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Crazy idea? Electric AC Compressor and Steering Pump.

andyobro

Well-known member
Joined
2 Nov 2007
Messages
252
Hi All,

I have an idea in my head, wondering if anyone else has had the same thought or implemented the thought. Or am I just nuts!

It goes like this.... the AC compressor and the steering pump both sit in the back congesting the pretty engine and robbing power from the engine. The pipes to both have to run front to back.

Why not have electric AC compressor and electric steering pumps housed in the spare wheel well. Move weight forward, get rid of lengthy pipes. The battery is right there to power them.

A very quick search around for possible solutions and I have found Tesla electric AC compressors are around 120 quid second hand, and mini electric steering pump around the same. I realize this is all non standard and purists will be have mild palpitations.

There seems to be so many positives, the only negative the lose of the spare wheel, maybe alternator is not up to the job? Wiring in should be pretty easy as they are both just simple pumps. Getting the required pipes made for the fluids is easy.

Positives.......
Less weight at the back.
Less plumbing to go wrong.
Easier maintenance on the engine.
The pumps are at the end of the car they supply fluids too.
Pretty engine bay.
10-15 BHP power not wasted.
Could be done so that everything can be returned to standard

So please comment and shoot me down if you think I am nuts??
:dont know:

Cheers Andy
 
I'd be all in favour of a solution that removes/replaces all the AC gear with newer tech. Not sure I'd complicate it with steering pump, too.

I've never really got my head around why the AC isn't replaced wholesale with a new system rather than just replacing like for like.
 
Jonny Hart at Classicretrofit has developed a system for 911s up to the 3.2 models. I understand he made a system for the Gunterwerks car which is based on the 993 platform, but he hasn't come back to me about whether he will release a 993 system for widespread purchase.
 
Robbing Peter to pay Paul. The lecky consumption would put a much greater load on the alternator and would suck more power out the engine.
 
Interesting stuff chaps. I shall keep exploring the idea.

I believe the 997 cup cars had an electric pump in the front for PS, so not such a silly idea.

Not sure 'robbing peter to pay paul' is correct, here's my theory.

Even when the AC is not running (clutch disengaged), the belt and and drive pulley are connected to the engine and create some sort of power drag. The Electric compressor would not at all.

The steering pump is only really under load at low speeds, so minimum draw on the alternator majority of the time, plus you have the capacitive storage of the battery to even out the power requirements. Again belts and drive pulley are always connected inducing constant power drag.

There seem to be a good few cars that have changed to an electric power steering pump, remember the rack is still hydraulic, so no change in feel like the full electric systems.

Cheers Andy
 
Sutton said:
Jonny Hart at Classicretrofit has developed a system for 911s up to the 3.2 models. I understand he made a system for the Gunterwerks car which is based on the 993 platform, but he hasn't come back to me about whether he will release a 993 system for widespread purchase.

Thanks for the lead on Classicretrofit

Here is the page on the compressor they do. http://classicretrofit.com/electrocooler-compressor-and-ecu/

My theory seems to be well founded.

Cheers Andy
 
Good luck with your project Andy.

I like the idea of relocating the compressor - removing it from behind the rear axle and putting that weight somewhere between the axles.

Let us know how you get on.
 
alex yates said:
Robbing Peter to pay Paul. The lecky consumption would put a much greater load on the alternator and would suck more power out the engine.
Indeed you couldn't run an RS pulley and each transition of energy incurs an energy loss, kinetic to electrical to hydraulic power, you'd end up with a net power loss.
Track cars may run electric PAS but don't have a/c. A few in the States have fitted electric PAS on their track cars because they have done an engine swap and it's simpler to do.
 
I would be interested to see the numbers but suspect electric PAS is more efficient as it only uses power when needed, unlike a mechanical one which is running the pump continuously.

I am looking at it for my 996 C4.

MC
 
Endoman said:
alex yates said:
Robbing Peter to pay Paul. The lecky consumption would put a much greater load on the alternator and would suck more power out the engine.
Indeed you couldn't run an RS pulley and each transition of energy incurs an energy loss, kinetic to electrical to hydraulic power, you'd end up with a net power loss.
Track cars may run electric PAS but don't have a/c. A few in the States have fitted electric PAS on their track cars because they have done an engine swap and it's simpler to do.

I get your thoughts on the loses, hmmmmm :)
 
Was just gonna post what Endoman posted. If it was that easy we'd all have electric cars with dynmos on the wheels to charge the batteries.
 
Yes, some good pics of the Electric Aircon kit from Classic Retrofit being installed in a nicely painted RSR '87 backdate.
 

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