Can a modern diesel engine produce more power and torque without removing or disabling its diesel particulate filter? At AUTOCHIP.LV, we carried out an individual Stage 1 ECU remap on a 2018 Opel Insignia equipped with a 2.0 CDTI diesel engine and an ACDelco E98 engine control unit.

The aim was to achieve a noticeable performance improvement without choosing an excessively aggressive calibration. Retaining the functionality of the diesel particulate filter was an important part of the work.

The vehicle was tested on a dynamometer before and after tuning. Measured power increased from approximately 163 to 187 hp, while torque rose from 423 to 495 Nm. Following the software adjustments, the workshop also performed a particulate emissions measurement to check the operation of the DPF.

Initial testing of the Opel Insignia 2.0 CDTI

This 2018 Opel Insignia uses a two-litre turbocharged diesel engine with quoted factory specifications of approximately 170 hp and 400 Nm. Engine management is handled by an ACDelco E98 ECU.

Before changing the software, the car was placed on a dynamometer to establish its actual power and torque figures. Baseline testing is useful because it provides measurable data for comparing the vehicle's performance before and after calibration.

The initial test showed approximately 163 hp and 423 Nm. Measured power was therefore around 7 hp below the quoted factory rating, while measured torque exceeded the nominal 400 Nm figure.

These differences do not automatically indicate an engine fault. Dynamometer methodology, test conditions, vehicle configuration and other factors can influence the results. Without further information, the precise reason for the difference cannot be established.

For this project, the baseline measurements were used primarily to evaluate the effect of the ECU tuning carried out by the workshop.

Custom Stage 1 tuning with the DPF retained

Stage 1 tuning generally involves modifying engine management software without requiring major mechanical upgrades. However, even a relatively moderate remap needs to account for the condition of the engine, turbocharger capabilities, fuel injection system and exhaust aftertreatment components.

For this Opel Insignia, the workshop selected a comparatively conservative individual calibration designed to improve power and torque while retaining the control strategies needed for DPF operation.

There was one important detail concerning the vehicle's emissions systems. Its SCR/AdBlue system had already been disabled through software modifications carried out by another workshop before it arrived at AUTOCHIP.LV. The AUTOCHIP.LV team did not perform that earlier modification as part of this project.

Consequently, the vehicle did not retain its complete original exhaust aftertreatment configuration, even though its DPF remained installed and functional during the test.

Maintaining correct DPF operation requires attention to soot production, fuel delivery, air supply and regeneration control. Increasing engine output without considering these factors can result in additional soot loading and potentially shorter filter life.

An individual ECU calibration should therefore consider how the engine's systems operate together rather than focusing exclusively on maximum torque or fuel delivery.

Dyno results: 187 hp and 495 Nm

After the software calibration was completed, the Opel was tested again using a 4x4-type dynamometer. The measurements provided a direct before-and-after comparison for the same vehicle.

Before tuning:

• Power — approximately 163 hp.
• Torque — 423 Nm.

After Stage 1 tuning:

• Power — 187 hp.
• Torque — 495 Nm.

The resulting improvement was approximately 24 hp and 72 Nm compared with the baseline measurement. This represents a power increase of roughly 15% and a torque increase of around 17%.

For a diesel-powered road car, additional torque can be particularly useful. It may improve acceleration response and provide stronger pulling performance during overtaking or when driving in higher gears. However, the actual driving experience also depends on the shape of the torque curve, transmission behaviour and other vehicle characteristics.

These were measured results from the actual car, not estimated power gains taken from a tuning catalogue.

Checking boost pressure and diagnostic parameters

Professional ECU calibration involves more than writing modified software to the engine control unit. Once the calibration has been changed, the engine's behaviour under load needs to be evaluated.

For this Opel Insignia, the AUTOCHIP.LV team recorded diagnostic datalogs and examined operating parameters before and after tuning. The checks included turbocharger boost pressure, intake air temperature, Common Rail fuel pressure and other engine management data.

Before tuning, the reported turbocharger pressure reading was approximately 1.8 bar. Following the calibration, the maximum reading was approximately 2.0 bar, a difference of around 0.2 bar.

