Originally Posted by brads911sc (Post 7498178)

Shoot the damn video WWEST.

Originally Posted by T77911S (Post 7498249)

the expansion valve is closed, limiting the refridgerant to the evap.

Yes, but "how" closed..? Possibly fully closed, or "almost" so?

That would seem to indicate that it might take an hour, or even hours, for the high and low side to equalize, certainly so with an evaporator condensate freeze-up.

But what if you "start" with an evaporator core ONLY at the 28F "off" point of the compressor? How soon will the TXV begin opening if there is no longer any cabin airflow for "heating" the evaporator (contents) ??

also, these compressors are pretty tough.

Maybe an advantage to keeping the OEM compressor in operation?

i have seen, and i use to do it myself, many techs charge the system on the low side with liquid refridgerant and never kill a compressor. in fact, i argued with a guy on here telling him he should not tell people here to do that even though he swore he has never killed a compressor this way.

what little liquid gets thru could turn to vapour in the long hot lines that run from the front of the car to the back, just a guess.

Originally Posted by wwest (Post 7498267)

Patience, PATIENCE...

I have a bit of an adgenda of my own.

R-134a BInary pressure sensor/switch.

Open = <28 PSI
Closed = <312 PSI
Open = 398 PSI

On/off hysterisis = 86 PSI

In our cars during factory standard operation otherwise, which switch will control the compressor cycling period? It seems unlikely that our systems would ever reach 398PSI, right? Of maybe only in temperature/humidity extremes, 100/100.

But ~400PSI vs the 150PSI I just measured at 57.7GF.....??

R-134a TRInary pressure sensor/switch.

Open = <28 PSI.
Closed = <369 PSI
Open = 454 PSI

On/off hysterisis = 85 PSI

Fan switch.

on = >227 PSI

off = <185 PSI

These trinary switch on/off point closely match the ones for my 95 LS400, '01 RX300, and gen I Prius. Have factory service/repair manuals for all.

I am well aware that the higher the refrigerant pressure/(temperature) the more efficient will be the rate of heat transfer to OAT airflow...

But 398 PSI...or even 454 PSI...

Wish me luck, my high side guage pegs out at 500 PSI. Might have to rely on condensor temperature rise beyond 500 PSI.

Originally Posted by T77911S (Post 7498371)

"and you cant argue speculations

Originally Posted by T77911S (Post 7498371)

"How soon will the TXV begin opening if there is no longer any cabin airflow for "heating" the evaporator (contents) ??"


i dont understand your point......it wont open if there is no air flow and the evap is frozen.

if your line was frozen its save to say it was 30 degrees which is about 30psi for r12. i bet your pressure was no higher than 24psi, which is 25 degrees. that still gives you 5 degrees of supperheat. not likely any liquid making it to the compressor. also, did you have an accuumulator after the evap? that will help prevent liquid from getting tothe comp.

you would really have to measure the superheat to determine if any liquid is getting to the comp, other wise you are just speculating, and you cant argue speculations

Originally Posted by brads911sc (Post 7498388)

All WWEST arguments are based on spectulation. That is why there are so many naysayers.

Originally Posted by GH85Carrera (Post 7498607)

I drove my 911 home from the office yesterday in 95 degree heat. The engine oil temp was showing 210 degrees. (yes I have the upgraded numbered oil temp gauge)

My first stop was for gas. I got a fill-up of 18 gallons. Fire it up and drive across the street for a second stop to buy some beer. Fire it up and drive 4 blocks to a local grocery store for some fruit and a gallon of milk. Fire it up and drive 4 blocks and sit at a red light facing due west. The sun feels hot on my hand through the windshield. Sitting there waiting I can feel cold air blowing on my face and I am comfortable. The AC was at max anytime the engine was running.

I don't know what the pressures were. I was driving the car. The AC worked. It does not leak after several years of driving. It used to leak at least a can of freon every year. The hoses use the same end connections. Now with four condensers I have more connections. They don't leak. Before I changed hoses I had a leak. Now with barrier hoses I don't have a leak.

Originally Posted by big911fan (Post 7498635)

Thank you GH85Carrera. That's what I was asking for in my post from a couple days ago. A real world comparison of someone who only changed to barrier hoses.

That's one vote for barrier hoses only. Any others?

How about anyone who only added a binary/trinary switch? Any one?

I suppose it might be argued that you changed the equation by adding multiple condensers and that was the reason pressures didn't rise.

Maybe the debate continues after all.....

Somebody just tell me when we have a proven solution to this annoying problem.

In the meantime my brain hurts....

