Electric AC for the 308

A couple of months ago I finished an install of an electric AC compressor in my 308 GTB (just in time for cooler fall weather ) and thought I'd share a few details. There were multiple goals with the project: reduce overall weight, move remaining weight forward, have a decent AC system, and mostly to just get that herking OEM compressor out of the engine compartment (I do my own mechanical work and I really disliked the OEM fitment)

I've never done any AC work before, but it was pretty straightforward: select some replacement components, figure out where to mount everything, and hook it all up. Only took me about a year. By the time I was done I had replaced every component except the original under dash evaporator, and even that was removed and reworked as the plastic housing was broken and needed repair. I left the fan assembly stock (I did add a new spall resistor bank in the passenger footwell), as I find it adequately powerful. One comment to those who find the fan and the two lower AC vents to be inadequate: you do spin around and open the round dash vents, yes? They share the plenum for the evaporator and when open move a lot of cold air when the AC is on. I found pointing the outer ones sideways and the center one straight back kept the cabin cool without getting too much air blast in the face.

I had already installed a high output alternator last year (Wosp 175A which was sold as a bolt in for a 308) in anticipation of the project. Probably overkill both in amps and dollars ($1100!) but at that time I hadn't yet selected a compressor and I wanted to ensure I had ample ampacity. The alternator came with an incorrect offset 7M pulley which caused a bit of a circus finding a suitable width and offset pulley. In hindsight, I probably just should have just used an aftermarket high amp unit from one of the speed shops and adapted it to suit. Note that the pulley V angle on the Ferrari is a nominal 60 degrees, while the typical US available pulleys (and belts) are about 40 degrees. I didn’t know that so ended up destroying a couple belts until I figured this out. I’m driving the alternator with an 11M belt directly off of the ‘inside’ large groove on the crank pulley that previously drove the mechanical AC compressor, and have added an idler pulley for the 7M water pump belt using used Ferrari parts I found on eBay. So basically a factory style two belt setup like the later cars.

The compressor came from China via eBay. No risk there. It's an 18cc 3 fixed speeds unit for R134a refrigerant with built in controls that just needs a selector switch to run, which makes for a tidy install. It was about $400 delivered (pre tariff). It has bolt on adaptors for normal #8 and #10 hose fittings. It is rubber mounted (with a provided mount unit) to the battery tray under the spare tire well (which I converted to removable a couple of years ago). The battery (a compact but high output AGM unit from Odyssey) is mounted on its’ side next to the compressor. Only a few holes drilled in the battery tray. The compressor draws about 27amps at the 2000rpm low setting, and 45 amps at the 3500 rpm medium setting. High setting is something like 65 amps, but so far I’ve never needed to go above the lowest setting (highest ambient so was 80F on a 90 minute drive). Next summer will tell the rest of the tale.

The modern condenser came from classicuautoair.com and is a generic unit (20” x 11”) suited for R134a refrigerant. I made simple brackets to bolt it to the radiator, which is an alloy unit from Superformance. Cooling fans are Spal units with mounting adaptors that mount and work as stock, found via a post here on the Forum, and bought on eBay.

The dryer and binary switch are new, and along with fittings and hose were sourced from coldhose.com which has a nice selection, reasonably priced. I fabbed the reduced barrier hoses using an Amazon sourced hose crimper (around $100).

The AC controls (two selector switches and a temperature control switch) were sourced from Southern Rods, and combined with knobs found on Amazon. For the moment I have these installed in a 3D printed snap in DIN module in the radio space (found online via Google), but will likely relocate the controls to the stock location one day.

Overall the system seems to work well, and the compressor is not audible at all when the engine is running. It’s barely audible when the engine is off. In the few hundred miles driven since the new condenser and fans were installed there was no perceptible change in engine temperature, but then, my car had no overheating issues before the project began.

Total cost without the alternator was about $850 for parts (including hose crimper) plus about $200 for a local shop to charge the system with oil and refrigerant.



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My car is a 77, so originally a single belt setup. But as I mentioned in my write up, I converted it to a 2 belt system with the larger 11M width for the alternator. No issues with belt squeal, but then the alternator load is still not super high even at the 45 amps of the compressor medium speed. An alternator will only put out as much current (and therefore will only work as hard) as the cumulative devices require.

I would add to anyone thinking about doing this, I believe the reason the system is working so well is that I changed condenser, fans, and expansion valve to maximize the efficiency of the R134a, which is a somewhat inferior refrigerant to R12. In other words, if you just throw an R134a electric compressor on the stock setup I don't believe it would work as well.