Go With the Flow: Moroso Explains How Temps Tamper With Oil Movement

Everyone worries about oil pressure and engine temps, because that’s what most engine read-outs register. May those readings be bone stock or aftermarket in nature, these figures often get misinterpreted, even by seasoned weekend track warriors.

This is precisely why Moroso has recently decided to hone in on this key topic of discussion, giving its race engineering brainiacs the ability to go beyond the old “pressure vs. volume” argument, and discuss things like drain-back concerns, oil levels, pressure, and flow rates. All of which are important issues that must be taken into consideration when setting up an oiling system or diagnosing an issue. May it be one way or another, it all cycles back to oil temps, and here’s why…

Moroso Oil Pump tester

Scott Hall walks us through Moroso’s oil pump test rig.

Moroso Makes a Stand for Oiling Equilibrium

Recently, Scott Hall from Moroso shot the video embedded above and uploaded it to YouTube.

Apparently, a friend of Hall’s had a dry-sump system overflow on him upon engine warm-up at the race track, despite having been calibrated and filled with the requisite amount of oil.

According to Hall, the issue was caused by the system being set to run on a predetermined warm-up temp, and not at the higher heat levels one encounters after a few passes have been made. So once that sump setup got “track hot,” it turned into quite the hot mess. Literally…

To help illuminate what was going on behind the scenes, Hall took it upon himself to conduct a little testing over at the Moroso Assembly Department. There, Moroso’s oil pump test stand was put to use, all in the hopes of showing how both external dry-sumps and internal wet-sump systems operate and fluctuate under varying levels of heat.

Those of you who are familiar with Moroso’s history may recall that this is the same test stand that made sure Dick Moroso’s oiling units were working correctly back in the day. Later, it served as the diagnostics lab for the systems that lubricated and cooled various Xfinity team vehicles.

Nowadays, the test stand is part torture tester and digital read-out lab, and part historical monument of sorts. Outfitted with the latest RacePak data acquisition sensors, a laptop, and a team of highly trained specialists like Scott Hall, this test stand allows Moroso to inspect and illuminate all types of oiling topics. The significance of oil temps and how they affect flow being their most recent endeavor.

Moroso chose to use RacePak’s IQ3 display and datalogger to be able to accurately monitor all of the channels required by the test stand.

Under Pressure…

To demonstrate how flow rates change when oil temps rise (or fall), Moroso needed to take its test stand, and adjust the resistance (i.e. oil pressure) levels within the system itself. 

But before diving into all that noise, Moroso points out that its test stand “…doesn’t take into consideration the expansion of the engine and… there are far too many variables that exist…”

Instead, Moroso says that testing an oil pump against a set parameter, and not just focusing on how the engine is influencing or reacting to the oil pump is key. 

To adequately monitor what actually matters, Moroso utilized one of RacePak’s digital data acquisition systems. The IQ3 model then allowed Hall to monitor temps, oil pressure (both before and after the filter), as well as oil filter shakedown schematics in case further testing was required. A flow meter was also implemented to measure movement in gallons per minute, while crankcase vacuum monitoring was registered up top for good measure in case things pertaining to blow-by became an issue.

For dry-sump pump monitoring, Moroso utilized a box that simulates an oil pan, thus allowing the team to adjust vacuum levels as needed. This was done because no two custom engine builds (or oiling systems) are the same. Additionally, a 10-quart oil tank with heating and cooling functions was brought in to allow a far more real-world simulation to occur quickly and effectively.

Finally, things like horsepower draw were measured via the use of kilowatt read-outs, with a focus on high-performance track car power being the focal point of the test video.

Let’s Talk Temps for a Tick

In the video, Hall explains that the oil pump was driven at 1,250 rpm, while maintaining 60 psi across the board. This translated to the oil pump cycling around 4.1 gallons per minute, before the oil was heated-up.

Testing started with oil temps registering 80 degrees Fahrenheit. Oil temps were then tweaked in 20-degree increments to showcase what changes look like when the pressure remains constant, but temperature increases.

According to Hall’s calculations, if water temps register 160 to 170 degrees after a little pre-race warm-up action, that oil will have likely have only just begun to hit the 100-degree mark. This translates to approximately 1 gallon-per-minute increase in flow. So although engine temps may have spiked by 80 degrees, oil temps only jumped 20 degrees or so by that point.

The results show that at the same pressure, as the temperature increases, the viscosity decreases, and subsequently, flow increases.

Do a burn-out, followed by a hot lap, and chances are your oil is hitting 140 degrees, which translates to 5.7 gallons of flow per minute at 60 psi. Complete a few more passes without incident, and that flow rate will likely sit at 7.0 gallons per minute, with internal oil temps hovering in the 160-degree range. All told, this would likely translate to the pressure changing about 10 psi during that time, and the flow increasing exponentially.

The Hot Oil Rub

So what does that mean for us automotive enthusiasts? A whole lot of doubling-down really.

In essence, doubling your oil’s temperature translates to doubling its flow rate, so make sure you know precisely what temp your oil is sitting at when you check its flow rate and pressure. This can make a massive difference in how effectively that lubricant circulates within the engine itself, but also how well it cycles back into your engine’s oil pan and onboard pump system.

Who knows? Chances are you may not have an oiling issue after all, just inadequate readings, or readings pulled at the wrong time.


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Micah Wright

Raised on LEGOs by grandfathers who insisted on fixing everything themselves, Micah has been a petrolhead in training since age four. His favorite past times include craft beer, strong cigars, fast cars, and culinary creativity in all of its forms.
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