help! my MPG is dump!!

[fade2grey]

my ave mpg drops a lot while the car is warming up, then creeps up (if I'm lucky) - short runs in this weather will kill your average mpg [img]images/graemlins/frown.gif[/img]

lpg anyone? [img]images/graemlins/smile.gif[/img]

A

[daddyjohal]

i always thought warming the car up while staionary was 'bad' for it, isn't it? any idea why the mpg drops with this weather? isn't all that lovely cold air good for turbos?

[chris22]

So did I [img]images/graemlins/confused.gif[/img]
Colder air means better performance (less heat)
Better performance means more fuel being used
I think.. Anyone think different.
Bass [img]images/graemlins/s3addict.gif[/img]

[fade2grey]

warming up while stationary isn't recommended.. something to do with oil pressure not being enough at tick over & the bores wearing.

Cold air is great for turbo's - more dense air & fuel means more power [img]images/graemlins/wink.gif[/img] but all of this is designed to work in a specific temp range so it's a case of drive easy until your water & oil temps are up, ideally trying not to hammer your turbo's too much (pretty hard on the S4 since they come in at about 5rpm!).

[samtheman]

warming up while stationary isn't recommended.. something to do with oil pressure not being enough at tick over & the bores wearing.

oh sh1t, i start my car on cold mornings and leave it running for about half an hour to defrost it.. [img]images/graemlins/033102bad_1_prv.gif[/img] it cant do it to much damage can it??

[daddyjohal]

apparently so. oops!

[samtheman]

who told you that?

[wazza]

i start my car on cold mornings and leave it running for about half an hour

and you wonder why you have bad mpg figures [img]images/graemlins/confused.gif[/img]

[samtheman]

he he fair enough, but i haven't done that for atleast 3-4 tanks of petrol..actually, when i did do that, the mpg figures were higher anyway!?? [img]images/graemlins/spineyes.gif[/img]

[daddyjohal]

who told you that?

READ YOUR OWNER'S MANUAL!!!!!!! [img]images/graemlins/wink.gif[/img]

[samtheman]

oh!! [img]images/graemlins/suicide.gif[/img]

[DavidT]

Manufacturers recommend warming the car up with gentle driving. This is because the warm up period causes most (70% ?) of engine wear so the longer the engine spends warming up, the more wear it suffers.

With the S4 i'd say no boost if possible until the oil is at least 90 C because the turbos are a weak element of the car and should therefore be warmed (and cooled down) gently.

Just my 2p

[daddyjohal]

off the top of my head, i don't think my oil temp ever reads 90c!

[ajsl]

I take it pretty easy until the oil temp is a least over 60deg. I don't really see the temp over 90 very often though! Perhaps I'm too easy on it [img]images/graemlins/wink.gif[/img]

[fade2grey]

With the S4 i'd say no boost if possible until the oil is at least 90 C because the turbos are a weak element of the car and should therefore be warmed (and cooled down) gently.

Yup, I'd agree with that, though once the water reaches 90 the oil gauage is alredy at about 60-70 degrees on mine. As long as the oil guage is moving I start to give it more gass. Mind, it's hard not using the turbo's - I was amazed when I first got the car, driving down the road with the window down, you could hear them spool from about 13-1400 rpm! cool! [img]images/graemlins/smile.gif[/img] My alfa 155 Q4 does NOTHING until about 2800 & then wham it gives you the lot! - it also pulls full boost to the redline which I miss but hey, the S4 is more comfy! [img]images/graemlins/smile.gif[/img]

A