Tech Review: Peterson’s new R4 Oil Pump

Late last year we began getting news about Peterson Fluid Systems developing a new wet or dry sump oil pump. Peterson Fluid Systems has been manufacturing top notch oil pumps since 1979, and the company enjoys a fine reputation among the elite race teams. We’ve been following the progress of Peterson’s R4 “Nitro” pump since we first got a whiff of its development in July of last year.

The first round of track testing for the R4 pump began in early August, and according to Mike Morten of Peterson Fluid Systems, “The initial testing exceeded our initial goals in both pressure stability and vacuum numbers.” With a positive first round of track testing behind them, the guys at Peterson brought some of the best names in dirt late model racing on board to run the pump in sanctioned races for a second round of track testing.

It didn’t take long for the R4 pump to find its way into the winner’s circle when Vic Hill won with the R4 pump on Aug 15th at Tazewell Speedway. Vic had been a part of the initial round of testing with the R4 pump on the dyno, and he reported a 22hp gain over the previous top version of Peterson oil pump. Not to anyone’s surprise, the pump also posted better vacuum numbers and less fall off at sustained RPM.

Follow-up Track Testing of the R4

Following up Vic Hill’s success at Tazewell, Team Peterson member Billy Moyer won the Dirt Track MSRA event at Beebe Speedway and the MLRA event at Lucas Oil Speedway while running the new R4 pump. According to Peterson representatives, “Oil pressure at both races were a rock steady 80 psi during the race and 40 psi at idle after the race with 240º oil temps.” Drivers using the R4 pump continued to rack up race wins therefore establishing the R4 as the oil pump to have in 2010.

All eyes turned toward the 2009 PRI Tradeshow where Peterson Fluid Systems would be unveiling the R4 pump and taking orders for the anticipated release of the pump to the market. We were able to talk to Mike Morten at the tradeshow, and he gave us the lowdown on the R4 pump.

Video of R4 Pump from the PRI 2009 Show:

Peterson Fluid System’s R4 Pump at the PRI Tradeshow

Advanced but Affordable

Morten explained to us that “the R4 pump was Peterson’s third generation of oil pump design since 1979”. Peterson Fluid Systems had focused on manufacturing oil pumps with GeRotor design features. The engineers at Peterson decided to utilize a Roots Rotor design with the new pump which helps reduce the overall weight of the oil pump by getting away from a steel GeRotor type gear. Morten explained the the new rotor design is a “twisted four lobe aluminum rotor, similar to a roots rotor”. The new rotor design provides excellent flow and “rock steady” pressure even at very high temperatures. Morten also told us that the R4 Pump “is not only advanced but also is affordable”.

Bantam Weight & Patented Technology

The weight reduction in the new R4 oil pump is significant. Morten told us that the new oil pump “6 stage unit is 10 pounds lighter than the second generation Peterson oil pumps, and the dirt late model rear mount 5 stage R4 is about 6 pounds less”. With the trend in racecars going to lighter weight components, the R4 pump is destined to be a favorite with the super competitive dirt track, sprint car, and dirt late model crowds.


Roots style rotors have been used for years in various applications, however, the roots designed pumps have not been as prevalent in positive pressure type fluid pumps. Morten explained, “The unique rotors in the R4 pump took a lot of design time.” Getting the rotors to pump at a consistent rate and maintain vacuum was a delicate balance in the geometry of the rotors and the housing. Peterson Fluid Systems is confident that they have the optimal geometry of the internals in the R4 pump, so much so that they applied for a patent on the rotor design. The helical shape of the gears is visual explanation of how the pump forces fluid through the system. The angle of the helical design is the secret of its success.

Features of the R4 pump:

  • Lightweight design (stage 6 pump is only 10 pounds)
  • Modular mount system allows for a variety of mounts for the same pump
  • Rear drive available
  • 4 lobe rotor design
  • Made in the USA

Article Sources

About the author

Bobby Kimbrough

Bobby grew up in the heart of Illinois, becoming an avid dirt track race fan which has developed into a life long passion. Taking a break from the Midwest dirt tracks to fight evil doers in the world, he completed a full 21 year career in the Marine Corps.
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