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Summary
  • A twin-engine car is exactly what it sounds like 一 a vehicle with two engines.
  • A twin-engine setup is also referred to as an inline twin, vertical twin, or parallel twin. It has two cylinders that are arranged in a line along the crankshaft.
  • The Citroen 2CV Sahara and Tempo G1200 are the only two factory-built twin-engine vehicles to date. Other twin-engine layouts are modifications.

The engine is complicated enough as it is. How it works is a mystery to many, especially those who have just gotten the hang of the steering wheel.

New drivers are probably trying to wrap their heads around the inner workings of the engine, as well as the parts that make it up.

Understanding how one engine works can be quite challenging, and the operation of a twin-engine setup will probably add to the confusion.

That’s right 一 twin-engined cars are real, and we’ll be talking more about it in this article.

What Is a Twin-Engine Car?

A twin-engine car is exactly what it sounds like 一 a vehicle with two engines.

A twin-engine setup is also referred to as an inline twin, vertical twin, or parallel twin. It has two cylinders that are arranged in a line along the crankshaft.

A Tale of Two Engines

The idea of developing a twin-engine car came about when a man named Howard O. Carter got stranded a couple of miles away from his house because of a disabled engine.

Afraid that it might happen again, Carter came up with the ingenious idea of creating a vehicle layout that had two engines sitting side by side.

In Carter’s design, the two engines were connected via cone clutches in the flywheels and Morse silent chains. The entire setup was then connected to a three-speed transmission at the center of the car.

Carter saw the need to install another engine to have a backup powertrain in case the other failed.

What’s interesting about this setup, however, is that it doesn’t add too much weight to the vehicle. According to reports, a vehicle with Carter’s engine can go from 250 to 2,500 rpm without any issues.

How Do Twin-Engine Cars Work?

Only one crankshaft is used for both engines. Based on Carter’s design, engine A turns and runs first before engine B.

Under challenging road conditions, the clutch on engine B will engage while the vehicle is running at a high speed.

From there, engine B will start, supplying the vehicle with double the horsepower than before. This lets the vehicle run smoothly without dropping to a lower gear.

Today, the concept of twin engines goes beyond diesel and gasoline-powered machines.

Hybrid electric vehicles (HEVs) are generally considered to have twin engines, given that they have a petrol engine and a battery-powered one.

In a hybrid vehicle setup, the electric motor usually drives the vehicle at low speeds, and the petrol engine takes over as the speed increases.

Most hybrid vehicles also have options where you can drive solely on gasoline or go all-electric.

Two Is Enough: Factory-Built Twin Engines

Before the concept of hybrid vehicles, the twin-engine setup was more of a modification that drivers do once they’ve bought their vehicles.

For some car owners, installing a secondary engine is more practical (in terms of costs) than buying a vehicle with a four-wheel drive (4WD) feature.

But did you know that there were factory-built vehicles that came with twin engines back in the day?

The list isn’t that long. In fact, there are only two factory-built twin engines to date.

Tempo G1200

1936 tempo g 1200 offroad wikimedia
Tempo’s G1200 can be steered on both front and rear axles. Paired with an independent coil spring suspension, the model had an impressive amount of wheel travel. Image source: Wikimedia.

Tempo was a Hamburg-based automaker that initially developed three-wheel delivery vehicles.

Between the mid-1930s and mid-1940s, the German Army (Wehrmacht) planned to standardize family vehicles with a four-wheel drive setup. Tempo wanted to do the same thing to grab a share of the market.

With the limited resources Tempo had, it was able to produce the G1200.

Tempo’s three-wheel delivery vehicles already ran on 600cc two-stroke inline twin Ilo engines. All Tempo had to do was to stick one on each end of the 4WD vehicle they were developing to get 1200cc.

Each engine was capable of generating 19 hp, which doubled to 38 hp when both engines were at work.

Tempo’s G1200 can be steered on both front and rear axles. Paired with an independent coil spring suspension, the model had an impressive amount of wheel travel.

Two spare tires on independent axles sat on each side of the G1200 to help the vehicle maneuver across rough road conditions. The setup also prevented the G1200 from getting high-centered.

Sadly, the German Army wanted nothing to do with the two-stroke engines that Tempo had. Fortunately, countries like Austria, Turkey, Finland, and Romania were interested in the G1200, so Tempo was able to sell about 1,200 of the G1200 units.

Citroen 2CV Sahara

1961 citroen 2cv sahara wikimedia
To create the 2CV Sahara, Citroen strapped a pair of gas tanks under the front seats and relocated the spare tire from the trunk to the hood. A second 425cc air-cooled flat-twin occupied the trunk instead. Image source: Wikimedia.

The Citroen 2CV Sahara was the only other factory-built vehicle with a twin-engine setup.

Between the ‘50s and ‘60s, the French saw the need to develop a cheap and light vehicle that could take on desert terrain without much trouble.

During this time, the French were conducting oil exploration activities in North Africa, particularly in the Sahara Desert.

A 4WD setup was perfect for exploring the Sahara, but it was also important to have a vehicle with two drivetrains in case one engine failed while traveling across the desert.

Luckily, Citroen didn’t have to start from scratch. Its 2CV model was the ideal vehicle to work with because it already had substantial ground clearance and a flexible suspension. It was also light and inexpensive.

To create the 2CV Sahara, Citroen strapped a pair of gas tanks under the front seats and relocated the spare tire from the trunk to the hood. A second 425cc air-cooled flat-twin occupied the trunk instead.

Bigger carburetors set the 2CV Sahara apart from the original 2CV, which only had a mono-engine.

Early versions of the 2CV Sahara generated 13.5 hp for each engine 一 a figure that later soared to 18 hp for the succeeding units.

A total of 694 2CV Saharas were built between 1960 and 1971. There are approximately 27 units left in the world today, and each one has an estimated selling price of $100,000, making them the most expensive 2CVs to date.

About The Author
Written By Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

File Under : Trivia and History , Features
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