sco mentioned in another thread that he was fairly happy with his fuel economy on long trips with the aircond on. As I bought my car in late Feb this year, it's a point I hadn't considered before.... that, and the fact I live in Melbourne.... :p It doesn't seem to me that the compressor puts much of a load on the engine, which would account for sco being happy with his economy.

So, to the questions......Have any of you Queenslanders noticed just how much effect the aircond has on the RX-8's fuel economy? Anyone done the figures? And just how good is the aircond on really hot days?

Cheers, Gomez.

 

Hi Gomez,

I can't notice any difference between air on / off, and taking it real easy and flogging it. It just seems to guzzle the juice no matter what, so might as well hook into it and get your monies worth!

My 2c.

Deano.

 

Hahaha, yeah deano,.....but I don't think the car guzzles fuel. Not when you consider the power output. It probably hold the record for fuel consumption/cubic cm of physical engine block size though!

I'd see a fair spike in consumption when on the fang, you're obviously heavy on the loud pedal all the time .

Air has come a long way, I reckon. My airconditioned V8's seemed to really suck through the juice when the air was on, and I notice when the compressor kicks in when I'm driving the XR8. The revs don't seem to vary at all when the air cycles on the Mazda.

Gomez.

 

I think that there is only a marginal increase in fuel consumption. However the air con seems inadequate on hot days. Especially in situations where you have to park the car in the hot sun.

skc

 

I've found the air con adequate even on the hottest days. However, my car isn't black.

Haven't got any hard facts on impact of air conditioning -- and will probably have to wait until next winter until I can get some!

 

I'm sure there are worse cars for fuel consumption, I'm using to driving a 3cyl 800cc Daewoo as my work car so anything is going to look bad next to one of those for fuel usage!

Deano.

 

I agree with Deano, I couldn't tell any difference in fuel consumption with air on or off, only on how heavy your right foot is.

The air con is enough for the size of the cabin and my car is black, I know because the weekend when I first got my car, it was the hotest weekend and it read 40 for amb. temp.

 

I recall doing a run to Sydney with a/c off, then driving back with it on, and measuring fuel consumption. It was, I recall, about 0.05-0.1L/100k more economical with a/c off; ie, negligible

 

Thank's for the replies guys and thanks for the figures timbo....when summer hits I'm gonna set it at 21deg and forget about it for four months. This is the first car I've had with climate control, I'll see how it goes.

Gomez.

Edit: actually, it's the second....I'd forgotten all about the bucket of puss Peugeot!

 

Expect a few control error Mez... teh fan speed goes up and down - sometimes it is just too cold for a 22 degree, other day it is too warm.

I think after Michael (L&L) told me to shift the rego sticker away from the sensor, it has been doing alright.

We will see. - today is kind of hot.

 

21 degrees?! Mine rarely gets set below 23. Maybe that's why I have no complaints about the performance of the A/C???

 

You too with the sticker? City Mazda pre-delivery need a rocket up 'em...

sco you have a good point about the temp setting, I experimented a little with the temp today and 21deg is a little too cold. Ideal room temp is 22deg, isn't it....? I figured a little less than that would be ideal since you're surrounded by glass. Must get the car tinted before the summer hits....

Gomez.

 

I agree, the change in fuel consumption is negligable with or without the a/c on. In fact, the extra drag of having the windows all the way down would probably give you worse economy than having the windows up and the air on.

I've heard that tinting the windows makes a big difference when it come to a/c effectiveness. My windows are tinted and I thought the a/c it was adequate last summer in Brisbane.

I believe ideal room temp is 23deg. My bank has a thermometer on the wall and it reads 23.1deg everytime I'm in there.

Remember also that the a/c disengages from the engine any time the throttle position exceeds 65%, i.e. overtaking etc. No need to leave the a/c off because you think you will get more power.

Wildcard

 

Most magazine experts seem to suggest that without air con and with windows open causes as much fuel consumption due to excessive drag caused by the window being open as with the air con running with the window closed.

As to the rego sticker, I think every dealer puts it there because that's where all rego stickers go. I should move it.

I've found that the air con will run higher if there is more sun on the car, so my guess is the light/sun sensor takes priority. Maybe its trying to be clever and compensating for soon to be a hotter car because the sun's out.

 

Timbo i have done that road plenty of times with another car.. Going to canberra always takes less fuel than coming back to sydney. Maybe its going UP towards canberra?

 

We did ~ 1000 km on the weekend with the A/C on, all open road stuff (Sydney to just north of nambucca heads and back) and averaged 10.1 L/100 km. including some big 3rd gear squirts to overtake dunderheads (I managed 10 cars in 1 single, smooth clean pass at one point D)

Car was GOLD all weekend.. :D A/C was great-- bordering on 2 cold at times..

Rowds