Comparison of TU3 and TU5 Engines by Iran Khodro

The TU3 and TU5 engines are among the widely used powertrains in Iran Khodro’s products. Despite their age, they remain popular due to their low wear and tear and affordable maintenance costs. In this article, we aim to take a closer look at these two commonly used engines and analyze the differences between the TU3 and TU5 engines, as well as the advantages and disadvantages of each.

History and Introduction of TU3 and TU5 Engines in Iran

Before diving into the detailed differences between the TU3 and TU5 engines, it’s useful to look at the history of these powertrains in Iran.

Both TU3 and TU5 engines belong to the TU series, designed and manufactured by the Peugeot-Citroën group (PSA). This series was first introduced in 1986 and, over nearly two decades, underwent continuous improvements, being installed in various Peugeot and Citroën models. Among six different versions in this series, only the TU3 and TU5 engines entered the Iranian market.

TU3 Engine: Background and Use in Iran

The TU3 engine has a longer history in Iran’s market. It was first introduced in 2001 (1380 in the Iranian calendar) alongside the Peugeot 206. Initially, this engine was mounted on types 1 and 3 of the Peugeot 206, though these versions had limited production, and most people recognize the TU3 engine mainly in the type 2 Peugeot 206.

Besides the hatchback Peugeot 206, the TU3 engine was also used in different trims of the Peugeot 206 SD (V6, V19, and V20). The TU3 was produced in 10 different versions, with power output ranging from 64 to 99 horsepower depending on the fuel system (carburetor or fuel injection) and software programming. The version imported to Iran is known by the code TU3 JP.

When Peugeot 206 production stopped in 2023 (1402 Iranian calendar), it was expected that TU3’s era in Iran would end. However, Iran Khodro continued using the TU3 engine in one of the Peugeot 207 versions, introducing a new trim named 207 TU3. Currently, TU3 is produced only in this Peugeot 207 trim.

TU5 Engine: Introduction and Evolution in Iran

The TU5 engine entered the Iranian market in 2003 (1382 Iranian calendar) alongside the Peugeot 206 type 5. At that time, it was considered much more modern and efficient compared to other engines, quickly attracting buyers.

Like the TU3, the TU5 was produced in 10 different versions, with power output ranging between 89 and 123 horsepower. The version used in Iran is known as TU5 JP4. After type 5, this engine was installed in types 4 and 6 of the Peugeot 206 hatchback and also in various versions of the Peugeot 206 SD, including types V1, V8, V9, and V10.

Differences and Technical Features of TU3 and TU5 Engines

Both TU3 and TU5 engines belong to the PSA engine family, but they have significant technical differences that affect their performance and applications in different vehicles. The TU5 engine, with higher power and better efficiency, is a suitable choice for cars requiring a more powerful engine, while the TU3 is known as a longer-lasting and easier-to-maintain powertrain.

In the following analysis, we will examine these differences in detail and compare the advantages and disadvantages of each in terms of fuel consumption, power output, wear and tear, and maintenance costs.

TU3 and TU5 engines each have their unique characteristics that make them suitable for different vehicles. TU3 is more recognized for its low wear and maintenance costs, whereas TU5, with greater power and improved efficiency, is preferred by those seeking higher performance. Ultimately, the choice between these Iran Khodro engines depends on the driver’s needs and preferences.

The TU5 engine quickly became one of Iran Khodro’s strategic powertrains, gaining such popularity that it was installed not only on the Peugeot 206 but also on various models including Peugeot 207, Peugeot Pars, Peugeot 405, Rana, and even the Dongfeng H30 Cross. This engine remains one of Iran Khodro’s most widely used motors and currently powers several Rana Plus models with metal roofs and most Peugeot 207 versions.

In recent years, the TU5 underwent modifications and optimizations and was introduced as the EC5 engine. This version has been used in vehicles like the Peugeot 301, Citroën C-Elysée, and Peugeot 2008. During the JCPOA era, Iran Khodro and Saipa, through cooperation with Peugeot and Citroën, gained technical know-how of this engine. The outcome was the production of TU5 Plus engines at Iran Khodro and ME16 engines at Saipa.

