Hi all, just a quick update on my fuel consumption and efi thoughts:
Firstly fuel - my car has averaged 13.9mpg , including a c.150 mile drive home from Warminster to near Cambridge on mostly dual-carriageway (what a wonderfully old-fashioned expression!). My intial horror at a fag-packet calculation of 10mpg came from assuming the fuel gauge was accurate, but it seems a tad on the pessimistic side. Unless it doesn't take account of the reserve?
Otherwise I absolutely luuurve the car. I adore idiosyncratic touches like the plaited leather glove-box handle, the weight of the switches, the flip-up front wings and the lovely chrome seat brackets. It's really comfortable, the ride is good now that I've got the (new) rear dampers on their softest setting, the brakes and steering are great and I've solved a lot of the (terrible) windnoise from the driver's door. I'm hoping that the rest of the windnoise (or most of the rest, in view of the age of the shape) will be solved when I get the driver's door hinges rebuilt over the winter. I haven't started on the oil leaks yet, (in a sense it's free rustproofing) so the only really annoying thing is it's reluctance to start when cold......
So I've thought long and hard about the cost/benefits of a new Carb vs an aftermarket efi, originality vs efficiency, and so on. In the end I summed it up in my mind as shotgun/carb vs rifle/efi: both are effective but the rifle is more controllable, more precise and less wasteful. With efi the fuel/air ratio is essentially commanded via sensor input, especially with a wide-band oxygen sensor covering a wider spectrum of A/F ratios. If I've understood a carb correctly the A/F is reactive - dependent on pressure drop & jet sizes. So I've pretty much decided on a Holley Sniper 550-516; and a Holley in-tank drop-in returnless fuel module with a 255lph pump and Hydramat reservoir 12-131. I hope to use the existing supply line and I won't need a return line. The engine bay will still look largely the same, especially if I leave the existing machanical fuel pump in place (without the pushrod, and with a new gasket to stop the oil leak!) so it acts as the block-off plate. Any rubber lines will be R9. So I'll have a stealthy ethanol-proof system that seems to get good reviews and is 40+ years more advanced than the worn-out Carter which is currently in place. Will order from Summit Racing and do the deed over winter. Will report back then. And yes, I will have a grown-up holding my hand in case you're worried......
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