Peterson Fluid Systems Unveils New, More Robust Wetvac

Following six months of strenuous in-house development and testing, Colorado-based Peterson Fluid Systems, a leader in high performance oiling systems, has proudly unveiled its latest product offering: an all-new, more robust version of its familiar Wetvac, which combines their world-renowned dry and wet sump oil pumps with a vacuum pump in a single, in-line configuration.

The latest and greatest Wetvac was made possible through a partnership with Steve Fackett and his team at Star Machine in Maryland, manufacturers of high-end racing vacuum pumps. According to Peterson Fluid Systems’ Pat Haberkorn, after twenty years of success with their original iteration of the Wetvac, the ever-growing range of engine applications and increases in horsepower in the racing market necessitated a redesign to be more of a one-size-fits-all product.

The old WetVac would be fine in most applications but in a few select max effort builds the pump would underperform and not pull as much vacuum as the engine builder/customer had hoped for. – Pat Haberkorn, Peterson Fluid Systems

“The old WetVac would be fine in most applications but in a few select max effort builds the pump would underperform and not pull as much vacuum as the engine builder/customer had hoped for,” Haberkorn explains. “This made us start looking at other solutions. We tried many different variations of rotor sizes, body porting ideas, and fitting orientations to try and come up with a solution. Unfortunately we we’re not pleased with any of the solutions we tested, so we started to look elsewhere. We contacted Star machine in August of 2016 and purposed an idea that had been run by us a year prior by Leonard Long of G-Force transmissions. Leonard competes in an all-motor class up North and had been using this combination for a few years. Leonard said it had performed flawlessly.”

The intention was to combine Star’s tested and proven vacuum pump design with Peterson’s likewise trusty R4 oil pump to create a bulletproof combination pump, and that’s precisely what they achieved. Peterson’s development team brought in a Star pump to verify fitment and analyze the performance of the unit before further investing in the project. And so, a vacuum pump was purchased and married  to an R4 pump for in-house testing on a test stand for several days before being installed into the big-block drag racing machine owned and driven by a member of the Peterson staff for real-world R&D prototyping. As Haberkorn shared, the pump combination “performed flawlessly all year long on his car and pulls 14-inches of vacuum in Denver at 8,000 feet of altitude and has seen 18-inches in Topeka, Kansas at sea level conditions. We knew right then this was the way we needed to go with our WetVac offering.”

The numbers that the team found were right in-line with the vacuum goals; while vacuum targets are application-specific, Haberkorn says bracket racers are typically looking for something in the 10-inch neighborhood, while more max-effort, heads-up vehicles find 15- to 18-inches more sufficient.

The new Wetvac utilizes Peterson’s existing R4 oil pumps, which have been in production since 2009; a billet aluminum adapter plate has been machined that bolts to the rear of the pump that the Star vacuum pump then bolts up to. Any R4 pump can be reconfigured to accept the vacuum pump. As Haberkorn shares, the conversion process requires a new pressure body, new main shaft, adapter plate, and the vacuum pump itself, all of which can be completed in one to two weeks.

The vacuum pump can be mated to any of Peterson’s R4 oil pumps, be they two stages or five.

“That’s the beauty of this product,” Haberkorn says. “It can be adapted to any of our oil pumps. We’re starting to see more four-stage rear drive drag pumps being configured with the vacuum pump option.”

You get the best of both worlds, supreme oil control and as much crankcase vacuum as you desire. – Pat Haberkorn, Peterson Fluid Systems

The two pumps operate at the same shaft speed, or drive ratio — the vacuum pump being driven directly off of the oil ump via a 3/8-inch hex drive, which is common in circle track fuel and power steering pumps. “The speed of the vacuum pump was our major concern when configuring this set up. We don’t usually spin our pumps any faster than 5,000 RPM of pump speed at absolute max. Most pump ratios are set up in the 4,000 to 4,800 RPM range, which Star was comfortable running their vacuum pump at.”

The parasitic horsepower losses via the crankshaft from the accessory belt drive for this configuration is equivalent to running them separately, as Peterson has found in its testing.

“You have to figure the crank is only trying to turn one accessory with a little more load rather than two accessories on two separate belts. Typically vacuum pumps are ran off a v-belt setup which requires quite a bit of tension to operate without slippage. One large benefit to this set up is that it only requires one belt, which really cleans up the engine bay and the mandrel side of things,” Haberkorn explains. “There are no more headaches trying to figure out where you can fit a vacuum pump, trimming the standoffs down on the vacuum pump mounting to get the correct alignment to the drive, and no need to spend a hundred dollars on pulleys and a belt to run the vacuum pump.”

In regards to positioning and plumbing next to the block versus out front, Haberkorn confirms the Wetvac setup does add two additional -12 lines to the engine bay. The vacuum pump can also be clocked using a second pattern machined into the adapter flange to allow some flexibility in the positioning alongside the block to simplify your plumbing, regardless of the space on-hand. The addition of the vacuum pump to an R4 pump adds approximately 5.5-inches to the overall length of the pump assembly. The Wetvac can also be configured with Peterson’s dry sump oil pumps, as well.

For the most unique of applications where the Wetvac won’t fit regardless of the clocked position, Peterson will work to accommodate your situation with a custom mounting bracket, if necessary.

Peterson sums their new product up quite nicely: “Superior oil control and as much vacuum as you desire.”

For more information on the new Wetvac and other product lines, visit

About the author

Andrew Wolf

Andrew has been involved in motorsports from a very young age. Over the years, he has photographed several major auto racing events, sports, news journalism, portraiture, and everything in between. After working with the Power Automedia staff for some time on a freelance basis, Andrew joined the team in 2010.
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