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AC enhancement

Shade on Sat September 04, 2010 11:18 PM User is offline

Year: 2010
Make: Cadillac
Model: CTSV
Engine Size: 6.2
Refrigerant Type: 134a
Ambient Temp: 105
Country of Origin: United States

I have a new caddy that doesnt cool as well as I would like. At highway it gets down 42 if its kept indoors then driven.
Takes awhile to cool down if left out in the sun, and at idle you can feel the temp rise
So I asked a technician at the dealership if there is anything that could be done to enhance performance further...
He said the condenser on these cars are super small so a larger condenser would work well and the compressor would handle it no issues....
Assuming airflow stays the same under all conditions how much better would a larger condenser do?
I have a company that can make a custom condenser with a larger core(50%) increase and possibly increase the over all dimensions to fit in the alloted space.
Dont get me wrong this thing is blowing within spec I just like things to work better than spec
Thoughts?

I've been trying to find out the dimensions on the factory unit that in the car now but there is nothing online giving me any specs about the unit. Any help? TIA


Ryan

Edited: Sat September 04, 2010 at 11:21 PM by Shade

bohica2xo on Sun September 05, 2010 12:46 PM User is offline

Wow. Cadillac has been trying to compete with the euro-weenies for some time now, and they have built some incredibly high performance cars doing it.

Now it looks like they managed to meet the euro-spec on A/C too - weak. Congratulations caddy, you now have A/C just like a benz. Works ok if you park in an air conditioned garage, and never drive in traffic.

Sorry Shade, I would be handing the dealer the keys. It was 107f here yesterday, and if a car I just paid north of 60k for would not keep me cool they would be well aware of how unhappy I was.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

chris142 on Sun September 05, 2010 4:29 PM User is offline

I have not seen a Caddy that new yet. Has the system been recharged to spec properly? I'd really be suprized if the system was so undersized that it won't keep you cool.

But then my Jeep AC has always suked. As long as it's under 95F it's ok. Get it over 100 or 118 in AZ where I was yesterday and I melt. Mine was blowing 65F yesterday @ 70 mph in 118F heat on I-40.

Shade on Sun September 05, 2010 5:11 PM User is offline

Dont get me wrong - it keeps me cool driving and in traffic its still OK - I would say it fits the bill for 90% of the country.
Again it blows 43 at highway speeds and in traffic like 50 ish. So its definately in spec but I want 40's all the time which is the reason for the question....
Would a larger condenser fit the bill? I know I have enough room to fit it in the engine bay, I just think GM cheaped out and went with a smaller unit not thinking of us poor saps in AZ.

Unfortunately bohica once you sign a deal its not easy to get out of. You can whine to GM, BMW, etc all you want but unwinding a deal is super tough unless you can prove lemon law, Mag moss, etc.

Thanks for the replies.

Edited: Sun September 05, 2010 at 5:11 PM by Shade

ice-n-tropics on Sun September 05, 2010 5:56 PM User is offline

Shadie,
If the tech determined that the A/C is fully charged w/ R-134a then the condenser upgrade is probably a good start if you intend to get goose bumps and hang meat. You probably have a dark colored car?
1) Increased condenser face area is the most effective for increasing heat dissipation.
First, the condenser should have at least the same heat exchange core face area as the radiator, therefore, measure the radiator core and compare to the present OEM condenser.The forced convection air flow (cooling fan and ram air) is only effective through the condenser face area that is in line with the radiator core.
2) A too thin condenser (13 to 16 mm ) will improve radiator air flow but decrease condenser performance. Some OEMs get silly with cheap/thin condensers with really dense /close spaced fins that choke the air flow.
Additional thickness beyond 21 or 23 mm (for a multi pass, micro tube condenser) quickly reaches the point of diminishing returns(capacity), because of additional air flow restriction. Less air flow can cause engine overheating.
3) A pusher electric fan in front of the condenser will help your idle cooling problem.
4) Your custom condenser company needs to have the high tech designs of present state-of the art used by OEMs, then a thicker condenser can bring results. Old style thicker tube and fin condensers probably wont help. What is the name of your condenser company?
I replaced a tube and fin Harrison tube and fin "piccolo" Suburban condenser with a 1.625 " thick Modine serpentine condenser for a 2 evaporator A/C system with about a 30% heat dissipation improvement.
5) Some "most extreme" A/C overachievers add another additional condenser in series with the existing OEM condenser. This may be a smaller condenser mounted in front of the OEM and plumed first. Or, the additional condenser may be mounted remotely.
I did dual series plumed condensers on vehicle with 3 evaporators, but one evaporator would be turned off at extreme discharge pressures.
see "How To Air Condition Your Hot Rod " from AMAZON
hotrodac

