Idea for quad & mega cab A/C upgrade

[firefighter_2000]

Had an idea for an upgrading the quad cab, crew cab, and mega cab. It probably wouldn't be too cheap, but it would be WELL worth it in the long run.



My idea comes from emergency vehicles, specifically ambulances (some fire engines). On a cutaway chassis, the factory air conditioning is installed for the cab just like normal. A second set of hoses runs to the rear of the truck to a second condenser and fan setup, and if Im not mistaken, everything runs off the factory compressor. One company that makes that setup is Hoseline Inc in St. Cloud FL.



My idea is to do a similar setup, mounting the second condenser and fan unit in a specially fabricated box under the arm rest between the front seats. The center seat position would no longer be usable. For the mega cab (which is what I have) the duct running to the rear would be removed & blocked off AT the dash. The auxillary system would cool the rear of the truck and hopefully carry over to the front and cool the entire truck more efficiently. Im going to work on trying to figure out what all would be required to do this modification, as I'm not familiar with the inner workings of a/c systems.



Ideally, if I could come up with a condenser, fan, & electronics all in one metal fabricated box. Hookup would be as simple as running the power to the box, and running the two hoses from the compressor.



I know that t-fittings at the compressor would be needed. Additional R-134a would be required for the hose & condenser. Im sure there are additional parts & equipment needed to make it all happen.



Any thoughts ideas etc?



Craig

 

[AH64ID]

That is similar to how the rear a/c on a suburban works.

 

[firefighter_2000]

Suburban

Which model suburbans have that option? Certain years and/or models? Might be something I could find parts out of a wrecked suburban I could modify for this use.

Craig

 

[AH64ID]

I know at least 92+ had rear a/c as an option.

 

[Scottyg1]

I know at least 92+ had rear a/c as an option.

I know you can back to at least 89

 

[BLoging]

how about a 2002 dodge grand carvan has some what of the same set up!!!

 

[firefighter_2000]

Pro air 1100

So here's what I've found so far. I've been searching all day and this seems like probably one of the easiest routes to go so far.

Its a Proair LLC model 1100 hvac unit.



#ad




Seems to be an all in one unit. Im thinking, I might be able to use this,and put it in a nice sheet metal enclosure. It has both heat & air. Would be nice if there was one available with AIR only and no heat. I think I may call them tomorrow and tell them what I have, and see what options I might have.



Craig

 

[WMoroni]

I installed an a/c in and old r model Mack with a universal unit by DTAC. Came with compressor, hoses, condenser, evaporater, dryer, blower, everything you need even all the mounting brackets. The parts cost me $1100. Took about half a day to install. The unit in the cab mounts to the back wall is about 12"w x 20"H x 12"d. They make different ones to fit all sorts of equipment so they may have something that you can make fit. Check with Napa or some place like that.

 

[Bernie]

My idea comes from emergency vehicles, specifically ambulances (some fire engines). On a cutaway chassis, the factory air conditioning is installed for the cab just like normal. A second set of hoses runs to the rear of the truck to a second condenser and fan setup, and if Im not mistaken, everything runs off the factory compressor.

Yes and no on the AC configuration in emergency vehicles. Yes, quite a few are configured that way, but not all. Most custom cab fire trucks are that way, and many ambulances are that way. Some ambulances and commercial rescue trucks (think International) will have a second complete AC system, with its own engine mounted compressor and roof mounted condenser. The cab will run off of the "stock" cab system, the box off of the second system.

But, the important thing to remember is on the systems you are describing, all the components are larger to meet the larger cooling needs. Those chassis are ordered to be emergency vehicles, with larger compressors and condensers to handle the additional cooling needed to run the cooling coils in the ambulance box.

I think the things to figure out before you fabricate the set up you are proposing:
-Is the surface area of the cooling coils the limiting factor in your system? If yes, than adding a second bank of cooling coils / fan to your system like you described will work.
-Are the capacity of the condenser / compressor the limiting factor? If that is the case, adding the additional cooling coils will not help.

My gut feeling is all the components in out trucks are matched to each other. Adding a second bank of cooling coils may not increase our overall cooling capabilities.

 

[firefighter_2000]

I understand what you mean. I checked and the setup I have pictured above requires an additional 10 ounces of refrigerant (plus whatever the hoses would require). My thinking is not necessarily extra cooling (colder temps on the coils) but with extra blower capacity. It would work similar to how the above poster refered on the suburban and mini vans. If I had an additional blower going across a second set of coils (lets just say double the cubic feet per minute since I would be using two blowers) plus blocking off the rear air outlet would give a bit more capacity to the front.



I dont know if an a/c compressor is the same as an air compressor, but if I had an air compressor with a ten gallon tank, and switched it to have a fifteen gallon tank, it would still reach that max pressure, just take a little bit longer to get to that pressure. Once it got to that pressure, it SHOULD be able to maintain that pressure.



Can anyone chime in and verify that my thinking is correct?

Thanks

Craig

 

[B.G. Smith]

What you will be dealing with is capacity or cfm out put of the compressor. Like if you have an air compressor that maintains 125# @ 2 cfm and you are running a grinder that uses 2 cfm @ 125# and you add another power tool that uses 2 cfm @125 it ain't gonna work. You will also be adding a little more heat load to the condenser. However I think your idea is great and adding a small evaporator will probably give you additional cooling where you need it. The unit in your truck uses an orifice tube for cooling, I think most of the older units in the vans used expansion valves? I think both evaporators would need to use the same expansion device to be effective. Keep us informed on what you end up with. bg

 

[Linker]

Durangos have rear air and their own compressor/fan assembly

 

[JMarketos]

but it would be WELL worth it in the long run.

