Normal run scenario is a scenario when no shifting is being performed, and previous one (if so exists) is finished completely (no-post shift slip exists).
During this state GCU uses following tables to define clutch pressure output:
- MAP – RPM Clutch Pressure [0-100%]
- MAP – Gear Clutch Pressure multiplier [%]
- RPM – PPS Clutch Pressure multiplier [%]
- TPS – Gear Clutch Pressure multiplier [%]
- MAP – PPS Clutch Pressure multiplier [%]
Even though maps 2-5 are named multiplier all tables are being multiplied. This means that user can choose which table is best base reference for his tune and use others just as modificators. HTG hint: we mostly use MAP – Gear table as a base table in boosted applications, or TPS – Gear in N/A setups leaving all others at 100% level (meaning no modification of base map). Modificators can give extraordinary precision but can be tricky at start to tune.
Effective pressure that is being applied to the clutch packs is the value of Clutch pressure tables multiplication and Line pressure value (main pressure in the transmission). It’s good to adjust Line pressure value to have Clutch Pressure final value around 90% clutch pressure making nice, complete clamping force at full power of the engine.
Line pressure table is basically a main transmission pressure RELIEF table, meaning that higher value results in more pressure being released to oil pan – less pressure in the system. Lower value means higher pressure in the system.
HTG hint: make line pressure value high enough to have in combination with Clutch Pressure tables proper clamping force, but don’t set it too high in order to avoid excessive power losses – keep in mind that oil pump takes power to pump pressure 🙂