The recording does not establish whether these figures represent absolute or gauge pressure, so they are presented as the diagnostic readings discussed during the test rather than as an independently determined boost specification.

The workshop also monitored intake air temperature and reported that it remained at an acceptable level during the checks. Fuel rail pressure and other available parameters were examined to assess the chosen calibration.

These checks matter because increasing diesel engine output can affect combustion temperatures, soot production, turbocharger operating conditions and fuel system loads.

Reviewing the data helps assess whether the engine is behaving as intended under the specific conditions tested.

DPF particulate emissions test after the remap

Another important part of this project was the particulate emissions test carried out after the Stage 1 calibration.

The technician initially stated that the workshop would perform an additional particle measurement free of charge. The continuation of the recording then showed the test taking place.

The workshop used the same type of particulate measuring equipment employed at Latvia's CSDD vehicle inspection stations. A measuring probe was inserted into the exhaust pipe of the Opel Insignia.

During the measurement, the instrument displayed very low readings of approximately 0.7, followed by values around 0.8–0.9.

This was an encouraging result, indicating that the DPF was effectively capturing particulate matter under the conditions of the test, even after the engine output had been increased.

The exact units associated with these displayed values were not established in the recording, so no units have been assigned to them. The figures should also not be interpreted as evidence of absolutely zero emissions.

Although the result confirmed effective filtration during the workshop test, a single measurement cannot establish long-term DPF durability or guarantee that future regeneration cycles will always operate correctly.

The workshop test is also not equivalent to confirmation that the vehicle has passed an official CSDD roadworthiness inspection.

Why does DPF-friendly tuning require careful calibration?

A diesel particulate filter captures soot particles produced during combustion. As soot accumulates, the engine management system initiates or supports regeneration under suitable conditions to burn off the trapped material.

If ECU tuning causes excessive soot production, the DPF may become loaded more quickly and require more frequent regeneration. Incorrect changes to temperature monitoring or regeneration strategies can create additional problems.

For this reason, increasing diesel engine performance should involve appropriate control of fuel injection, airflow, boost pressure and relevant exhaust aftertreatment strategies.

The Opel Insignia test demonstrated that the chosen Stage 1 calibration was compatible with effective particulate filtration at the time of measurement. It did not establish that all possible long-term effects on the filter had been eliminated.

It is also important to distinguish between DPF and SCR/AdBlue systems. The DPF captures particulate matter, while SCR is designed to reduce nitrogen oxide emissions. A low particulate measurement does not demonstrate correct SCR operation or establish full emissions compliance, particularly where the SCR system has previously been modified.

How much did the custom Stage 1 tuning cost?

At the time of the recording, the technician quoted €300 for the work carried out on this Opel Insignia.

The price included individual ECU calibration, dynamometer testing, diagnostic datalogging and a printed comparison of the results before and after tuning.

The workshop also performed the particulate emissions measurement at no additional charge for this customer.

This was the price quoted for the specific job at the time of filming, not a verified current price for all vehicles. Costs may vary depending on the ECU, programming access requirements and the diagnostic work involved.

Conclusion: measurable Stage 1 gains with DPF testing

The 2018 Opel Insignia 2.0 CDTI received a custom Stage 1 ECU remap at AUTOCHIP.LV while retaining its diesel particulate filter.

Measured power increased from approximately 163 to 187 hp, while torque rose from 423 to 495 Nm. That represents an improvement of around 24 hp and 72 Nm compared with the baseline dynamometer test.

The tuning process included dyno measurements, diagnostic datalogging and checks of boost pressure and other engine parameters. A subsequent particulate measurement produced very low instrument readings, providing positive evidence of DPF performance immediately after the remap.

This case illustrates how a measured improvement in diesel engine performance can be combined with retaining and testing the DPF. Nevertheless, long-term filter reliability and full emissions compliance require separate consideration, especially because the vehicle's SCR/AdBlue system had already been modified before this work.

The accompanying video shows the dyno graphs, tuning process and particulate emissions test in greater detail.