Limits

This section contains all the safeties built into the ECU.

Rev Limit we’re all familiar with. The ECU cuts fuel and spark when RPMs > than the value in the table.

Fuel cut is nothing more than a function which checks airflow (load) and compares it to RPM and if the airflow exceeds the table for 1000ms (or 1 second), it cuts the fuel. It’s a great safety feature should your wastegates become disconnected or if you over boost in high gears.

The double mod was my way around the 1byte limitation. Now the max engine load is 638 LOAD which I don’t ever see anyone hitting.

While tuning, I usually disable fuel cut by setting the timer to something very long (like 5000ms). After everything is setup, I review the peak airflow from the logs and set the table to be about 10-15 load greater and set the timer for 500ms instead of the stock 1000.

The Speed Limit Function must be enabled in periphery 0 bit 6 in order to function. It’s disabled from the factory. When engaged, it only cuts fuel, not spark.

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This page was posted on Wednesday, April 17th, 2013 at 12:09 am by bfarnam and last modified on Friday, April 19th, 2013 at 11:34 pm by bfarnam