This performance chip picks up where the legendary ECUtune, Inc Stage 1 chips left off.
The 92 through 95 model year US market SVX engine control units have a 28 pin memory socket which when activated allows the programming of the control unit to be updated/replaced. While the memory devices intended to be used to update the control unit firmware are now obsolete we have memory adapters which allow us to use modern memory to update the control unit programming.
By installing this performance chip you are completely replacing/updating the firmware (the programming) of your engine control unit.
In this version we started with 94 JDM (Japanese domestic market) SVX firmware. This is our "base code." The programming and the tuning of the JDM SVX is significantly different from the US market units. One big difference is that JDM SVXs do not have EGR systems. Installing this firmware will de-activate the EGR system in a US market SVX. It will also eliminate all the engine control unit's checks of the EGR system's functionality. This eliminates the check engine light you get if your EGR system fails (some of the parts commonly needed to repair the EGR system are now "NLA" = no longer available from the dealer.) Japanese SVXs also do not have an atmospheric pressure sensor. The JDM firmware doesn't attempt to take atmospheric pressure sensor readings into consideration. The fuel and ignition timing tables are significantly different from the US firmware. There are many differences in the actual coding--not just the tuning data but the program portion that calculates and controls everything.
Modifications made to the 94 JDM base code in this performance chip:
The 180km/h speed limiter has been removed.
The rev limiters have been increased to 7400 RPMs.
The fuel table has been modestly reworked.
Most importantly both the primary ignition and ignition revision tables have been overhauled to forego most of the learning process that is necessary for stock SVXs to achieve good performing ignition advance settings.
In SVX engine control units a primary ignition timing table specifies a base ignition timing setting. A revision table specifies a maximum amount that can be added onto the base values in the primary table. The programming of the control unit then uses the readings from the knock sensors to guide it in deciding how much revision to apply.
The attainable ignition timing with the stock JDM firmware is very good if everything goes well with the learning. Adding the full values of the JDM revision table to the JDM base table results in an ignition timing map much like you would expect to see in a well tuned performance car. In fact, it is very much like the map we use in our performance chip. The difference with the performance chip is we don't rely on the knock sensor readings and control unit's algorithms to learn to use that advance. Full performance ignition timing is specified in the base map. Doing this results in more power, a smoother power band, and thanks to an increase of several degrees of ignition advance during cruise there is even an improvement in fuel economy.
This solid performance upgrade is a must have for any SVX enthusiast.
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