Simeon

Trunk mounted air conditioning planning

30 posts in this topic Last Reply

Recommended Posts

I have been doing a bunch of stuff over this Christmas holiday but today I made a start on my interior and my air conditioning planning.  This consisted today of ripping out my old carpet and removing the back seat. I am going to strip the floors of old sound proofing with dry ice, treat any rust and paint. 

 

My future plans include removing the heater box for a rebuild and removing the dashboard to refurbish. Mine is pretty badly cracked and so I am considering one of those stitched leather dash covers. I would be interested in anyone’s experience in fitting them and what you think of the finished product. I am then going to fit some new seats in black vinyl and do a colour change for the rest of the interior to black using spray vinyl dye. A friend of mine recently dyed the bench seat in his old Holden EH Ute and seeing the results up close it was impressive. This will then be topped off (bottomed off?) with a salt and pepper carpet set from Esty with no console. 

 

My air conditioning planning consisted of a lot of staring into my trunk, peering under the car and running a tape measure over a lot of things. My plan is as follows:

 

Fit an Old Air Products IP-200T between the wheel housings. The 4 x 2” ducts will see two of them mounted into the supplied louvre and installed in the centre of the rear parcel shelf.  And the other two ducts fed through the bulkhead behind the seat back in the centre where they are then split either side of the transmission tunnel and fed out to the seat base up stand where they will attached to some dash louvred let into the upstand. There is just enough space inside the seat back in the middle where it bulges out for the two ducts to slip down under the seat base. I figure that nobody ever sits in the centre position so a bit of a lump in the lower back won’t hurt anyone. The seats either side of the hump will be untouched so the utility of the back seat should remain unaffected. 

 

A530DCE3-DAA5-4BCE-B254-8DF95E78720E.thumb.jpeg.12f11e0223aa84c245c5ac8176053140.jpeg

 

I had big plans for the return vent but I am not sure that I can follow through. I had thought about tying this in to where the plastic ‘elephant trunks’ above the wheel arches extract stale air via the gap between the headliner and the rear screen but this just seemed too difficult as I need to flow the equivalent of 4 x 2” ducts. The elephant trunk ducts are an equivalent area to 1.5 - 2” at best at their narrow point and I would struggle to get another 2 x 2” duct through the firewall to take care of the rest without making the rear seat useless.  Instead, I am going to stick with the single 4” duct and bring it through the parcel shelf but offset from the centre. I currently have a third brake light low down which will have to go - thanks to @halboyles I will have a slim, beautiful replacement to go in at the top of the screen out of the way. I will mount the one large louvre, with 2 x 2” ducts in the centre to blow straight ahead to the front of the car. The usual installation would see both louvres installed on the parcel shelf but these would clash with the 6x9 speakers that I already have in place and would tend to blow straight into the back of the neck of anyone sitting in the back seat (instead of the back of the neck of anyone sitting in front!). I will also be welding in some reinforcements to the seat belt mountings. I am a bit concerned that all of these cutouts in the parcel shelf steel may be weakening the panel at the back.

 

3CC8789B-3D05-442E-8021-0893CE4315F0.thumb.jpeg.aea3904be7a4a29bbfed8cd042172d9d.jpeg

 

I currently have a 3/4” plywood board mounted under the shelf to take the speakers and a thin Masonite upper cover with cutouts for the speakers covered in speaker cloth with wire mesh underneath. I will hopefully modify this arrangement to keep the return air vent hidden, ‘breathing’ through the speaker cloth which provides a minimal obstruction to air flow. This should maintain the symmetry of the shelf but if it doesn’t work, I will put a dummy vent in the other side to balance it up. 

 

9A099EF6-FC95-4D9A-B3EB-458E5BCA5C4A.thumb.jpeg.db372877438ebc2a1382355f73aa28af.jpeg

 

I will finish it off in the trunk with a removable trim panel to cover all of the evaporator gubbins and still leave room for a bag of golf clubs or a dead body. 

