OK, this makes some sense to me. Any advantage in connecting the stacks into
a common plenum? Or does this have to be below the throttle plate?
John
----- Original Message -----
From: "Dave Dahlgren" <ddahlgren@snet.net>
To: "Thomas E. Bryant" <saltracer@awwwsome.com>
Cc: "John Beckett" <landspeedracer@email.msn.com>; "Skip Higginbotham"
<saltrat@pro-blend.com>; <land-speed@autox.team.net>
Sent: Saturday, June 16, 2001 6:17 AM
Subject: Re: Fuel Systems
> What you are missing John is that with an IR setup the cylinder only sees
the 1
> butterfly for airflow. With the carb it sees all 4 so the airflow is not
all
> that much different for the most part between the systems.
> a 2.5 in butterfly has 4.9 square inches as far as my calculator says. a
950
> holley if memory serves me right has 1.75 venturi but has 4 of the for
9.62 sq
> inches with 2 cylinders on an intake stroke at any one time that gives you
4.8
> sq inches per cylinder so the flow increase is perceived not actual.
> Dave
>
> "Thomas E. Bryan" wrote:
> >
> > John,
> > Since I am a injector user, I feel the need to respond to your question.
> > The last carburetors that I ran were Stromberg "97s" and I don't have a
> > clue as to the cfms. It goes without comment that carburetors have
> > greatly improved in the last forty years (it has been that long since I
> > chose to go with the injectors.) If you discount the electronics,
> > injection hasn't changed much during that time, except for getting
> > larger in cfms. I do believe that there are advantages and
> > disadvantages to either system. Most probably choose injectors because
> > of convienent jetting and changing of fuels.
> >
> > It appears that there is a belief that there is HP in manifolds, for I
> > see more systems all the time where injectors are set on top of a custom
> > manifold. This also gets rid of a couple of the weaknesses in older
> > injection systems, a restricted nozzle or unbalanced air intake to the
> > cylinders causing a burned piston, or at least loss of performance.
> > With the carburetor system, velocity is key. Fuel delivery is heavily
> > dependent on the proper cfms for the engine, particularly at the lower
> > rpms. I suspect that either system's need for cfms is controlled by the
> > cylinder heads at top rpm. I run the 2 1/2" Crower injectors which give
> > the engine an abundance of available cfms, but as someone has already
> > said, regardless of the system the engine only uses the cfms it needs.
> >
> > Tom, Redding CA - #216 D/GCC
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