Safety limits

Rev limit

Description

The factory revlimiter is sequential fuel cut. With prjmod an ignition cut limiter is also provided.

Maps

• Rev limiter - fuel cut - start rpm - Main fuel cut limiter. Max RPM value it to allow.
• Rev limiter - fuel cut - engine speed exceeded - RPM threshold to throw overrev DTC.
• Rev limiter - fuel cut - cyl 1-5 - How many cylinders to force off sequentially. If you set it somewhat lower, you can have a softer cut. It can start cutting one or two cylinders before it starts aggressively cutting everything.
• Rev limit - spark cut - set this lower than the fuel cut limiter to use the spark cut limiter. Not recommended with ceramic catalytic converters.
• Rev limit - spark cut - knock control disable - Because of the fuel explosions in the exhaust the ECU will sense knock, if knock control is not disabled. Set this value to 80-120 RPM lower than the actual limiter, so that when it is banging on the limiter the knock control is off and does not cause false positives.
• VMax limit - Top speed limiter, sequential fuel cut, just takes speed instead of RPM as control variable. Useless if you do not have VSS.

LOAD limit

Description

There are two limiters. The initial one, if exceeded for a certain amount of time, will turn off boost control and cut fuel to all cylinders, also logging an overboost code.
After that, a second limiter is used, without a delay - if you exceed the load specified, fuel is instantly cut.
These limiters are essential to set, because they will save your engine from destruction in case a wastegate line gets damaged for example. Because on some highly tuned cars the LOAD can exceed 255, the values in the maps have been multiplied by 10 compared to standard.

Maps

• Max calculated load - Irrelevant in prjmod.
• Fuel cut - Hard load limit - If the LOAD exceeds the value in this map for the specified time, N75 is forced to zero, fuel is cut to all cylinders, fault code thrown and 2nd map activated.
• Time for LOAD to exceed cut for trigger - Debounce time for how long the LOAD must be over the threshold specified to cause limp mode and fuel cut.
• Fuel cut - MAF error, limp mode - Secondary fuel cut which gets activated once the first fuel cut is hit. It has no delay and it is instant. Recommend setting a conservative value, because if you are hitting it, most likely something is really wrong with your hardware.