How much power loss when air-conditioning is on?
15 July 2002, 06:46 PM
#1
Scooby Newbie
Thread Starter
Join Date: Jan 2002
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
Anyone have a figure as to how much bhp is reduced when the air-conditioning is on?
I have heard a rumour that it can be as much as 5bhp!
Anyone done a rolling road with air-con on and air-con off and everything else the same?
15 July 2002, 08:24 PM
#5
Scooby Regular
Join Date: Sep 2000
Location: Notts, UK
Posts: 4,935
Likes: 0
Received 0 Likes
on
0 Posts
Just to add to what David said I can remember reading that above 40mph you will use more power and fuel having the windows down than running the aircon due to drag.
Modern systems don't use as much as the early systems but 5bhp is possible when both the compressor is engaged and the electric fans are running.
Lee
Trending Topics
15 July 2002, 10:45 PM
#10
Scooby Regular
iTrader: (1)
Join Date: Dec 2001
Location: You only live ONCE But if you do it right >>>>> ONCE is enough
Posts: 7,327
Likes: 0
Received 0 Likes
on
0 Posts
A/C is defo cut on power demand.On hot day in cool car put foot down & car temporarily warms up as A/C is cut.Then returns to blow cold on return to sanity.
Well it does on my UK300 anyway.
Mark
Well it does on my UK300 anyway.
Mark
17 July 2002, 03:08 AM
#15
Scooby Regular
Join Date: Feb 2002
Posts: 1,343
Likes: 0
Received 0 Likes
on
0 Posts
Hi guys,
I have to say without a doubt that my STi-7 JDM and my old car a turbo mistubishi eclipse GST (210 bhp) are significantly slower with the a/c on even under full accelleration. It is especially noticable under 4,000 rpms.
You can see from where I live that the a/c is just about always on but when I want to go for a punch I turn it off as the difference is very significant. My 2 cents
Cheers,
Ray
I have to say without a doubt that my STi-7 JDM and my old car a turbo mistubishi eclipse GST (210 bhp) are significantly slower with the a/c on even under full accelleration. It is especially noticable under 4,000 rpms.
You can see from where I live that the a/c is just about always on but when I want to go for a punch I turn it off as the difference is very significant. My 2 cents
Cheers,
Ray
17 July 2002, 10:15 PM
#17
Scooby Regular
Join Date: Sep 2000
Location: Notts, UK
Posts: 4,935
Likes: 0
Received 0 Likes
on
0 Posts
Madmart,
Sorry mate but I cant see how revs make a difference. The two main components of an aircon system that take load are the compressor and cooling fan both of which are constant load items. They should take the same power to run at tickover as they would at the redline although some cars limit the running of the aircon below 1500rpm while some lift the tickover.
The compressor cuts in and out to maintain the pressure in the system, if its not too hot and humid the evaporator and condensor wont be working as hard and the refridgerant will not be gassing as much, this means the compressor wont be kicking in as much keeping the refridgerent in liquid form to the evaporator. Likewise the cooling fan will not need to run as much to keep the condenser cool and return the gassy refridgerant back into liquid form.
With the aircon on you may have the following situations.
Compressor stood, fan stood.
Compressor stood, fan running.
Compressor running, fan stood
Compressor running, fan running.
The above will depend on how hard the system is having to work to cool and dehumidify the interior.
Lee
[Edited by logiclee - 7/17/2002 10:31:30 PM]
Sorry mate but I cant see how revs make a difference. The two main components of an aircon system that take load are the compressor and cooling fan both of which are constant load items. They should take the same power to run at tickover as they would at the redline although some cars limit the running of the aircon below 1500rpm while some lift the tickover.
The compressor cuts in and out to maintain the pressure in the system, if its not too hot and humid the evaporator and condensor wont be working as hard and the refridgerant will not be gassing as much, this means the compressor wont be kicking in as much keeping the refridgerent in liquid form to the evaporator. Likewise the cooling fan will not need to run as much to keep the condenser cool and return the gassy refridgerant back into liquid form.
With the aircon on you may have the following situations.
Compressor stood, fan stood.
Compressor stood, fan running.
Compressor running, fan stood
Compressor running, fan running.
The above will depend on how hard the system is having to work to cool and dehumidify the interior.
Lee
[Edited by logiclee - 7/17/2002 10:31:30 PM]
17 July 2002, 11:19 PM
#18
dehumidify the interior
Thats a good one, how many of you switch the aircon on for a few seconds to get rid of steaming up inside the car when you have been through a car wash or something else made it steamy.
Works a treat, takes a few seconds to clear all the windows.
Thats a good one, how many of you switch the aircon on for a few seconds to get rid of steaming up inside the car when you have been through a car wash or something else made it steamy.
Works a treat, takes a few seconds to clear all the windows.
Thread
Thread Starter
Forum
Replies
Last Post