Help design my a/c hose routing

[quattrorunner]

Originally Posted by tirwin

Not sure why they quit but I wouldn't want one because I don't need anything hanging any lower below the car. Seems like road debris and snagging on speedbumps is a possible downside.

Yeah that's the one I worry about. Will need even more care to navigate.

[wwest]

"why they quit..."

Didn't even come close to solving the MAJOR shortcoming of the factory system.

That was/is the lack of adequate refrigerant condensing efficiency with engine RPMs consistently low.

Obviously not every owner will encounter this problem but enough do that makes a condenser/fan addition a much more suitable purchase.

[rusnak]

I would think that body twist/ torsion would be one reason they quit making them. Other than placing them on the roof like a 18 wheeler reefer, underbelly seems ideal from a theoretical standpoint.

I would go with the shortest hose routing possible. You're talking about a LOT of GD hose any way you look at it.

[Pazuzu]

It's held in place by the straps, so no real torsional problems. Obviously I've deleted the rocker panels, but they might hang almost that low themselves.
As you can see, for a daily driver, there is no obvious damage from speed bumps or anything, it hangs about as low as the front cross member.

EDIT: There is one more hose on the passenger side. So, compressor-underbelly hose is pass side, underbelly-decklid is driver's side, decklid-front is driver's side (passes through that shield on the end of the underbelly unit), then on to the dryer and evaporator. Although, it looks like it might go to the dryer before the front condenser, I'll have to check that more carefully.

[ganun]

Great pics Mike, for us who had never seen such a thing....one comment, its HUGE. Looks like side skirts will totally cover it from the sides.
But watch out running over things, I just clipped with the right front what I think was a 6 inch piece of a 2x4, what a loud BANG, right under the passengers feet, dented the floor! I was going 65.
Sh... happens.

[Pazuzu]

Update:
I received my hose and most of the fittings and went to work this weekend.

1) Decided to go with the underbelly condenser first

2) Decided that the hose between the rear condenser and the front condenser would be #6 hose, with a #6 and a #8 fitting. The factory setup is a #8 hose with a #6 and a #8 fitting. Reason I went smaller was 2 fold...I had the extra #6 hose but not the extra #8 hose, and the factory used the larger hose because the system wasn't yet liquid after only one condenser, while my system that hose is after two main condensers, so the refrigerant should be partly/mostly liquid at that point, so the smaller diameter would work.

3) Went with all o-ring fittings, using flare-oring adapters in a few places.

4) Little known fact...Sanden compressors have replaceable and interchangeable backs. So, don't use adapters or weird fittings or kludged togehter piping to get your ports to work, just buy a back that has the accessories and attachments you want! $25-30, 10 minutes to swap it out, and you have exactly what you need! also helpful if you bung up the aluminum threads...

5) Making A/C hoses at home is FUN and EASY and CHEAP. The 3 foot hose between the compressor and rear condenser? The one people tell you to change when going to R134? The new one that has the binary switch included? I can build that hose for $30 (custom, with the switch mounted, custom length, custom fitting selection). The vendors that sell that hose? $150+ (no custom length, no custom fitting selection). Why buy new??




This is what 60 feet (60 FEET!!) of hose looks like. I removed everything to check all equipment, check hose lengths and fitting orientation, and generally get a sense of the whole system. This is my routing, I will follow it with the new stuff.



So, at the end of the weekend I have the hoses 90% complete and installed (I need 3 fittings still). I am also making stubby hoses that can replace the dryer and expansion valve, so I can do a complete system purge and flush at once (one inlet, one outlet, flushing all hose and all flushable parts).


All said and done:
25 feet of #6 hose (used 25 feet)
25 feet of #8 hose (used 20 feet)
15 feet of #10 hose (used 13 feet)

$336 shipped for the hose, all fittings including the male fittings for my stubby hoses, and adapters. $167 for the crimper. So, $500 for completely custom hoses, with a few extra inches on each one to help with routing, full freedom of fitting clocking, etc.

[ganun]

Nice pic Mike, man that's a lot of hose.....you know minivans use Al tubing but that's a moot point.
You have already made the hoses just like the pic, I see, but that dumps the heat under your feet first.
You could have gone front, tail , center (less heat to the floor) or front, center, tail (less heat to the engine).
Any particular reason for choosing what you had, besides it WORKED.

[Pazuzu]

Originally Posted by ganun

Nice pic Mike, man that's a lot of hose.....you know minivans use Al tubing but that's a moot point.
You have already made the hoses just like the pic, I see, but that dumps the heat under your feet first.
You could have gone front, tail , center (less heat to the floor) or front, center, tail (less heat to the engine).
Any particular reason for choosing what you had, besides it WORKED.

