Fuel Consumption

[aroy7]

The trip computer polls every 100m or so and spits out a cumulative average fuel consumption for the whole trip up until that point. So right after you reset after filling up at the servo you are doing a lot of driving in 1st gear so average consumption for the distance you have driven since you reset is quite high... once you are on the highway your consumption is low and so you notice the average consumption decreases gradually until it eventually approaches your instantaneous consumption. Even though you use lots of fuel when in 1st gear, the distance covered is small so its overall effect on the average consumption is outweighed by the large distances and low consumption of highway driving. Of course if you never do highway driving and your sole use of the car is stop-start in 1st or 2nd gear, then the fuel consumption figure will not decrease as you have observed.

Also, the longer you have gone without resetting your trip meter, the harder it is to make the fuel consumption average change (since it is taking the average of all the fuel consumption figures since you last reset which may have been many thousands of kms ago).

It's all to do with the mathematics of taking an average I reset my Trip A about 20000 kms ago, the fuel consumption is a solid 8.5 L/100km which pretty much never goes up or down. Then I use Trip B to see my fuel consumption per tank.

Same here, the auto reset on fill-up function for the trip computer is genius!

[Euro_Dave]

I filled up my CU2 for the first time since getting it almost 2 weeks ago.

It took 57L to fill the tank and the Trip was on 635km. 10 km's into the "Low fuel" warning...(which I work out to be an ave of 8.9L/100)...however the onboard reading from the Trip computer was telling me I was getting 8.2L/100.

I am wondering if the computer only calculates the L/100 when the car is moving.
I have noticed that when the OSD is set to show real-time mileage, under acceleration it shoots right up beyond 15, on the FWY it seems to sit between 4-6 but when you come to a stop at the lights it falls to 0.

Obviously the car is still using petrol when idling (even though the computer is seeing 0L/100), so I am wondering if this may account for the difference in displayed mileage vs "actual" mileage derived from Litres required to refill the tank and kilometres travelled.

Does anyone have any thoughts on this, or able to explain why there is such a difference?

I thought 8.2L/100 was quite good until I did the maths after filling up and realised 8.9L/100 was still quite reasonable, but a far cry from the figure the computer was telling me. This is with approx 65% FWY, 35% urban/CBD driving - with only a couple of brief burts into VTEC territory (just to open her up and see how she went) - love that sound

I'm also not sure just how full the tank was when I picked up the car (or what fuel they put in it), so I am interested to see roughly how far the next tank of petrol lasts for (I decided to try my local/usual Vortex 95 for a few tanks and then Vortex 98 to see the difference - if any).

Lovin' the Euro!

Dave

[noel]

Hi, All

My base model Euro (don't t know the model designation, but it's a MY2013) now with 1500 k's on the clock, is doing 15l/100K's mainly around town driving - and, in case you're wondering - I'm no geriatric racer.
On the local freeway it surprised with 6.5. The motor doesn't appear to be running rich and both tailpipes are showing no sign of sooting.

The car generally is loosening-up nicely.

Any idea when I can expect fuel mileage to improve.

BTW Following one test that returned 10.7l/100, the Distance to Empty read-out was 720 kilometres - from a full 65 litre tank. Perhaps it's more intuitive than we give it credit for?

CHEERS
NOEL

[Jasemas]

Is it an auto?
Or manual?

How'd you go with breaking in the engine?
And what RON fuel do you use?

How do you calculate fuel usage? By the trip meter
Or fill up and divide by kms travelled?

City driving ALWAYS uses more petrol

[noel]

Hi, Jasemas

My Euro is an auto, which was driven normally during break-in, giving it a few extra revs in short bursts occasionally on the freeway.

I fill from halfway, alternating 95 and 98 RON.

Fuel consumption is calculated by the trip meters, one of which hasn't been reset since new.

If the motor is started, I always run it until fully warm on the road.

Recent cars have all been heavier on petrol around town; matter of fact, my Honda Civic '09 model, often came in at 12/13l/100k's around town, and 6 or so on a run. The Euro with 1000 k's on the clock, used 6.5 l/100 over 150 k's mostly on a freeway.

Time and kilometres will tell I guess.

CHEERS
NOEL

[Jasemas]

Reset the trip meter as its giving you an average over 1500kms, not the recent 200kms or so travelled
So it's going to be inaccurate
And yes the car is still in its break in period

[Euro_Dave]

Hey Jasemas,
Do you have any thoughts on why my "displayed vs actual" mileage is so different (8.2 displayed vs 8.9 L/100 actual) - as posted above?

And have you or others here found a similar variance?

I suspect it's a bit like your speedo showing you're doing 100 km/h when in reality you're only doing 96 km/h or so...???

Dave

[Jasemas]

I have no idea
I don't own a cl9/cu2 - butt will do in the future and have read ALOT into them
I'd suggest doing a manual recording of fuel used - write down how many litres put in and how many km's since last filled up
Rather than trust the computer

[Euro_Dave]

Yes indeed.
I have started keeping a log of km's travelled per tank, L required to refill tank (and which RON I have used) along with displayed mileage vs actual mileage - so after several tanks I hope to see a pattern.

Cheers,
Dave

[noel]

Reset the trip meter as its giving you an average over 1500kms, not the recent 200kms or so travelled
So it's going to be inaccurate
And yes the car is still in its break in period

Sorry, I should have mentioned that Trip A has not been reset from new, but B is reset at each fill-up.

Good to read that car is still in its break in period; it seems to be running even better each day.

CHEERS
NOEL

[Fredoops]

Btw don't be too gentle during the break-in period either, it's known to cause issues.

[noel]

Btw don't be too gentle during the break-in period either, it's known to cause issues.

Ta, Fredoops, I've heard that. I once asked a salesman about 'running-in' our new Civic and he commented that I could 'drive it like buggery, up to the Queensland border' (from Newcastle) and could come back 'with an extremely good car, at least with a bloody good car'. I think he was saying to run it in hard. As. It turned out , I drove it normally -- and it took 40,000 k's before it really performed at its best. Virtually the same with the next Civic (2009 LE). I'll start to give the Euro more work to do, I reckon.

It's now done 1500 k's and I still believe the car doesn't steer at low speeds, like it should. The brakes, when new, were a bit 'nothingness' , but have improved nicely.

CHEERS
NOEL