fuel economy

[98se40]

Hi Guys,

I have my 98 4.0 and the engine has been completely rebuilt, as I had the misfortune of blowing it up. It is now fantastic.
Everything on the car works and runs like a dream.
The only issue I have is the fuel usage. I only drive about 6klms to work and 6klms home again per day. I use 95 octane and I always reset the fuel consumption when I refill.
I only get between 22-24 litres /100 around the city....on a trip I get approx 12-13 / 100.
Is this normal due to my short trips only? The car itself doesnt miss a beat, purrs beautifully etc etc, plenty of power.
Any advice would be appreciated

Cheers

[BigJon]

Sounds pretty close to right to me.

[PhilipA]

I only get between 22-24 litres /100 around the city....

With a 6km trip , about 1.5-2KM will be under 82C when the injection goes off enrichment.
I now have a digital temp gauge on my 92RRC and it takes over 2Km to get to 82c.The GEMS has the supposedly faster warm up but still it will take quite a while.
Even on my Honda Jazz , the consumption goes from about 6.5 L per 100Kms for 13Km trips ( over a mountain), to over 7 Lper 100 Km if it does only short trips.
Regards Philip A

[RR P38]

I agree also.
I run about 20 round town and the wife gets it up round 22.5.
Its always good on a trip.
So the 4L has the same consumption as the 4.6L

[pat911]

As a contrast to resetting the fuel consumption on every fill, I only reset mine every couple of thousand kays. My long term fuel consumption, which includes both highway and city driving is about 18 l/100. That's on a 1995 4.0l with 250,000k on it.

I've read that the 4.6l can be more efficient than the 4.0l because it works less hard. Remember, both motors are pushing around the same weight with the same rolling resistance so differences in fuel economy will come about due to different efficiencies of the motors and how they are driven. Just because a motor is "bigger" doesn't necessarily make it thirstier, especially when pushing the same vehicle.

Cheers
Pat.

P.S. My fuel consumption also goes way up when the wife is driving.

[Hoges]

Same figures here, esp in winter, which is why I try and avoid short trips (<25km) in mine unless i'm carting something somewhere...

Driving 6km back and forth, especially in the colder months, probably with aircon operating as well, is in reality an example of "extreme" operating conditions. On the weekend you might consider going for a 50km (at least) uninterrupted run to bring the engine up to operating temp and getting rid of condensates etc which build up in the sump as a result of blow-by. If this is a constant feature of operating then you need to change the oil more frequently also.

By way of comparison, my wife's Astra 1.8 achieves only 10-11.5 l/100km (at the pump) in stop-start traffic on the inner city 11km round trip to/from her work each day... but 6.8 -7.2 L/100km on a round trip from Bris-Toowoomba (250km)!

[PaulP38a]

My 1999 4.0 gets 20+ l/100Km around town while my wife's 2000 4.6 gets 16-17. There is some merit to the theory that the bigger engine runs more efficiently.

Even my 3.6L Crewman ute gets no bettter than 16-17 around town.

The TD4 Freelander puts them all to shame... but ONLY in terms of economy... not quite true, it is more comfortable than the Crewman.

[PeterAllen]

Over the past 13,000 klm my 4.6 has an average of 16.1 litres/100km. I would estimate 3,000km would be above 80km/highway driving and the rest city urban stop and start. The average speed recorded on this was only 37kmper hour. My drive from home to work is 13km in mostly heavy traffic and is reading 17.8-18.0. By the sounds of it the 4.6 may be a little better at the pump then then 4.0 (at least around the city).

[jsp]

I would hav thought 20+ per hundred is a bit high, mine used to chew between 16-18 around town and 11-12 highway, untill it was tuned for lpg and then those figues went UP.

The classic gets low 20's around town.

The TD6 happily sits on mid 11's around town

[Keithy P38]

Tyre size may also effect fuel comsumption, I noted that my speedo was out with the standard 255/65/16 tyres on both P38's that I've owned. At an actual 100km/h they both read 108km/h, with my current 255/70/16 tyres at an actual 100km/h my speedo now reads 99km/h. This showed in fuel consumption.

Pre tyre change I would usually average 15l/100km around town, now I'll see an average of around 16l/100km.

That's in my '99 4.6 Bosch with 230 000km on the odo.

Cheers
Keithy

EDIT: those are dash displayed figures, at the pump there is almost no difference.