the Walnut Diary

Without a bulk diesel tank at the farm I run down the highway to the local service station for tractor fuel. Out of curiosity I measured the TAFE’s consumption over a week of bush hogging around 20 acres of seedlings. Note at the end of the article I built in a correction for tach hours.

1995 Tafe 351DI fuel consumption observation

June 9-13, 2010

5′ medium-duty rotary mower, trimming long grass, medium density to light on moderate slopes
8.5 km paved road surface transit

hrs observed 424.5- 412.8 = 11.7

tank topped 28.31 litres

consumption rate 2.41965812 litres per hour at PTO speed

According to the charts I found on the Internet, it must be using between 16 and 18 hp to do its thing with the 710 lb. cutter, loader, loaded tires and all.

Here’s the lastest raw data.  Again I was mowing medium to light hay and grass, though I ran the TAFE in high range, first gear today to see how the new mower would cut at a ground speed of about 6 mph.  No problem.  That’s not a misprint below:  the thing seems to use $2.00 worth of diesel per indicated hour at June, 2010 diesel prices in Ontario.

UPDATE: The manual states that the tach/hour meter measures at 1500 rpm. Pto delivers 604 at 2000 rpm, so that means it runs at 1788.07947 to deliver 540 pto rpm. So if you multiply the consumption rate by 1.19 you’ll get a more accurate figure, somewhere between 2.5 and 2.8 litres per hour. Still good, but not unbelievable.

july 18/10 449.3 449

30.88 12.7

2.431496063 litres per hour at PTO speed

Corrected, that’s 2.89 litres/hour for this interval.