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Andre Jute Andre Jute is offline
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On Sep 9, 2:54 pm, "Dave Plowman (News)" wrote:
In article om,
Bret Ludwig wrote:

The snag with the DCOE Webers and similar designs is the poor
atomisation at low flow rates - ie low engine speeds. It can also be
near impossible to get smooth progression. The SU alters the venturie
size to keep relative airflow speed high to aid atomisation. The
downside of this is you can't make such a clear flow path at maximum
power. But for road cars it's a good compromise. Other ways of course
are twin choke designs with a small and large venturie - but these
aren't known for long reliable service life. Other thing with fixed
jet carb is there is no compensation for the inevitable wear - an SU
unless bodged or neglected can be adjusted as needed.

90% of carbs on the US road anymore, if not 95% are four barrel
Holleys with progressive operation, two small and two large. Most are
on 60s-80s V8s.


Interesting point was that just about the only US V-8 that ended up being
made in the UK was the Buick unit which became the Rover one - and gained
some 20 bhp when being fitted with SUs. Of course that wasn't the only
mod. But I'm not sure what the original carbs were.


The particular aluminium engines that came from Buick to Rover were
marine engines, if that gives a clue to their carburettors and tune.
If you're right and they picked up so many horses on being fitted with
SUs, they couldn't have put out more than about 110-120hp in US trim.
We had one out of a Rover Coupe on the dyno in the middle 60s and it
was good for less than a four and a quarter Bentley engine, which was
pretty choked and good only for a smidgin under 130bhp. (I seem to
remember people often spoke of 135 horses for that engine in the Mk
Vi.) We were looking at the Rover V8 because back then it was the only
engine we knew with any power that two guys could pick up between
them, a wonderful thing. It wasn't much chop though; a very unreliable
engine if you breathed on it even lightly. Still, a decade later it
made the SD1 into one of the greatest cars BL ever built; such a pit
they didn't see fit to carry forward the second-best thing about the
P8, the De Dion rear axle, a beautiful thing of 300B-like purely
linear motion..

Just as a mattter of historical evidence, Ford apparently between the
wars made their flathead V8 in England, possibly in a tax-friendly
smaller size as well. I spoke to someone only at the beginning of the
summer who had once owned such a British Ford V8; he said it was the
only one he ever saw at the shows he went to; it is probably logical
that the British preferred the lower-tax fours.

Andre Jute
Off-topic? Me? See the 300B reference above.

But where people were converting 80s cars with TBI to
carb ten years ago, now we are seeing EFI on everything from old
Beetles to flathead Ford V8s.


IMHO the reason is injection no longer holds the same fears for home
mechanics who also now realise the considerable benefits.

You have to realize that at least in these parts the easy availablity of
credit and $100/hr shop charges have denuded the US roads of cars older
than ten or fifteen years.


Pretty rare here too. Certainly 15 year old ones.

Last time I was in England the numbers of old cars I saw vastly exceeded
what I have seen anywhere in the US, except for a couple of college
towns and parts of Los Angeles.


Heh heh - you saw all of England?

Of course, we are going to see a massive credit implosion.....but
that's another matter.


I hope it doesn't end up being as bad as some fear. It will hit the
poorest most - as usual. Many have been predicting a property crash here
in the UK too. But so far it hasn't happened.

--
*The early bird gets the worm, but the second mouse gets the cheese *

Dave Plowman London SW
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