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Racing Oil vs. Regular Oil: What’s the Difference?

Scott Douglas AMSOIL racing truck

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

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

  1. Racing engines are more severe than my engine
  2. Racing engines use racing oil
  3. 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.

Scott Douglas AMSOIL racing truck

Scott Douglas AMSOIL race truck

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.

DOMINATOR® 15W-50 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:

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.

All You Need To Know About Motor Oil Cold Flow

All You Need To Know About Motor Oil Cold Flow

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.

Do’s and Dont’s using Diesel Oil in Gas Engines

Do’s and Dont’s using Diesel Oil in Gas Engines

Can I Use Diesel Oil in My Gas Engine?

It’s good to familiarize yourself with the topic as there are particular conditions which you may benefit from using diesel oil or perhaps you have a fleet and are looking for one oil for everything, one size fits all.. The short answer: It depends on the brand – the approach to the end user.. Read on.

The simple answer: Yes, you can use diesel oil in a gas engine, provided the diesel oil meets the appropriate specifications and viscosity requirements of your engine.

For example, if your gas engine calls for a motor oil that meets the API SN specification, you can safely use a diesel oil of the correct viscosity that meets the API SN spec. For the typical gasoline application, a diesel oil isn’t required and the more appropriate choice is a quality gasoline motor oil for both performance and value.

The detailed answer: It’s common for some owners of modified gasoline-powered vehicles to favor diesel oils over their gasoline counterparts.

Many assume diesel oils are more durable and more capable of withstanding the increased heat of a powerful, turbocharged engine.

Others lean toward higher-viscosity oils to protect against wear, and it’s sometimes easier to find a 40- or 50-weight diesel oil than a gasoline motor oil. Others favor the increased detergency of diesel oils.

While you can use diesel oil in a gas engine, provided it meets the appropriate specifications and viscosity requirements, there’s far more to the topic than that, as I learned after talking to Mark Nyholm, AMSOIL Technical Product Manager – Heavy Duty.

AMSOIL Sioux Falls Dealer note: Call me if you have any questions on these items. I can help you dial in on the best oil for your particular need. 605-274-2580

Can diesel oil safely be used in gas engines?

Nyholm: It depends on the specifications the diesel oil carries and the recommendation of the original equipment manufacturer (OEM).

The American Petroleum Institute (API) publishes its “C” category of specification for diesel oil (currently CK-4) and its “S” category for gasoline motor oil (currently SN). It’s common for today’s diesel engine oils to carry both the API CK-4 and SN specifications.

Though they’re truly designed for diesel applications, they can be used in gasoline applications for those drivers who want to use one oil in all applications. If the diesel oil carries both specs, feel assured the oil is safe to use in diesel and gas applications. If the diesel oil does not carry the “S” category, I strongly recommend against using it in gasoline applications.

Signature Series Max-Duty Synthetic Diesel Oil 5W-30

Shop AMSOIL Synthetic Diesel Oil

Why do some motorists favor diesel oil over gasoline motor oils?

Nyholm: There are many reasons people choose the oil they use.

Since oil is not top-of-mind with many motorists, it’s typical for people to purchase based on viscosity alone. Many gasoline engines today call for 5W-30, with more and more requiring 5W-20, meaning those viscosities are typically what’s readily available. So, if you’re looking for a 5W-40 or 15W-40, it’s often easiest to find that viscosity in the diesel engine oil aisle.

Others use diesel oil under the assumption it’s a more “heavy-duty” product and must be better than gasoline motor oils.

They may have been told diesel oil is formulated with special components not available in gasoline motor oils, such as more robust detergency additives to handle the soot inherent to diesel engines. In their minds, diesel oils are analogous to better protection.

Shop AMSOIL Synthetic Motor Oil

Do most gasoline engines really need some of the additives in most diesel oils?

Nyholm: Diesel and gasoline oils are formulated with a variety of additives that improve wear protection, corrosion protection, resistance to foaming, viscosity retention and more. Whether the application is gasoline-powered or diesel-powered, many of the same additives are used based on what we are asking them to do in the formulation.

Now, there are additives designed to manage the byproducts of combustion, and some of those byproducts change, depending on whether you’re burning gasoline or diesel. If you’re running a gasoline engine, it’s best to use an oil that contains the correct additives to handle the byproducts of gasoline combustion. The same holds if you’re operating a diesel engine.

When should someone use diesel oil in their gas engine?

Nyholm: If your gasoline engine is heavily modified to put out more horsepower, using a diesel oil can be beneficial. It’s likely modified engines will need a higher viscosity to withstand the increased stress. You can turn to diesel engine oils for those needs or you might want to consider a racing oil, depending on your engine modifications and lubrication requirements.

Many times the engine builder will help provide insight as to what success they have found. Outside of that, if you have a bone-stock gasoline-powered application it’s best to stick with a gasoline motor oil.

They are designed for that type of application and have the components required to manage that engine. Sure, you can run a diesel oil in a gasoline engine; however it’s likely the formula has additional components your gasoline application doesn’t require, which might end up costing you more money.

