Why not use Racing Oil in my Car If It’s Tougher?

John Baker|Nov 29, 2019 8:00 AM

When deciding if racing oil is right for their vehicles, gearheads and other enthusiasts sometimes offer this line of reasoning:

Racing engines are more severe than my engine
Racing engines use racing oil
Therefore, I should use racing oil in my vehicle for best protection

It’s true that your average racing engine creates operating conditions more severe than the average passenger car engine.

However, that’s not to say that modern engines aren’t tough on oil.

The turbocharged, direct-injection engines in modern vehicles generate increased heat and contaminants compared to their predecessors. Motor oil bears the brunt of the added stress.

That’s why industry motor-oil specifications keep growing tougher and automakers are increasingly recommending synthetic oils to meet these strict performance specs.

Should I use racing oil in my car?

Racing, however, is a whole different animal.

The powerful, modified engines in racing vehicles produce extreme heat and pressures your average car or truck simply will never see.

A 900-hp Pro 4×4 race truck can produce engine temperatures in excess of 300ºF (149ºC). Engine temperatures in a typical passenger car/light truck fall somewhere between 195ºF and 220ºF (90ºC – 104ºC).

The difference is even more striking when you consider that the rate of motor oil oxidation (chemical breakdown) doubles for every 18ºF (10ºC) increase in oil temperature.

The tremendous shearing forces the oil bears as it’s squeezed between the interfaces of the pistons/rings and cam lobes/lifters pose another problem. The pressure can tear apart the molecular structure of the oil, reducing its viscosity and film strength.

Racing oil has to be formulated differently to protect these demanding engines. Even so, it doesn’t mean you should order a case of AMSOIL DOMINATOR® 10w-30 Synthetic Racing Oil for your car.

Buy AMSOIL Synthetic Racing Oil

Racing oil is changed more often

So, why not use racing oil in your daily driver? For starters, racing oils are changed frequently.

Most professionals change oil every couple races, if not more frequently. For that reason, racing oils are formulated with a lower total base number (TBN) than passenger car motor oils.

TBN is a measure of the oil’s detergency properties and its ability to neutralize acidic byproducts. Oils with longer drain intervals have higher TBNs.

AMSOIL Signature Series Synthetic Motor Oil features a TBN of 12.5 to enable its 25,000-mile/one-year drain interval.

In contrast, DOMINATOR Synthetic Racing Oil has a TBN of 8 since we recommend changing it more often. As great as it performs on the track, DOMINATOR is not what you want in your engine when you’re driving thousands of miles and several months between oil changes.

Regular motor oil is designed to provide additional benefits

You also want to use an oil in your daily driver that excels in several performance areas:

Wear protection
Long oil life
Maximum fuel economy
Engine cleanliness
Corrosion protection
Oxidation resistance
Easy cold-temp starts

Motor oil additives produce many of these benefits. For example, anti-oxidant additives fight increased heat and extend oil service life.

Anti-wear additives interact with the metal surfaces of engine parts and guard against metal-to-metal contact.

Many additives form layers on metal surfaces. That being the case, they compete with each other for space, so to speak, like pigs competing for room at the trough.

Racing oils are often formulated with a heavy dose of friction modifiers to add lubricity for maximum horsepower and torque.

The boosted level of additives meant to increase protection and performance during a race doesn’t leave room in the formulation for additives found in passenger car motor oils that help maximize fuel economy, fight corrosion or improve cold-weather protection.

In effect, the ravenous pigs at the trough leave no room for their brethren, resulting in a less well-rounded formulation.

Bottom line: use regular motor oil in your daily driver

Achieving the tasks of a passenger car motor oil requires a finely balanced formulation. Too much or too little performance in one area can negatively affect other areas – and the oil’s overall protection and performance. The list of tasks required of a racing oil, however, is much shorter.

The right tool for the right job is an axiom with which you’re familiar. The same holds for motor oil. It’s best to leave racing oil to competition engines and use a properly formulated passenger car motor oil for your daily vehicle.

