Do High Gears Save Fuel - if so, how much?

Summary

In this video, the presenter tests the fuel efficiency of a 2014 SEAT Leon 1.4 turbo petrol with a six-speed manual gearbox at a constant 30 miles per hour across all gears. The experiment reveals that higher gears, despite initial skepticism, yield better fuel economy, with fifth gear outperforming others. The video debunks the myth of engine damage from low revs in modern cars and advises drivers to listen to their engine for signs of strain when choosing gears for fuel efficiency.

Takeaways

• 🚗 The experiment aimed to determine the most fuel-efficient gear for a car at a constant speed of 30 miles per hour.
• 📈 The car used was a 2014 SEAT Leon 1.4 turbo petrol with a six-speed manual gearbox and 189,000 miles.
• 🛣️ The test was conducted on a specific road section where the car could maintain 30 mph without interruption.
• 🏁 A squash racquet was used to mark the start of each test run and to reset the fuel economy trip computer.
• 📊 First gear at 30 mph resulted in 23 miles per gallon, which was surprisingly good for the high engine strain.
• 🌟 Second gear at 30 mph was the most economical, averaging 46.2 miles per gallon, a significant improvement over first gear.
• 🔝 Third gear showed an average of 61.6 miles per gallon, which was 33.3% more economical than second gear.
• 🚀 Fourth gear achieved an average of 75.8 miles per gallon, marking a 23.1% improvement over third gear.
• 🔝🔝 Fifth gear provided an average of 82.3 miles per gallon, an 8.5% improvement over fourth gear, and the best result in the test.
• 📚 Even though the car struggled slightly in sixth gear at 30 mph, it still managed to achieve a mean average of 88.1 miles per gallon.
• ⚠️ The video advises against using a gear where the car is struggling as it can be harmful to the engine and unsafe.
• 💡 Modern engines are designed to operate efficiently at low revs, contrary to older engines that may require higher RPMs to avoid damage.

Q & A

What is the main purpose of the experiment described in the script?

The main purpose of the experiment is to determine which gear is the most economical for fuel consumption when driving at a constant speed of 30 miles per hour.

What type of car was used in the experiment?

A 2014 SEAT Leon 1.4 turbo petrol with a six-speed manual gearbox was used in the experiment.

How many miles does the car used in the experiment have on the odometer?

The car has 189,000 miles on the odometer.

What method was used to mark the beginning of each test run?

A squash racquet was used to mark the beginning of each test run by placing it on the embankment at the side of the road.

Why couldn't the cruise control be used in first gear during the experiment?

The cruise control couldn't be used in first gear because it doesn't work in first gear, as the car needs to rev higher to reach 30 miles per hour.

What was the fuel economy reading for the first run in first gear?

The fuel economy reading for the first run in first gear was 23 miles per gallon.

How many runs were conducted in each gear, and what was the average fuel economy for second gear?

Three runs were conducted in each gear, and the average fuel economy for second gear was 46.2 miles per gallon.

What was the percentage improvement in economy from first gear to second gear?

There was a 108% improvement in economy from first gear to second gear.

What was the highest average fuel economy recorded in the experiment?

The highest average fuel economy recorded in the experiment was 88.1 miles per gallon in sixth gear.

What was the advice given regarding driving at low RPMs in modern engines?

The advice given was that it's generally fine to drive modern engines at low RPMs, as they are designed to maintain oil pressure and coolant circulation effectively at these levels.

What factors should a driver consider before deciding to drive in a higher gear where the car might be struggling?

A driver should consider the sound of the engine and the availability of power. If the engine sounds strained or there's no power when pressing the gas pedal, a lower gear should be chosen.