-------------------------
Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy.
AMAZON.com: How To Air Condition Your Hot Rod

bohica2xo on Sun September 05, 2010 6:17 PM User is offline

Shade:

I know exactly how hard it is to "unwind a deal". It is not impossible, but it can be tough - especially if you have had the car very long.

The big issue is even if you found a way to fix the problem, the average SOB dealer will void your warranty (at least on the A/C) instantly.

So I guess the alternative is to just "get used to" a 60k hotbox. A tough pill to swallow. Especially when a 3 year old Saturn has better A/C. If there is a cure at all it should be the Genital Motors / Dealership responsibility to find it - yeah, I know, no chance of that.

Maybe we can dredge up Joe from NY, seems he had a lot of late model caddy experience? Have not seen him post in some time now. I know NickD will have something to say on this one...

Good Luck to you Shade.

B.



-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

Shade on Sun September 05, 2010 6:43 PM User is offline

Quote
Originally posted by: ice-n-tropics
Shadie,

If the tech determined that the A/C is fully charged w/ R-134a then the condenser upgrade is probably a good start if you intend to get goose bumps and hang meat. You probably have a dark colored car?

**Yes, last time I buy black

1) Increased condenser face area is the most effective for increasing heat dissipation.

First, the condenser should have at least the same heat exchange core face area as the radiator, therefore, measure the radiator core and compare to the present OEM condenser.The forced convection air flow (cooling fan and ram air) is only effective through the condenser face area that is in line with the radiator core.

2) A too thin condenser (13 to 16 mm ) will improve radiator air flow but decrease condenser performance. Some OEMs get silly with cheap/thin condensers with really dense /close spaced fins that choke the air flow.

Additional thickness beyond 21 or 23 mm (for a multi pass, micro tube condenser) quickly reaches the point of diminishing returns(capacity), because of additional air flow restriction. Less air flow can cause engine overheating.

**Understood - I have been trying to find dimensions on the OEM unit but have been unsuccessful that might help the conversation. I did look at it while under the car and it was a teeny little thing.

3) A pusher electric fan in front of the condenser will help your idle cooling problem.

**Agreed on this car though there is no room for a pusher there is the supercharger heat exchanger in front of the condenser.

4) Your custom condenser company needs to have the high tech designs of present state-of the art used by OEMs, then a thicker condenser can bring results. Old style thicker tube and fin condensers probably wont help. What is the name of your condenser company?

**A stacked plate/parallel flow is the latest condenser style I believe and this is the style they are going to use(they arent going to reinvent the wheel and of course not use the old school tube and fin). They are going to go thicker, how much I am not sure, I dont have details yet.
My guess is they may not build one from scratch but find the right unit to fit the need..IE thicker core and larger overall dimensions.
The OEM unit is maybe 60% the size of the radiator and there are puller fans on the back of the radiator. I think if they went thicker and overall almost the size of the radiator there wouldnt be a cooling issue, the car runs cool now even in the hot summer at idle the temp guage doesnt budge from full open(210 degrees I believe)
The company doing the work is D3 cadillac



I replaced a tube and fin Harrison tube and fin "piccolo" Suburban condenser with a 1.625 " thick Modine serpentine condenser for a 2 evaporator A/C system with about a 30% heat dissipation improvement.

**It would be interesting to see what improvement there would have been from the same type serpentine --> larger core serpentine in heat dissapation

5) Some "most extreme" A/C overachievers add another additional condenser in series with the existing OEM condenser. This may be a smaller condenser mounted in front of the OEM and plumed first. Or, the additional condenser may be mounted remotely.

**I thought about this but there is no room up front to mount a second unit and I would be concerned with the computer system and a second unit. The computer controls much of function of the AC system nowadays so messing with a second may cause some other issue. It might throw the pressures out of spec from what the computer monitors - Thats just a guess though.