Originally Posted by wwest (Post 7498474)

Involved in an arguement/discussion with Kuehl (and 2 otherwise USELESS naysayers that only PARROT Kuehl).

Originally Posted by GH85Carrera (Post 7498607)

I drove my 911 home from the office yesterday in 95 degree heat. The engine oil temp was showing 210 degrees. (yes I have the upgraded numbered oil temp gauge)

My first stop was for gas. I got a fill-up of 18 gallons. Fire it up and drive across the street for a second stop to buy some beer. Fire it up and drive 4 blocks to a local grocery store for some fruit and a gallon of milk. Fire it up and drive 4 blocks and sit at a red light facing due west. The sun feels hot on my hand through the windshield. Sitting there waiting I can feel cold air blowing on my face and I am comfortable. The AC was at max anytime the engine was running.

I don't know what the pressures were. I was driving the car. The AC worked. It does not leak after several years of driving. It used to leak at least a can of freon every year. The hoses use the same end connections. Now with four condensers I have more connections. They don't leak. Before I changed hoses I had a leak. Now with barrier hoses I don't have a leak.

Originally Posted by big911fan (Post 7498635)

Thank you GH85Carrera. That's what I was asking for in my post from a couple days ago. A real world comparison of someone who only changed to barrier hoses.

That's one vote for barrier hoses only. Any others?

How about anyone who only added a binary/trinary switch? Any one?

I suppose it might be argued that you changed the equation by adding multiple condensers and that was the reason pressures didn't rise.

Assuming those are the "standard" aftermarket fender mounted condensor/fan assemblies, more NOT than maybe.

Unless some sort of after-run circuit is involved those fans STOP when the ignition is switched off. And the mounting location and orientation, plus the required direction of flow through the cooling vanes, makes it highly unlikely that convection airflow will be of any help.

So, switch off the ignition, COOK the already highly pressurized refrigerant in those condensors.

Maybe the debate continues after all.....

Somebody just tell me when we have a proven solution to this annoying problem.

In the meantime my brain hurts....

Originally Posted by big911fan (Post 7498735)

I'm trying to keep two issues separate in my mind. One is "What causes refrigerant leakage?" and the second is that of A/C efficiency.

My system holds R134a maybe 6 months. I replaced the compressor to evaporator hose with a barrier hose last season. It was hard to find but A/C techs found a small leak at the compressor low side hose fitting and replaced the hose (Kuell).

When newly charged my system will give me 39 to 42 Deg. vent temps on an 80 deg. day here in N. California. I specify CA because the humidity is very low.

The problem is it won't maintain a good cabin temp because of all the solar gain through the glass.

I could be happy though just keeping the R134a in the system for a year or two.

The problem I have with this debate is that my '87 Cab with original A/C and R12 never held a charge very long either. Longer than my R134A retrofitted '89 Coupe however. If replacing only the hoses will keep the refrigerant filled I'd do that in a heartbeat.

Originally Posted by kuehl (Post 7498662)

Non barrier hoses permeate refrigerant 24/7 with the AC off.

Do you mean "permeate" as in "soak into", or permeate as in "pass completely through? If the latter then I call you out for PURE BS. Why would refrigerant at only atmospheric pressure, PASS THROUGH....??

With the AC running, the leakage rate is higher; the more you use it the more you lose it.

Hmmm... Back to the EPA, SAE, and the scientists at DuPont. Their statements regarding this issue indicate that R-12 lubricants permeate the old legacy hoses and thereby prevent R-134a leakage.

Isn't also possible that the R-12 lubricant also prevents R-12 from leaking?

Assuming the statements from these august and well respected entities is correct, the R-12 lubricant "permeates" the non-barrier hose. Then wouldn't the system operational pressure, 250-300 PSI, result in long term loss of lubricant, FORCING it all the way though, and then OUT, of the hoses?

When the system is turned off the pressure drops below operating pressure

When, WHY...Just previously the cooling airflow from the engine fan (and/or..) was keeping the refrigerant pressure/temperature "in check".

Assume whatever operating level you wish.

Now, INSTANTLY, the refrigerant pressure/temperatore will no longer be held "in check" via OAT cooling airflow, and all the while that was going on, the radient heating from the engine/exhaust was a part of the cooling equation, NEGATIVE part.

And that NEGATIVE part doesn't just up and disappear. In point of fact there is substantive evidence that it becomes, temporarily, even a greater negative aspect of the equation.

, whether that 'operating' pressure is normal or unusually high for some reason, such as you front condenser blower motor fails.

