New A/C in an old 911

[nigel911]

Does anyone make a complete kit for a modern A/C setup in an older car?

My 72 came with factory air, but I figure it would probably cost as much to get it back up and running as a complete new system - and it will likely never perform as well as a contemporary or current A/C setup.

Thoughts and advice appreciated.

[HarryD]

Lots of threads on this: https://forums.pelicanparts.com/porsche-911-technical-forum/921754-classic-retrofit-lightweight-electric-air-conditioning.html

It would be the way I would go.

[GH85Carrera]

Originally Posted by nigel911

Does anyone make a complete kit for a modern A/C setup in an older car?

My 72 came with factory air, but I figure it would probably cost as much to get it back up and running as a complete new system - and it will likely never perform as well as a contemporary or current A/C setup.

Thoughts and advice appreciated.

Talk to Charlie Griffiths. https://griffiths.com/

He can advise you on getting great AC to meet your goals.

[ccallana]

2nd on Griffiths... I put his system in earlier this year and it is fantastic.... Just follow his directions and don't go roque and you'll have no issues

[chucksmith]

yep, Griffiths is the way to go. I would advise getting the whole system and not just a partial kit. You will be happy with the result and spend less time getting it done.

[usera]

If you are in Boulder, CO then I think the Classic Retrofit Electric AC is the way to go. Jonny is a great guy, but if you live in a humid area I would recommend the Griffiths system.

I live in SC and the electric system struggles to keep up.

[Duc Hunter]

I have Rennair (now defunct, and it’s like Griffiths setup) on one car and Classic Retrofit in another (Gen 1, they’re on Gen 2.5 by now). I like both. Griffiths is a stock style A/C on steroids and works well enough. CR's electric A/C is an all-new system that works in a very different manner. Here in Florida, having both styles, I would go CR every day of the week and twice on Sunday unless......

• It's a factory A/C car and worth enough money to keep it stock looking.
• Money is a big issue.
• You love the factory style A/C temperature and fan control setup (including the glass tube style temperature adjustment knob.
• You like running A/C lined up the length of your car (if it did not have them before), which means drilling holes in your rocker panels (a prime area of rust in these cars).

CR kit is more money and far more advanced (It's inherently Emory Outlaw 356's, Guntherwerks 993's, Singers, Tuthill 911k's, etc.). It's also lighter weight and takes lot less HP to drive. It also requires a new alternator. For a non-A/C car it makes everything in the engine bay look stock, and all your A/C lines can stay hidden up front in the trunk. It’s blower moves a lot more air than even the Griffiths style setup.

Griffith requires an engine drive compressor and its mount to the engine, lines up to the front of the car, and the blower and evaporator sit in the smugglers box. It also requires its own fan speed knob and temperature control knob. The Griffiths condenser sits in the rear deck lid (don’t bother with the other setups, for this style system this is the best place and plenty of condenser capacity, even in Florida), so running the A/C does add heat to the engine bay in the hot summer. Some think this can cause overheating, I don’t buy that based on my cars experience. That said the engine driven compressor takes a lot of HP to drive, and the condenser is putting heat into the engine bay robs HP too. Depending on your engines output, it could be significant. I think the compressor is something like 15hp, vs the electrical load is 3hp on the CR kit, and the CR kit wont introduce heat into the engine bay. On my 3.6 that’s a lot smaller hit than on a 200HP 2.7 or something.

It's all about compromises. I'm happy to chat more offline if you want. Just PM me.

Good luck on your choice.

By the way I am in Florida. Here is an update I just posted to my CR A/C thread. As you can see it rocks in FL's humidity.

Post 39 with a 2025 update to my A/C thread from 2018

[chucksmith]

I love the concept of the CR system ,but up until the above response, I have read mostly about issues with the system keeping up in hot humid weather. I am happy to hear it can be made to work well and would be a real option on my future builds. I would disagree that the rear tail mounted condenser is the best option for a Griffiths system. It makes more sense to use one (or two) in the rear fender area and avoid the engine heat issue. It doesn't require its own fan speed or temp control knobs but the stock fan speed switch is best upgraded to Griffiths variable speed unit. The long hoses are a pain and loss of HP is real ,even with my 300hp 993, I notice it.

[nigel911]

The CR system does look superb... but not an inexpensive solution - by the time you add a new alternator to the complete kit, plus taxes and shipping you'll be around $8k.

I'm in Spain so it would have to be able to deal with high humidity.

[Jonny H]

Originally Posted by nigel911

The CR system does look superb... but not an inexpensive solution - by the time you add a new alternator to the complete kit, plus taxes and shipping you'll be around $8k.

