The XEDE - Subaru Impreza STi

The XEDE is currently only availabe in wire-in form. There is no plug-in harness currently available for it. This means that you will have to cut a few wires on your ECU harness to install it. While this is not difficult, it does require basic wiring skills. Please email us at sales@vishnutuning.com for installation instructions.

The STi XEDE: An Overview

The XEDE (pronounced "ex-eed") is the only user-programmable engine control system that works with the factory ECU- not instead of, or against it. Every one of its functions has the resolution and flexibility to complement all factory ECU engine control strategies. From the factory ECU's boost-limiting safety features, to its active timing control, to its dual fuel maps, to its long-term learning algorithms, etc., the XEDE carries the tuning torch without inducing any compromise to performance or safety margin. A year ago, such coherence between ECU and interceptor-based tuning device would have been deemed impossible for a number of reasons:

1) No one had access to underlying fuel, timing and boost maps. This means that all piggy-back tuning attempts were subject to unknown. Variables that had influence over long-term fuel learning or knock correction. It was also impossible to determine and compensate for maximum RPM or Load limits which made extracting full performance without concessions to safety margin virtually impossible.

2) Limited resolution with respect to tuning control. With the factory fuel, timing, boost and knock correction maps offering up to 16x16 cell resolution with engine speed breakpoints every 400RPM, no interceptor-based tuning device of the time offered commensurate resolution. Without this resolution, it was impossible to compensate for sudden spikes or dips in underlying maps. Instead, compromise was inherent in such applications.

3) Poor crank angle sensor (CAS) replication. Prior interceptor-based tuning systems improperly replicated the crank angle sensor waveform, maintaining little more than signal peaks and valleys. While this was sufficient to manipulate basic timing advance, it often triggered factory diagnostic strategies, hard-starting, erratic knock correction and general rough-running characteristics.

4) Limited tuning software flexibility. As with virtually every aftermarket engine control systems on the market, tuning software interfaces offered resolution greatly inferior to that of the factory ECU it is attempting to influence. With the inability to place Load and RPM breakpoints wherever necessary for coherent management (and the restriction of having to use the same Load and RPM breakpoints for all tuning variables) the tuning process was shrouded in compromise.

The XEDE addresses all the above issues as following:

1) With our involvement with the ECUTEK re-flashing system, we now have full knowledge of all OEM fuel, timing advance, knock correction, etc,. maps. Knowing all underlying engine control variables, it's now possible to know exactly what one is tuning upon.

2) With the XEDE offering an ultra-high 20x20 map resolution, it is now possible to tune upon the factory maps without sacrificing granularity or having to compromise one zone for another. Additionally, XEDE users can define not only their own Load and RPM breakpoints for each map, they can also determine which Load variable to use (TPS, MAP or MAF) in order to best achieve their specific tuning goals. Simply put, no other form of engine management offers this degree of tuning flexibility.

3) Compared to the Unichip, the XEDE is capable of vastly superior CAS replication. This ability greatly improves active knock correction performance, general drivability and invisibility to the factory diagnostic system. Perfect CAS replication insures that there is absolutely no misunderstandings between the factory ECU and the XEDE.

4) Unlike the Unichip which is capable of modifying only Ignition Timing and MAF signals with fixed load (MAP) and RPM) breakpoints (every 500RPM, the XEDE is capable of modifying Ignition Timing, MAF, TPS, MAP and Knock sensor signals with respect to RPM (up to 20 user-definable breakpoints) and any one of three Load variables (MAP, TPS or MAF).

5) Unlike the S-AFC, the XEDE is capable of providing boost and spark timing control in addition to high resolution fuel management. Used appropriately, this enhanced functionality yields a broader power band as well as a much greater resistance to detonation.

XEDE Technical Specifications

• 1200 possible adjustments on the standard New Age WRX program
• 0.1% accuracy on MAF and MAP adjustments
• 0.1degree accuracy on timing adjustments
• Accurate reproduction of reluctor type timing signals, not just of triggering edge
• Direct plug-in adaptor (no cutting or splicing required)
• Fully sealed, rugged, and lightweight housing
• Support for hall and reluctor type crank and / or cam timing signals
• Support for analog or frequency MAF and MAP / load signals
• One additional 10-bit analog input
• One auxiliary digital input / output
• Internal storage space for up to 12 tuning maps
• Built-in boost control
• Built-in knock signal adjust feature
• Self-configurable load axis, input and output variables, adjustment range, and math function for each map
• 'Map Select' input to change between one of two unique tuning maps
• Two high-current Pulse Width Modulation outputs
• Remotely installable bi-color status LED
   

Introductory Pricing:

XUpdate (.zip file) XMAP Full-Functional Tuning Software (.zip file) Allows user to create new, or modify existing, XEDE tuning maps. Only recommended for those who want to tune and understand the consequences of improper engine management calibration.

FREE

XEDE Tuning Map Database

Getting Started with the XEDE (.pdf)

Installation Instructions

Click here for directions on how to Upload Maps into your XEDE (.pdf)

 

Subaru WRX STi
(2002-2004)

Stage: (Click for description)	91 Octane	93 Octane	100+ Octane
V340
V350
V370
V400

 

Warning: The following calibration maps are designed for STis running the factory intake system (stock box, stock filter, stock resonation, etc,.) Replacement of any of these components will result in MAF sensor mis-readings which will result in erratic and possibly dangerous engine performance. All calibration maps are designed for premium gasoline. Anything less will likely induce detonation which will damage the engine.
 

STi XEDE News and Updates

Dec 10, 2003
The STi XEDE is ready to go. It controls fuel delivery, spark timing and boost via 3D maps. Map resolution is outstanding, allowing 20x20 breakpoints for engine load and RPM. This is slightly greater resolution than the maps in your factory ECU. This approach is vastly superior to using simple 2D tables as provided by S-AFCs and other simple fuel-only controllers.  It is currently available as a wire-in.  This means that there is no plug-in harness currently available.  As such, a few wires in the factory ECU harness will need to be cut.  Click here for wiring directions.

Jan 20, 2003
The STi XEDE page (what you are looking at right now) is finally up and running.  The baseline maps seen here have been developed on several STis which we’ve tuned both in our shop and during out-of-state tuning trips.  They represent conservative and safe mapping and can be considered a good starting (and stopping) point.  Those who wish to custom-tune these maps should do so only if they are experienced and accepting of the risks involved.