club.liberty.asn.au

How long before an engine can be considered to return the best fuel usage? I've done 2000km in a new MY10 wagon and I'm getting a consistent 12.6l/100km in a mix of 60% urban/40% freeway driving. Even being *very* light on the pedal it seems impossible to bring this down. If the 'eco' gauge on the dash is to be believed, a 100-110km/h freeway cruise sits *just* below the average 12.6l/100km.

I know the manufacturer's figures are usually hard to match, but this does seem to be quite a way off - do I need a few more '000 k before I worry.....?

Before anyone chips in, I didn't buy the car for fuel economy reasons (it's a turbo after all), but if Subie are marketing it as a significant improvement over the previous gen then it should be, right.

Get a bigger turbo and your fuel economy will drop to well under 10L/100km (between 7-9L/100km).. I am getting over 500km to a tank now (before mods just over 400km/tank).. This includes a lot of stop start in traffic morning & afternoons.. And I am in no way 'light' on the pedal.. I didn’t notice a great deal of increased fuel economy from new until car was modified.. Also I always use PB Ultimate.. I had to use a lower octane rating fuel out west once and fuel economy dropped for that tank..

rsp8 wrote:How long before an engine can be considered to return the best fuel usage? I've done 2000km in a new MY10 wagon and I'm getting a consistent 12.6l/100km in a mix of 60% urban/40% freeway driving. Even being *very* light on the pedal it seems impossible to bring this down. If the 'eco' gauge on the dash is to be believed, a 100-110km/h freeway cruise sits *just* below the average 12.6l/100km.

I know the manufacturer's figures are usually hard to match, but this does seem to be quite a way off - do I need a few more '000 k before I worry.....?

Before anyone chips in, I didn't buy the car for fuel economy reasons (it's a turbo after all), but if Subie are marketing it as a significant improvement over the previous gen then it should be, right.

hmm,

I thought the new models were meant to be better in fuel economy?

I get consistent 9.8-10.2lt/100kms outta mine post tune and 9.6-9.8lt/100 pre tune (factory)

I dont do heavy peak hour traffic driving, but its not freeway either - its surburban commuting to work and back every day. On the hwy I'd see mid 8's from memory (been a long time since I have done an entire fill on a fwy only drive)

To answer your questions I'd give it 5,000kms to truly free up

AdamW wrote:Get a bigger turbo and your fuel economy will drop to well under 10L/100km (between 7-9L/100km).. I am getting over 500km to a tank now (before mods just over 400km/tank).. This includes a lot of stop start in traffic morning & afternoons.. And I am in no way 'light' on the pedal.. I didn’t notice a great deal of increased fuel economy from new until car was modified.. Also I always use PB Ultimate.. I had to use a lower octane rating fuel out west once and fuel economy dropped for that tank..

your tune is what is saving you the fuel........

Boxer wrote:
To answer your questions I'd give it 5,000kms to truly free up

+1

senator wrote:
your tune is what is saving you the fuel........

Larger turbo kicks in at higher RPM……… Therefore if most of your driving is HWY & in traffic its hard to drive in such a way that your larger turbo kicks in… Where as when I had smaller turbo it was engaged more often on HWY and in traffic.. Thus using more fuel…

Also my mods were done in four stages over quite a few months as parts became available.. First modification being tune only (minimal increase in fuel economy)… Last modification being turbo (all of a sudden I had a massive increase in fuel economy……………

I've been keeping track of my fuel usage since I got my MY10 manual sedan and over the course of 9 tanks and just over 6000km so far my best economy is 8.27 and worst is 9.14, which roughly matches what the digital readout in the car says I'm doing.

I'd have to say I've done more longer highway trips but each tank has also had shorter runs mixed in and I've put no real effort into economical driving, if it matters I've been using sport mode most of the time with some sport+ and no intelligent mode since experimenting with it when I first got the car.

Got to agree somewhat wih AdamW re. bigger turbo being on boost less often during highway driving compared to the stock turbo in most setups.....however I don't think there is anything available for the MY10 as far as a turbo replacement yet. A good tune and a free'er flowing exhaust should net better fuel efficiency as most us know already as generally the stock tune can be quite rich out of the factory and the stock exhaust is inefficient.

Our MY06 2.5T XT was a great example.....averaged around 10l/100kms running a VF34/P20 (217wkw) (a 90% country run netted 8.5L/100kms).....prior to the tune and mods, best I could get was 13-14L/100kms. It had better off boost response than the stock setup simply because the inlet/exhaust/tune was more efficient.

The stock fuel maps in the 2.5L (pre MY10) are shockers from a fuel economy point of view. Unless you drive round in closed loop all day any decent sort of boost pushes you into a 10.x:1 AFR sort of zone. Elsewhere you'll find a full on track car running in the mid 11's say 11.5:1 AFR and at much higher boost levels too. There is quite a bit or room to improve your economy with a simple tune. I haven't seen an MY10 rom though so who knows. I can guess its pretty similar though
I've looked at the wifes car tonight an its smack on 11.1 l/100 kms compared to the stock 12.x L/100kms this is in heavy sydney traffic too where it takes you an hour to go 20 kms LOL
Oh yeah X3 for the motor being better after 5000 kms

Way more than 2000km to get representative fuel economy. At 5000km you'll notice better performance and economy than what you're getting now and it'll keep improving for a while after that. This has been consistent for me with 2 Subaru turbos + other non turbo subies. Our 2.5T has got around 47,0000km on it now and got best economy ever from it on holidays over xmas - 8.2l/100km on Midlands Hwy in Tassie.

2,500 km and coming down pretty rapidly now - easily achieve 10.6 on suburban commute to work, and the 10km freeway blast is running under that.....relief!

good to hear

FWIW my 08 gtb 6mt wagon gets ~10l/100km around town, not much freeway work, goes under 10 if I do some freeway work.
Went to canberra and back last weekend , sitting on speed limit all the way, got 8.0l/100km over 1400 kms. Its got 48k on it. 2 pax, luggage.
I suspect you need to let it bed in some more. Mine didnt really rev freely until maybe 10k. The longer the run-in takes, the longer it will last is my belief.
jp

I obviously need to stop WOT all the time.

MY08 with 25,000 odd and I average between 11-12.2 l per 100 Klm in city traffic.

GTB Liberty wrote:I obviously need to stop WOT all the time.

MY08 with 25,000 odd and I average between 11-12.2 l per 100 Klm in city traffic.

I got 15 l/100 off my last tank....

Lukovitch wrote:

GTB Liberty wrote:I obviously need to stop WOT all the time.

MY08 with 25,000 odd and I average between 11-12.2 l per 100 Klm in city traffic.

I got 15 l/100 off my last tank....

Giving the rev limiter a workout?