I did dual series plumed condensers on vehicle with 3 evaporators, but one evaporator would be turned off at extreme discharge pressures.

see "How To Air Condition Your Hot Rod " from AMAZON

hotrodac





Thanks for the input

Edited: Sun September 05, 2010 at 6:51 PM by Shade

Shade on Sun September 05, 2010 6:50 PM User is offline

Quote
Originally posted by: bohica2xo
Shade:



I know exactly how hard it is to "unwind a deal". It is not impossible, but it can be tough - especially if you have had the car very long.



The big issue is even if you found a way to fix the problem, the average SOB dealer will void your warranty (at least on the A/C) instantly.



So I guess the alternative is to just "get used to" a 60k hotbox. A tough pill to swallow. Especially when a 3 year old Saturn has better A/C. If there is a cure at all it should be the Genital Motors / Dealership responsibility to find it - yeah, I know, no chance of that.



Maybe we can dredge up Joe from NY, seems he had a lot of late model caddy experience? Have not seen him post in some time now. I know NickD will have something to say on this one...



Good Luck to you Shade.



B.



Yeah understood - I think the dealer wouldnt know if I went bigger they would just see the new sticker for the amount of 134a that was put back into the system. It would be a little more I'm sure since the condenser is larger but I doubt will be anything alarming. Im not too sure they will pull the system apart and look at part numbers to void warranty, were lucky if we can get the dealership to do things right the first time, let alone do detective work on something like this.
Im always open to listening to others opinions though.

bohica2xo on Sun September 05, 2010 7:05 PM User is offline

Shade:

A secondary heat exchanger & fan works well, but there is virtually no room on that car - and the dealer would spot it in a heartbeat. They will work very hard to deny warranty status, I know this all too well.

A wider or taller heat exchanger might be possible. Thicker obviously as Tex has pointed out has it's good & bad sides.

More airflow would obviously work, but is there room for another fan?

Finally, is it the heat exchanger - or simply not enough compressor volume at idle? Does the air get measurably colder if you hold 2000 engine rpm parked?

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

Shade on Sun September 05, 2010 7:19 PM User is offline

Quote
Originally posted by: bohica2xo
Shade:



A secondary heat exchanger & fan works well, but there is virtually no room on that car - and the dealer would spot it in a heartbeat. They will work very hard to deny warranty status, I know this all too well.



A wider or taller heat exchanger might be possible. Thicker obviously as Tex has pointed out has it's good & bad sides.



More airflow would obviously work, but is there room for another fan?



Finally, is it the heat exchanger - or simply not enough compressor volume at idle? Does the air get measurably colder if you hold 2000 engine rpm parked?



B.

There is no room for a second fan or that would be done in a heart beat! I would have to assume its the heat exchanger the tech said this compressor is used in much larger vehicles so its pretty stout. Ive never tried holding the car at idle but increasing the rpms. What does it mean if it does get colder under this test?

Thanks again for the time.

ice-n-tropics on Sun September 05, 2010 7:48 PM User is offline

What is GM thinking? Class 8 trucks never put the condenser behind the Charge Air Cooler. Sounds like GM has handed off the engine cooling design to Harrison again. The super charger cooler preheats the air into the condenser which is part of the problem
I've got a Modine serpentine condenser 1.625 " thick approximate face area of 16" X 24"
Another 1.25 X about 16" X 22"
hotrodac

-------------------------
Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy.
AMAZON.com: How To Air Condition Your Hot Rod

bohica2xo on Sun September 05, 2010 8:19 PM User is offline

Shade:

The object of that test is to take the compressor into the max capacity range. Many times on high rpm vehicles, they tend to underdrive the compressor to keep it from spinning too fast. The compressor may have been used on a larger vehicle with a different drive ratio.


Tex:

That charge cooler location is not a surprise. have a look at the '08 & up Super Duty heat exchanger package below. The A/C condensor might as well be behind the radiator. They are very proud of the fact that the "stack" is 100% quick coupled (even the radiator hoses) & can be removed as a unit with 4 bolts. Now servicing anything in that stack means opening every system connected to it because the stack comes out as a unit. "F450" is now pronounced 'Cha-CHING!"



-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

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