Fuel Economists,
US EPA/FEA mileage figures for the North American Spitfire (1978) were:
22 MPG City
35 MPG Highway
27 MPG Combined
This is about the MPG I got from my car when it was new (with complete
working emissions kit). I'm also getting about the same MPG when
running Weber DGV or dual SU HS4 carbs, but with signigicantly more
horsepower. Using OD pushes highway MPG to closer to 40 on reasonably
flat terrain. Weber DCOE carb cuts these numbers in half, but it
demands a more "spirited" approach to driving the car, which may
account for some of the drop.
When comparing US vs. UK MPG figures one must remember that Imperial
gallons (i.e. MPG figures) are (~x1.2) bigger than US gallons. We
have the same fuel tank. Also the US cars had "de-tuned" engine,
air pump and 3.89 diff. ratio further reducing MPG.
Renowned Spitfire expert John Thomason recently conducted some
interesting MPG/HP experiments by fitting a single SU carb setup
(from Dolomite 1300) to his car. He noted an increase from 33-34
MPG to 36-37 MPG (imperial gallons). Horsepower was slightly
higher with the single carb below 3500 RPM. Above 3500 RPM the
HP increased significantly with the twin carb setup. Full details
can be found in the June '98 issue of the TSSC "Courier" magazine.
Of course, as always...... YMMV
--
Bob Sykes
"Sometimes one pays most for the things one gets for nothing."
--Albert Einstein
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