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Old 7th June 2011, 14:32   #1
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Question Using an AC in an open car?

I was told that one can use an AC in a convertible or open jeep. The blower directed on your face will keep you cool.

What would be the cons of this? Suppose i have an open jeep and keep using the aircon to keep me cool. What are the cons? I don't mind refilling the gas yearly. What else?

Let's not debate on why i may want to use it in an open car. I just need to know the drawbacks.
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Old 7th June 2011, 14:48   #2
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Default Re: Using an AC in an open car?

I have actually done this with a ford mustang.
It was very cold, but we had rented the mustang, so we needed to have the top down.
So with blower on full heat on the Yosemite highway, we cruised along. Till around 30-40mph it was okay.
Above 40-50mph our ears were frozen, but noses were warm.

I guess, you could do this with AC, but with less effectiveness, unless you have a AC capable of 4 degree C grill temperature even with blower at full settings.

As your car speed will increase, hot air from outside will rush in with even more force.
Rolling up the windows will help to an extend.
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Old 7th June 2011, 14:57   #3
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Default Re: Using an AC in an open car?

Correct me if I'm wrong, I think Air conditioners work by sucking in the air from the cabin/ room, cools it and sends it back to the cabin/ room, so I think the thumb rule for any AC to work is a closed cabin/ room which in other case will clog the suction filter. Better option should be setting up a compact Air Cooler inside the jeep.
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Old 7th June 2011, 14:58   #4
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Default Re: Using an AC in an open car?

Quote:
Originally Posted by tsk1979 View Post
As your car speed will increase, hot air from outside will rush in with even more force.
Rolling up the windows will help to an extend.
+1; when we did this we started off with the windows down but realised it was kinder on our ears when the windows were up. Of course, this is at higher speeds on the freeway; when we were back in the city, the windows were down again.
Pennywise point: you may want to consider fully closing/ taping the vents which cannot be directed at people/ occupants.
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Old 7th June 2011, 15:41   #5
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Default Re: Using an AC in an open car?

Quote:
Originally Posted by Tejas@perioimpl View Post
What would be the cons of this? Suppose i have an open jeep and keep using the aircon to keep me cool. What are the cons? I don't mind refilling the gas yearly. What else?
IMO the only con apart from reduced cooling, is the compressor has to work hard ALL the time. May affect the life of compressor in the long run

If you have a all-correct cooling system, 'theoretically' you should not be refilling the gas. Gas refill is required only when gas leaks out of the system.
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Old 7th June 2011, 15:53   #6
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Default Re: Using an AC in an open car?

I have done this with the windows rolled down in the M800 and the Bolero, aka The Dark Knight. It is a good compromise if you have occupants who can't "handle' air-conditioning. You know those people who get all sorts of aches or cold if they are in air-conditioned environments for too long.
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Old 7th June 2011, 16:38   #7
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Default Re: Using an AC in an open car?

Actually I have been considering an A/C for my soft top Gypsy. I don't expect cool climate in the car, just hoping for direct cooling on my body to prevent sweating. Moreover it is stuffy with windows rolled up and one cannot drive with wind blasting into ones ear drums all day long, it is very fatiguing.

I don't want to convert my ST into a hard top for the next 30K km at least.

Interested in the feedback.

Seems to work: http://www.wranglerforum.com/f5/soft...-ac-56530.html and there is an insulation pad that Bestop sells that they call a headliner. We could stitch something similar locally. (http://www.quadratec.com/products/11193_44XX_PG.htm)

More here: http://www.offroadheros.com/liner.html

Thanks
--Ragul

Last edited by Ragul : 7th June 2011 at 16:53.
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Old 7th June 2011, 16:43   #8
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Default Re: Using an AC in an open car?

A soft top is not really an "open jeep". Even a soft top offers decent insulation, and AC will cool the front passengers nicely.
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Old 7th June 2011, 16:59   #9
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Default Re: Using an AC in an open car?