Take the load off the engine as much as possible.
I don't think that the front condenser is up to the task of being the first in line, AND it's built with #6 lines and fittings, while the rear condenser is built with #8 fittings. Clearly, the guts are different, and the front one should be last in line.
I could have gone with new custom condensers, but these are in fine shape.
I could have gone (and might in the future) with a wheel well setup in the front driver's side, removing the front factory piece all together. This could be done with just cutting and recrimping the hoses, since the inlet/outlet to the front condenser travel through that wheel well anyways.

[SilberUrS6]

Originally Posted by Pazuzu

Take the load off the engine as much as possible.
I don't think that the front condenser is up to the task of being the first in line, AND it's built with #6 lines and fittings, while the rear condenser is built with #8 fittings. Clearly, the guts are different, and the front one should be last in line.
I could have gone with new custom condensers, but these are in fine shape.
I could have gone (and might in the future) with a wheel well setup in the front driver's side, removing the front factory piece all together. This could be done with just cutting and recrimping the hoses, since the inlet/outlet to the front condenser travel through that wheel well anyways.

First off, don't bother replying to wwest, it only encourages him to take the thread OT and aggrandize himself. Best to ignore him, or to invite him to start a new thread to discuss his pet theories. Onto the meat:

I think you are correct about the front condenser. If you wanted to take the heat load off the engine, I'd suggest the rear fender condenser. Since there are off-the-shelf solutions, that would be the most simple choice. I would route the hoses so that the fender condenser is first in line, then the belly, R/D, evap, compressor. This would also reduce some of your hose run. Delete the front and decklid condensers. If you wanted to go really nuts, dual fender condensers. Also and off-the-shelf solution. Finally, do not give a passing thought to radiant heat issues from the road or the exhaust. The effect is so vanishingly small (especially from the road, LOL) as to lack meaning. OAT is the big driver here, not any radiant heat source.

[Pazuzu]

So close...so very close...


That was last night, hit it with a 60psi pressure test then pulled a 2.5 hour vacuum which reached 27 inches, sealed things up, and I'm about ready to go downstairs and see the 12 hour status.
I'll backfill with a can of R134 then pump for 4 hours, which will give me an OAT of 95ish to fill this afternoon.

I wanted to be here 24 hours ago, but learned that my rear condenser had 2 pinhole leaks as I tried to pressure test the entire system (Grrrrr.....). Figured I was down and out for at least 2 weeks and had a $500+ bill ahead of me, when I stumbled across an early single row decklid condenser for sale, just an hour away! Weeeeeeeeeeeeeee!!!

So, only delayed half a day not 2 weeks.

[SilberUrS6]

Originally Posted by Pazuzu

So close...so very close...

Nice work, and nice to have good luck. I guess we know where your refrigerant went, and again show that methodical testing, and not WAGs, are the way to troubleshoot these systems. Anyone who continues to listen to wwest should have their heads examined. OK, here's a totally OT question for you - your fan and shroud look fantastic - did you refinish those yourself?

[A horse with no name]

Hi, would you mind telling me whose brand of barrier hose that you used? I see that their are quite a few brands out there. I've read that Duponts are very good.

BTW, are the condensers that you used from the rear trunk of a 911 or are they a special item?... Last but not least; how in the end did it work out for you? Like 'cold'?

Thanks in advance!

[Pazuzu]

Originally Posted by A horse with no name

Hi, would you mind telling me whose brand of barrier hose that you used? I see that their are quite a few brands out there. I've read that Duponts are very good.

BTW, are the condensers that you used from the rear trunk of a 911 or are they a special item?... Last but not least; how in the end did it work out for you? Like 'cold'?

Thanks in advance!

Finally getting around to answering things in this thread!
First off, I did not have A/C until last night.
Secondly, the hoses are a mix of Galaxy and Parker, I ordered bulk from ColdHose, and they sent two different brands.

The rear condenser is an early 911 part from a '77. It's a single layer of coils, instead of 2 layers likes the SC and later condensers. I'm not concerned about that for 2 reasons, one because it makes the condenser thinner and it cleared my coil better and second because the underbelly condenser is the primary one, so a smaller thinner secondary in my engine bay is just fine.

So, system was charged and running on September 10th. On September 11th, the system was completely empty. Slow leak somewhere, no oil dripping to follow.

