Unleaded Fuel – Raw Figures

Explanation of the Fuel Consumption Figures

These are the raw fuel consumption figures from when my Triumph Spitfire 1500 ran on unleaded fuel – after a new cylinder head was fitted. These figures were used to create the graph of unleaded fuel consumption.

The consumption figures are in miles per litre (mpl) as this is the easiest values to record in the UK now fuel is sold in litres. But for those who prefer miles per gallon (mpg) figures, a UK gallon is approx 4.5 litres. So:

9 mpl = 40.5 mpg
8 mpl = 36 mpg
7 mpl = 31.5 mpg
6 mpl = 27 mpg

Table of Figures

Date Litres Miles Actual Values Rolling Average
19 Apr 1999 16.89 144 8.53 8.53
20 Apr 1999 18.54 153 8.25 8.38
23 Apr 1999 19.97 154 7.71 8.14
05 May 1999 20.60 99 4.81 7.24
10 May 1999 22.07 181 8.20 7.45
23 May 1999 20.37 192 9.43 7.67
30 May 1999 12.81 91 7.10 7.48
12 Jun 1999 25.95 163 6.28 7.13
12 Jun 1999 19.60 173 8.83 7.94
14 Jun 1999 15.66 112 7.15 7.74
18 Jun 1999 18.08 143 7.91 7.40
19 Jun 1999 13.35 73 5.47 7.17
30 Jun 1999 20.86 186 8.92 7.85
18 Jul 1999 20.29 178 8.77 8.02
29 Jul 1999 19.18 150 7.82 7.84
02 Aug 1999 20.36 163 8.01 7.96
19 Aug 1999 21.61 179 8.28 8.03
31 Aug 1999 21.32 173 8.11 8.32
04 Sep 1999 22.52 195 8.66 8.29
11 Sep 1999 15.86 159 10.03 8.55
04 Oct 1999 19.78 130 6.57 8.27
09 Oct 1999 8.04 61 7.59 8.20
17 Oct 1999 22.08 187 8.47 8.29
07 Nov 1999 13.73 118 8.59 8.24
20 Nov 1999 21.20 190 8.96 8.39
28 Jan 2000 16.70 106 6.35 7.80
29 Jan 2000 17.59 153 8.70 8.20
11 Feb 2000 15.70 108 6.88 8.06
13 Feb 2000 16.19 154 9.51 8.20
26 Feb 2000 19.66 160 8.14 8.14
20 Mar 2000 15.00 129 8.60 8.03
20 Mar 2000 8.95 87 9.72 8.30
25 Mar 2000 17.71 160 9.03 8.58
11 Apr 2000 20.21 152 7.52 8.38
12 Apr 2000 13.77 115 8.35 8.58
12 Apr 2000 10.07 92 9.14 8.49
22 Apr 2000 18.36 174 9.48 8.64
24 Apr 2000 12.68 114 8.99 8.76
29 Apr 2000 20.63 171 8.29 8.70
29 Apr 2000 13.13 129 9.82 8.75
05 May 2000 17.45 168 9.63 9.08
07 May 2000 15.61 145 9.29 9.21
20 May 2000 18.32 140 7.64 8.86
21 May 2000 18.34 175 9.54 8.97
03 Jun 2000 20.36 163 8.01 8.91
09 Jun 2000 15.41 141 9.15 8.83
11 Jun 2000 14.65 123 8.40 8.64
15 Jun 2000 23.44 185 7.89 8.39
17 Jun 2000 20.49 171 8.35 8.50
18 Jun 2000 12.27 112 9.13 8.39
01 Jul 2000 16.58 112 6.76 8.21
22 Jul 2000 16.75 141 8.42 8.10
05 Aug 2000 15.65 118 7.54 7.98
12 Aug 2000 12.12 111 9.16 8.15
14 Aug 2000 15.86 137 8.64 8.19
11 Sep 2000 22.71 179 7.88 8.01
23 Sep 2000 18.12 142 7.84 8.18
24 Sep 2000 11.04 94 8.51 8.18
15 Oct 2000 17.77 99 5.57 7.81
05 Nov 2000 12.28 124 10.10 7.93
05 Nov 2000 9.15 63 6.89 7.70
11 Nov 2000 13.60 123 9.04 7.87
18 Nov 2000 16.18 130 8.03 7.91
13 Jan 2001 20.24 140 6.92 7.61
03 Feb 2001 20.45 141 6.89 7.85
03 Mar 2001 16.86 128 7.59 7.51
31 Mar 2001 21.35 171 8.01 7.66
01 Apr 2001 18.58 175 9.42 7.79
12 May 2001 12.31 78 6.34 7.59
29 May 2001 25.26 189 7.48 7.68
30 Jun 2001 10.30 75 7.28 7.80
14 Jul 2001 20.49 163 7.96 7.86
22 Jul 2001 17.32 163 9.41 8.09
16 Aug 2001 15.80 127 8.04 7.83
20 Aug 2001 18.96 163 8.60 8.14
22 Aug 2001 13.32 110 8.26 8.33
01 Sep 2001 15.55 138 8.87 8.52
17 Sep 2001 21.31 172 8.07 8.54
22 Sep 2001 16.53 148 8.95 8.46
13 Oct 2001 21.24 149 7.02 8.23
04 Nov 2001 19.58 173 8.84 8.28

Significant events during this period:

  • 9 July 1999 – Full service + carbs cleaned out.
  • 17 October 1999 – Multispark fitted. (see Note 1 below)
  • 8 February 2000 – Kenlowe fan fitted. (see Note 2 below)
  • 17 April 2000 – Service + leaky exhaust manifold fitted.
  • 9 February 2001 – Full service.
  • 14 October 2001 – Service.

Note 1

The Multispark is a unit placed in line with the lead to the distributor cap which delivers many sparks instead of one big one to each of the cylinders. Although as you can see there seems to be little or no impact on the fuel consumption, the engine was immediately a lot smoother and appeared to have more power so I perservered with it.

The pre-Multispark average consumption was 7.86 miles per litre and the average after was 8.25 miles per litre.

Note 2

The Kenlowe fan is an electric fan which replaces the previous mechanically driven fan. I was not expecting there to be much effect on fuel consumption, but there seems to be a small boost to the rolling average shortly afterwards.

I’d always recommend fitting a Kenlowe fan as the car was a lot quieter afterwards. Also there were no more tense moments sitting in heavy traffic on a hot day watching the temperature gauge rise. You can see a picture of the Kenlowe fan at the bottom of the Car History page.

 

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