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

[dlee6204]

This system will keep you cool even on a hot day. Currently the system I am running is merely a "stock" system with an upgraded compressor and R134. Switching to r134 definitely puts a limit on the system. I'm envious of those that get super cold temps with r12. I'll be working to improve my system this season and do some more research to see what can be done to get temps down even further. I'll probably start by replacing my condenser with an improved version. I'll of course keep keep this thread alive with new developments.

[3d914]

This system will keep you cool even on a hot day. Currently the system I am running is merely a "stock" system with an upgraded compressor and R134. Switching to r134 definitely puts a limit on the system. I'm envious of those that get super cold temps with r12. I'll be working to improve my system this season and do some more research to see what can be done to get temps down even further. I'll probably start by replacing my condenser with an improved version. I'll of course keep keep this thread alive with new developments.

Doug, I refurbished the stock system in my 2.0L years back with a Sanden. The schematic you posted was one I created for that system. The biggest aid I found to help the A/C work better in Phoenix was a cockpit cover. Had a custom one made with a cloth-backed vinyl that covered all glass and the engine lid. Made a huge difference in A/C performance since it wasn't an oven to start with and the A/C could keep up.

Great job on the thread. Keep us up to date on changes.