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Electric Air Conditioning. Will it work?


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Says the man who cut off the roof of a Mini!

 

Mark

 

Ok, it's a fair comment but I think I paid £50 for that car and I was 17. It was an 850 if I recall so worthless - (edit: bugger just looked at 850 prices now :o )

 

Come to think of it, the roof panel was the only thing that wasn't rotten.

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Back to the A/C, are there any implications of the proposed system having far less refrigerant that the OE system?

 

I would assume that there being less fluid in pipes (albeit with the evaporator and condenser being full) would make it comparatively more efficient (even before the tendencies of long pipe throws to go porous over time) than an OE style system...but I was never *that* good at physics!

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I feel sick every time I see a drill going anywhere near an old car! I will utilise existing holes / panels for as little disruption as possible. I can't promise zero body mods on this one, but every one will be carefully considered. Unlike Porsche, am determined to use the fresh air inlet rather than have yet another system. Hope to drive it all off the existing cable controls as well so no goofy extra dials, switches etc. Understated simplicity is the word.

 

 

That sounds perfect to me!!

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Back to the A/C, are there any implications of the proposed system having far less refrigerant that the OE system?

 

I would assume that there being less fluid in pipes (albeit with the evaporator and condenser being full) would make it comparatively more efficient (even before the tendencies of long pipe throws to go porous over time) than an OE style system...but I was never *that* good at physics!

From what I've read, if a hose absorbs heat from the surroundings it makes the compressor work harder. On the standard setup, the hoses have to get from the engine bay (which is hot) to the front of the car and it is routed outside which is also hot on days when you need the AC. This can't be great for efficiency.

 

On our system, the system components are all within a few feet of one another. The hoses is in a relatively cool environment (luggage bag) and they could also be insulated.

 

Anyone know the hose lengths for the standard setup?

Edited by Jonny Hart
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I have taken mine completely off the car, it worked and is complete but its in storage so won't be able to get to it for measurements for another couple of weeks. Let me know if you had no joy by then.

 

Another benefit is taking something quite heavy from the rear (mostly) and replacing with something lighter in the front, think the complete original system weighs over 20kg.

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Anyone know the hose lengths for the standard setup?

 

Does the setup not change slightly for lhd/rhd due to component locations? I can dig the hoses out for a lhd car if that helps?

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^ Yes, on the LHD they use the smugglers box for the evaporator but it's behind the passenger footboard on a RHD. Other changes too.

 

Just want a rough idea on lengths. I guess perhaps at least 25ft of hose on the original system.

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Just want a rough idea on lengths. I guess perhaps at least 25ft of hose on the original system.

 

I'll have a look later today - will also lob them on the scales that might also be a useful bit of data for you to help sell stuff. Shall I weigh the compressor too or do you have one of those already?

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You could always talk to someone about that road rage you know...

 

No road rage mate.....but just got a speeding ticket in the post :cry:

Edited by R2D2
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You lot have given me a bit of a prod to progress this. I have decided to break the project down into smaller goals so it doesn't seem quite as daunting. This last week the mini-project is entitled:

 

How do you get a modern evaporator into a 911?

 

Questions raised:

 

1) Why can't cool air just blow out of the existing vents, just like the fresh air?

2) How do you get it to look original and not mess with the car too much?

 

In order to achieve #1 the evaporator (the bit that goes cold) would have to be between the air inlet duct and the fresh air fan. I started by dismantling the fresh air system and taking the fan and cowl out.

 

Here's the original cowl:

 

sm_original_cowl.jpg

 

well, as you can see there is no room in there at all!

 

The evaporator has to be fairly large to get adequate cooling. It also can't impede the air flow. After a considerable amount of offering up, cardboard templates, swearing (a lot of that), I got a reasonable prototype together out of ABS plastic bent with heat over metal angle. When this is finalised, I may plastic weld it to the original parts or vacuum mold a complete new front section of the cowl.

