[Spridgets] Carb dashpot oil.

[Dean Hedin]

Right on Ron,   BTW, I'm just the opposite.
The simple mass, spring, damper, and Bernolli priciples of the SU I understand.
Outside of EFI, I can't imagine doing it any other way.

I cannot grasp the discrete circuits of other types of carbs.  They are like
the old automatic transmission valve bodies.  Little passages and orfices
going everywhere.

Plus I hate any carb where I can't adjust the main jet with the engine running.



----- Original Message ----- 
From: "Ron Soave" <soavero at yahoo.com>
To: <spridgets at autox.team.net>
Sent: Monday, February 09, 2009 10:25 PM
Subject: Re: [Spridgets] Carb dashpot oil.


> --- Dean Hedin <dlh2001 at comcast.net> wrote...
> ...a good explanation. A couple of clarifying points -
>
>> when the butterflys go wide open.   The delayed rise is a
>> result of the damper (and
>> naturally the viscosity of the oil in the damper).
>
> Also, the resistance to the piston rising is greater than the resistance to the piston falling.
>
>> the engine draws more fuel through the main jet.
>
> Just to clarify if you're wondering how the needle "not rising" increases the fuel flow, the piston damping increases the velocity 
> of the air across the venturi and the bridge. The rate of fuel flow is directly proportional to the velocity of the air, so you 
> get a richening effect.
>
> I can't tune an SU worth a damn, though. The ones on my race car were set up by Craig Chima and I was told not to touch them. My 
> 1970 Midget has the SUs as they came out of the factory, and my street Bugeye has a Weber!
>
> Ron
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