  • Like 2

Share this post


Link to post
Share on other sites
(edited)

I actually followed your write up quite well because I just spent a bit of time installing my back seat delete carpet set by esty. I know that area a little too well for my own good. I think your plan could work.

 

The only place I could think of for the return was the parcel shelf. You could then delete the supply vents up there and enlarge the supply vents in the back seat upright to get the desired air flow. Your supply and return vent will be fighting each other up on the parcel shelf anyway and not circulating. Yes, peoples ankles sitting in the back seat will have cold air blowing on them but with a good fan you should be able to cool your car just fine.

 

Alternatively, you could reverse that concept and run large supply vents in the parcel shelf and the return in the seat upright. I'm no HVAC specialist, but I'm thinking you want those supply/return vents far away from each other for maximum circulation.

 

Nick

Edited by NYNick

Share this post


Link to post
Share on other sites

Wow this is such a cool idea. [mention=39712]simeon[/mention] please keep us updated on your plans...

 

 

Sent from my iPhone using Tapatalk

 

Share this post


Link to post
Share on other sites

Next up is a request: Does anyone have a really good picture of the underside of an 02? I saw one on here but I can’t find it now for the life of me.

 

Planning my pipe routing and weighing up between hardlines run from where the front frame rail dives under the floor pan, along the flat area to the side of the seam along the rocker, alternatively just stick with rubber hose and minimise any in line joints (which has to be beneficial for keeping the system leak free. I am going to get someone to fold me up a long ‘top hat’ section in steel sheet to protect the hoses / pipes where they are exposed on the floor pan. I would need to cut this into angled sections as the hoses would follow a light zigzag along the various pressed in ribs in the floor pan rather than a simple straight line. 

 

The hard lines are available by the foot and have ‘o’ ring fittings and nuts that are silver soldered on the ends. Anyone had any experience with these? Hardlines could be small enough in section to run them within the transmission tunnel, if I can figure out the clearance around the gearbox. This might be preferable in terms of keeping them away from damage but may be harder to achieve depending upon space and how many things I need to remove to gain access for proper installation. 

Share this post


Link to post
Share on other sites
(edited)
On 1/6/2019 at 8:55 AM, NYNick said:

 

..,Alternatively, you could reverse that concept and run large supply vents in the parcel shelf and the return in the seat upright. I'm no HVAC specialist, but I'm thinking you want the supply/return vents far away from each other for maximum circulation.

 

Nick

 

+1

 

If hot air rises and cold air sinks, I agree wholeheartedly with Nick’s alternate approach. Blast the freshly-cooled output air into the warm upper half of the interior: that glassy greenhouse is the source of much of the heat. When I’m driving, I’d rather have a cool head and warm feet.

 

The A/C will then be pulling in some of the cooler air — from the floor level — which should give it a small “leg-up” towards cooling the air as it passes through the evaporator.

 

Done!

 

I’m very excited about this project. I’ve dreamed of rear air for decades. Could you split the vents so that two vents, one at each end of the parcel shelf, handled the distribution in lieu of a single center-mounted vent. Recall: the major issue with previous ‘02 A/C’s is its distribution being limited to the center of the car,

 

Best regards,

 

Steve

 

Edited by Conserv

Share this post


Link to post
Share on other sites

My trunk smells like gas even though I've adequately vented my fuel tank. I think it's due to excess fuel pressure from my problematic Megasquirt system. One of the things I need to address before doing AC.

 

For the pickup, I think enlarging the vent tube area on one of the sides would be ideal. You could cut a hole in the side of the bench seat and the rear door card allowing a space for ducting to run into the cabin. Then, mount the pickup vent at the feet area below the rear passenger bench seat. There is a small gap between the bench seat and the frame rail in this area, but I don't think there is enough room and you would need to modify the structure of the bench in this region to make this work. I would also consider splitting the pickup vent, routing air ducts through both vent tube holes, and source an OEM vent that could replace the ashtray on each rear door card. Clean and easier than modifying the interior pieces.

 

This is a cool project! Hoping to hear this works for you.

 

Share this post


Link to post
Share on other sites

Wow. I have no real input other than, im rooting for you, good luck and definitely following this project!