 

 

sm_cowl_mod.jpg

 

 

The only mod required was to bend up the tab you can see in front of the fan and I might be able to get round that by rotating the fan slightly. All the original hoses and bowden cables fit.

 

The controls and all the heating still work in the car. You can even shut the front lid (that was a 'moment'!) This is probably the 99th in and out attempt but got there in the end...

 

 

sm_evaporator_in_car.jpg

 

 

Pretty pleased with that. Looks kind of stock. Perhaps Porsche would have done this if they had today's smaller more efficient evaporators?

Edited by Jonny Hart
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Thanks!

 

I am coming round to the idea of the wheel arch condenser in place of the washer bottle. It would make the a/c hoses super short, probably less than 3m for the entire system. Super efficient. Less weight etc.

 

Is there anyone up for a bit of fabrication for the condenser / fan 'module' in place of the standard washer bottle? Need someone who can CAD and preferably make something from folded sheet metal.

 

I can supply the parts and describe the design goals. Might help to speed the project along.

Edited by Jonny Hart
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Is there any chance of a second version for those of us with existing AC, using the existing front condenser location and an evaporator in the smugglers?

 

The pipe throws should be pretty short...maybe...

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Second version? Haven't got a first version yet! :)

 

The old 'tube and fin' a/c components are outdated technology. These days, everything is parallel flow which is more efficient. It may be possible to get modern replacements to fit in the same enclosures as the standard a/c but that is another load more effort. I am not convinced the surface area of the front under belly condenser alone is enough.

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I think the arch mount is the way forward, the huge washer tanks are a waste of time as they just fill up with algae and ruin everything. All the oil stuff is on the other side and the 3.2 intensive washer bottle is a perfect upgrade for an IB.

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^ Yep, been there!

 

I drew up a list of all the smallest vehicles I could think of but soon discovered that doesn't necessarily mean their A/C components are small. Cars with steep flat 'frontage' tend to take advantage of that by having tall condensers for example. We have the complete opposite, low frontal area and no height.

 

Modern evaporators tend to be integrated with the heater blower and matrix (which would be redundant) and the usual oddball shapes as is common with today's advances in 'packaging'. MX5 A/C blower was as close as I got, but they use triangular ducting! There's always some gotcha.

 

Originally I was thinking of an under dash evap/blower as you can readily buy these for kit cars. I measured up and found one that was a 'perfect size' and looked plain enough to not be an eyesore. On closer inspection, because of the way the 911 dash underside slopes down, I realised that the back of it would obscure the clutch pedal! They are all the same basic design with twin squirrel cage fans at the back and thus too tall.

 

Honestly, I could open a secondhand A/C parts store with all the bits I've tried!

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Good on you for the effort rendered Jonny. RE the above, was gonna ask whether the intensive washer could be used as a replacement for the enormous washer bottle! S'ppose in other countries where there are more bugs to kill you might need the OEM set up but not in the UK where most of the road kill is below the bumper.

 

Has anyone ever used there headlamp washers for example other than to wash down cyclists at traffic lights??

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I find the big washer bottle useful when driving in Europe- the small intensive bottle runs out quite quickly. I tend to clean the windscreen every day anyway to keep it as clean as possible. :twocents:

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  • 4 weeks later...

I'm supremely interested in this. Things get a bit toasty in the SC during summer and I once tried doing a search for A/C threads on Pelican. I spent a week in therapy recovering from the shock.

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I did look at the one in Chris Harris's car. SVP had a go at one also. Unfortunately, both systems looked like an octopus trapped in a suitcase and took up about the same amount of room in the luggage bay. I can't comment on their cooling performance.

I hope I can get this to go in an IB without taking up much room. I have the main components of the prototype trial fitted in the car. So far I have managed to do this without drilling a single hole, certain holes in the shell are repurposed.

My aim is to get it piped up and gassed for the end of the month. Will post up some pics then.

I agree, those Pelican A/C threads are bonkers. I am staying well away for the time being!!!

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