Aftermarket AC compressors Options

[technicalninja]

Does anyone have a modern compressor installed in a 914?

If so, I'd love more information on this.

I run a shop that specializes in automotive AC systems and my play-toys all have killer ac.

https://granburyautoac.com/

I'm planning a 134 conversion that uses a condenser behind the bumper and I need a modern compressor to make this work. The bumper has to be either a fiberglass replacement or something else (space reasons). I'll be using a modified 916 front cap.

The square York style needs to "leave the building"...

Any suggestions?

[technicalninja]

Bob, whatever you do make sure the compressor is a real Sanden.
Sanden "style or type" means a Chinese copy.
Sanden stickers are normally green. UAC stickers are solid blue.
UAC is Chinese crap...

Sanden compressors are NOT expensive. Here's one from Vintage Air for $230...

https://www.vintageair.com/custom/product-p...hp?pn=04808-VUA

You can get it polished for another $55 or chromed for $120.
If you look close at the pictures on the VA site, you can see the green stickers.

Do a bit of searching and I bet you can find a real 508 for less than $200.

Sandens are drop dead reliable. The 508 is the single most adapted compressor in history. Mounting one as you have suggested has been done many times. I found threads this forum regarding exactly this.

You can get a 508 with many different drive pullies and many different end caps (where the hoses connect). This model is definitely the most adaptable compressor that I am aware of.
 
This is an old school cycling style compressor that has enough load to be obvious when it cycles. I want to avoid a cycling style compressor if possible.

I'm hunting a variable displacement compressor. All of the new cars have changed to a computer controlled variable displacement, but manual variable displacement compressors were around first.
The GM V5 and V7 compressors were some of the earliest.
VAG had a bunch of these in the late 90s/early 2000s.
These compressors never turn off...
They just vary their displacement as the system requires.
This is seamless and the engine speed doesn't change nearly as much as a cycling compressor installation.
At idle you cannot tell it's on...

A computer-controlled compressor requires a PWM driver, multiple sensors, wiring harness and programming.

The mechanical style requires NOTHING! Many came with direct drive break-away pullies and didn't even have a clutch on it.

I'm also trying to mount it under the tin on the right side.
I haven't found one that can be turned backwards like the York can.

My current thoughts are 4 rib serp belt from crank pully to 8 rib idler bearing.
Second 4 rib belt to 4 rib compressor pully. This should allow me to offset the compressor enough to work.


For Cris914n6

The real cooling DOESN"T happen when the fans are on...

On a 100 degree day running the engine at 1500 rpm with both the cars fans on high and a BIG ASSED shop fan also on high will result in high side pressures at 250 on a well-designed system and 325 on something average. This is in the shop with the car stationary.

Run that same car at 40 mph and you will see 125-200.
Run it at 75 and the numbers will be 100-150.
You get 5280 CFM per square foot at 60.
A Chevy truck has about 6 square feet of exposed condenser.
At 60 you could have over 30,000 CFM going through the condenser.
This is enough airflow to cool a 10-unit apartment block.

The fans are only needed below 20 mph.
If the fans are on at all times you're doing it wrong...

My 914 already has the normal aftermarket AC installed and I'm planning on using two modern condensers stacked on each other and the biggest fan I can stuff in the box.
The box might get modified for more room as I am moving the spare tire to the back trunk.
Multiple condensers are a good idea.

I may stay R12 as the high side pressure never exceeding 300 PSI is a good thing.


HUGE SAFTEY TIP!!!!

If you change to R134 you HAVE to install a high-pressure cut-off switch. Most R12 systems didn't have one. The compressor clutch should be disconnected somewhere above 400 PSI (425 is a common switch point). Failure to install a switch could end badly!!!

Most R12 systems have a low pressure cut off switch installed on the receiver drier.
Two-way switches are common nowadays. I can buy a two way that installs exactly like the original 1 way and gets the job done fine. A two way might be labeled "40/425" so it breaks contact below 40 and above 425.

Be careful of "transducers". These are actual pressure reading devices that give the computer high side pressures. They are very accurate (and how I know what high side pressures look like at 75mph) but they CANNOT be used without the computer control components.

You want a simple two-way high-pressure switch for a R134 914 conversion.

[Chris914n6]

The fans are only needed below 20 mph.
If the fans are on at all times you're doing it wrong...

Let's agree to disagree peacefully. Sounds like you are mixing analog car ac and ultra modern digital engineering. None of us regular folk will be using always on variable compressors controlled by a computer. It will be basic 80-90s tech. Fans will be on when the AC button is on.