Sent from my SM-G960U using Tapatalk

Share this post


Link to post
Share on other sites
4 hours ago, Conserv said:

 

+1

 

If hot air rises and cold air sinks, I agree wholeheartedly with Nick’s alternate approach. Blast the freshly-cooled output air into the warm upper half of the interior: that glassy greenhouse is the source of much of the heat. When I’m driving, I’d rather have a cool head and warm feet.

 

The A/C will then be pulling in some of the cooler air — from the floor level — which should give it a small “leg-up” towards cooling the air as it passes through the evaporator.

 

Done!

 

I’m very excited about this project. I’ve dreamed of rear air for decades. Could you split the vents so that two vents, one at each end of the parcel shelf, handled the distribution in lieu of a single center-mounted vent. Recall: the major issue with previous ‘02 A/C’s is its distribution being limited to the center of the car,

 

Best regards,

 

Steve

 

 

I am still thinking this over so anything is still on the table. The problem, as I see it, is that the return needs an equivalent of 4 x 2” ducts and I am struggling to see how I can get these all into the passenger compartment and keep the back seat useable. I am also trying to keep the speakers in the shelf but I would be willing to concede them if I could get a better outcome. 

 

The system is designed so the return vent and both louvres (4 x 2”) are mounted in the rear shelf (easy in a large American car). The velocity of the air output will be relatively higher than the velocity of the return through the large 4” duct and therefore I would expect that the cold air would be projected forward and warm air pulled from the rear. I suspect that this is all a compromise really but I can see how that may work in my head. If the return was 4 x 2” as well then I think I would definitely need to be more conscious of placement to avoid them fighting. I could still see me making a manifold for the return to split into 4 x 2” at which point I would look  again at the ‘elephant trunks’ to take air from the top of the screen, run another 2 x 2” return under the seat and then put both louvres on the shelf (ditching the speakers). I suspect a lot of this will come to me in a flash when I have the car pulled apart and the pieces all lying in front of me. 

 

I thought of the single duct (actually two ducts) in the centre, as a means to project the air to the front as efficiently as possible for immediate cooling and the two low down to do the ‘base load’ work with the return vent on the shelf by adding cold air from the bottom and pushing hot air upwards. Through this I had hoped to get some decent circulation and avoid having louvres blasting cold air directly into the back of the neck of anyone in the rear seat. 

 

I did look at taking the ducts straight down through the trunk floor, make them bend around the corner on the outside of the car before coming back in again through into the under seat area. The problem with this is the rear subframe and diff which I figure are essential. I also thought about how I could get into the space behind the rear quarter trim cards but can’t see that without making major changes to the seat back structure that potentially compromises the rear seats (more). 

 

Still mulling it over!

Share this post


Link to post
Share on other sites

I think the less ducts the better. Seems to me you could get one large duct in between the speakers on the parcel shelf and two return ducts on either side of the rear seat upright. You essentially need the square inch area to be equal.  I recently cut that parcel shelf for speakers. It's robust, but easily reinforceable from above or below if need be. (BTW, tough noogies on the cold air on the rear seat passengers necks. I imagine they might be thankful)

 

And I wouldn't really worry about air circulation being sufficient in such a small area. It's like four feet from front to back. I would be concerned about putting a supply vent next to a return vent regardless of air velocity however.

 

BTW, LOVE the idea of using the ash tray openings in the rear door cards. Love it!

Share this post


Link to post
Share on other sites

OK, done a bit more thinking about routing of the ducts and I think I have figured out a way to get out from the trunk and behind the rear quarter panels.  While I am trying to not compromise at least the two outermost rear seats, I notice that the structure of the seat back would allow hoses to be fitted in the top corners of the seat back without too much impact on the comfort of the seat as the sprung section is pretty deep here.  This would then be turned into a hole to be cut into the vertical panel on the rear quarters to allow the hose to dive behind the rear quarter cards.  I might need to slightly alter the steel frame under the seat back to allow this cutout to be made in the return which sits up against the rear quarter to allow the seat back to be easily removed and installed.  The duct would then be terminated on a Vintage Air 'kick panel' installed through an enlarged ashtray opening from the rear of the card with a nice chrome 'eyeball'.  This will  allow the front seat passengers to get in on that freezing neck action!  Alternatively, I could just finish this with a flush mounted, rectangular louvre that fires laterally, towards the centre of the car.  Might be a bit more 'low profile' of an installation.

