[adj50]

My new i30 1.6 gasoline 4 speed auto is 5 months old now with 4,500ks, 90% in city/suburbs. Fuel consumption has moved up from an initial avg of 7.5LHK during the first 2000ks to 10LHK and I was disappointed and curious as to why?
 It’s now winter in Melbourne, temperature average high-low is 14-4c and often windy and wet. So my driving pattern has changed –it has become mainly short trips to the 3 closest shopping centres i.e. 1,2 and 5 ks per one way trip respectively. The car’s government rated urban (city) consumption is 8.9LHK. I was surprised and disappointed that, despite my economic driving style, I was, with 10LHK, well above that number. So I set about researching just why and what I could do about it.

I began with some carefully managed checks.

The first was a 80k trip of urban eco styled driving through Melbourne suburbs stopping for about 10min respectively at 3 different Hyundai workshops to discuss i30 fuel consumption with the staff – the resulting brim-to-brim avg was 6.5LHK. Great –that indicated that the car’s technical performance together with my eco driving style was working effectively.
As a second check, out of curiosity, I set off down the freeway and drove 100ks, relatively flat, fine weather, cruising eco style in medium density traffic at 100kph. The avg this time was 5.5LHK, which is under the government rated extra urban (country) consumption of  5.9LHK. 

The cause of the 10LHK obviously appeared related to the numerous cold-start short trips, so I started researching the subject on the internet. I found a lot of generalised statements about the impact of rich fuel mixtures during cold starts, and their significant impact on fuel consumption, but no comparative tests of individual cars and conditions.

So over many a long evening, I dug deep into spritmonitor.com and noted the driving/consumption stats of over 100 owners of the contenders in my original buy decision i.e. Hyundai i30, Mazda 3, Corolla, and Golf cars, with gasoline engines, auto transmissions, who drove exclusively in the city, and filled up only every 3-4 weeks indicating mainly short trips. While this is certainly not a robust scientific study, the numbers, in summary, showed that these cars were averaging between 10-12.5LHK, which is 10-30% above their respective government rated urban consumption.

Conclusion: As they say in Australia, “I am a very happy little vegemite”. My i30 is, comparatively, a very economical car, conditions considered. And while 10LHK was a shock, I have, during winter, only driven half the distance I had originally budgeted for, so money wise, I am way in front. And as we all know, the most economical car is the one that spends the most time at home in the garage.

[Phil №❶]

Glad you're happy with the results & good that you bothered to find the information rather than just simply complain. As the infernal (sic) combustion engine is a thermal engine, a lot of energy is used in initially heating itself up to operating temperature. You shouldn't expect to get anywhere near the quoted figures until the engine has reached operating temperature. During the warm up period the mixture to the engine is purposely set to rich and the oxygen sensors in the exhaust are effectively out of the loop until the exhaust reaches operating temperature also. This has a detrimental effect on fuel consumption.

[Dazzler]

 

Excellent post adj50.. makes me feel  a lot better about the current elevated fuel useage of our Hybrid Camry..

With less, long highway trips and a particularly cold and wet winter here in Tassie it has crept up to 6.6 LPH (usually around 6.3 and recently averaged 6.1 in March/April on our 5000km mainland driving holiday)

[Surferdude]

Excellent post adj50.. makes me feel  a lot better about the current elevated fuel useage of our Hybrid Camry..

With less, long highway trips and a particularly cold and wet winter here in Tassie it has crept up to 6.6 LPH (usually around 6.3 and recently averaged 6.1 in March/April on our 5000km mainland driving holiday)

The batteries are wearing out Dazz..............................

[Dazzler]

Gee, I hadn't thought of that 

[Doggie 1]

Stick your tongue on them and see if you get a tingle.

[rustynutz]

 

[Dazzler]

Stick your tongue on them and see if you get a tingle.

Don't think I will .. It's something like 200 volts i think 

[rustynutz]

That should get the old heart pumpin'! 

[Dazzler]

That should get the old heart pumpin'! 

I would have permanent sleep apnea   

[rustynutz]

 

[Lester]

My December 2011 build i30 Trophy 2L manual now has 1400km on it.  The first 300 km, I thought it was a bit thirsty, but now engine is run in, getting better economy, I reckon I could get 750km from a tank of 53 litres.  Am only putting 95 or 98 grade petrol in it.

So!  Is there any truth in the rumour that new engines burn more fuel?

[Dazzler]

I've had way to many new cars and I'm not convinced... My economy have never improved by a large (noticeable) amount  (no doubt I will get shouted down by some for saying that) 

[rustynutz]

I won't shout you down. Daz.....

I believe a new engine will use slightly more fuel but, in saying that, it's probably not as noticable in more modern engines because the manufacturing tolerances are more precise than back in the good ol' days.
Regardless of this, things still need to "bed" in....

[Doggie 1]

Plus we probably tend to drive more sedately in a brand new car.