Doug's A/C System, R&D/Build Thread Options

[dlee6204]

I thought I would document my A/C adventure in the hopes that it would be a good reference for anyone else considering A/C. I’ll first touch base on the stock system and on custom options and then start building my own system to start testing on. I’ve working on a few systems before but I'm sure there is someone that knows more than me so don't be shy sharing or adding anything. (IMG:style_emoticons/default/smile.gif)


To begin things off here is one of the better overviews of an A/C system. Follow the link and you can see a breakdown of the whole system.


http://www.movacs.com/How%20it%20works/index.html





Anytime I refer to the stock system I will be referring to the dealer installed VPC system mostly because the only A/C cars I had came with this system and I have plenty of parts around.

I also borrowed some photos off this site so if I used any of yours... Thanks. (IMG:style_emoticons/default/smile.gif)


Compressor:

The compressor that came on dealer installed A/C systems was a York Piston style compressor that had a capacity of 6 cubic inches/Rev. From what I could find it used about 7-10 horsepower from the engine. You can still use this compressor however there are better, more efficient options out there. When choosing a new compressor it is a good idea to find one with a similar capacity. In this case going bigger does not mean better. An A/C system works as a whole unit and if you dramatically change one aspect of it, you will likely see negatives effects elsewhere. Choosing a compressor that’s too big will overwork the system, yielding no little to no benefit, and create a not-as-efficient system. During my search I looked mostly at Sanden style compressors so that's what I'll be referring to in my build. Using a modern compressor like the Sanden will only use about 3-4 hp from the engine. I have heard quite a few people use the Sanden 508 compressor with good results. It has an approximate displacement of 8 cubic inches/rev, which IMO is slightly more than I'd like to make a jump to. I'm not saying it wouldn't work, it obviously works, however I think I will get slightly better results and pressures using the Sanden 507 (approx. 7 cubic inches/rev). The SD507 is also slightly smaller in size than the 508.

Here is a picture of the York Compressor


A side by side with the SD507





And here is a SD508

[stateofidleness]

K guys, I wanted to dig in a little more on this because honestly I have always been curious about the AC in this car myself. I am planning on dropping the engine in this one for the first time so I started work on getting the AC stuff out of the way at least. Car is winning though... Without much documentation on this setup, I can't research the proper way to unmount it. At first I was attempting to take the entire thing out (compressor+bracket) in one piece and we found that it is still swiveling on a bolt directly underneath the compressor mount (you can see it in the pic). It appears this has been broken by a P.O., but I can almost forgive them because I can tell why it's broken. Absolutely no way to get any kind of tool on it.. tried everything!!!!

So then we tried unmounting the compressor from the base plate and got 3 of the 4 bolts off, but there's one near the firewall directly behind one of the pulleys that seems impossible to get at as well... no combination of wrenches or sockets seemed to help...

So I gave up and told Dad I'd be consulting the experts (IMG:style_emoticons/default/type.gif)

Took a pic of the bolt underneath that I can't get a wrench/socket on (seems to be a 14mm). Found some other markings on it and took some pics. I'll post in a few. There's still some original stickers and other markings on the very front but can't get a camera between the pulley and the firewall yet. Stay tuned!

The yellow arrows are pointing at the last bolt that seem to be holding the whole thing to the engine... no way to get a wrench on it though!! The blue arrow is showing the broken hole on the fan housing.




Here is closer view. The top pic is a bigger pic to give you some idea of where we're looking: