Lotus Club Queensland
Dedicated to the promotion and enhancement of the Lotus experience
Login
Register
  • Home
  • About Us
  • Membership
    • Member Login
  • Events
    • Calendar
  • Motorsport
    • Lakeside DTC Timed Laps
    • LAKESIDE DTC RESULTS
  • Magazine
  • For Sale
    • Merchandise
    • Classifieds
  • Posts
  • Galleries
  • Directory
    • Suppliers & Parts
    • Advertisers
  • Archives
s1-aircon-banner

Retro fit aircon in an S1

By Barry Mather.

Back in 2018 (I think) I had grand plans to take my S1 Elise on a road trip of a few thousand kilometers. There were two major things that needed addressing though; luggage storage and aircon.

Working out how to carry a suitcase or duffle bag is necessary as I’ve removed the boot of my S1 to make way for more important things. At the time it was a turbo – that’s since been replaced with a nicely made ‘over the top’ exhaust manifold. So I set about designing a luggage rack to sit over the boot lid.

I procured some 25mm (ish) aluminium tubing with ~2.5mm wall thickness and set about bending and welding a rack together. The back of the rack slots into the wing mounts (I have to take the wing off to use the rack, but its only 4 bolts) and is held in place with a stainless pin with an R clip for easy access to the engine bay. The front of the rack attaches to a cross bar that is bolted through the clam near the rear windscreen with a spreader plate on the inside of the clam. It’s only 3 bolts per side to remove. The rack is then hinged using heim joints.

I gave the rack a ‘John Deere’ paint job and overall I’m pretty happy with the results. There is space for a couple of waterproof duffle bags to be held on with ratchet straps. The wing mounts are braced under the clam to the rear subframe so should be plenty strong enough for a few bags.

With the luggage rack sorted I turned my attention to the much more complicated problem of aircon.

I transitioned through a few different designs before I settled on a suitable solution. The first iteration used an electric compressor – at first I thought this would be a great solution, it kept the pipework short and I’d already relocated the battery from the front to behind the driver’s seat (it’s a small lightweight battery). But what I didn’t realise was how much power would be required. The stock alternator wasn’t producing enough juice to run it and the battery was too small. I didn’t want to install a much bigger battery or alternator so the electric compressor was removed and stored for another project.

So I moved onto a more traditional plan of using an engine powered compressor. The Honda compressor is quite large and will not fit in the Lotus chassis – but there was potential space where the power steering pump is normally located; just above the intake manifold. So I took a few generic measurements and headed to a wreckers yard – but there are not too many left in Brisbane that you can wander around and remove whatever parts you need, possibly something to do with insurance. But I found ‘King Auto Wreckers’ in Willawong and headed there with a small toolbox.

I wandered around for an hour looking at all the various cars trying to find the smallest a/c compressor. I ended up with a ‘D09’ compressor from a 2017 Mazda 3 – and from what I can tell all Mazdas from this era use the same compressor. I made sure to get a few a/c fittings and tubes while I was there and I set about making a bracket to fit the compressor in. It turned out to be fairly easy by bending some thick wall steel tube and making a few tabs – everything was almost too easy and of course the picture tells a thousand words!

Under the compressor there is another bracket to brace it and it’s extremely stable. One downside is that the Mazda compressor is only a 6 rib belt against the 8 rib Honda pulleys, but I didn’t think it would be an issue to run a 6 rib belt on 8 rib pulleys.

Routing the hoses was pretty straight forward using a mixture of hard lines and along with 10″ and 6″ flexible hoses. I sourced bulkhead fittings at the front and rear of the sills from Speedy Air Spares who carry a large range of a/c fittings and hoses.

I also purchased a hydraulic crimping tool specific to a/c hoses given I’d need to make up a few custom length hoses. Running the hose through the sill was tight, and I ended up with a few scraped knuckles but it works.
I then turned my attention to the front – I needed to install 3 items; a condenser, an evaporator/blower fan and a dryer.

I removed the front clam and engine radiator/shroud and installed a large condenser under the main radiator along with a single large fan. The dryer was easily installed on the side of the crash structure (the same as later S2/S3 Elises) and I made up several hoses to connect it all together. Then it was time to design and build a box for the evaporator. I searched through many online images to try and find one that would fit – I’d already removed the heater box so I had plenty of space, but I also have to leave space for the ABS unit (that’s a story for another time though).

