6 pot

I have noticed that when I have the air con on in the car ( it keeps the windows clear) power seems to be reduced quite considerably, does anybody know what sort of power drop you actually get from this.

car is MY03 WRX

brickboy

My old scoob didn't have aircon but my last two cars have ... most people reckon that aircon on full blast takes about 7-10% power.

In the Volvo T4 I had, there was a sensor which automatically shut off the aircon compressor if you hit full throttle .... on the basis that if you were using full throttle you needed ALL the power available. So it must take a fair %.

I think you probably notice it more at low rpm / low throttle opening because the compressor is presenting more of a drag to the engine.

johnfelstead

the impreza shuts off the aircon on full throttle also.

6 pot

What I actually get, is a noticable drop between 3 -5000 rpm, but it then tails off even more over 5000, does anybody else experience the same problem.

It almost feels like its running off boost.

johnfelstead

mine doesnt feel that bad, in fact its pretty easy to forget its on.

6 pot

Maybee I am just driving to hard and expecting to much.

Leslie

It must cost a bit of power to run the aircon pump, but like John I dont notice mine very much either.

Les

Neilo

silly question but what fuel are you running?

the reason i ask is that i havent really noticed much of a power drop at all when air con is on.....but when i used to run the car on 95RON, it went like a sack of s**t over about 4.5-5k RPM.

Just a thought.

Edited to say: mines an 03 WRX also.

[Edited by Neilo - 11/26/2003 12:38:12 PM]

chrisp

Yep, funnily enough I cant tell any power drop either with it on .

Mind due mines nearly always set to auto climate control.

[Edited by chrisp - 11/26/2003 12:40:33 PM]

johnfelstead

mine is always on auto climate control, but i still switch the AC off/on when needed.

Butty

iTrader: (2)

Summer time is a double whammy if you have an air filter kit without an effective cold air feed.

This info taken from http://members.tripod.com/wrx_act/tech/wrx_faq.htm


<<
Greg grega@indcomp.com.au MY98 Evo2
I have a 'Group A Rampod' supplied by MRT. I decided to run some temperature tests of my own to see if it is really worth buying an airbox with a cold air induction. The results were interesting.The temperature readings were taken at the intake to the rampod air filter.

At an outside temperature of 35C and a long drive to let the engine heat soak

Cruise at 40kph A/C On 65C
A/C Off 55C
Cruise at 60kph A/C On 55C
A/C Off 48C
Cruise at 80kph A/C On 50C
A/C Off 45C
Cruise at 100kph A/C On 48C
A/C Off 43C
Idle 60 seconds A/C on rose from 55C to 65C
A/C off rose from 48C to 55C
Idle 2min A/C on rose from 55C to 70+ (gauge cuts out at 70)
A/C off rose from 48C to 65C - and kept rising!

As you can see the air conditioner makes a big difference to the temperatures. This seems to be
because of the thermo fans running while the a/c is on. When the a/c is off and the thermo fans cut
in and out, the temperature rises briefly while they are on. I assume this is because those fans are
taking the heat out of the radiator and a/c elements. It took a while for the engine to heat up to these temperatures from cold,
about 1/2 hour in traffic. The temperature seems to get steadily higher the more you drive due to the heat soaking into all of the
metal of the engine. Once it is hot it stays hot for ages. I took over three hours to cool to 55C after shutting off.

At an outside air temperature of 22C the results were as follows...

Cruise at 100kph A/C off 35C
Start/Stop Traffic A/C off about 50C on average
IdleDown and Shutoff A/C off rose to over 65C in 3 minutes

This has simply confirmed what I always suspected, you need an airbox and cold air induction to get
the most out of your rampod, especially if you drive a lot in traffic. The performance hit in hot
weather and when the engine has heat-soaked is huge so I imagine an airbox and cold air induction
should reduce intake temperatures by about 20 to 40C depending on the conditions, improving
performance and probably allowing the engine to run better overall.

<<

I wonder how many summer engine blows are due to AC being on and high sustained temp?

Nick
1997 Forester S/tb

6 pot

Interseting Thought!!!!!!!!!!!!

Stephen Moore

I think air con consumes about 7-10bhp so when on would be neally the same performance loss as having another passenger!

6 pot

I supose I should look at some performance enhancing mods, to try and overcome the misting up of the windows.

Sounds kinda weird but I'm sure its what I need.