DIY: A/C Insulation

[Black_griffin6]

Hey guys, I just bought the stuff to do this with.

I got the insulation and the zip-ties, and now I need to get the tape to reflect the heat.

I've got a few concerns though...
What if moisture gets under the insulation? The pipe won't rust will it? I'm rather worried about the long-term affects.

I'll give it a whirl anyway seeing as how nobody has said anything bad about it.

[poorsh2]

I put the insulation on with ss "zip ties" you can get them at harbor freight

[LugNut]

I too did this modification, a couple of months ago, in response to the very weak AC performance. Thanks for the idea!



I did the entire suction line, from the firewall to the compressor. I mostly used insulation for 1/2 in. copper tubing (one stick, from Home Depot), but also a little for 3/4 in. on some bigger sections. For even bigger parts, like the in-line accumulator, I had to wrap with two split pieces.

There's definitely more cooling capacity, but at the cost of fuel economy. Before I could barely detect a difference in lugging of the engine with the compressor engaged. But now there's a big AC load on the engine.

On warm days I now get 40F air, but today, at 105F outside, I only got 52F. And still definitely not enough total cooling capacity even though the supply air is much cooler than before. But much better than no AC at all!

In response to some questions/concerns by prior posters, yes, there should be insulation on this line (but do at your own risk). My RAV4 does have some factory-installed insulation for part of the run. And if you have a split-system AC at your house/apartment, look at its large line ("suction"/"vapor") -- it hopefully still has its black foam insulation. But the small line ("pressure"/"liquid") definitely should not have insulation -- the refrigerant is still very hot coming out of the condenser, so losing more heat on its way to the expansion valve is a good thing.

Also, yes there is danger in doing this mod. First, lots of sharp edges, etc. under the hood! But there's also a danger that if the system is overcharged, or the AC is operated when too cold outside, that "liquid" refrigerant could enter the compressor and damage/destroy it. The accumulator is there to help prevent this, and I almost left it uninsulated. But I've done AC work, so repairing a system isn't that scary to me, and this insulation mod was intriguing. Glad I did it, so far. You, though, might want to have your refrigerant pressures checked immediately after doing this mod.

[teddy]

Originally Posted by LugNut

There's definitely more cooling capacity, but at the cost of fuel economy. Before I could barely detect a difference in lugging of the engine with the compressor engaged. But now there's a big AC load on the engine.

Is this true? I can't see how insulating a line would actually affect the load of the compressor. It should simply be reducing the lost cooling in the pipes.

[CoryM]

Originally Posted by teddy

Is this true? I can't see how insulating a line would actually affect the load of the compressor. It should simply be reducing the lost cooling in the pipes.

First time seeing this topic. My concern would be that you are removing some of the engineering that was so carefully put into the A/C system. By this I mean that the liquid coming out of the compressor needs to evaporate completely. Some of which is expected to be done in that line (not where you want it, but they probably allow for the loss). If it stays liquid the compressor tries to do the impossible and compress the incompressible (liquid). This would explain the extra load noticed when the a/c is on. Basically the compressor pistons are in mild hydraulic lock (and hating it). Compressor life will be reduced.

Probably less likely in ridiculously hot/arid places where the evaporator will deal with it. But in humid areas, or more sane temperatures, you may run into this.

Cheers.

[schume]

Originally Posted by CoryM

My concern would be that you are removing some of the engineering that was so carefully put into the A/C system. By this I mean that the liquid coming out of the compressor needs to evaporate completely. Some of which is expected to be done in that line (not where you want it, but they probably allow for the loss). If it stays liquid the compressor tries to do the impossible and compress the incompressible (liquid).

You could be right and they might have engineered the A/C system to compensate for the loss due to uninsulated suction lines. I insulated my line and I only use the A/C when it's hot, so I'm sure I'm getting good evaporation. Maybe if I ran the A/C on cold below a certain temperature, I could start having problems.

The accumulator is there to prevent any liquid from reentering the compressor, but I guess we'll wait and see if there are a lot of A/C failures reported in the future :)

[Em_]

i tried it and it melted , it's a fire hazard from my point of view even with reflecting tape,
if the car burns the insurance won't cover
the only solution would be exhaust insulating fabric

[PatrickJohnson]

Originally Posted by Em_

i tried it and it melted , it's a fire hazard from my point of view even with reflecting tape,
if the car burns the insurance won't cover
the only solution would be exhaust insulating fabric

Then you did it wrong. I've had mine on for years now, with no issues.

[Bluevitz-rs]

Originally Posted by Em_

i tried it and it melted , it's a fire hazard from my point of view even with reflecting tape,
if the car burns the insurance won't cover
the only solution would be exhaust insulating fabric

here's an example of what not to use and what you should've used...

http://www.thesolarshop.eu/acatalog/...nsulation.html

[LugNut]

Originally Posted by Em_

i tried it and it melted ...

105F here today, and just got back from a drive. 41F air. Insulation still in original shape. I don't know what went wrong with yours -- maybe (seriously!) lower temperature materials are sold up there?

[swidd]

I've had mine insulated for 3 years or something now, and left it on during cold season, and have never restricted my use of A/C when cold outside. No problems at all, and the high temperature resistant tape holds up nicely.

[yours_falsely]

So now that some time has passed since it's first been tried, what I'm taking from this is that there don't seem to be any long term negative effects. Correct?

[PatrickJohnson]

I'm at 2 or 3 years, and no problems here.

[yarisitis]

For those of you who first did this mod in 2009, how's it holding up? Any negative effects on the AC system? Foam melting?

[Betrivent]

I did this a year or two ago. The insulation right above the exhaust manifold has melted slightly, otherwise it's help up fine. Didn't REALLY notice a big difference though, but every little bit counts!

[Alexrahl]

I did this on my car. Aluminum taped rated to 300f. Wrapped the low pressure line over pipe insulation. It is definitely colder now.

[rningonfumes]

Sorry for necroposting.

Can someone entertain some questions?

1.First does anyone have pics from the original post?
2. Has anyone quantified the change? As in a before and after. I realize the OP did it.
So I stuck a meat thermometer in various circumstances. 1. Idle with fan at low. 2. Idle with fan at max (4). 3. 3k RPM fan low. 4. 3k RPM fan max (4).
1. Gave me a reading of 44. 2. Gave me 47. 3. gave me 45. 4. gave me 45. ** I'll do the measurements again tomorrow these are off the top of my head. In all scenarios the fan is set to face and the window vents are closed. Thermometer is in the right center vent. *degrees Fahrenheit.


3.I've been reading a lot here and whatever google pulls up for me. It only gets cold after passing through the expansion valve. Where is the expansion valve in our car?
4. That cold piping that people say they are wrapping, isn't that piping that comes out from the evaporator which is the exit flow back to the compressor?

Here are some pics form a different member who applied insulation. http://www.yarisworld.com/forums/sho...sulating+a%2Fc

[*MAD DOG*]

Originally Posted by Echostatic

http://www.phreque.com/_tempor/camrig/lpl_insul8.wmv

Is this the "butt ugly" one or the other one?