Cooling The Old Condenser

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1GCamaro
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Cooling The Old Condenser

Post by 1GCamaro »

I've got the new Sanden Style Pro6Ten compressor on the Camaro, and it's a perfect fit replacing the A6 (metric bolts though). System charges and cools but man is that high-side pressure through the roof! You guessed it: Spray water on the old condenser and pressure drops to normal. (Condenser has been flushed 3 times and there are no restrictions).

Engine does not overheat. A/C System is charged per spec.

I'm working on improving air flow across the condenser by getting a better belt-driven fan and clutch. Old 4-blade non-clutch fan in place now. I'll also add the foam seals around the edges between radiator and condenser to improve fresh air flow and reduce recirc hot air being pulled through.

You guys have the knowledge and experience, so I'll ask now: Will I eventually be forced to install a new parallel-flow condenser to make this thing truly decent in city traffic and at idle? Or do you think improving air flow is going to help enough?

And one more question: I've seen the HVAC guys walking around with a device measuring the air flow out of vents and ducts in buildings: Is there a similar device I can use to measure air flow across a condenser or radiator so I can gauge the difference as I make these modifications?
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bohica2xo
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Re: Cooling The Old Condenser

Post by bohica2xo »

The 4 blade fan was a non-ac fan to begin with. No way it will cool well.

Do you have the OEM fan shroud in place?
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Re: Cooling The Old Condenser

Post by tbirdtbird »

My experience is that these Sanden Style Pro6Ten compressors are not all they are cracked up to be, especially since they are all Chinesium now.
In my opinion will need a PF condenser. And the shroud will be essential

Condenser needs to be as close to rad as possible

Remember the best air flow using a shroud, no matter what anyone tells you, is to have the rear edge of the fan blades stickout out from behind the shroud 1/2". Per the racers
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1GCamaro
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Re: Cooling The Old Condenser

Post by 1GCamaro »

Yes - OEM shroud is in place and old fan is in the right position even though my clearances aren't exact. I'll be using a 17 inch 6-blade fan instead of the 18 inch 7 blade fan since I'd be touching the shroud at the bottom with an 18 incher.

Shroud is a deep one: Leading edge of fan is 5 inches from radiator.

When new fan arrives with clutch I'll use spacers as needed to get the blades about half in shroud and half out of shroud - maybe slightly deeper than half and half but definitely partially out of shroud. Factory placement of the old condenser is not perfectly parallel to radiator but the space between them is about 1 3/4 inches at the top and 2 1/2 inches at the bottom. The difference seems to be a function of the condenser brackets bringing it out farther from the radiator support core at the bottom. Since the condenser needs to be as close as possible to the radiator, I'm hoping placing the foam seals around the perimeter will help the fan pulling air thru the condenser.

Anyone ever use a push fan on the outside of the condenser, or is that a bad thing?
Last edited by 1GCamaro on Sun Jun 27, 2021 3:37 pm, edited 1 time in total.
tbirdtbird
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Re: Cooling The Old Condenser

Post by tbirdtbird »

I have added them in tough cases, but of course the mechanical fan must be there. Pusher electrics do not work as well as pullers, but they can help
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bohica2xo
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Re: Cooling The Old Condenser

Post by bohica2xo »

The 17" fan should do the job with a proper shroud. Obviously the fan shroud should meet the radiator well, so that the fan draws air from the whole radiator.

The condenser needs to be coupled to the radiator so that no air bypasses it - sneaking around the edges if you will. This can usually be addressed with a little foam weatherstrip or some other soft filler to close the gap. Modern cars have what we call a heat exchanger stack that does this with mechanical parts.

Fan placement within the shroud is of course important. 50% of the blade pitch at the edge of the shroud is fine. On some cars doing that requires a bit of overhang on the clutch assembly. Old small block water pumps came in two lengths. If you need a big spacer to make the fan line up, you might consider going to a longer pump - if you have a short one mounted currently. There are a few clutch choices as well, with different lengths. Avoiding an added spacer would be the best plan.

Pusher fans are a waste of time if you have a proper mechanical fan.

Of course a parallel flow condenser will always be more efficient, but it will still need just as much airflow. Square the fan away first, then decide on condenser upgrades.
1GCamaro
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Re: Cooling The Old Condenser

Post by 1GCamaro »

Thanks for all the advice! This is all helpful. I'm not sure if there's a special kind of temp-rated foam to use to stack the condenser and rad, or if most any kind of dense foam will work. Perhaps I'll order one of the foam kits made especially for this purpose in order to see what type foam is used - then buy more locally since I'm pretty sure I'll need more than the two 23 inch pieces shipped in the kit. With my condenser and rad 2 1/2 inches apart across the bottom, I may need two layers of the foam insulation ... one layer between rad and core support frame - and another layer between condenser and core frame. When I add the foam I'll also be blocking just a bit of condenser area and hope the improved air flow will more than make up for the loss.
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bohica2xo
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Re: Cooling The Old Condenser

Post by bohica2xo »

Stuff like this works well

https://www.mcmaster.com/8694K145/

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1GCamaro
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Re: Cooling The Old Condenser

Post by 1GCamaro »

bohica2xo wrote: Sun Jun 27, 2021 8:15 pm Stuff like this works well

https://www.mcmaster.com/8694K145/
Thanks! This is the type of dense foam I thought would do the job. Since this is 1/2 inch thick and has an adhesive, I'd need to stack it (double or triple) to fill my gaps - but it looks like that will work fine.
1GCamaro
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Re: Cooling The Old Condenser (UPDATE)

Post by 1GCamaro »

Well, I've got the 6-blade fan and the fan clutch - and the fan is in the right place. I've added the foam insulation that blocks air from entering the radiator from the periphery - so almost all the air is being pulled through the condenser when idling.

If I keep the hose spraying the condenser, HP stays at 250 and all is well. With engine at fast idle and no water on condenser, HP jumps to around 300 or a little above. That's when I shut it down or spray water again to keep it from going through the roof.

Since it isn't driven much, I might just leave it like this rather than get a PF condenser (more $$$).

And here's the unusual question: At what driving speed will the condenser have enough air to keep it cool and prevent the pressure from getting too high?
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