Boss I have done this for a number of years in 30-40deg heat in Oz in 2 different convertibles, a Ford Capri and an MX5. In these cars the drawback was that the compressor does not get a chance to switch off as roof is down nand the set temp is not acheived.The MX had sunviisors that flipped up and a windbreaker between the headreasts to minimise buffeting in the cabin.With Jeep with the top down, your blower direction/mounting/vents are very important, there will be more buffeting in the car and you need to ensure that the cold air hits your face/body before it is sucked out of the car. It is nice to drive with the top down on a hit day that is not too sunny, if the sun is out you will be toast in 30 mins!With the soft top up (providing it is reasonably sealed) it is almost equvalent to any other car.

Last edited by KMT : 7th June 2011 at 17:01.
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Old 7th June 2011, 21:11   #10
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Default Re: Using an AC in an open car?

Quote:
Originally Posted by Tejas@perioimpl View Post
I was told that one can use an AC in a convertible or open jeep. The blower directed on your face will keep you cool.
========
Let's not debate on why i may want to use it in an open car. I just need to know the drawbacks.
If you dont keep it at max cooling temperature for the compressor, it should be fine. Slightly more tear and wear to the compressor that is all. FYI even a modern car like Swift has continuously running AC compressor once switched ON. Dont worry too much about this, use proper parts and new parts while at it.
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Old 7th June 2011, 21:21   #11
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Default Re: Using an AC in an open car?

Quote:
Originally Posted by KMT View Post
With the soft top up (providing it is reasonably sealed) it is almost equvalent to any other car.
Is it true that a metal roofed car with padding inside provides the same heat transfer/insulation as a 1.5 to 2mm thick nylon fabric layer?

--Ragul
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Old 8th June 2011, 09:48   #12
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Default Re: Using an AC in an open car?

My german collegue took me for a ride in his Citroen with top down and i too asked the same question when he switched on the AC and put it to hot mode.It was around 10 degreess outside and it did give a warm feeling.
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Old 8th June 2011, 11:18   #13
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Default Re: Using an AC in an open car?

Thanks for the feedback. So till now what i gather is:

- There will be an additional load on the compressor
- I may not get the cool blast of air on my face due to buffeting of wind.

Anything else? So it's a possibility to do this without major adverse problems?
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Old 8th June 2011, 17:54   #14
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Default Re: Using an AC in an open car?

Quote:
Originally Posted by Tejas@perioimpl View Post
Thanks for the feedback. So till now what i gather is:

- There will be an additional load on the compressor
- I may not get the cool blast of air on my face due to buffeting of wind.

Anything else? So it's a possibility to do this without major adverse problems?
Tejas, the question would be - why do you want to do this?

A/C on with winodws down means - more work for the compressor and hence more fuel consumption - compressore is coupled with the engine and takes power from there. Air coming out the A/C vents will not be colder as the system efficiency will be less.

If some of the passengers are not comfortable with the cooling (a con for all A/C which are not auto), the best way to control the temperature is to use the heater control in such a way that temp is optimal. Switching off/on the A/C is not the best way to do it as you will be consuming more fuel again - you will be running the A/C at its full capacity all the time - not a good thing to do.Once the cabin is cool. A/C may run as low as 50% of its capacity - which is good on your pocket.

Again, if you switch mode from re-circulation to fresh air, you will spend more fuel. However it is essentail to do this time-to-time during long drives - cars in india do not take fresh air in the re-circulation mode (I guess no regulation!!) and you will feel sleepy because of excess CO2.

Heater could be switched on when windows are down, but then again not during the intial period in very cold conditions. High end cars have coolant flow control for heater units and opening the windows might affect the engine efficiency (since the coolant is working overtime to keep the cabin hot, engine takes longer time to reach to optimal temperature).
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Old 10th June 2011, 11:16   #15
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Default Re: Using an AC in an open car?

Tejas,

An air-con even in an open Jeep will provide you relief in traffic or when stationary (which is probably when you'll need it the most). Considering that you are going to be touring in your upcoming monster 4x4, I suggest getting simple plastic door cut-outs and a bikini top. Takes 5 minutes to remove once you reach your offroad destination!

Quote:
Originally Posted by Ragul View Post
Actually I have been considering an A/C for my soft top Gypsy. I don't expect cool climate in the car
As I found out in my Jeep, a powerful air-con can chill soft-top interiors too.
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