Fuel Consumption

14 September 2008

Early fuel consumption figures indicate that the “sweet” speed for our Winnebago Motorhome is approxiimatley 85-88 kph (flat and wind free).  Indication to date is 13.6 litres per 100k’s at this speed.

These early numbers are confirmed by the recent economy run involving several Winnegabo Motorhomes being driven from Queensland to Winton in Victoria under controlled conditions.  Bottom line was that 85-90 provided the best economy.  It was also revealed that by “putting the foot down” and increasing speed to 110 kph, fuel burn increased to 18 litres per 100 kilometers.

You don’t need to be Einstein to figure out the additional cost.

26 October 2008

We monitored fuel consumption on the return journey from Fingal Bay via Newcastle and the F3 to Hornsby and taking into consideration a couple of long hills where the consumption rockets, the overall result doing around the 90-95 kph mark (as per GPS as the speedo on the Iveco is out by about 4 kph) was 14.01 litres per 100 kilometres. Under the circumstances, we were very pleased with this result.

22 November 2008

We monitored fuel consumption over our weekend trip to Moss Vale via the M5 and then the Hume Highway.  Our experience with the new motorhome had indicated that the best speed for fuel consumption is around the 85 kph mark.  Our previous fuel fill was at Newcastle with average comsumption being 13.7 litres for the trip back to Sydney.  As we headed south, we watch as the average consumption steadily rose until it reached 16.41 litres.  This was the result of driving directly into the wind for about 120 kilometers.

Average fuel consumption on the return trip fell to 14.01 litres per 100k’s overall by the time we parked the motorhome in our drive away.

On one occasion on Saturday, the IVECO computer indicated that the current consumption was 22 litres per 100k’s (into the wind).  On the same stretch of road on Sunday, we were cruising along using 7 litres per 100k’s.  This was with a direct tail wind.

21 March 2009

We have kept detailed fuel consumption records of our trip over the past three weeks.  Unfortunately the results have not been as expected.  The vehicle is heavy and is being operated close to the maximujm GVM of 4495 kg.  We have averaged 16.14 litres per 1ook’s (manually calculated on distance against refill) over 3000 kilometers.  This is slightly higher than the average shown on the Iveco trip computer.  The average was impacted by very strong head winds early in the trip when the consumption was 18.38 litres per 100k’s.  Best average was 15.53 when travelling from Horsham VIC via the Grampians to Ballarat and on to Bendigo VIC.  We having been maintaining a speed of around 83 kph and note a rise of 2 litres per 100k’s when increasing to 90.

18 October 2009

We have continued to keep detailed fuel consumption records and it is now clear that the economy is not the same as that achieved with the previous Blue Snoopy.  In considering the economy, we have to consider that the current Blue Snoopy is over 400kg heavier than the first and the shape of the vehicle could provide some additional drag.

According to the Iveco’s computer (which we suspect is out by about 1.5 litres per 100 k’s), we are using around the 13.8 mark when traveling around the 90k’s per hour and this increases to 15 at 100kph.

Manual calculated figures would be 15 and 16 litres per 100k’s respectively.  We have found that there is not a significant difference in consumption between the speed of 83 kph (our initial “sweet” speed) and 90-93kph.  Range is calculated to be in the vicinity of a very safe 530 kilometers and probably up to 600 kilometers if you want to take the risk and this is also dependent on wind direction.

The difference in consumption between the lower and higher speed need to be considered when compared to the time saving from travelling at a higher speed.  In some cases, the savings in time from increasing speed by 10-15 kph far outweighs the cost of the additional fuel.  We will put this to the test when traveling to Victoria in November as a maximum speed of 110 kph for 5 to 6 hours to Albury NSW seems far more attractive than 80 kph for 7 to 8 hours when the cost for the extra 2 hours is only about $23 in diesel fuel cost or about $12 per hour in time savings.

21 May – 24 May 2010
(from our blog entry)

We monitored fuel consumption on our recent trip to Canberra in the ACT.

Fuel consumption on the way down became a major concern when consumption started to head towards 17 litres per 100k’s when travelling in the 95 to 100 kph bracket.  We slowed to around 90 and fortunately watched the consumption slowly reduce to an average of 15.80 litres per 100k’s.  We have travelled at this speed before and cannot ever recall seeing the consumption that high.  The only thing that we can put it down to is that we were travelling directly into a subtle head wind that was in no way obvious.

Much to our surprise, our return trip was very fuel efficient.  Average speed on the return journey was in the 90 – 100 kph bracket but the fuel consumption averaged at near 13.10 litres per 100k’s.  How did this happen, we have no idea other than assuming that there must have been a tail wind and the engine temperature contributed to the excellent economy?

Tank Size

I mentioned above that the “Range is calculated to be in the vicinity of a very safe 530 kilometers and probably up to 600 kilometers if you want to take the risk and this is also dependent on wind direction”.  Prior to collecting the Winnebago, an advertising brochure for the vehicle suggested that the fuel tank size was 100 litres. There were the usual caveats regards the accuracy of the information “correct at time of publication” .  When delivered, the Iveco documentation confirmed that the tank size was only 90 litres.  This was not a major issue but highlights the need to exercise care if you calculate the range of the vehicle against consumption figures.  Until we confirmed the size to be 90 and not 100 litres, we believed that we had a reserve which was not the case.