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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 problem.” — 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.

  Setting the 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.”
—Steve Critchlow

  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.

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