I ended up with an evaporator of the perfect size – from the rear cabin of an NM Pajero. I bought a second hand unit along with the TX valve and setup about building a box for it. I made sure to leave around 20mm of space under the evaporator to allow for condensation to collect which drains through a 10mm hose into the wheel well – there is a handy hole already there to route the hose through. I bent up some 1.6mm aluminium to house the evaporator with an inlet for a cage fan and an outlet for some flexible hose to link into the standard Lotus air plenum leading to the cabin.

With all of the physical parts of the a/c system installed it was time to look into how to control the clutch on the compressor. I turned to eBay and found a fridge/freezer control that fits the bill perfectly. There is a small temperature probe that’s installed into the airstream from the evaporator and you simply set the temp desired and run a wire to the compressor to activate the clutch – simple!

Getting the system charged with R134 was easy enough and I can now enjoy cool, crisp 16 degree air. I transitioned through several different designs for the evaporator unit, the Pajero one is by far the best fitting solution and is perfectly sized for the Elise cabin.

So, can you have a/c in an Elise S1? Of course! It’s not hard to do and really only requires a few weekends to put together once you have the shopping list of parts!

rack1
rack2
rack4
rack3
Evaporator-box
Evaporator-box-2
Ducting-to-evaporator-box
Bulkhead-fittings
Dryer
compressor-mount
IMG_3229
Control-unit

[Show slideshow]
Targa High Country 2022 Historic Elan Chassis 26/0196

Related Posts

mp-banner

Events, Gallery 2022, Homepage, Racing

Morgan Park Sprints R4

kevs-banner

EMRs, Gallery 2022, Homepage

Kev’s Big Day Out

duratec-banner

Articles, Homepage, Technical

Duratec Elise – better late than never

Random images

CRW_6407_RJ impressive-machinery organiser-Colin-McKay-collecting-the-money MG_6262 Helen,-Rob,-Clive,-Mal mt-mee 20130814_093123 16.Clive-Richard 15.Lunch-orders Bright-sunny-Lotus-lovers concours-13 IMG_8426 IMG_4866 IMG_4450 IMG_6822 IMG_6820 IMG_6730 image_109 IMG_3300 Pit-Crew IMG_3323 Cairns-2 Bling-on-the-landscape_gw Elisa-gave-a-presentation-and-of-course-her-grandfather-Romano-featured Phil Gail and Alex - The Timing Crew vb-Matt Pies-at-Fernvale Garage helmet-planters IMGP0426 Lunch time D71_6369_full Jeff Danielle dtc-8 8. Just chatting & dreaming _MG_4587 as Smart Object-1 Craig- IMG_7377 122_2239_IMG IMG_6399 main-10 Mar-main-100 Mar-main-86 Mar-main-47 main-10 IMG_5209 Moira-and-Jenny main-32 main-18a 2006_08_27_Gympie_Skid_Pan0018 P1060107 IMGP2245 DSC_5291 20130511_101707 P1050558 IMG_5310 IMG_5208 MG_4267 PICT7262 IMG_2463 IMG_1288 Climbing_Mt_Cootha Hassling_Ferraris IMG_8590 Club_Lotus_Dec_08_028 DSC03862 IMG_8100 IMG_8140 P6220130 IMG_3043 P1020765 Presentation BBQ night at Lotus Cars Qld_gw All-to-attention-to-be-briefed-by-Daryl IMG_6173 Its-not-a-proper-Concours-without-thorough-nitpicking John and Debbie's Evora 1 mals-elise IMG_9689 main-6 IMG_8205 Left Right Adam-master-of-the-wheel-by-Gavin-Goeldner Adam-and-a-trial-fit-by-Craig-Wilson Wybe-Geertsmas-Lotus-Elite-runner-up-in-Class-1-1950-1962 Lunch-at-Old-Petrie-Town-gw Start esprit-2 20200816_133736 IMG_1899 main-32 Transport-Museum-Rolls-Royce-1923-1 Jon and Dick IMAG5945 Low Line IMAG5947 Jason Trophy Chris and Patty

Recent Articles

  • Morgan Park Sprints R4
  • Kev’s Big Day Out
  • Duratec Elise – better late than never
  • Gold Rush Hill Sprint – 2022
  • Marburg Pub Run – 4 Sept 2022
  • Unique +2 Road Trip to Brisbane
  • Leyburn 2022
  • August 2022 DTC

Latest Gallery Images

20220220_093834 20220220_093818 20220220_093827 20220220_093743 20220220_093812 20220220_093730

Search articles by category

Archived articles

Lotus Club Queensland
© Lotus Club Queensland   |   Site by Black Eye Studios