AMSOIL formulates a complete line of gasoline and diesel oils for nearly anything you have. They’re dialed in to deliver outstanding protection for their intended applications. Consult the AMSOIL product guides for recommendations for your vehicle.

Find AMSOIL Products for Your Vehicle

Synthetic Warehouse Note: Mark forgot to mention in this last section a popular need for diesel in gas engines are customers who want one oil for their business or fleet.  AMSOIL has products marketed for one size fits all. One popular is our first product which is excellent for RV’s motorcycles and fleets – It’s a 10W-40 that flows nicely and great for anything pre 1999. Check out the AMO 10W-40.

Another is a 5W-30 which makes a lot of sense and is in the newer Signature Series Diesel line – the DHD 5W-30 which is great for the latest API specifications, classics, Ford diesels, cars, mowers and equipment. Excellent for golf courses.

Automatic & Manual Transmission Fluid: What’s the Difference?

manual transmission gears

Automatic Transmission Fluid & Manual Transmission Fluid: What’s the Difference?

Back in 2006, original equipment manufacturers (OEMs) offered buyers the choice between an automatic and a manual transmission in 47 percent of new cars. Fast forward to 2018, when only 2 percent of vehicles sold had a manual transmission, according to edmunds.com. 

Even with manual transmissions on the endangered species list, questions about automatic vs. manual transmission fluid still arise. Whether you opt for a stick or a slush box, you want to use the correct transmission fluid to maximize its performance and life.

Four responsibilities of a good automatic transmission fluid

The differences between automatic and manual transmission fluid lie in what each fluid must do. You don’t have to be an engineer to know that an automatic transmission is far more complex than a manual. Fittingly, so is the fluid it requires to function properly.

Automatic transmission fluid must perform several functions, including…

1. Act as a hydraulic fluid

Automatic transmissions use pressurized fluid to change gears. In essence, automatic transmission fluid is hydraulic fluid.

When your vehicle’s computer decides its time to shift gears, it sends an electric signal to the appropriate transmission solenoid. The solenoid directs fluid through a complex series of passages in the valve body to engage the correct gear. The fluid squeezes a series of plates together inside a clutch pack to connect the engine to the transmission output shaft and route power to the wheels.

In a properly functioning transmission, this all happens instantly and goes largely unnoticed.

However, fluid that’s too thick (it’s viscosity is too high) can fail to flow quickly for crisp, confident shifts. That’s one reason automatic transmission fluid has a lower viscosity than manual transmission fluid.

Fluid that has accumulated foam can also fail in its role as a hydraulic fluid. The foam bubbles collapse under pressure, causing elongated or inconsistent shifts (not to mention gear wear). For that reason, automatic transmission fluid must contain foam inhibitors.

2. Deliver the correct frictional requirements

As noted, pressurized automatic transmission fluid squeezes the clutch packs together to engage the correct gears. These clutch packs are comprised of bare metal plates and plates coated in friction material. Engagement and disengagement must occur seamlessly to provide the driver with the best driving experience.

The fluid’s frictional properties determine whether this complicated choreography of moving metal and fluid creates crisp shifts or has you scheduling a time to change transmission fluid.

As such, automatic transmission fluid is formulated to provide precise frictional properties not required of manual transmission fluid.

Shop AMSOIL Synthetic Automatic Transmission Fluid

3. Protect gears from wear

Automatic transmissions contain an array of sun, planet and ring gears that require lubrication to protect against wear. The fluid must form a durable fluid film on metal surfaces to prevent metal-to-metal contact and wear.

4. Fight heat

Heat is automatic transmission fluid’s number-one enemy. It chemically breaks down the fluid (known as oxidation). Fluid that has broken down leads to sludge and varnish, which can clog narrow oil passages and contribute to clutch glazing. Soon, your vehicle can begin to shift hard, jerk or hesitate.

Automatic transmissions typically run hotter than manuals, meaning the fluid must provide enhanced protection against heat. That’s one reason some vehicles have automatic transmission fluid coolers.

Shop AMSOIL Synthetic Automatic Transmission Fluid

Three responsibilities of a good manual transmission fluid

Just because they’re less complex doesn’t mean manual transmission lubrication requirements are simple. A good manual transmission fluid must serve several roles, including…

1. Enable smooth shifts

Nothing connects vehicle and driver like a smooth-shifting manual gearbox. Enthusiasts won’t tolerate a transmission fluid that interferes with that link.

Here, we have some cross-over between automatic and manual transmission fluid. But they go about enabling smooth shifts differently based on different component architecture.

Most manual transmissions are equipped with synchronizers. As the name suggests, the synchro equalizes its speed with that of the gear being engaged, allowing a smooth shift. Without it, the gears spinning at different speeds would clash as they try to mate.

The synchronizer unit is comprised of two main components: the sleeve and the blocker or synchronizer ring. When the driver selects, for example, first gear, the sleeve moves to the first gear and locks onto the gear engagement teeth, also known as dogs. Depressing the clutch pedal and selecting second gear results in the sleeve moving the other way and selecting second gear in the same fashion.

