Ready to retrofit air-con

[andy brad]

Well as i said every day is a learning day Having said that i have never had to top up the ac on the excel not bad for a 1991 car thats the great thing about these forums the knowledge is fantastic the later cars have a sander comp without cut out and both fans do come on with the ac. Amazing mind you the ac has never failed the only thing i would find easy to fix sods law
Funnily enough i have just re piped a turbo esprit 1982 and i have not found a low pressure switch on that and all three fans come on with the ac. great forum.
andy b

[amarshall]

Exactly how late are these later models ?

Lotus' own parts list gives a single pump for all variants, and being an A079 part it was originally fitted to the Esprit and never changed.

[AndyLotus]

Well this took a bit longer than I thought it would. There was a problem with my re-spray which meant delays to starting the air con.

I actually made a start in early March so here goes the first photos.....

After removing the dash and blower motor I found the heater itself had to come out as the foam used on the control flaps was falling apart like powder and would make a heck of a mess if blown through the car. So first step, dismantle and re-build heater with all new foam.

This is the inside before, and below is after:


Next was offering up the evaporator housing. I had heard that there was a change in the body moulding to accommodate the evap unit but how different could it be???? Very.

This photo shows the section I had to cut out of the transmission tunnel to make it fit. I then riveted in place a formed ally panel to fill the hole. A hole was drilled in this for the drain tube.

Next pic shows the compressor mounted on the standard bracket which had to be modified to accommodate my mods for mapped ignition. Also mounted is the drier.

You may notice that the oil cooler take off has extension pieces. This is because I fitted a thermostatic oil cooler take-off which means the pipes didn't stick out as much and fouled the back of the compressor, hence the extensions.

Next pic is the parallel flow condenser mounted to the original rad. This is fitted using those push through ties used to mount cooling fans with rubber spacing pillars. The condenser is very light so it is fine.


I mounted the rad yesterday after cutting a hole in the top of the inner duct for the air con pipes to come through.

So far this has been a complete arse of a job. Fighting me all the way and needing lots of little things to sort out issues. There is light at the end of the tunnel now but it has taken far longer and cost far more than I expected. One ac fitting could only be bought from the States!!

In hindsight I may not have bothered but for me it was either be cool with AC or sell the car so I had to try.
Next exciting instalment soon....hopefully.

[Simpatico]

Bravo a thorough approach sir

[alanbell]

in this wretched climate i rather think that air con on a lotus is a waste of power , about 8 bhp, and petrol, never had it or wanted it, just open a window (also wastes fuel) or switch the heater controls to cold.

[robertverhey]

Believe it or not, the climate in Sydney at present (and for last couple of weeks) has also been wretched. But that air con is great for keeping the windscreen clear too!

[alanbell]

dear Robert,
i did not look closely enough to see that you were from Oz, in scotland when the windscreen needs cleared hot air is essential or hypothermia sets in.

[Hawaiis0]

I like the tidy parallel tie mount, and I assume they are being held by the cooling fins in the core. Are they reinforced? If not, even lightweight, I dont think it will hold long once exposed to the vibrations due to the engine and road if not strengthened.

May I suggest you consider supplementing the 4 already in place ties with additional ones which pass through the 2 vertical bars on the original rad for added support strength.

[shaunw]

Hi Andy, Ive been looking for a refurbished compressor for mine, can I ask where you got yours?

Regards

Shaun

[AndyLotus]

Well I don't know about wretched climate, summer down south last year was rather hot and with a full black leather interior and glass area a greenhouse would be proud of I think AC is a very good idea.

I found that even opening the windows fully failed to create much breeze although the kids in the back got blown all over the place. (aerodynamic quirk?) As a supposed GT car, long distances at speed with the windows wide open isn't great.

The power loss isn't a problem as I'll be adding compressor cut out at anything above 3/4 throttle.

Good plan about adding extra mounts through the vertical bars, I may do that.

The compressor (Sanden SD7H15) was bought (used) from a guy on e-bay. He was very helpful and assured me it worked well. It is also designed for using modern gas and as I have replaced all the O-rings, including the ones in the evaporator, for R134 compliant gas it seemed like a good one to use.

Next step is running the hoses and adding a thermostat so I can adjust the evap temperature.

[Excel Jeff]

Andy,
I have some questions about your condenser. I just pulled my radiator to replace it with the alloy radiator from China, which looks nice. Wanted to replace the condenser since it has a lot of corrosion on it, and the AC has not worked since buying the car. IS this the Sanden 12x23x20 on fleabay, since it certainly looks like it. Do the connections come with it? I was thinking of mounting it similar to yours since the original ones cannot be bought anymore other than by having one custom made from my research. Would you happen to know the threading on the fittings, hoping it will bolt right up to the original hoses, but if not will have the hoses cut and new ends put on so that I can connect it to the original hoses.
This could be a good aftermarket replacement for the condensers since they are no longer available, not an exact replacement fit, but should do the job and not look horrible.
Jeff

[AndyLotus]

Hi Jeff,
I got the condenser from Advanced Radiators Ltd.
It was the one listed as 16-23X12M, which cost £77.82.

This is a parallel flow condenser which is reckoned to be about 25% more efficient than the original. It's also very light.

The fittings are 3/4-16 UNF at the top and 5/8-18 UNF at the bottom.

I ended up using the through ties but also at the top of the condenser 2 right angle brackets bolted through the top fibreglass duct, similar to the rad.

I have now got all the hoses made up and I'll update this thread with some more pictures soon.

ANdy.

[AndyLotus]

Progress!!!!!
It works

Pictures to follow.

Basically the system was pressure tested with Nitrogen to 150 PSI - No leaks.
It was then vacuumed down, which held nicely.
Oil, dye and refrigerant was added and fire it up. Nice and chilly.

It operates slightly differently to the Lotus system.

You have to have the fan on and then press the switch to engage the clutch as normal, but it is controlled by a Trinary switch. So the fans don't come on initially, once the pressure builds in the system both fans cut in for about 10 secs then switch off for roughly 10 secs. On the move above about 40 mph they shouldn't come on at all.

I also have a thermostat in the system linked to the heater slide control. This just changes the amount of time the compressor cuts in for and therefore adjusts the temperature.

Frankly I'm slightly amazed it all worked perfectly first time, I'm still in a state of shock.

Just need to get the dashboard back in now....

[AndyLotus]

Photos...

Evaporator installed with the stat attached to the top. You can just see the control wire snaking off to the heater slide control.


One of the ports as it exists the evaporator, nice and easy to get to and the correct fitting for R134a.


The other port for ease of access. Obviously the hoses haven't been clipped in place yet. I wanted to make sure it all worked first.


Trinary switch all wired in.


Finally the all important switch. The 'Econ' button is a bit superfluous as the stat is fitted but at least the original switch fits the panel properly.


Here's to a hot summer (It's obviously my fault if it turns out to be rubbish)

[Excel Jeff]

Andy,
So how are you enjoying that air-con now??
Jeff