TSI and TDI are two different types of engines made by one manufacturer. Used mainly in VW cars, the TSI is a turbo petrol engine while the TDI is a turbo diesel.
Despite being different both engines are used in smaller cars. They share similar tech and are often offered as alternatives in the VW lineup. Which then raises the question, which is better? TSI or TDI?
Which Engine is Better? TSI or TDI?
Based on the basic comparison, it is safer to say that if you need a fast, light car, with great acceleration that doesn’t cost much, then the TSI is a perfect fit. If you need a torquey vehicle with higher fuel efficiency that will last longer, then TDI is the go-to engine.
The difference between TSI and TDI is not set on one parameter. Using different kinds of fuel already separates them. You like petrol, go with TSI, you love diesel, go with TDI. But comparing both technologies needs a more detailed breakdown. So let’s start with the TSI.
TSI- Turbo Stratified Engine:
The TSI stands for Turbo Stratified Engine developed by Volkswagen. It uses the combined tech of TDI and FSI (Fuel Stratified Injection ) engines to give us a small yet power-packing turbocharged petrol engine. A TSI engine uses direct fuel injection to pump fuel directly on the cylinder at higher pressure.
This enables the engine to produce more power, more torque, be more efficient and make less harmful emissions. Compared to the old MPI (multiple point injection) engines, the TSI powerhouse is better in every way. It is also equipped with superchargers and turbochargers to give boosts at both low and high ends.
TDI- Turbo Direct Injection:
The TDI on the other hand is a Turbo-Diesel engine. It has been around for a while. And has greatly been used by 50+ brands including Audi, BMW, Alfa Romeo, Volvo, Hyundai, Honda GMC, etc.
A TDI engine is a CRDI engine with a turbocharger. It has a common rail direct injection system boosted by a turbo.
Compared to a classic CRDI tech, a turbo jamming in the air with an intercooler that cools it down, direct fuel injection with CRDI ability to inject multiple times in one stroke, diesel fuel‘s higher energy density: all create a powerhouse that is not just insanely powerful but also power-efficient.
Thanks to the higher power and torque bandwidth, TDI engines are made smaller compared to CRDI. This helps manufacturers make more spacious cars.
Now that we have known about both engines, let’s see their basic similarities and differences.
Similarities between TSI and TDI:
- They are made by the same manufacturer, Volkswagen.
- Both engines are turbocharged and equipped with an intercooler.
- Both engines use direct fuel injection to inject fuel.
- Both engines are known for being highly efficient, have greater power output, and have a compact make.
Difference between TSI and TDI:
- Only the TSI engines have superchargers.
- TSI is lighter and also cheaper than TDI.
- TSI engines also make more horsepower. While TDI being a diesel engine produces more torque.
- TSI engines are also only offered in VW cars. TDIs are used by major car manufacturers.
- TSI engines are also smaller in size mainly 1.0L, 1.4L, 2.0L capacity while TDI goes as big as 4.0L V8 Turbo.
If that’s not enough, below is a list of 6-point comparisons between TSI and TDI so you can choose better.
Also read: Are EcoBoost Engines Good? (+ Problems They Have)
TDI vs TSI: Available Engine Options
| TSI Engines | TDI Engines |
|---|---|
| 1.0 L | 6.0 L V12 |
| 1.2 L | 4.0 L V8 |
| 1.4 L | 1.2 L |
| 1.5 L | 1.4 L |
| 1.8 L | 1.5 L |
| 2.0 L | 1.6 L |
| 3.0 L | 1.9 L |
| 2.0 L | |
| 2.5 L | |
| 2.7 L | |
| 2.0 L V6 |
Volkswagen has made quite a bunch of TSI engines. The smallest one is a 1.0L 3-cylinder that is used in Skoda Fabia, Seat Arona, and VW T-Cross. It produces 109 hp @ 5000 rpm. A 1.2 L TSI engine with similar power output uses a 4-cylinder configuration. This engine was seen in the older Polo GT TSI.
In the TSI list, you also have a 1.4L, 1.5L, 1.8L, and a 2.0L TSI engine featured in the VW Jetta, Polo, Passat, T-cross, and Tiguan. The largest TSI engine is a 3.0L V6 engine used in the VW Touareg. It produces 240hp and 550 Nm of torque.
