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

[friethmiller]

Starting the A/C Compressor Install. Hired a young man with a lathe to machine out a pulley spacer based on Doug's specs. Had to buy 8mm longer Allen head bolts (m8x1.25x50) to reinstall the fan with the spacer. Working on positioning the compressor mount prior to welding the feet in place. I plan on tacking the remaining legs on and then removing for a final welds. My concern right now is the clearance at the top for the compressor with the firewall. Might move the compressor/mount back toward the oil filler a little more. Maybe Doug or others can give their 2 cents before I start welding. I might have that first leg (driver side) mounted on the wrong side of the fan housing. Also, I'm curious as to the best orientation of the compressor. Is it better to have the connections on top? Or, pointing to the passenger side?

[914sgofast2]

Starting the A/C Compressor Install. Hired a young man with a lathe to machine out a pulley spacer based on Doug's specs. Had to buy 8mm longer Allen head bolts (m8x1.25x50) to reinstall the fan with the spacer. Working on positioning the compressor mount prior to welding the feet in place. I plan on tacking the remaining legs on and then removing for a final welds. My concern right now is the clearance at the top for the compressor with the firewall. Might move the compressor/mount back toward the oil filler a little more. Maybe Doug or others can give their 2 cents before I start welding. I might have that first leg (driver side) mounted on the wrong side of the fan housing. Also, I'm curious as to the best orientation of the compressor. Is it better to have the connections on top? Or, pointing to the passenger side?

How will you set or check the engine timing with the AC compressor mounted above the timing port in the fan housing?