Ultimately, the beating heart of cars such as Tara, Rana Plus Panorama, new automatic versions of Peugeot 207, and Saipa Shahin Plus all house versions of the TU5 engine.

Structurally, the differences between the TU3 and TU5 engines are quite noticeable. A detailed breakdown of all structural elements would be lengthy, but the main difference lies in their displacement and the number of valves.

The TU3 engine has a displacement of 1.4 liters (1360 cc) and 8 valves, while the TU5 engine has a displacement of 1.6 liters (1587 cc) with 16 valves. This difference in displacement and valve count results in better performance and efficiency for the TU5 compared to the TU3, which we will explore further below.

Differences Between TU3 and TU5 Engines in Terms of Performance and Efficiency

The TU3 engine can produce a maximum power of 75 horsepower and 118 Newton-meters of torque. In contrast, the TU5 engine upgrades these figures to 105 horsepower and 142 Newton-meters of torque. It is worth noting that the early versions of the TU5 engine, installed in vehicles before 2012, could produce up to 110 horsepower, but after localizing the engine in Iran, its power decreased by 5 horsepower.

In terms of power output per liter of displacement, the TU3 produces about 54 horsepower per liter, while the TU5 produces around 66 horsepower per liter. These figures clearly indicate that the TU5 engine ranks higher than the TU3 in terms of technical performance and efficiency.

Although the TU5 consumes more fuel due to its larger displacement, this difference in fuel consumption is minimal. Overall, the higher performance of the TU5 easily justifies this slight increase in fuel usage.

Other Structural Differences Between TU3 and TU5 Engines

Another noticeable difference is the transmission type. The TU3 engine is only paired with a 5-speed manual gearbox, while the TU5 engine is used both with this manual gearbox and also on vehicles equipped with a 4-speed automatic transmission.

Another difference relates to the compression ratio. The TU5 engine has a compression ratio of 10.5:1, whereas the TU3’s compression ratio is 9.6:1. The higher compression ratio of the TU5 indicates that this engine is more sensitive to fuel quality, although this difference is not significant enough to be a major concern.

In conclusion, the TU5 engine, due to its larger displacement and improved technical features, offers superior performance compared to the TU3, while the TU3 remains a suitable option for regular use and certain specific vehicles.

Comparison of Advantages and Disadvantages of TU3 and TU5 Engines

After becoming familiar with the fundamental differences between the TU3 and TU5 engines, it is now helpful to take a closer look at the advantages and disadvantages of these two popular powertrains.

Advantages of TU3 Engine

• Optimized Fuel Consumption: The TU3 engine generally consumes less fuel compared to some other engines.
• Lower Spare Parts Cost: Due to more affordable components, maintenance costs for this engine are lower.
• Less Sensitive to Oil: The TU3 engine is less sensitive to the type of oil used, which can be a significant benefit for long-term use.

Disadvantages of TU3 Engine

• Lower Power: Compared to some other engines, the TU3 produces less power, which might not be suitable for drivers who require higher acceleration.
• Weak Cylinder Head Gasket: One weakness of this engine is the vulnerability of the cylinder head gasket, which may need early replacement.

Advantages of TU5 Engine

• Reasonable and Higher Power: The TU5 engine delivers more power than the TU3, providing a smoother and faster driving experience.
• Optimized Fuel Consumption: Like the TU3, this engine also has good fuel efficiency and is generally economically efficient.

Disadvantages of TU5 Engine

• Higher Spare Parts Cost: Due to its more complex technology and higher power, the parts for the TU5 engine are usually more expensive than those for the TU3.
• Greater Sensitivity to Oil Quality: The TU5 requires higher quality oil, otherwise its performance may be negatively affected.

Which Engine is Better: TU3 or TU5?

Ultimately, the better choice depends on your intended use of the vehicle. If your main purpose is daily city driving with modest acceleration needs, the TU3 engine—with its lower price and adequate performance—is a logical option. On the other hand, if you seek more power and better performance at higher speeds, the TU5 engine, despite its higher parts cost, offers greater value.