I have A/C (well sorta anyhow)

[MAS956]

Some of you may have seen this thread in which I asked a ton of questions about my A/C situation.

Well, this afternoon, in an attempt to further baseline my current set up, I took the car out for a spin and decided to check center vent temps in 74 degree ambient weather. Darned if I didn't see 36 degrees at the center vents. Now that was taken at speed with the blower on the middle setting, but hey, I was surprised nonetheless.

I think I may just leave this issue for the Spring at this point - I was pleasantly surprised with the results. I still plan to flush the condensers, change the expansion valve, I'd ilke to add a pull fan to the rear condenser for stop and go traffic events and add the ProCooler, but for now I'm happy.

I think the kick-a$$ Robinaire vacuum pump I bought + the use of HC12a refrigerant were just the ticket for my application.

Thanks to Scottb, Scott R and Jim Sims for all the advice!

[scottb]

Mark: 36 degrees is about as good as it gets, especially with a basically stock system. Keep in mind, though, that with only a 74 degree ambient temperature, you've got a 38 degree differential between the ambient temp and vent temps. On a 90 degree day, you likely have vent temps in the 50s.

I don't mean to burst your bubble, but the "acid test" will be how the a/c performs on a hot day.

Scott

[MAS956]

Scott,

You're absolutely right that my system as-is may well be a marginal performer in the heat - I'm looking forward to the test and getting psyched to take the system to the next level as I didn't drive the car much this past summer. Frankly, I was surprised that the system worked at all.

Thanks to you and the others who have helped, with an investment of about $400 (most of that was the vacuum pump and manifold gauges), I now have a system that works and a good gameplan for additional improvements come Spring.

Thanks!

[scottb]

Mark:

Good investments!

If you're going to do modifications, now through spring is the time to do them simply because you're going to need a/c in the summer, and that's not the time to be messing with your system.

They key to improved 911 a/c performance is condenser surface. Whether you add one in the front or rear fender, or underneath, you should seriously consider that as your primary modification (along with barrier hoses). Other mods, like a ProCooler, updated evaporator, etc., are helpful, but they're not essential. Condenser surface, which provides heat exchange, is essential, however.

We're here to help, so keep us posted!

Scott

[MAS956]

So the underside of the condenser in the engine bay seems to be uniformly black - Did it come that way originally or is it caked in engine grime? If the latter, can it be safely dipped in something to remove the grime or is there another recommended approach?

[Jim Sims]

Some condensers come painted black and some are an aluminum color. The below aersosol flush can be used on the condenser (internally and externally). I would remove the condenser from the car before using the flush externally. It won't hurt the paint on the condenser but it may (or may not) cause problems with the decklid paint.

http://www.ackits.com/merchant2/merchant.mvc?Screen=PROD&Store_Code=AMA&Product_Code=AR4201

[MAS956]

Thanks Jim,

I'll give that a try when I pull the condenser for the flush. I'm pretty sure it's paint I'm seeing but equally sure the whole things needs cleaning.