Fast forward to this weekend (the first chance I've had to get under the hood). Since then I bought:
a replacement receiver dryer (the cheaper $35ish one, fits just fine)
30 pounds of DuPont R134a (from Pepboys, they had it in stock and a 30% off coupon, was $150 after taxes)
A few extra fittings to make jumpers for the expansion valve and receiver drier (for flushing)

So, set up the system so I could do a 100% flush at once...remove R/D and expansion valve, place jumpers in their place, disconnect at compressor, run a drain line from the #8 fitting to a bucket. Flush using a flush gun into the #12 line. I ran a full gallon of flush through, and that setup flushes every single line and condenser all at once.

Blew out the lines with compressed CO2 until dry.

Pull a vacuum for ~1 hour. Backflush with R134a to static pressure (~80psi). Note hissing sound.

So, my evaporator had a #12 flare fitting and a #8 o-ring fitting, which I thought was strange. I assumed that when the PO had the A/C upgraded, that the shop brazed an o-ring end on the factory evaporator. So, since I went all o-rings on the hoses, I needed a #12 flare to o-ring adapter placed there.

Hissing was coming from that fitting. vented (oh, I mean, recovered) the static load of R134 in the lines, cracked that fitting apart to examine it...and found that in fact my evaporator had a #12 o-ring fitting with a o-ring to flare fitting on it. It was so crushed together that it appeared to be a solid end, but in fact was one of those little adapters in there. So, I actually had: male o-ring/o-ring to flare adapter/flare to o-ring adapter/female o-ring hose setup...
Peeled that off, cleaned out the crunchy o-ring that was crushed in there, put a fresh #12 o-ring on the now o-ring male fitting, and ran my o-ring female hose right to it.

Pulled a new vacuum, backfilled with a static charge of R134a, repeat 2 more times.

Remove expansion valve and receiver drier jumpers and install expansion valve and new drier.

Change vacuum oil

Pull a hard vacuum for 2 hours. Backflush with R134 static charge. Pull another vacuum for 1 hour.

Prepare to fill.
I picked up a 50 pound capable digital scale for $18 on Amazon. Checking it out, I find that it is precise if not accurate. That means, I put my can of R134a on there over and over and get within 0.2 ounces each time. Press down on it and let go, goes back to within 0.2 ounces. Pull up and let go, same deal. So, for differential weighing like we're doing, it will be perfect. I don't care if the can is 30 vs 30.75 pounds, I care that when it says its 30 ounces lighter, that it is.

Car specs: Sanden S508, all new hoses. Routed compressor/underbelly condenser/decklid condenser/front condenser. About 58 feet of hose. Stock evaporator. Wirbelsturm evaporator fan (so, higher air speed than stock). Some extra insulation of the evaporator housing, etc. Some sort of upgraded bowtie center vent.

R134a can on scale, connect to gauge set, flush yellow hose of air.
494 ounces total for the can.
Open gauges, fill system with static charge.
488 ounces 86psi, OAT 98 degree. Car has been sitting in the sun for 2 hours, as has the R134 tank.

Start car, close decklid, box fan on decklid. doors wide open, full fan, full cold. I have temp probes reading the ambient air at the dashboard, one in the inlet for the evaporator, and one at the vent outlet.
Open blue gauge fitting.

474 ounces (differential 20 ounces). 26/235psi
468 ounces (differential 26 ounces). 30/275psi Inlet air temp 95, outlet air temp 65
464 ounces (differential 30 ounces). 28/295psi Inlet air temp 94, outlet air temp 61
456 ounces (differential 38 ounces). 33/325psi Inlet air temp 93, outlet air temp 61
Started venting (oh, I mean, recovering) by cracking the blue hose fitting. don't know ounces vented.

first dropped to 29/310psi, then to 28/305psi. That gave me a 93-59 inlet outlet temp. Should be about 31, 32 ounces?


So, I noticed (and it was like this a month ago as well) that my low side never gets above 35ish. I see numbers more like 55 for OAT of 95-100. Why can't I get that high? Is lower better? The high side will happily increase with increasing charge, I went to 325 and stopped.
Am I too low right now at 28/305, OAT 98ish? Or too high?


Sealed everything up and grabbed a beer. Left car in garage (well heat soaked!), doors closed, windows closed.


Start car, windows closed, full max speed and cooling. Drive to work on 30ish MPH roads with normal stop and go traffic.
7:41am Dash temp 86 degrees, inlet temp 83 degrees, outlet temp 86 degrees
7:45am Dash temp 84 degrees, inlet temp 74 degrees, outlet temp 51 degrees
8:08am Dash temp 71 degrees, inlet temp 62 degrees, outlet temp 42 degrees. System was cycling at that point.

I'll get a good highway speed check done in the next few days. I expect that the system will excel when the car can move at a consistent 40mph or more.


WEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE!!!!!!

[A horse with no name]

Thanks for all the info!... Much appreciated .