4 Pass A/C condenser? Not a Camaro

[Knuckle Dragger]

I've got a S10 Blazer with the 5.3 swap done. It runs dead on 210 regardless of outside temp or how hard I'm on it. I'm having less then spectacular performance from the a/c at idle, stop and go etc, but works well when moving for longer then just the next stop light. If we are under 110 outside it's pretty good all the time, but better when moving. I have some improvements to make as far as air flow focus but I bought a cheap universal condenser when I was putting it all together. I'm going to go back into it once it's under 117 outside, but while I'm tweaking the airflow I'm going to replace the condenser with a 4 pass piece. I'm out of room for anything larger then I have now so I figure giving is a couple more trips across the air flow will help.

Anyone have any of that HVAC guru advice for me? The limited info I have found on Google talks about 4 pass heat exchangers using water and the only caution they give is possible lower pressure which I don't think will be an issues with A/C.

 

[camarochevy1970]

I have this issue with some of our cars. It's all air flow, as you have pointed out. If I am moving steady state works great, stop and go it's a challenge. I am assuming the fans are moving enough air when the A/C is on at idle?

 

[ULTM8Z]

Can you put an aux fan on the condenser? I did that on mine and it helped (didn't really measure the improvement in terms of how many degrees colder out the vents), but at prolonged idle, you can tell the difference.

As with mine, if you wire it into the PCM to turn on when it sees the A/C request signal, there should be a parameter in the PCM to have it turn off above a certain vehicle speed (I set mine to 35 mph).

The other thing of course is thermal efficiency of the vehicle. The ceramic window tint REALLY made a difference on mine. Even mid-90's to 100F outside, I'm literally only running my blower on low to maintain cool temperature in the cabin. Also when getting into the car after prolonged exposure in the sun, the system doesn't have to work as hard to cool down the cabin.

 

[Knuckle Dragger]

I have this issue with some of our cars. It's all air flow, as you have pointed out. If I am moving steady state works great, stop and go it's a challenge. I am assuming the fans are moving enough air when the A/C is on at idle?

Yeah, I'm using the Intrepid fans that are so popular on this swap. Depending on who you believe they pull 2,800 to 3,100 CFM. It pulls air hard enough to pull your shirt to the grill if you walk close. Plenty of air through the radiator to stay cool no mater how hot. I for sure have to block off areas around the condenser to direct that flow a little better but I'm mostly curious to see if anyone has some theory on the 4 pass condenser and how it will change system pressures and such.

 

[BonzoHansen]

I'm no ac pro,novice at best. But I kinda remember hot climate option parts looking through parts lists over the years. Def remember hot climate orifice tubes. I dunno how that works lol

 

[Knuckle Dragger]

I'm no ac pro,novice at best. But I kinda remember hot climate option parts looking through parts lists over the years. Def remember hot climate orifice tubes. I dunno how that works lol

That's something that completely slipped my mind. I know changing the orifice diameter makes a difference. It's been so long since I was in school I'll have to do some refresher research on it.

 

[John Wright]

Sort of a side note, but are you running the blazer front spoiler? I know for a fact that makes a huge difference, even moreso if you have room to add on to the bottom of it.

 

[FS87LT]

Having the front spoiler is a DEFINITE plus to cause air flow through the radiator/condenser as it causes a low pressure area behind the radiator as the vehicle is moving. There is also a "variable orifice" (which NAPA used to sell) that was mentioned in some older posts at www.ackits.com. The posters claimed it helped their OEM GM systems in Suburbans cooling well in the AZ heat, back in the 1990s and since.

Rather than a 4-pass condenser, what about a "mass flow" condenser as the R-134a systems have OEM?

FS87LT

 

[Knuckle Dragger]

In case any one was interested. I went from:

to

I went from ECM controlling the fans on at all times with A/C to a high side pressure switch. The one I have switches on too late and off 45ish pounds later so it cycles the fan off and on about every 45-50 seconds. I can't really judge the pressures until the new switch gets here and the fan is operating as it should. When the fan comes on it drops the high side almost instantly in 95 degree weather (at 2:30 in the fricking morning). Based on my drive home it's better but I'm anxious to see where the pressures are with the new switch. I hope USPS gets it here by Saturday.