• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Slight redesign of A/C system

Leroy, got any updated status on your A/C mod? Did your interior cooling improve? Did that oversize A/C condenser have any effect on your engine cooling.
 
I decided to wait til the new engine is in before continuing. I'll definitely update when I have something new.
 
Shoot, the truck a/c system is probably enough for your house in the summer time. The fact that your meat supply comes covered in a wool blanket on their head and shoulders says a lot.
 
Burning oil said:
Here's a poor pic of the acumulator insulation. It sould have a top piece too. The line from condinser to evap you can basically wrap any insulation around it. I think the silver reflective stuff would be the cat's ass.

View attachment 42694
Click to expand...

Wrapping the exhaust and using a turbo blanket also helps.

The accumulator insulation on R134A never made sense to me for a long time as far as efficiency and why bother. Only one of many jobs of the accumulator is to make sure excess liquid freon from the flooded evaporator doesn't make it to the compressor. It also makes sure oil is flowing to the compressor. Yet the catch is this with yet another job for the accumulator: The accumulator can hold 1/4 to 1/2 LB of freon - this would be a leakage reserve designed into the system and any overcharge. Different conditions can lead to an overcharge with a factory correct fill weight, but, this is another discussion. The 1/4-1/2 pound of freon is liquid in the accumulator. So if you are boiling it off with engine heat the pressure in the suction line is higher and less freon boils out of the evaporator.

In summery because there is liquid freon in the accumulator insulating it improves AC performance.

The AC liquid line to the condenser being insulated does help too.

Another area to watch is the oil coolers in front of the AC condenser. If they are too hot, specifically over ~160 degrees, they heat up the condenser. This is very critical on the liquid outlet side of the condenser (passenger side bottom on our stuff) more so than the driver side because you can re-cool the freon on the outlet side if it is heated on the other side. Condensers run ~160 degrees in the 110 degree AZ weather so figure this is the high head pressure high temperature number ballpark. A good example is running hot transmission oil through the air to oil cooler in front of the condenser before running it through the radiator. Not only does it kill AC performance it also runs the transmission 20-30 degrees hotter. An IR temp gun will show you if the oil coolers are heating the condenser back up by taking readings around it on the condenser.
 
For sure going to use a turbo blanket and exhaust wrap. Helps the heat stay in the pipe and out of the engine bay.

If I understood, you say insulating the accumulator is a good thing? That is my plan anyway.
 
Insulatng the accumulator IS a good thing. GM didn't do it for nothing. If you put the orifice in the evap itself, then theres no reason to insulate any of the other liquid lines unless they run really close to the manifold or turbo. I know my DURAMAX came stock with heat shields, but insulating the lines made a HUGE difference. I personally don't insulate the vapor line from the accumulator to the compressor. This helps to act as a safety to boil off any liquid that may get past the accumulator. And that little canister just before the compressor is muffler/liquid brake so make sure it's in there.
 
OK will do. My plan is to put orifice in evap, insulate accumulator and line from condenser to evap. I'm wanting to install the pancake filter in hose from compressor to condenser unless someone says no.
 
dangerousdave said:
Did you insulate the hardlines to the rear evap too?
Click to expand...

Not the ones under the BURB, but in the engine compartment yes. Anywhere a liquid line passes by a heat source I insulated it. The line from the Y to the front evap is insulated, the accumulator, and the line going to the back under the hood. I figured under the BURB there wasn't enough heat sources to cause boil off insode the line to justify insulating it. The only low side line under the hood I didn't insulate was the line from the accumulator to the compressor. I did this to help act as a buffer to reduce the chances of liquid ever making it to the compressor. You NEVER wan't liquid to make it's way to the compressor! EVER! PAG oil carries just fine in refrigerant gas just as well as it does in liquid, it is DESIGNED to do so. Where you have a problem is when the charge is low enough that there isn't a good stream of gas flowing to carry the oil back to the compressor.
 
Just got back!

Well after a 5000 miles driving vacation I can report the A/C functioned flawlessly. Driving though the deserts, over the Rockies and Sierra Nevada's it never let me down. 39* the whole time.
The orifice in the evap is louder but not bad.
It may sound weird, but Im really proud of it and being able to pull it off.
 
You must log in or register to reply here.
Back
Top