These days more and more buyers are opting for diesel cars because of the cost difference of the fuel against petrol cars. Diesels are inherently more fuel efficient and provide much better torque compared to petrols. Yet, there are some who want more power from a diesel car.

CarToq examines a few common methods of modifying your diesel car to extract more performance from it. These modifications apply to only modern common-rail diesel engines that are ECU controlled, although a couple of them could be used on older diesels too.


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ECU Remap

The easiest way to extract more performance from you diesel car is to “remap” the engine control unit. This is done by professional tuners who connect a laptop to the car’s ECU and load it with new software that changes some key parameters. This includes telling the engine to inject more fuel for a given rpm, which results in more power building up quickly. Diesel engines need two things to work efficiently – more air and more fuel, as they are high-compression engines. A remap will ensure it gets more fuel. The downside is the engine will drink more fuel at higher rpms and will be slightly less fuel efficient. Also see: CarToq Diesel Decider: Find out if a diesel car makes economic sense for you!

ECU remaps are a permanent setting on the ECU and you need to go back to the tuner if you want to revert to stock settings on the car. If your car is still under warranty, this will void the warranty – and it will show up when the service station plugs in its diagnostics computer to the car.

A remap will cost anywhere between Rs. 20,000 and Rs. 28,000 depending on your car. Companies such as Pete’s and Dieseltronics provide these services in India for most common-rail diesel cars.

Diesel tuning box “Chipping”

If you want a more flexible solution to more power, then a “piggy-back ECU”or “diesel tuning box” also known as “chipping your car” is a useful solution. What this diesel tuning box does is to connect between the car’s ECU and the fuel injectors, and fool the ECU into thinking that the engine needs more fuel. Tuning boxes can be installed and removed quite quickly without disrupting the car’s wiring – they are almost plug and play. Also read: Do you need premium diesel for your car?

Installing a tuning box is useful if your car is still under warranty, as it can be removed whenever the car is sent for service. (Of course, this is unethical!). These days you get tuning boxes with “switchable maps”, where you can drive the car in stock mode, fuel economy mode or in sports mode, depending on what you need. This can be adjusted by the driver with a separate switch.

Tuning boxes are the most popular diesel performance modifications. Tuning boxes cost between Rs. 28,000 and Rs. 35,000. Again companies such as Petes and Dieseltronics supply them in India for almost all popular common-rail diesel cars and SUVs.  Tuning boxes can squeeze out up to 20% more power and torque from the car.

Hi-flow air filter

A high-performance air filter will help your car breathe better. You get two types of high-performance filters – universal cold air intake performance filters and stock replacement filters. Stock replacement filters are specific to the model of your car as they fit exactly into the slot of your stock air filter. K&N and Green Cotton are two popular high-flow air filter brands for most cars sold in India.

High-flow air filters contain a mesh with an oil-film coating that traps dirt particles, but allows more air flow into the engine. If maintained properly a high-flow air filter can give the car a 5% increase in power owing to more air rushing into the intake. However, in the long term since high-flow filters have wider gaps in the filter material, some particulate matter can build up in the intake system, if the filters are not serviced regularly.

Stock replacement filters cost between Rs. 5000 to Rs. 7000, while universal filters cost over Rs. 10,000 depending on the plumbing required for the intake.

Upgrade turbo or intercooler

Another way to boost performance of your car is to give it more boost (if the engine can take it) or give it thicker, cooler air to breath as this improves combustion. Upgrading the turbo is expensive and turbochargers cost upward of Rs. 50,000. A slightly cheaper method would be to install a bigger intercooler that can cool turbocharged air more efficiently leading to better performance. Intercooler upgrades cost upward of Rs. 25,000.

Sports clutch

With increased power, the part that gets most stressed in the car’s drivetrain is the clutch. If you are increasing power substantially, then it’s better to change the clutch friction plate and pressure plate to one that can withstand higher temperatures and faster shifts. Companies like Greddy and Valeo make performance clutches for a range of cars, although the range is limited when it comes to cars sold in India. Prices are upward of Rs. 25,000 for these replacement jobs.

LPG fumigation

LPG fumigation is an unorthodox way of boosting performance of diesel cars. It is just like using NOS (nitrous oxide injection) in petrol cars to get a boost in power. LPG fumigation basically provides more combustible fuel to the engine. What it does is to spray some amount of LPG gas into the air intake of the diesel engine, so that when the diesel ignites and burns in the cylinder, it also ignites the LPG-mixed air mixture which provides a lot more power.

LPG fumigation kits are not easily available in India. Even if they are installed, such kits are not really legal to use. Kits are available online and cost over Rs. 35,000. LPG can be refilled using AutoLPG pumps (but this is again unethical).

Also check out this story: Premium diesel hatchbacks with safety features

These are some ways to boost performance of your diesel car. Share any more pointers you may have on increasing performance of your diesel car with the CarToq community.