Most major engine oil marketers-such as Castrol, Mobil, Pennzoil and Valvoline-as well as numerous independents offer a range of racing formulations. Their chemistries are closely guarded to prevent rivals from reverse engineering and stealing the formulas, according to the Wall Street Journal. And each aims to meet the needs of a particular type of vehicle/engine combination. This is because each racing mode puts different stresses on the engine and requires close attention. Among the biggest racing types are open-wheel, dragster, NASCAR and road racers.

Open-wheel racers include both Indy and Formula 1 racing cars. These are the highly streamlined buckets with a very cramped drivers seat. Behind the driver sits a 1.5-liter dual overhead cam, electronic ignition, fuel-injected engine that delivers upwards of 800 horsepower at 12,000 revolutions per minute. They are designed to go all-out for about 500 miles.

Lubrication of these engines is very specialized, as they utilize a dry-sump system. Basically, the engine oil travels between the engine and a separate reservoir with no time spent in the crankcase.

In this type of system, oil that drains from the engine is immediately pumped to an external tank, keeping the fluid cool and free of air bubbles. According to Popular Mechanics, most modern racing oil is a very low viscosity (e.g. SAE 0W-20) with different additives from those found in regular motor oil. For example, oil for passenger cars contains anti-rust additives to protect parts between lengthy oil changes. Racecars get fresh oil prior to each race, so some of these additives are not necessary.

A dry-sump system offers many advantages over a wet-sump. The main advantage is that it yields an increase in power output. In addition, dry-sump oiling offers improved engine reliability due to consistent oil pressure, and increased oil capacity by using a large external reservoir.

Dry-sump engines are very tolerant of foam, too; they employ a gang of small pumps to transfer oil and foam to a tank where the oil is swirled and allowed to rest while the foam breaks. Oil then is drawn from the bottom of the tank and sent to the oil cooler, leaving any foam behind.

There are disadvantages to dry sumps, however. Most notable are the added cost, complexity and weight to any racecar. There are also issues with lubricating the areas normally protected by splash systems.

Racing oil also must deal with driving conditions unlike those seen by your passenger car or SUV. It must be able to protect key engine parts and surfaces under heavy loads and high speeds, not to mention exposure to methanol fuel. That means an extra measure of antiwear agents. It also needs to be very stable for the relatively short duration of operation, so synthetic base stocks are the norm.

Putting It Together

Open-wheel racers are probably the most famous racecars in the world, dominated by the track-oriented IndyCar Series in the United States and prestigious Formula 1 on-road races elsewhere. In the 1980s, Pennzoil sponsored Roger Penskes Indy cars and enjoyed a decade of winning racing. Knowing how those oils were created can offer some insight into the formulating strategies still used today.

In the early 80s, Pennzoil sought the help of additive representative Ed Gellner of Chevron Oronite. An avid racer himself, Gellner brought some of his practical expertise to the game of formulating for the Indy car Pennzoil sponsored. He noted that these engines run for a relatively short time between overhauls, so deposit control isnt a big issue, especially ring-groove deposits. They operate at relatively normal temperature ranges and burn methanol, so sludge deposit control isnt a problem, either. With no sulfur in the fuel, the only acids to neutralize come from oxidation products. Valvetrain loadings are high, so an extra amount of zinc dithiophosphate antiwear was required.

Gellner also noted that racing engines are run on a dynamometer and then may sit for weeks or months before they are installed in a car, so a good slug of rust inhibitor was needed. Foaming wasnt a big problem, but if uncontrolled, it could be really bad. On his advice, the antifoam level was raised to 13 to 14 parts per million-double or triple that found in regular engine oils.

The final formula contained about 0.14 percent weight zinc, split between primary and secondary ZDTP. There was neutral sulfonate for rust inhibition and some overbased detergent to control piston under-crown deposits. This raised the total ash content to about 0.5 percent. There was a supplemental rust inhibitor and some friction modifier. Ashless dispersant held everything together. Penske and Pennzoils wins showed that it was a successful composition.

Every Mile Counts

Oil viscosity is also important in racing due to the need for as much fuel mileage as possible. For IndyCar races, fuel is strictly controlled with only so much allotted to each car. Run out of fuel, and youve blown the race.

For decades, most IndyCar maintenance chiefs wanted as high a viscosity as possible to protect the engine. Yet as we know, higher viscosity means poorer fuel economy. There are decades-old examples of lighter oils being evaluated in engine dynamometer tests that simulated the driving cycle on the Indianapolis Motor Speedway, using an Indy engine and SAE 10W-30 racing oil. Results showed that the engines could operate for the equivalent of 1,000 miles-two full races-without any mechanical problems. In addition, the lower viscosity meant better fuel economy. But pit crews still felt that higher viscosity oils, such as SAE 20W-50, were needed.