Before the sleeve can lock onto the gear, the rotational speed of each must first be synchronized. The friction between the blocker ring and a cone on the face of the gear equalizes their speed, allowing gears to mate without clashing. The entire process happens quickly and goes unnoticed in correctly operating transmissions.

Lubricant viscosity plays a vital role in shift feel.

Viscosity that is too high could prevent shifting until the transmission warms up or result in abnormally high temperatures during operation. Viscosity that is too low could cause the synchronizer and dog gear to engage too quickly, resulting in grinding or hard shifts and abnormal transmission wear.

2. Fight wear

Again, manual transmission fluid must protect against wear, just like an automatic transmission fluid. Manual transmission fluid, as noted earlier, tends to be a higher viscosity than automatic transmission fluid. This helps the fluid develop a thick, durable protective film.

Shop AMSOIL Synthetic Manual Transmission Fluid

3. Protect brass synchronizers

Synchros are usually made of brass, which is softer than other metals. Certain lubricant additives aren’t compatible with brass and can damage the synchros.

The properly formulated manual transmission fluid for your vehicle will protect synchros to ensure they last as designed and promote smooth shifts.

As you may have figured out, automatic transmission fluid can, in some cases, work fine in manual transmissions. Which raises another question…

Will automatic transmission fluid work in a manual transmission?

Yes – provided the original equipment manufacturer recommends it. It’s important to check your owner’s manual to make sure before dumping ATF in your manual transmission.

In fact, some manuals may call for a gear lube or even a motor oil in older units.

I should also point out that continuously variable transmissions (CVT), popping up on more vehicles today due their increased efficiency, take their own fluid. And so do dual-clutch transmissions (DCT), which you’ll find on many sports cars.

Whichever you prefer, AMSOIL formulates a transmission fluid to help maximize transmission performance and life.

Shop AMSOIL Synthetic Transmission Fluid

Help! How Many Quarts of Oil Does My Car Use?

Help! How Many Quarts of Oil Does My Car Use?

How Much Oil Does My Car Need?

The answer seems simple: probably about five quarts.

But, if you drive a small car with a four cylinder engine, it’s likely closer to four quarts. However, the V-8 engine in your truck could require about seven quarts. My in-laws’ RAM diesel pickup takes 12 quarts of motor oil.

You can see how the answer isn’t so simple after all.

To find out precisely how much motor oil your car needs, do one of the following:

  1. Check the owner’s manual

Dig the owner’s manual out of your glovebox and look up the information in the index. Eventually you’ll find it.

  1. Check the AMSOIL Product Guide

You can skip the hassle and use our Product Guide instead. Just input your vehicle information and, below the motor oil recommendations, you’ll find motor oil capacity (circled below in red).

What if the oil level is too low?

It could be due to a couple issues, including insufficient oil added during the last oil change or oil consumption. There are several reasons for oil consumption (in fact, you can read about 40 of them here). But here are a couple of the more common.

Leaking seals or gaskets – your engine uses seals in various places to ensure oil stays inside the engine while contaminants stay out. A prime example is around the crankshaft where it sticks out of the engine and connects to the transmission. Gaskets seal the uneven metal surfaces between parts to ensure, in part, that oil stays inside the engine. The cylinder head gasket is a notable example.

If the seals and gaskets become worn, brittle or deformed over time, they can result in oil leaks. The engine oil level will drop, depending on the severity of the leak. If your engine leaks oil, visit a mechanic and have it fixed.

Volatility – engine oil can evaporate when exposed to heat. The less stable the oil, the more readily it evaporates. As the engine is running, a thin film of oil coats the cylinder wall and piston skirt. Given its proximity to the fiery cauldron inside the combustion chamber, the oil in this area of the engine can easily volatilize, or evaporate. The by-products can exit the tailpipe as emissions. But they can also form harmful carbon deposits inside the engine that reduce efficiency and eventually lead to engine failure.

Synthetic motor oil is more resistant to volatility than conventional oil, so use a good synthetic to reduce oil consumption due to volatility and help keep your engine clean.

What if the oil level is too high?

It’s likely due to operator error; someone simply added too much last time the oil was changed or topped-off.

Too much oil is a bad thing. The spinning crankshaft and churning engine parts whip air into the oil, which can cause foam. The tiny bubbles travel between moving parts, where they rupture. When they do, nothing is left to protect metal surfaces from wear. Foam also increases heat, which causes the oil to chemically breakdown sooner.

If the crankcase is overfull, drain the excess oil until reaching the correct level.

Increased oil level can also be due to fuel dilution. This is when fuel enters the crankcase and contaminates the oil. In severe cases, enough fuel can enter the crankcase to noticeably increase the oil level. This is bad. Very bad. Fuel dilution leads to sludge, varnish and engine wear.

Check out this post for more on fuel dilution.

The presence of coolant in the oil can also increase oil level. Again, this is bad. Anytime something that shouldn’t be in your motor oil is present, wear protection suffers. Coolant in the oil is likely due to a bad head gasket, which is a costly repair.

One last word of advice: check your oil at least monthly to ensure the proper level. Make sure the vehicle is parked on a level surface to get an accurate reading. Finding out the oil is too low or too high before something goes wrong can save you a ton of grief in the long run.