Less Oil Can Increase Engine Power

Who would have thought that the quickest, simplest way to increase an engine’s power is 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. However, this outcome was not even the video 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 test a modified GM LS V8 engine on a dynamometer using different oil quantities.

This engine takes 11 US quarts (10.4 litres) of synthetic 15W-40 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 surprising. The difference in peak power recorded between the first test, with five quarts of oil, and the final test, with nine quarts, is substantial: 649 hp (658 cv) and 589 hp (597 cv), respectively. That amounts to a 61 cv gap, which is remarkable.

In the middle test, using seven quarts, the engine delivered 630 hp (639 cv). Torque figures also showed sizeable variations, with 617 Nm in the five-quart test and “just” 559 Nm with nine quarts.

Why does less oil produce more engine power?

The reason for this effect is fairly straightforward. With less oil present, the engine’s crankshaft, the shaft located in the lower part of the engine, encounters less resistance as it rotates.

It therefore does not need to use as much force to overcome that resistance and turn, increasing torque and, with everything else unchanged, power.

The risk of seizing the engine

The gains are impressive, but it is worth remembering, first, that this is a “family-sized” V8; and second, that this inexpensive trick carries a potentially costly consequence: seizing the engine. Correct engine lubrication is vital to ensure its long-term durability.

The test also shows that, with the V8 running on the lowest quantity of oil, oil pressure drops to almost half the ideal level, 36.1 psi, from 5000-5100 rpm. If it remains low for too long, several engine components could be damaged, or the engine could even seize.

During the seven-quart test, oil pressure rises to 68.1 psi at the same engine speed. It continues climbing as revs increase, only falling after 7000 rpm - indicating that there is no longer oil in the sump.

With nine quarts of oil, the huge V8 has sufficient oil to sustain pressure at any engine speed, even 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 in drag racing

Increasing engine power by removing oil is not a recent discovery. In the world of motorsport, particularly drag racing, it is a well-known longstanding practice.

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

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