you need in their kits
Written by Scott Sparrow
Pump it up
Since every install/motor combination will be
different, there is little point in giving detailed
information here for our specific car. However, it
is safe to say that no matter what set up you
have, there will be brackets and spacers to make
the installation a breeze. If there are any issues
with getting things right, GZ is only a phone call
away, and they’re very willing to walk you
through it. For Critchlow, it took roughly five
hours to finish up the install per the directions.
“High pan pressure can
cause leaks and the
pump helps stop that
— Greg Zucco
Greg Zucco, owner of GZ Motorsports, took a
little time to explain why people should consider
using a vacuum pump on their engines. Although
they tend to perform better in an engine with lowtension
rings, Zucco believes there are benefits
regardless. “They reduce the oil contamination in
the combustion cylinder and help keep the rings
perpendicular to the cylinder wall for a better seal.
If you run low-tension rings, it magnifies both of
those items. If you don’t use low-tension rings, you
still get horsepower as well as wear benefits,
because it increases the longevity of the engine. It
also stops leaks. High pan pressure can cause leaks
and the pump helps stop that problem,” Zucco
added. “Our pumps are designed to operate
around an eccentric pin, meaning the veins never
touch the outer case, which reduces parasitic
horsepower loss resulting from the centrifugal
force applied to the case by the veins in other,
more conventional systems,” he concluded.
y now, vacuum pumps on race engines
are pretty well common place in an
effort to promote better ring seal, cut
down on blow by and, as a side
benefit, sometimes increase hp. What also is gaining
popularity these days is running a pump on higher
end street motors–especially blown ones.
When Steve Critchlow was building his car, he
knew that the boost numbers would be close to
30-pounds, so it was no secret that some type of
crankcase evac system would be needed. In his case,
he was more interested in keeping the combustion
chambers clear of oil mist to starve off detonation
rather than the potential hp increase that a vacuum
pump could give, although as he discovered, there are
horsepower advantages as well.
Critchlow was building a Dart-based 306 cubic inch
blown small-block Ford utilizing billet internals,
free flowing TFS heads and force fed by a Vortech
YSi-Trim, hoping to see 800-plus hp at the flywheel.
Critchlow turned to Greg Zucco and GZ
Motorsports, who suggested the VP103 Pro kit, which
included the pump and all the trimmings. With the
installation complete, it was time to crank the engine.
“After running up to temperature, we shut down and
rechecked all hoses and fittings for leaks.
vacuum is straight forward with the control valve
installed on the valve cover. I ran the motor up to
the shift point of 7,000 and the vacuum remained the
same throughout the range,” said Critchlow.
“After an hour or so on the dyno, we discovered
that the breather tank was over half full and oil was
coming out of the filter - ideally, it should suck up
about a thimble full for every quarter-mile pass. In
other words, the pump worked a lot better than we
had anticipated,” said Critchlow. Zucco said this does
happen in some cases, but there are ways to resolve
it. Critchlow opted to take the vacuum from the tall
oil fill tube, which solved his problem. Zucco suggests
a couple other quick fixes: baffle the intake, or add a
GZ Motorsports billet lock-in panevac breather to the
top of the valve cover.
“In other words, the pump
worked a lot better than
we had anticipated.”
Since Critchlow’s time on the dyno was limited, he
didn’t have time to do an “A-B” comparison, but feels
confident that the pump garnered his engine plenty
of extra ponies.
“Considering how steady the pump pulls and keeps
the mist out of the chambers, I have no doubt that in
our case we gained at least 25-horsepower at the
flywheel,” Critchlow said.