So whats different today? Not a lot. The key shift in formulating has come in the viscosity of the oil, with SAE 0W-20 very common now. Open-wheel racecars still run for a short time between rebuilds, and they burn fuels that allow low ash levels. At their core, their engines are similar in design to engines in use nearly 40 years ago. The implication is that they were advanced for their time and reflect what has become todays state of the art in racing engine design.

Formula 1 open-wheel racing-think of the Monaco Grand Prix and other road circuits-has stricter engine use rules than IndyCar. Formula 1 engines must last four or five races or the driver is penalized in grid starting positions. As a result, the oils contain something closer to a complete additive system, albeit probably not the same.

Full synthetics are a must for Formula 1 racing, where engines operate at up to 15,000 rpm and deliver 1,000 hp at more than 230 miles per hour. These racers also have strict fuel usage limits. As a result, they prefer to use low-ash to totally ashless additive packages. All the race oils are now ultra-low viscosity and loaded with friction modifiers as well as antiwear and antioxidants.

Gone in 3 Seconds

Another popular racing vehicle is the dragster, or hot rod. Designed for all-out acceleration for a few seconds, their needs are quite different from Indy cars. The engines are large and fairly loose in build. A top-fuel dragsters exact horsepower is a mystery-there isnt a dynamometer that can handle one. Current estimates are in the 8,000 hp range.

A dragster engines basic layout is very similar to a 1964 Dodge Hemi 426 V-8, 16 pushrod-activated valves; but with two spark plugs for each cylinder and a total displacement of 500 cubic inches. The supercharger, which is essentially a belt-driven air pump that force-feeds the engine, is so massive that it takes 700 hp to run it. The extreme internal forces literally flatten the crankshaft bearings and destroy valve springs during a pass. So after every run, a team of eight mechanics performs a hurried rebuild in just 40 minutes.

Of the many classes of drag racers used in National Hot Rod Association competition, only two (Top Fuel and Funny Car) use nitromethane fuel. The rest use alcohol or gasoline. For classes that use regular fuel or alcohol, the lubricant could be similar to IndyCar.

For nitro-fueled engines, youre looking at an SAE 60 or heavier-with a zinc-containing antiwear additive, a nitromethane emulsifier and not much else. These engines carry a 12-gallon dry-sump system and hope to hold it all together for a run that normally lasts just 3 seconds.

Daytona or Bust

NASCAR racing, best known for the Daytona 500 and other oval-track endurance events, presents an entirely different set of circumstances. Custom racing engines need to endure high rpm and operating temperatures, so they require specially formulated, advanced motor oils.

More than half of all NASCAR teams use Mobil 1 motor oils, but other brands also have skin in this game. According to Race Line Central, a NASCAR engine holds 16 quarts of oil, and here again dry sump lubrication systems dominate, according to Popular Mechanics.

One example is the 2018 Ford Fusion fielded by Stewart-Haas Racing. It is a 358 cubic inch (5.9L) Ford FR9 overhead valve V-8. This engine operates at a compression ratio of 12:1 and delivers an unrestricted 850 hp at 9,000 rpm and 550 foot-pounds of torque at 7,500 rpm. There are often subtle modifications made to improve combustion and gain horsepower.

Most engine builders have modified their clearances to live with low-viscosity engine oils. Dirt track racers primarily burn alcohol fuel and run for long intervals (25,000 laps or more) between overhauls. Oil sump capacity (3 to 5 gallons) in the dry sump and frequent oil changes mean the oil degradation is pretty minimal.

Many NASCAR and SCCA race engines are derived from production cars, but with high valvetrain loadings and usually lower drag rings. A standard API SN or ILSAC GF-5 passenger car oil is usually a good fit, even with ZDDP limited to 0.08 percent wt; teams may source additional zinc-containing antiwear material from various suppliers.

Fred Peterson, formerly of Chevron Oronite, raced in SCCA events and shared some of his personal experience. He learned to work on 1960 TR-3 and Sprite engines.They had fairly wide clearances and seemed to last longer with SAE 15W-40 or even SAE 50 engine oils.

When he later raced Mazda Miatas, he started with the higher viscosity oils in those engines, too.Each year at seasons end, Peterson would build a spare engine to use the next year. Step one was to tear down last years engine, measure it and then reassemble it using new parts where needed.

Peterson said he quickly learned that he didnt need a high-viscosity oil and transitioned to an SAE 0W-20 synthetic for these engines. He reports there was still no measurable wear from one year to the next. As for horsepower, he ran in a racing class where it was set to a maximum number on a specific dynamometer, so any advantage from lower viscosity was not available.

The real story of auto racing is that each type is a world unto itself with engines, fuels and lubricants specifically designed for that purpose and that purpose only. However, a great many technical insights have been transferred to the regular motoring public. z