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Electric Air Conditioning. Will it work?


Jonny Hart

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  • 3 months later...

Read this thread a few months ago with great interest.

Has there been any further progress as I would find this a very tempting kit as my car came with AC that I ripped out years ago due to it's poor performance?

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Has there been any further progress...

Yes and lots! We've spent the last few months working on the design for the LHD and RHD kits. As with all our products, we want the kit to be as easy to install and have the least possible impact on the car as possible. We want to avoid having too many variants of the kit but also make it tailored to the 911. This isn't easy as we are trying to cover cars from 1965 to 1989. We also wanted to ensure that all the parts used are modern and readily available.

The major development has been the custom ECU which is key to the operation of the system. Without it, the compressor would overload the charging system. I can't say too much as it is our IPR but essentially, this will be the only electric system out there that can regulate the power consumption of the compressor with the capacity of the charging system. In the middle of the development we have been approached by two major names in the Porsche world so it's all rather exciting.

As well as my own SC, there are currently a number of cars being built with our A/C in various states of build:

1) Tuthill Porsche. 3.6 Hot Rod.

2) BS Motorsport. '67 Race car.

3) Twin Spark Racing. '69 S.

4) GT40 replica.

5) V12 Jaguar E-type.

The most advanced of these is the Tuthill's car which is due for completion around February (I think).

The plan still is to have the system ready to be taking orders in March.

Here's a sneak preview of the RHD compressor module and ECU. (The LHD one will fit in the smuggler's box)

img_2508.jpg

And here's it on the bench with ECU and wiring harness under test:

img_2517.jpg

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Looking really smart Jonny :cool:

Is it the cooling and heating system or just cooling?

Just cooling. We have spent a considerable amount of time looking at heating but the level of complexity of the pipework, valves and control would make the system very complex and heavy.

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I know this is a stupid question (but it's never stopped me from asking) - this ECU is just for the aircon system isn't it? It doesn't affect the car's ECU - only asking because I have a non-standard ECU fitted (And in my mind ECU meant Engine Control Unit but on reflection it must mean Electronic Control Unit). As I'm typing it seems even more stupid but I'm still going to ask.

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I know this is a stupid question (but it's never stopped me from asking) - this ECU is just for the aircon system isn't it? It doesn't affect the car's ECU - only asking because I have a non-standard ECU fitted (And in my mind ECU meant Engine Control Unit but on reflection it must mean Electronic Control Unit). As I'm typing it seems even more stupid but I'm still going to ask.

I reckon the Extra Cooling Unit secretly supercools air using liquid nitrogen then when the driver is cooled the spent air is injected into the engine to provide more power.... :homersimpson:

Edited by Dr Rock
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Yes, Electronic Control Unit, although I do like the Doc's interpretation!

The main reason many have failed to get electric a/c to work, is that the power required to drive the compressor can be very high. With most DC electric compressors being on/off or fixed speed, that's a recipe for a flat battery at best.

In recent times, variable speed compressors have become available. The current required is proportional to the speed of the compressor. So, if you can monitor the current usage, you can regulate the speed of the compressor and not flatten the battery. That's basically what our ECU does, it constantly adjusts the compressor speed to match the available power from the charging system.

There's a bit more to it than that, but hey. Additionally, it handles input from the single 'smart button' control and does some nerdy stuff with bluetooth.

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  • 1 month later...

Hi Jonny, just seen your update on Facebook, lovely looking piece of kit.

when it does become available will you do a fitting device, or as with the fuse panel  provide a comprehensive set of instructions.

 

 

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Just as much thought has gone into the installation as the product itself.  So yes, good instructions, minimal mods to bodyshell (if any) and common tools.  

The install should be achievable comfortably within in a day.  It will almost certainly take longer to remove an existing factory a/c system than to fit ours, so this is best tackled ahead of time.

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Basically, the pre-requisites are:

1) You must install a C3.2 (90A) alternator or better.  So SC and earlier need upgrading.  You can either swap to a C3.2 fan housing or have the housing machined a little deeper to cater for the slightly longer 90A alternator.  In conjunction with this, the wire from the alternator to the starter needs uprating to 110A wire.  Ditto the alternator to engine case ground wire.

2) On an IB, The condenser fits in place of the washer bottle under the wing so an alternative washer bottle solution must be found.  There's the intensive wash system or I am using a type 2 VW bus bottle in front of the spare wheel.

 

Install:

There are no modifications required to the bodyshell whatsoever.  We utilise holes already present in the front slam panel and inner wings to route hoses.

On LHD cars, the compressor has a cradle that allows it to sit in the smuggler's box (similar to a Rennline battery mount).  On a RHD, the compressor lives next to the battery ahead of the fuel tank.  We have designed a bracket that secures to existing boltholes - you can still fit the spare wheel and standard jack.  There is no drilling or cutting of any holes, save perhaps a couple of P-clips for hoses.

There are no additional vents required.   The system 'repurposes' the existing vents, providing a recirculation function and the ability to push any combination of hot/cold/aircon air out of any vent.  For example, you can have a/c air out of the footwells and hot air from the centre vent.  Both of these are impossible with a factory 911.  

Slider controls are all keep as standard but do slight different things.  The only addition in the cockpit is a single push button switch to control the a/c.

I can put the a/c in my car in around 2-3 hours once the old gubbins have been removed.

 

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On 17/02/2017 at 9:09 PM, Jonny Hart said:

The system 'repurposes' the existing vents

Is that not a limitation on SC's and earlier Jonny given how comedically small the end of dash vents (slits!) are? 

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