DeltaECU is EcuTeK's ECU reprogramming software for the 1999 to 2002 (incl current) model years of Subaru Impreza and Forrester Turbo (see supported vehicles list). The software allows reprogramming of the original ECU, in-situ via the diagnostics port, along with serious features that allow accurate and successful mapping.

Who is DeltaECU for ?

DeltaECU has been designed with the professional tuner in mind. Those familiar with engine management will find the software intuitive, and a pleasure to use. Written by tuners for tuners, DeltaECU is the software that we at EcuTeK use to produce our performance ECUs. This product is available to the commercial tuner only

What cars does DeltaECU support ?

There are now five Software options to choose from to enable access to the Subaru ECU. (Flash 99) supports the 1999 and 2000 model years of cars such as WRX, STi and Forester GT. (Flash 2002) supports the 2001, 2002, 2003 and 2004 model year of Impreza WRX and GT Forester. (Flash 2002 STi) supports the 2001, 2002, 2003 and 2004 model year of Impreza WRX STi. (B4) supports the Twin Turbo B4 2001 to 2003 (Flash 2004) supports the 2004 onwards model year of Impreza STi (USA only) Forester XT and Liberty GT turbo.

The current list of supported cars is as follows:

How is the ECU reprogrammed ?

To reprogram the ECU, the DeltaECU programming interface is simply plugged into the diagnostic socket of the car. Any of the ECUs listed above can then be reprogrammed in under 2 minutes !

Unlike other 'chipping' solutions, DeltaECU, requires no soldering and no physical access to the ECU - an altogether quicker, cleaner and more reliable method of tuning. Rather than spending time soldering and desoldering hair thin chip legs, the tuner's time can now be spent more productively, with less time spent soldering and more time actually improving mapping of the customer's car.

Once an effective map has been produced for a particular combination of modifications, further identically mapped ECUs may be rapidly produced. This is extremely useful for companies who wish to package a premapped ECU with their exhaust manifolds or turbo/FMIC kits.

Why Reprogram the Original ECU ?


Tuneable Parameters

The following ECU parameters may be altered using DeltaECU:

Graphical Map Views

Both ignition and fuelling maps may be viewed graphically to fast interpretation of map shape. This also allows errors to be quickly spotted. The example below shows a fuel map that is being viewed graphically, to show the spectrum of air/fuel ratios used by this ECU.

Live Map Access View

Whilst testing the car, either on the road or dyno, access to fuelling, ignition and boost maps may be viewed in real time to show which parts of the map are being accessed by the ECU. DeltaECU will also colour the zones of the fuelling or ignition maps based on the knock correction and lambda values retrieved from the car under test. This allows the tuner to quickly see which areas of the map require attention.

The example above shows an ignition map that has been coloured with the knock correction that the ECU has applied to the map. From this colouring, it is evident that a portion of the map is far too advanced and that the ECU is having to retard the ignition. The colour key shows the level of knock correction that each colour corresponds to. Below is another test, performed after the ignition timing has been altered. The high levels of det (dark red) have been eliminated by retarding the ignition by 3 to 4 degrees in this area.

The example below shows a fuel map that has been coloured with the lambda sensor voltage from the exhaust as this car is put through a dyno run. By referring to the colour key, it can be seen that the mixture is lean as the turbo is spooling. Dramatic improvements in spool up time can be obtained by filling in this fuelling flat spot.

Ignition Map 3D View

WRX Air Flow Sensor Scaling

Dyno Plots

For sample dyno plots please refer here.

System & User Requirements


For further information on DeltaECU, or to arrange a personal demonstration, please contact us.

Map Switching

This revolutionary feature allows the driver to select from two performance levels while driving. Available for 2001 onwards US, UK, EU & Aus spec WRXs

How it Works
EcuTek have customised the function of the software in the ECU to allow dynamic switching between two sets of performance maps. To switch between these performance levels, the driver simply holds full throttle and toggles the rear heated window switch. This may be done with the engine off or on.

The two performance levels may be specified by your client to you as a EcuTek tuning partner. Your cleint may choose to have one performance level for road use and on for drag racing. Alternatively, they may choose to have a high performance and an economy mode. Or they may choose to have a valet mode with only a rpm limit of 1000rpm, (great for people who park their cars in city car parks daily, or at the airport valet, or if you ship your car by road trasnport truck etc) basically you can help your client get what they need!

How to get it
To use map switching on a WRX, the ECU must be programmed with a special map switching ECU calibration. If the cleint has already had their ECU reprogrammed by an EcuTek tuning partner, they can contact them or you for an upgrade. If they are a new customer, they simply choose an EcuTek partner from the dealer list and specify that they would like the map switching feature when your ECU is tuned.


ECUTEK (Australia)
Phone: intl+ 61 2
9767 4545  Email:

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Some content of this web site is used with permission from EcuTek Ltd. Uxbridge UK.