> Can you tell me some more about these pumps? For example, do they
> have a positive earth model? Are they bolt and connector compatible
> with stock SU pumps?
Don't know the answer to either question, my Midget HAD a mech fuel pump on the
side of the engine. I ripped this out and ALL asscoiated fuel lines, canisters
and other garbage. Then I fitted the fuel pump on the underside of the body,
on the vertical part next to the prop shaft. Used a combination of rubber fuel
line and rigid fuel line to get to the carb.
> I'd like to get a new carb for my '80 Spitfire 1500.
> I'm looking at a single Weber side-draught vs. a single Weber
> down-draught. Is there a significant difference in performance?
> fuel economy? (not a big problem -- the Spit's just for fun)
I have both the downdraft and the side draft on the Midget 1500 (obviously
not at the same time !!!!!). The difference from the Zenith to the downdraft
was phenomenal and in creased mileage from 30mpg to 34 mpg.
Installation was simple, even the linkage hooked up directly, and I converted
to a cable choke (I prefer the manual control over the water type chokes)
It is advisable to fit a 4 branch exhaust manifold when installing the Weber,
clearance with the stock manifold is a pig (and you have to do some grinding
to make it fit)
I have not tried the side draft yet, I was going to do it over the weekend,
but I read the relevant chapters in David Vizard's book and decided to do some
research before I bolt the side draft on. Bolting the side draft on will
probably do nothing to the performance of the engine. These carbs have to
be tuned for the specific engine. As David says just bolting the side draft
on will probably harm performance, until the carb is tuned. He makes
a very good analogy between a simple point-and-shoot camera and a
sophisticated camera in the hands of a professional photographer
and a layman.
My opinion is if you want to get as much power out of the engine (and
can live with the 20-24 MPG), then get the sidedraft (DCOE 40 or DCOE 45 ?)
learn how to tune it and start collecting various jets/chokes/emulsion
tubes etc to fine tune the carb (BTW - the only way to properly do this
is on a dyno)
> I think the conventional wisdom is that the side draught is a better
> performer but is worse on economy. I have not seen any direct comparison
> to back this up however.
I agree
> problem. I have a friend who put on the down draught and he has a gone
> through a couple of accelerator cables because the linkage kit that came
> with the carb made the cable come in at a funny angle. This caused the
> cable to rub against the cable guide.
I have not had this problem
> I would recommend the TriumphTune performance catalog to any Triumph
I agree
Gerry
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