<VV> Carbs

[Hugo Miller]

Yes indeed - the Rochester does perform well. Surprisingly so given its 
level of complication. I never said it didn't work - my gripe is that it 
is a complex solution to a simple problem, although it is no worse than 
the majority of carbs in this respect. The advantage of the SU is that 
it is so elegantly simple - just one jet in the whole carb and a 
vacuum-operated piston to vary the size of the venturi. Only two moving 
parts in the whole thing. Plus there is a vast range of needles so you 
can tweak the mixture at every degree of throttle opening. The only 
disadvantage of the SU is that it works the opposite way to most carbs - 
instead of speeding up the fuel flow by giving it a squirt when you 
press the throttle, it slows down the airflow by damping the piston, to 
give the fuel time to catch up. This means that the throttle response is 
a nano-second slower, although you'd never notice that unless you're on 
the track, but it also makes them very economical carbs. That's why all 
the best British cars fit them (or used to, before this new-fangled fuel 
injection and computers came along); Rolls Royce, Bentley, Aston Martin, 
Jaguar, MG - even my little Morris Minor has one. And soon my Corvair 
will have a pair also ;)


On 2020-03-05 20:27, Charles Sadek wrote:
> Well, you caught  me flat-footed. I get a stitch in my side just
> laughing at your antics as if the SU were the sole carb... Wot a
> heel!!!   :)
>
> Smitty is right about the carb. Well-set up, it performs admirably
> well. Even in road racing at over 7500 rpm.
>
> -----Original Message-----
> From: VirtualVairs [mailto:virtualvairs-bounces at corvair.org] On
> Behalf Of Hugo Miller via VirtualVairs
> Sent: Thursday, March 5, 2020 6:25 PM
> To: Smitty
> Cc: virtualvairs at corvair.org
> Subject: Re: <VV> Carbs
>
> Haha there is never only one way to do something. Were that the case,
> we'd all still be living in caves. An Indian cook once said "There is
> only one recipe. But there are many ways of doing it"
> Anyway that's enough philosophising - Yes I agree that the Rochester
> carb works. But it is certainly not what I would describe as an 
> elegant
> solution to the biggest problem that all carburettors have to 
> overcome -
> the fact that air is lighter than gasoline and therefore speeds up 
> more
> rapidly when you open the throttle. SU carbs, on the other hand, are 
> a
> picture of elegance - they do it all with one jet and a variable
> venturi, together with a vast selection of needles which enable you 
> to
> tweak the mixture precisely at any degree of throttle opening.
> Here's a rare piece of useless information for you; the initials "S 
> U"
> stand for 'Skinners Union". The Skinner brothers were part of the 
> large
> British shoe manufacturer at the dawn of the motor car, and they
> designed this clever carburettor. Originally, instead of that 
> beautiful
> spun aluminium dashpot, they had a bellows made of calf-skin, 
> hand-sewn
> by old Mrs Skinner herself. But the principle was as elegant as it
> remains to this day.
> Einstein's equation E=MC2 is also described as elegant, because it is
> so concise. If it were Rochester's theory of Relativity, it would be
> three pages long.
>
>
>
> On 2020-03-05 12:22, Smitty wrote:
>> Hugo you are standing on my Corvair lovin toes calling the Carter HV
>> an abomination.  It may have lots of valves and levers but each of
>> them serves a design purpose.   Once the carb is set up as intended
>> it
>> is as precise and reliable as any mechanical device can be.  My
>> station wagon had almost 450,000 miles on it original carbs with no
>> rebuilds and only an occasional replacement of the accelerator pump
>> cups and float valve needles.
>>   I have no problem with you experimenting ways to set up and 
>> balance
>> the two carbs.  I have had an occasional bout with tinkeritus
>> myself..
>> but you can try gauges and hissing hoses and all kinds of crap but
>> until you set them up with a flow meter you are still poking at them
>> in the dark with a stick.  There is only on way to do a complete
>> setup
>> on HVs, one way to mechanically join them together, and one way to
>> synchronize them.  It’s in the book.                  Regards.
>> Smitty.
>>
>>
>> Sent from my iPad
>
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