[DeTomaso] Predator Carb

[Daniel C Jones]

The Predator is a constant vacuum, variable venturi, design and uses a pair
of spring loaded air valve doors on top and a pair of throttle plates on the
bottom to form a single, variable-area venturi that is rectangular in
cross-section.  Depending upon air flow requirements, Predators will flow
between 600 to 930 CFM at wide open throttle.  Tuning the Predator is very
simple, as there are only three basic adjustments: idle mixture, idle speed,
and fuel metering cam.  The metering cam, located inside the fuel bowl, is a
flat piece of brass that is cut to a certain slope.  The particular slope of
the cam is determines the air/fuel ratio from roughly 3000 RPM and up.
Note that certain race versions of the carb have no idle adjustment.

The Predator is designed to bolt onto standard 4 barrel intake manifolds
and uses a base plate with fastener slots that allow it to bolt onto both
squarebore and spreadbore manifold flanges.  It comes with an adapter that
allows a standard 5" base air cleaner to be fitted and measures 5 1/4" in
height, from the bottom of the base to the rim of the air cleaner adapter.
Since there are no vacuum hose connections on the Predator, vacuum will
have to sourced from manifold or carb spacer ports.  On a naturally aspirated
motor, 6 PSI at wide open throttle is required for maximum performance.

Vizard reports that Predators will usually deliver good fuel economy and
excellent street driveability, though they will sometimes not produce the
expected top end.  This is probably due to the fact that the manifolds
they are usually mounted on are designed for the four point fuel pattern
of a conventional four barrel carb, not the spray bar pattern of the
Predator.

> Has anybody run one on there Pantera?

Not on a Pantera but a friend  borrowed my Holley Strip Dominator intake and
tested a Predator on a 372C in a 1969 Mustang.

> I vaguely recall criticism (not from him) that they sometimes didn't idle
> well.  But, I am running the risk of perpetuating a falsehood without
> specific data I can recall where to find.

The Predator circuit is an air bleed to lean out the car at idle.  Predator
recommends that you do not run a PCV tap into the carb plenum as it can screw
up the carb signal.  The Holley Strip Dominator intake has the vacuum tap on
#8 runner.   Jim plumbed the PCV into that port.   Apparently the PCV
(essentially a controlled vacuum leak) took the place of the idle circuit air
bleeds.  If he plugged the PCV port, the carb calibration went immediately
rich and idled poorly.  With it hooked up, it idled well and worked great
across the RPM range.  On the single plane Strip Dominator, it produced very
good low end torque, better than a dual plane with 4 barrel carb.  Be aware
they don't have an idle circuit and are difficult to cold start in weather
below 50 degree F.  They are also tall and in the '69 Mustang, a Boss 429
hood scoop was required for clearance.

> In any event, I used to hear more about them and now I hear nothing. I
> thought the company had disappeared

Predator
810 Cross Street
Lakewood, NJ 08701
(732) 367-8487
(732) 367-0148 fax
www.predatorcarb.com
Predator variable venturi carbs.

The Predator was originally marketed as the Kendig carburetor.  I've got
a book that shows Dyno Don's 351C powered Pro Stock Pinto witha pair of
Kendigs.

Dan Jones