

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Warhammer said:
Here's a shot of the AC line I wanted to insulate. Plus, you can see the ghetto insulating I already did. The original insulation I picked up from Home Depot was complete junk. The adhesive that came with it did not hold very well so I used glue to keep it shut. Doesn't look pretty, but it did the job.
But you said this....
 

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Discussion Starter #73
Since when does a post or anything on the internet for that matter need to go through a First Article Inspection and a full engineering review panel?!?!?

Read the other posts and you'll eventually get my drift.

The original insulation I installed was from Home Depot and sounds like what you described. By insulating just what I could reach (in the first pictures) I noticed a "slight increase". After insulating the rest with the more dense professional grade insulation did I notice a more dramatic difference.

The one thing I didn't mention; because I thought it was unnecessary at the time, was the fact that the AC technician I mentioned earlier said the Home Depot bubbly insulation was complete junk. It's not dense enough to provide a good thermal seal hence the reason why I included where you can buy the good stuff.

I think I've been around on this forum long enough and have demonstrated I know what I'm doing. What are you getting at? Do you think I'm lying or trying to mislead anybody?

If I have definitive results, that doesn't mean that it will definitely help someone else. There are too many variables to consider.
 

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To get the same results as Warhammer, the parameters must be the same, which means using the same insulating material as Warhammer has used. To be honest, I thought I could get away with the stuff from home depot too. Now that I know I need better stuff, I will go to an AC shop.

Although the hot season is almost over, I still plan to do this mod. I think it makes perfect sense. Thanks Warhammer!
 

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Discussion Starter #76
Thanks for the support guys, but I have one more note to add to my observations:

One thing that my MO had a hard time with was getting the AC ice cold while sitting still in a parking lot. It would get cool but not cold. With the heat from the engine, heat from ambient temp, etc I'm thinking that the air movement from the electric fan wasn't adequate enough to cool down the condenser.

I remember this because there were multiple times I would go to a store and after I was done shopping (30 minutes or so) I would need to change my son's diaper in the parking lot. I would turn on the motor and turn up the AC to make the cabin more comfortable for him. I would get frustruated because it wouldn't cool down that fast and even then not get ice cold.

So maybe Nitely has a point in regards to the insulation not making a difference (or that much of a difference) when the MO is at speed. Where the main difference would be is sitting still in a parking lot after the engine is still hot and trying to get the AC to work well.

Maybe this will be another test point for people if anybody decides to insulate their low PSI line.

Good luck! :D
 

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This all great info guys, as a HVAC tech I wanted to point out that with out the right amount of air across the condensor assembly it just wont remove the heat, so I would be real interested in any mods to the cooling fan. I feel that this is the real root of the lack of cooling capacity in our MO's.
 

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Just finished insulating the whole line ...

It took me two weekends to finally complete this mod, I found it to be not that simple. But then again the insulation I bought was quite thick and hard to work with.

Anyway, took off the wipers, the metal bits and all the rest in between the A/C plastic hose and the firewall, so I could get to the all the metallic parts of the line. Not a hard thing to do, but you do have to be methodical, organized and patient, as many things can break and get lost.

Pulled everything off, and started working on getting the insulation on, and it was a nightmare as the insulation I had bought was too thick and not flexible enough to bend and go through all the tight spots and turns the line has. Still it took me a very long while but I managed to get all the insulation on. I bought something similar to what Warhammer used, but went on to wrap it all up in aluminum foil tape (AC tape). It looks quite good and actually helped me seal everything properly. Once the upper metallic pipe was insulated I got down to the part that goes from the compressor to the plastic tubing.

That was very hard, I tried getting at it form the top and the space in between the radiator, engine and pipe is very small, scratched myself pretty good many times. So I decided to get at it from under the MO, and that did not work too well either. I removed a plastic cover underneath, only to find little stones and gravel falling on my face as I removed, literally got covered in gravel. If any of you ever remove this plastic undercover, I would strongly suggest taking a deep breath and doing it very very patiently, as the plastic clips or pins that hold it to the chassis are full of dirt and do not come off easily, you really need to work them slowly for some time until they pop open.

Once the plastic panel was off I could see the pipe, but it also was very cramped and also scratched myself a couple of times getting my hands in there. I finally gave up on going at it from below, and came up with an idea that finally worked.

I decided to try and wrap the plastic hose that is between the two metal pipes with the insulation, and slowly started to slide it down towards the compressor , this worked really well, although, again it took for ever as I could only slide it a couple of centimeters at a time. but eventually I managed to get all the piping covered with the insulation.

As to the result .... I have noticed that the AC does get colder faster and it does get colder than before in absolute terms. I actually had my head ache when I tried on the AC with the new insulation, as I have most vents pointing towards me due to the AC being not that cold before, and now this actually caused my head to ache, something that had not happened ever before even at night, I keep the auto on at 19 degrees C, which is my ideal temperature. So I would say there is a noticeable difference, although I should have tested it out somehow with a meat thermometer or something.

Still it was a great MOD to do, kept me busy for days and looking at different kinds of insulation etc. Thanks Warhammer !!!!

I don't care if others don't think it should work, it feels colder to me, maybe it's just that summer is almost over and autumn is coming in too soon.

PS
I generally don't do much highway during the day it's all slow traffic and stop lights, I do get a lot of highway going to and back from work early in the morning and late at night, but truthfully the ambient temp at those times is not too high and the AC generally worked well then without the mod. It was daytime, packed traffic driving that really strained it.
 

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Another issue to deal with

I have found that, at least in my case, there is another major contributor to my lack of cooling. I recharged the system with some R134a that has a UV dye. Turns out my low pressure valve has a leak. It lost almost 10 PSI of pressure after sitting in 90+ degree temps in about 7 hours. Replacing the insert does not fix the problem so it would seem to me that the seat itself is leaking.
Does anyone have a guesstimate as to what this may cost to repair?
 

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Okay, had the low pressure line to the compressor replaced, that's the line with the low pressure port. Total cost was $250, not including taxes. That included the evacuation, recover and recharge with r134.
The AC is much better but we haven't had bad weather, (hot & muggy) since. Once we get above about 92 and 45% plus humidity, that will be a good test. I still suspect the AC system is weak but at least I have a major leak fixed.
 
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