Admittedly, I haven't looked for any history or read any other of the OP's previous posts- maybe there's a specific issue at play here that I'm not aware of.

OP seems to start out with the conclusion that the factory AC is inadequate, and is looking to go to the significant extra expense and effort of installing a second AC unit. Has the integrity of the stock AC unit (and blend doors etc. ) been verified ? I have a stock 05 QC, silver with charcoal interior, and I find the cooling to be more than adequate. (Truck was bought new and lived several years in the metro Atlanta area, with trips to FL and LA). Typically I only need to run the blower fan on high for about 10 minutes, then can back it down. I acknowledge that can be subjective, so I'll also offer that I typically prefer cooler temperatures, so I'm not one of those who is simply OK to sit in a warm room. What is being proposed is a major undertaking- both effort and $$. I'd recommend as first step to make sure the existing AC system is healthy.

Not to totally dismiss OP's desire- maybe (his) trucks are run in short trips where there isn't lots of time to get cool and there is need for freezer type cooling capacity. If the decision is made to install a second unit, I'd echo the above replies, with one other suggestion... The echo is to do some homework up-front and note that the stock compressor under the hood is ultimately what will determine the cooling limit. Vehicles like minivans and SUVs have larger cabin volume, which justifies the addition of a second AC unit in the rear. Another echo is gee, seems like you might have an easier time just re-using one of the existing passenger type units for rear air from a minivan or SUV as suggested above. Personally, I think it would be a good idea to consult someone with specific vehicle HVAC knowledge, who can talk turkey about compressor capacities and what would be the limitations etc. Seems like that would be worthwhile, given the amount of time & money under consideration- it sounds like a major undertaking! Lastly, the "other suggestion"... If you're seriously considering addition of a second AC unit, I'd recommend only as a last resort to put it inside the cab. Depending on the size of the actual unit, you might find that you could locate it under the cab and run ducts through the floor. Yes, it would involve environmental sealing, but might be easier in the long run. Also remember- that 2nd unit will have a fan and make noise of its own.

Whatever you choose, wish you all the best.

 

[Wertles]

The problem lies with the fact that Craig has an 06 MC. Dodge did not take into account the added interior space that needed cooling and put the same AC unit that worked great in the regular cab, adequate in the QC, but was horriby undersized for the MC. I had my AC system checked out in summer 06 because I had to run the AC on high all the time to make it tolerable for the front but the rear passengers were always hot. Everything checked out all right. The air coming out of the vents is cold, there's just not enough of it. I may be wrong bit IIRC, a larger AC unit was put in in 07 or with the 6. 7. There haven't been too many complaints since then but if you search back a while, there were many threads back in 06 about bad AC and they were all MC owners complaining.

 

[firefighter_2000]

not yet

I do know that at least one of my blend doors is not working properly. I will be purchasing the heater treater doors soon to correct that. I will not be doing any major modifications until a little later and verify that it will or will not do what I want. With my 99, I can park the truck at idle in 100 plus degree tems & in short order the truck will be ice cold inside. I just like the cold temps and want my mega cab to do the same thing. I've had my 99 for over ten years and plan on hanging on to it for some time. Over the last ten years I've done modifications to it here & there to "make it mine. " The same will go with the mega cab. I plan on owning this truck for a long time and plan to make it mine. Being able to be cool & comfortable in the truck is VERY important to me. This will probably be a project for me to complete over the next couple of years and will take some more thought & ingenuity to make it happen.



I would love to hear more thoughts and ideas that people might have (that maybe I didnt think of) that could put this closer to happening. Only real requirement is I dont want to put it behind the back seat. I want the reclining and space capability. That was the main reason I had the idea to put it under the center console in a sheet metal box that would look good.



Please, throw more ideas out.

Thanks

Craig

 

[rashwor]

What about adding one of the ac roof units like is on motor homes or dressing compartments of horse trailers? Inverter for electric power and the rest of the unit is self-contained... not particularly stylish but I think you could hang meat in the cab then.



I know I am wanting to do something to improve the cooling in my '05 quad cab. For me, I think a bigger condenser up front with an electric fan on it would be good enough. I don't really know though.

 

[firefighter_2000]

Thought about that...

I actually briefly considered that but decided against it. I DID have another idea today... Of getting the same system I referenced earlier in the post and mount it inside my toolbox in the back of the truck. And run ducts through the back of the cab on the sides of the seats. Just another idea. Throwing them all out there.

Craig

 

[RDeFayette]

try vintageair.com they make stand alone systems for almost every car ever made.

Specializing in older cars that never came with a/c. Bet they have/could come up with or could tell you what would/wouldn't work.

 

[GCroyle]

Craig,



I don't have an idea for you, but my '05 QC does pretty good as long as I'm getting good underhood airflow, at least that is my interpretation. It is a street only truck, and I just got a look at the CAC and radiator, clean and healthy. I read a bunch of threads last year and it's just getting into the hot season here. My issue is when I slow down in traffic, you can almost feel it immediatly warm up. No, sorry no data right now. Last year it was annoying enough for me to fork out for a full gage and hose set to try to help understand this one. Local ex-dodge dealer poked at it last year and gave it a thumbs up, but IIRC they did acknowledge the warm up too.



Is it a less than correctly functioning fan clutch assy? Geno's has the newly offered Dorman replacement fan clutch.



Hey, TDR, how 'bout an AC expose article for us?



Stay cool.

 

[firefighter_2000]

Thats the ticket...

Spoke with the guy at vinage air, and he offered several options but most are much bigger than I have space. Most of theirs are made for under dash applications with bigger blowers than will fit in the area Im looking to fit.

Thanks

Craig