STi-Frenchie

Finally put my finger on why sometimes my scoob (MY02 STi7) will limp away at a standing start and other times will drive normally - the air conditioning!

We've been getting a roasting here the last couple of weeks with temperatures going up to 38-40 degrees daily so I switched the aircon on as even the air (what little there is of it) is hot!

Since last week, I'd noticed that my car had been running "off" - just not herself, with a noticeable lack of power at launch time. Yesterday, I switched off the aircon (which is set to the lowest/coldest setting with the a/c button on) and put down all four windows. The result? Instantaneous return of power. Tried my "theory" out several times just to prove I wasn't imagining things and sure enough, aircon on means loss of power.

Question: Is this normal?

EvoDraven

I have an STi8 and I have noticed exactly the same symptoms along with quite an alarming noise (I mean a noise that worries me, not the sound of the alarm!) when the air con is running. Turn the air con off and the engine noise disappears and the power returns.

[Edited by EvoDraven - 6/24/2003 6:40:02 AM]

uksti

they all do that sir

JohnS

iTrader: (1)

Yes,

it's a well known "feature". You don't get smoething for nothing, and it does take a fair bit of power to drive the air-con compressor, typically about 10 - 15 bhp I believe.

At low revs, on a low compression turbo charged engine, there isn't much power being produced anyway, and a steady 10bhp makes a big difference to the available power.

The system is clutch operated, and if you fully press the accelerator, then the air-con should disengage giving you full power.

John

missyc

and just think what affect 10-15 bhp loss does for us Sport drivers!

'aircon off' is now laughing known as my boost switch

Redkop

Also, IIRC fuel consumption goes up by approx 12% when aircon is on

STi-Frenchie

Thanks for the replies and explanations folks - good to know it's nothing I have to worry about.

EvoDraven - I also get a noise with the aircon on, sort of like a low whine, most noticeable when I'm stopped at the lights.

Redkop - increased fuel consumption with the aircon on would definitely explain why I've been filling up every two days instead of every three as usual, thanks for that!

SiDHEaD

Its not just a problem to scoobs really. It'll do it in most cars. If you're cruising along at constant RPM and shove the aircon on u feel the car lurch as the power is sapped.

Andy

SJ_Skyline

yup, great fun when you are driving a 65bhp Clio Diesel!! I sometimes get scoob_babe to get out and push

CataIunya

I thought the aircon gets switched off the second you accelerate ?

Huffer

hahaha - cant believe you peeps hadn't figured out the air con system eats power. My sport wagon revs higher at idle, about 750rpm vs. 500rpm when I switch a/c on!

It's now known as my "rumble" switch at the lights. I have a full zorst setup but the sports are naturally quiet at idle, so if I feel like rumbling I hit the a/c button.

The A/C also switches off if you have the fan set to zero. flick the fan on and the A/c should kick back in.