I'm in Spain so it would have to be able to deal with high humidity.

Most of the time I'm in Spain it is hot but super dry. Nothing like Florida for example. Where are you?

Careful not to compare apples with oranges.

The traditional upgrades do require that your original AC parts are in good order. You will have to recondition/rebuild the factory blower/evaporator, check that the ductwork, controls and wiring still work etc. Fans may be seized so factor that in.

Our kit is complete with all new parts, it doesn't use any of the original Porsche AC parts.

Many of the mechanical compressor based upgrade kits also load the alternator (since they run more condenser fans) and it is doubtful your 55A alternator would be up to the job.

[Duc Hunter]

Originally Posted by nigel911

The CR system does look superb... but not an inexpensive solution - by the time you add a new alternator to the complete kit, plus taxes and shipping you'll be around $8k.

I'm in Spain so it would have to be able to deal with high humidity.

See my recent post here about my Florida humidity and A/C performance. Right now here in Florida is 88F air temp, 77% humidity, and a feels like of 110F. Is Spain that humid?

Post 39 is the post you want. Post 29 has a very slick center vent someone else posted. I might go that route soon!

[nigel911]

I'm in Moraira, Valencia - pretty much beachfront - exterior humidity today topped out at 78%, tomorrow's high forecast to be 87%.

Another barrier to entry for me is import duties, an additional 31% on top of the UK price.

System looks great but not without it's imperfections / challenges, and to be honest, if I was spending that much I would expect it to be all but perfect.

Appreciate the insight and contributions.

[PeteKz]

If it works well in Florida or the US Gulf Coast in the summer, it will work better anywhere else!

[Peter M]

Originally Posted by Duc Hunter

I h
That said the engine driven compressor takes a lot of HP to drive....... Depending on your engines output, it could be significant. I think the compressor is something like 15hp.....

Really Chris? Wouldn't we be banging our heads on the steering wheel every time the compressor cycled on?

[GH85Carrera]

Originally Posted by Peter M

Really Chris? Wouldn't we be banging our heads on the steering wheel every time the compressor cycled on?

Yea, 15 HP is total BS. I do not feel my compressor cycle on or off at all, even at idle. I do have Griffith's infinite fan speed controller, and his temp control module. It has a LED to show me the AC compressor on or off. I can't have it at max cold all the time, or the evaporator will freeze up, even on hurricane fan speed on a 100+ degree day. I have to back the temp back off just a bit to make the compressor cycle.

After well over 100,000 miles and 17 years, I have never once under any condition felt a power loss from the compressor cycling on. I bet is is less than three HP at most. The factory OEM modern Denso rotary compressor is very efficient.

[Duc Hunter]

Yeah Glenn I guess I am total BS.

I can feel my compressor come on in my 3.2 on for sure. Head hitting the steering wheel, no. I do feel it. And that 15hp may be a little high, though I have seen that number thrown around for many other cars.

In doing some research here on Pelican many people have said 6-7HP. The electric system costs less than 1hp. So….

[shamrok]

Originally Posted by Jonny H

The traditional upgrades do require that your original AC parts are in good order. You will have to recondition/rebuild the factory blower/evaporator, check that the ductwork, controls and wiring still work etc. Fans may be seized so factor that in.

Our kit is complete with all new parts, it doesn't use any of the original Porsche AC parts.

I think this is the issue a lot of people will run into more and more. The factory stuff is all brittle 40 year old plastics that can't be easily replaced. If a previous owner ditched this stuff, you're pretty much hosed.

I'm really glad Jonny is pushing new tech for our cars, and I don't doubt that his stuff is engineered really well, but it's a spicy $$$ bill for sure. It's a bit maddening you can get an entire modern system for a classic Mustang for less than half of a CR system.

[colingreene]

In this case its all about economy of scale.

[Jonny H]

Originally Posted by colingreene

In this case its all about economy of scale.

Exactly, our parts are not mass produced and we pay our staff proper wages. The package space is too small to adapt / modify any 'off the shelf' products as a lot of the cheap kits do.

If you consider some of the other small volume engineered upgrades for these like active suspension or throttle bodies / EFI, both of those are $10k+ additions.

[Showdown]

FWIW, when Jonny points out that iTBs or suspension, or even new wheels can cost absurd amounts of money, having good seats and AC are two investments that make being in the car much more tolerable and enjoyable and it’s hard if impossible to place a value on that.

I haven’t pulled punches when talking about AC systems and have modded my CR gen 1 system quite a bit, and even now, it’s probably one of the elements of the car (other than good seats) that I wouldn’t trade for any amount of HP.

If AC means you drive the car more, isn’t that a no brainer?


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