The VW TDI engines have similar displacement to the TSI. However, unlike TSI, VW has made a bigger TDI engine including a 6.0 V12 used in the Audi Q7 between 2007-2012. Currently, the largest TDI you can buy is a 415 hp, 4.0L V8 engine fitted in the VW Touareg and the Audi SQ7.
TDI also has several smaller engines including 1.2 L and 1.4 L 3-cylinder engines. 80-100 hp 1.5L, 1.6L, 1.9L, 2.0L four-cylinder engines, a 2.5L five-cylinder and 2.7L, 3.0L V6 engine.
TDI vs TSI: Lifespan
If maintained properly, a TSI engine can do 200.00 miles. A TDI engine can easily make 300.000 miles, and some of the TDI engines might even last up to 500.000 miles.
TSI or TDI, Volkswagen are known for making durable engines. They use the best of techs with the highest quality. However, the lifespan of the engine is also dependent on the fuel type. To know more read our post on petrol vs diesel.
In general, a TSI engine is rated at 150,000 miles. If maintained properly, you can do 200,000 miles after which the engine itself would need some work. Being a petrol engine, TSI is also easy to maintain and repair.
But compared to a diesel lifespan, TSI doesn’t seem that durable. Generally, a diesel engine is rated at 300,000 miles. But TDI engines have lasted for 500,000 miles or 30 years. TDI engines also need less maintenance and fewer repairs compared to TSI. But they sure are costly.
TDI vs TSI: Fuel-Efficiency
One of the major benefits of getting a TSI engine is its fuel efficiency. Using direct fuel injection with turbo boosts the engine efficiency as it produces more power with less fuel wastage and rich combustion quality.
A TSI engine offers great fuel economy in between 30-40 mpg. Driving at a lower commute speed helps you get the maximum fuel efficiency. But with the TDI, you get an average of 40-60 mpg. Since diesel produces 20% higher energy than petrol diesel engines are intrinsically more fuel-efficient.
However, this difference is mainly seen on highways. If your primary objective is driving inside the city, TSI engines are perfect due to their superchargers.
Also read: Is 1.9 TDI a Good Engine? What Problems Does it Have?
TDI vs TSI: Reliability
A TDI engine is usually more reliable, and it doesn’t demand lots of maintenance. A TSI engine is a bit less reliable, but it does demand some care and it’s cheaper to fix.
TDI engines as mentioned are durable engines. They don’t break down easily and rarely have engine problems. However, while pistons or the engine block lasts forever, the injection system and electronics do fail often. You also get clogged EGR valves with timing belt failures and head gasket failure that causes oil leaks.
While these problems won’t seize your engine, they will make the experience rough and the aftermath expensive. Replacing your head gasket for example costs around $1500-$2000. Buying an injector for your TDI costs $200.
The TSI engines also face some common problems. Mainly you will see issues with timing chain tensioners, clogged fuel injectors, failed PCV valves, and high-pressure fuel pumps. However, unlike TDI, it doesn’t cost much to fix TSI engines.
TDI vs TSI: Performance
While both TSI and TDI are turbo engines, TSI engines are ones with better overall performance. They have better acceleration, lighter weight, and higher RPM range than TDI engines. TSI engines also produce more horsepower and higher top speed.
TDI being diesel engines have a greater torque output, however, the RPM range it is offered is rather narrow. Them being heavy also takes away from their acceleration. They also produce less horsepower.
If you compare the current Polo TDI vs TSI, despite the same power output at 108 hp, the TSI is 4 sec faster to hit 0-60 mph. It is also lighter and has less torque and has a top speed of 121 mph compared to 113 mph of TDI.
Simply said, a TSI engine is a high-performing engine that is suited for the city. The TDI high torque however makes it a perfect ride for the Highways.
TDI vs TSI: Maintenance
In between the TDI and TSI, the TSI is the more demanding engine. The frequency of maintenance on this engine is higher compared to TDI.
VW engines to begin with are low-maintenance engines. As per VW, whatever engine you use should go under maintenance once every 7,500 miles. Particularly for engines, the average maintenance includes oil and oil filter change at every 7,500 miles, spark plugs, timing belts, and transmission fluid every 20,000 miles. The average maintenance cost for a TSI engine is between $300-$500.
The TDI however requires less frequent services at 10,000 miles or every year. The general maintenance is oil and oil filter change with regular engine inspection at every 40,000 miles.
Unless you face a major problem such as a failure of a head gasket or ignition coil, the maintenance cost for the engine specifically is below $200. Which makes TDI less expensive to maintain.