Or likely more common to our systems there is a blockage in the suction side. The TXV is closed since the compressor continues to run, cycling, even with, as, the evaporator core temperature varies from 28F to 34F...

The reason the pressure is lower when the system is off as compared to when the system is on is simply because the compressor is not pumping.

Then explain this post...

And, after the system has been turned off the low side and high equalize
because TEV's never fully close.

You know that factually...? Or just speculation?

"...never fully close.." Okay, we'll assume mostly closed, how many seconds or minutes will it take a high/low pressure disparity, say 250 PSI vs 30 PSI, to equalize with the evaporator core at 34F and now wih NO incoming warm airflow to cool with the ignition off...??

Actual DATA..please.

The evaporator core could be a block of ice and the system will still equalize shortly.

""core could be a BLOCK of ICE..." Most any orchardist would advise you that ice makes a most excellent insolator.

But in any case we need something a bit more definitive than "shortly". Seconds, minutes?

The pressures do not rise.

Data? Factual data?

The laws of thermodynamics would indicate otherwise.


Some people have their own opinions above these topics, however these
are facts based on how the a/c systems work, as well as by observations made by people who service a/c systems. There is not theorize.

Originally Posted by brads911sc (Post 7498701)

I dont parrot anyone.

Oh, no..? Then give me, from your own personal knowledge base, factual basis why you believe any one of my statements you have claimed to be false is in fact, false. Speculation based on logic is acceptable.

I just ask for proof on theories that are stated as false

Calling a "theory" false doesn't make it so. Nor does an explanation, itself based on theory, make a case. Theories are just that, theories. So they cannot be legitimately called false absent actual proof, or at least a counter-theory seemedly based on equal, or more solid foundation.

by ANYONE who knows ANYTHING about how AC works.

Lots of people can know how AC works, but not have a clue as theory. Kuehl seems to match that category quite well.

I also asked Reid for proof.

Please, let's not go "there", I'd really rather not.

He also failed and has been challenged. When an verified idiot is proven to be wrong over and over, makes stuff up and presents it as fact, and then for two years refuses to prove it by saying they arent obligated to prove anything but rather everyone else has to prove their "facts" as false...

Wait, Reid might well be an idiot by many measures but none of us yet know if the product itself provides a real improvment or not. My guess is that Reid's front condensor will provide no more improvement than GTI's seriously flawed design. Serpentine vs parallel flow? 6 of one and 1/2 dozen of the other IMO.

anything they say going forward is then suspect and not readily accepted. We have asked for videos showing the pressure drop by using SPAL fans... never saw it.

Working...

Asked for videos showing any pressure rise at all after compressor is off... never saw it.

Star Trek computer voice...working..

Asked for proof that his Trinary switches /Fans solve anything as it relates to non barrier hose leakage.. never saw it.

Only years, 2 probably, will tell.

All just speculation because he either

1. Doesnt really know how these systems work.

a.) system pressure drop via using Spal fans.

Would you be so kind as to tell us your theoretical foundation, or simple spectuation, as to why you question the case. Not asking for proof, just your reasons for considering the possibility, liklihood, of the idea having no merit.

b.) Pressure rise...post system OFF.

Same question of you, politely...

c.) Trinary switch...leakage..

Tell us, please, he thinking behind your apparent expectation that any evidence of proof could possibly be provided short of at least 2 years having elapsed.

2. Bought a competitors product and it doesnt work

NO.

3. is paid by a competitor to Kuehl to trash Kuehl,

No.

4. is basing his theories on half baked google searches,

No, ALL have SOLID theoretical foundations.

or 5. a combo of the above.

No, obviously.

I think he just sits at his computer all day and pounds away.

No, take time for work, honey-does, Google searches,..SLEEP.

He has LDS and needs some relief.

What is LDS..?

Trying to bait us into his crazy little swamp cooler cotton field world..

My system is a combo of parts. My compressor is Rennaire, my barrier hoses are Rennaire, I have a Rennaire Procooler :pSUCKER.., My fender unit is ZIMS. Yes I have a Kuehl Front condenser:p:p, Upgraded Evap, High output fan, temp control and fan control, and kuehl vent. My deck is a New Factory Behr.

So I am by far a Kuehl parrot.

Typo, or....TRUTH...?

I did this upgrade incrementally. Which is why I know what worked and didnt work and what had the most impact. I actually had a rennaire Dessert Duty Condenser as well but swapped it for the Kuehl because of ground clearance at Euro height.

I like Keuhl because he offer great support. his products are top notch, Would talk to me about AC when I was using a bunch of Rennaire Parts, and gives great information proven with facts to us all for free.