Shop AMSOIL Synthetic Motor Oil

Winter (Cold) flow wear factors in your engine

Engineers agree that most engine wear occurs during cold starts. While the exact percentage depends on several factors and is difficult to define, the reasons include the following…

A richer air/fuel mixture at startup washes oil from the cylinder walls
Condensation forms inside the engine that causes rust and corrosion
Cold piston rings and cylinders don’t seal as well, causing combustion gases to “blow by” the rings and contaminate the oil
Gravity causes much of the oil to fall back into the oil sump, leaving components unprotected
Cold oil doesn’t flow immediately at startup, temporarily starving the engine of oil

While all these factors are important, lack of oil due to poor cold-flow properties is the biggest culprit. Fortunately, there’s something you can do about it.

“Cold” isn’t just for winter

First, it’s important to define a “cold” start. While true that oil thickens more in sub-zero winter weather and causes increased starting difficulty, an engine is considered “cold” after it’s sat long enough to cool to ambient temperature, typically overnight. Even in warm climates, cold-start wear is a problem.

The oil inside your engine cools as it sits overnight. As it cools, its viscosity increases (it thickens). When it’s time to start your vehicle in the morning, the thicker oil doesn’t flow through the engine as readily as it does when it’s at operating temperature. It’s during this time that vital engine parts can operate without lubrication, increasing wear.

The problem is more pronounced the colder it gets, particularly if you’re using conventional motor oil.

Waxes solidify in the cold

Conventional lubricants contain paraffins, or waxes, that solidify when the temperature drops. These waxes cause the oil to thicken. In the comparison shown here, we cooled a conventional oil and AMSOIL Signature Series 5W 30 Synthetic Motor Oil (ASL) to -40ºF. The conventional oil on the left thickened so much it barely flowed from the beaker. If that oil were inside your engine on a cold morning, it could prevent the crankshaft from spinning fast enough to start the engine, leaving you stranded. Even if the engine started, you wouldn’t be out of the woods. Thick, cold oil can fail to flow through the tiny screen openings on the oil pickup tube (see facing page), starving the engine of oil for several vital moments before the oil begins to heat up and flow throughout the engine.

In addition, thick oil can fail to flow through the tiny passages in the crankshaft to lubricate the main bearings. Similar oil passages in the camshaft ensure the engine’s upper end is lubricated (see facing page). The further away from the oil pump these oil passages reside, the longer it takes the oil to reach components at startup, placing your engine at increased risk of wear.

Poor lubricant cold-flow properties can also affect variable valve timing (VVT) systems. Engines equipped with VVT have solenoids with tiny openings through which the oil flows and acts as a hydraulic fluid to actuate VVT components. The solenoid pictured to the right, from a Ford* 3.5L EcoBoost* engine, contains openings .007 inches across – about the thickness of two sheets of paper. Oil that fails to flow through these tiny passages reduces VVT performance and can trigger a check-engine light.

Here’s how to protect your engine

AMSOIL synthetic motor oils provide better cold-flow properties than conventional oils. Our synthetic base oils don’t contain the waxes inherent to conventional oils. As a result, they demonstrate reduced pour points and provide increased fluidity during cold starts. This translates into oil that flows almost immediately through the oil pickup screen and other tiny oil passages when you start your engine, protecting it against wear.

Look at the oil’s pour point to gauge its ability to flow quickly at startup, typically reported on the oil’s data bulletin. Pour point is the coldest point at which an oil will flow. Lower values equal improved cold-flow and maximum wear protection. AMSOIL Signature Series 5W-30 Synthetic Motor Oil, for example, provides a pour point of -50ºF (-58ºC).

Pique prospects’ curiosity

This type of information can help you create curiosity about AMSOIL products and lead someone from not looking for lubricants to looking for AMSOIL products. Ask pointed questions or provide useful information, such as…

Most engine wear occurs during cold starts. Do you take steps to guard against start-up wear?
Even in warm climates an engine is considered “cold” after it’s sat overnight.
Do you ever have trouble starting your truck on cold mornings?

Once they’ve shown interest, offer more technical explanation if required and offer AMSOIL synthetic motor oil as a solution to difficult cold starts and accelerated cold-start wear.

A little known fact

The differences in brands comparing a 5W-30 to the protection of a 10W-30 or 0W-30 can even be critical to the prevention of wear in the 50 to 65 degree F range. So just because you may live in a southern climate doesn’t mean you are in the green with a older specification viscosity.. A more advanced oil brand allows you to take advantage of the tech of the latest (lowest allowable) start-up viscosity year round.

Category: Knowledge Base

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