 

I have clumsily marked up some pictures to illustrate.

 

Rear quarter showing route for duct.

 

rearquarter.thumb.jpg.b18609540e3ff2d8c87132446a14fb47.jpg

 

Rear seat back showing area to be cut out on the side return on each side.

 

857904109_backseat.thumb.jpg.2711215a9ced4bd3a59f79a8ee6132c2.jpg

 

Vintage Air 'kick panel vent'

 

960-490500.jpg.f52d72291f230ad247af591a8ccf43c1.jpg

 

So, 2 X 2" ducts through the centre of the seat back and underneath the rear seat to blow out of the seat upstand and 2 x 2" ducts to the rear quarter ashtray vents.  Return air through the centre of the rear parcel shelf.  I still need to pull my rear quarter cards out and take a look at the structure under and around the vertical panel, up tight in the corner.  Hopefully, I won't need to move to far away from the corner to be able to insert and turn the duct behind the panel.

 

How do we think that would work for distribution?

 

 

  • Like 1

Share this post


Link to post
Share on other sites

Found this pic. Note some kind of reinforcement plate in the top corner of the rear door card area. Unsure if your car, which I believe is earlier than mine, has this. If so, I think it's in the way of your pass through. Looks like it serves a structural purpose so I'd be hesitant to cut it.

 

A rear seat delete solves all your problems.😀Just look at all that beautiful esty carpet that's dying for A/C vents!

20161129_144028.jpg

20181230_155137.jpg

  • Like 1
  • Haha 1

Share this post


Link to post
Share on other sites

Yes, the seat delete would be a lot easier to deal with! Why do I make things hard for myself?

 

Thank you for the picture, very useful. I am only planning to cut a 2” hole with a hole saw into that. I can’t see it weakening it that much. If it looks like an issue, I can always plug weld a reinforcement plate around the hole from behind. A double skin, perhaps with a few formed edges should stiffen that up. 

 

I was getting worried about the length of the hoses but thinking about a typical retrofit into a US classic car, they will install these units on the firewall behind the dash and then will run a duct to a louvre all the way over on the driver’s side. This is probably an equivalent length. I am also going to research what I can wrap the ducts in to minimise them ‘sweating’ with condensation. 

Share this post


Link to post
Share on other sites

I'd be onboard as well, Simeon, with a 2" hole in those gussets. The rear bulkhead area is pretty stout.

 

And, Nick, is that taped-off thing under your rear seat (delete) the tiny, light-weight battery you've discussed?

 

Best regards,

 

Steve

 

Share this post


Link to post
Share on other sites
7 minutes ago, Conserv said:

I'd be onboard as well, Simeon, with a 2" hole in those gussets. The rear bulkhead area is pretty stout.

 

And, Nick, is that taped-off thing under your rear seat (delete) the tiny, light-weight battery you've discussed?

 

Best regards,

 

Steve

 

That taped up coil is the wiring harness Steve. Here's a picture of the 3 pound battery installed.

20181208_135419 (1).jpg

  • Like 1

Share this post


Link to post
Share on other sites

Just thinking (I'm recovering from back surgery so I can't look at my car right now) that the farther forward your air returns will be from the cold air outlet the better the system to work that being said what if you used the rocker panel box for 2/3 of your air return system with lovers as a air inlet right up by the firewall and maybe 1 small one in the rear seat kick panel to make a 4x2 total for the system. There a couple of small drains in the rockers you could seal with body dum-dum at least in the summer I don't know how much rain you get there in the winter but you could remove the putty in the winter to restore the drains. Anyway you would be providing the air at the top of one end and returning it at the bottom of the other end that shoukd give you good circulation.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now