Removing Oil Can Increase Engine Power

Who would have thought that the easiest and quickest way to increase an engine’s output would be to remove oil from it? Yes, you read that correctly: less oil in an engine can make it produce more power.

That is what the video below from The Motor Oil Geek channel demonstrates. Yet this outcome was not even the video’s creator’s original aim. The video examines the correct quantity of oil an engine should contain.

To establish this, Lake Speed Jr., the channel owner and an engineer specialising in engine lubrication, joined Ben Strader, founder of EFI University, to dyno-test a modified GM LS V8 engine with varying amounts of oil.

This engine takes 11 US quarts (10.4 litres) of 15W-40 synthetic oil. Dyno runs were carried out with five quarts (4.7 litres), seven quarts (6.6 litres) and nine quarts (8.5 litres) of oil.

The findings were unexpected. The peak-power gap recorded between the first run, using five quarts of oil, and the final one, with nine quarts, was considerable: 649 hp (658 cv) and 589 hp (597 cv), respectively. That represents a difference of 61 cv, which is remarkable.

During the middle test, with seven quarts, the engine delivered 630 hp (639 cv). Torque figures also showed substantial variation: 617 Nm in the five-quart test, compared with “only” 559 Nm with nine quarts.

Why does it produce more power with less oil?

The explanation for this effect is fairly straightforward. With less oil present, the engine’s crankshaft - the shaft located at the bottom of the engine - encounters less resistance as it rotates.

As a result, it does not need to waste as much force overcoming that resistance and turning, which increases torque and, with everything else unchanged, power.

The risk of seizing the engine

The gains are striking, but it is worth remembering two things: firstly, this is a “family-sized” V8; secondly, this inexpensive trick carries a potentially costly consequence - engine seizure. Correct engine lubrication is vital to ensure long service life.

The test also shows that, with the V8 running on the smallest amount of oil, oil pressure falls to almost half of the ideal level - 36.1 psi - from 5000–5100 rpm. If it remains low for too long, various engine components could be damaged or the engine could seize altogether.

In the seven-quart test, oil pressure rises to 68.1 psi at the same engine speed. It continues increasing with revs, only dropping after 7000 rpm - indicating that there is no longer any oil in the sump.

With nine quarts of oil, the huge V8 has enough lubricant to maintain pressure at any engine speed, including beyond 7000 rpm. On the other hand, power and torque take a “tumble”. Even so, that is preferable to a damaged engine.

An established practice

Increasing engine power by removing oil is not a recent discovery. In motorsport, particularly in drag racing, it has long been a familiar practice.

After all, races last only seconds and cover just 400 m (a quarter-mile). Although the mechanical strain is high during that brief period, competitors can risk removing some oil to gain a few extra horsepower.

Even when the power increase translates into only a few thousandths of a second, it can mean the difference between winning and losing.