Automotive Air Conditioning Information Forum

First, a PF condenser is about 100 bucks.
Then, while we have some really really sharp guys on here, if you ask any racer (not a hot rodder, but a guy who actually races on a track; and they have to get it right) as mentioned, the best fan performance is with the rear of the blades sticking out from behind the shroud by 1/2", not 1/2 and 1/2.
Your car, do it how you wish

and BTW my uncle races......

tbirdtbird wrote: ↑Mon Jul 19, 2021 12:37 pm First, a PF condenser is about 100 bucks.
Then, while we have some really really sharp guys on here, if you ask any racer (not a hot rodder, but a guy who actually races on a track; and they have to get it right) as mentioned, the best fan performance is with the rear of the blades sticking out from behind the shroud by 1/2", not 1/2 and 1/2.
Your car, do it how you wish

and BTW my uncle races......

Thanks for the input and suggestions. I could add a half inch spacer and achieve the 1/2 inch blade exposure behind the shroud. I'll consider that. But I haven't seen the PF condensers anywhere that reasonably priced. I'll keep looking for the $100 version.

Have you priced one out from Tim, the forum owner?

Just for reference, a mid 80's Chevy Truck with giant t&F cond and R12. Had high side in the 350 to 400 range. Shutting down at 300 is again the World being scared by too much internet reading. It would help if you found out where it will stabilize. If the high side gets to 425, then shut it down.

Tim wrote: ↑Mon Jul 19, 2021 2:30 pm Just for reference, a mid 80's Chevy Truck with giant t&F cond and R12. Had high side in the 350 to 400 range. Shutting down at 300 is again the World being scared by too much internet reading. It would help if you found out where it will stabilize. If the high side gets to 425, then shut it down.

This is a '67 Camaro with Sanden style compressor converted to R134 and after we got it all together I was not present when it was charged. We did confirm proper charge and oil and the guy who charged it said it rose to 375 before he hosed it with water and brought it down to 250 stable. I'll crank it back up and see where it stabilizes with engine idling but will watch carefully when it's above 350. I was afraid compressor might get sick if pressure was much above 350 for very long. High side of compressor to condenser is red hot today after running it a few minutes up to 300 --- but that Internet fear-factor kicked in and that's why I shut it down or watered it down above 300.

The fan depth is less important than the radial clearance. Running a shroud with an extra inch of radial clearance is much worse than the depth issue.

Obviously radial clearance was dictated by rubber engine mount clearance. As long as you have at lest half of the fan inside the shroud the tip spill is minimal.

I agree with Tim, run it up to 1500 engine RPM and see where it stabilizes. If it goes past 425 shut it down, you have other problems.

These guys would have a litter of kittens if I posted some fan pics. None of them overheat here at 115f

Thanks for clearing that up......

bohica2xo wrote: ↑Mon Jul 19, 2021 5:01 pm The fan depth is less important than the radial clearance. Running a shroud with an extra inch of radial clearance is much worse than the depth issue.

Obviously radial clearance was dictated by rubber engine mount clearance. As long as you have at lest half of the fan inside the shroud the tip spill is minimal.

I agree with Tim, run it up to 1500 engine RPM and see where it stabilizes. If it goes past 425 shut it down, you have other problems.

These guys would have a litter of kittens if I posted some fan pics. None of them overheat here at 115f

I'm running the 17 inch 6-blade fan although I'd rather be running the 18 inch 7-blade fan. My clearance at the bottom of the shroud is just a little too tight for that to work. Yeah, I know. Raising the engine 1/2 inch or dropping the rad and shroud 1/2 inch would be nice but just not feasible. The A/C is cooling nicely when it's running, BTW.

bohica2xo wrote: ↑Mon Jul 19, 2021 5:01 pm
These guys would have a litter of kittens if I posted some fan pics. None of them overheat here at 115f

Kitten's is good BBQ for the neighbors.

Yeah, keep the kittens away from the GM 1580696 fan however.

One of the best answers for airflow on any reverse rotation fan application (back side of the serpentine drive).

At 20 inches in diameter 10 blades, with no tip spill it sort of covers the argument about where to end the shroud...

2005 trailblazer, Saab 9-7x etc. fan blade.