With the release of the latest version of RaceROM patches you can now increase the target clutch pressure past 16 bar, this aids in keep clutches engaged properly in big power cars and stopping slip. The key to getting your 20basr 1st gear clutch pressures is the RaceROM Clutch Pressure Max. This increases the factory limits to where you need them.
To up the clutch pressure use the latest version of patch and make sure the following maps have been adjusted:
Set target limit
to the desired pressure for the car
Next you will need to change the Clutch A/B solenoid compensation maps (example attached) not currently scaled but numbers are essentially milliamps.
And set your line pressures (Min Tgt Line Press A & D and Target Line Pressure E)
You also need to raise the current limits and use these as hard limit for likely pressure (maybe higher for this car.
Usually current limit work out a bit like this.
1.6 amp should give you 18 bar
1.7 amps should give you 19.3 bar
Notes and Tips
Bad Shift behaviour with built transmissions and aftermarket clutches we would normally point you towards the Clutch Friction tables in the TCM tune. You can try reducing the friction coefficients for the low slip high pressure cells of the coefficient map.
There are also shift limits, and schedules that may need adjustment to allow higher rev limits and improved shift points so these maps should be reviewed and adjust as per the requirements of the customer.
There is also a limit where the TCM is not able to see over 8192RPM from the ECM, when the RPM is above that it causes a large error in Clutch Speed vs engine speed. This results in a negative slip value effecting the estimated clutch slip and temperatures which can throw up a DTC's resulting in the TCM bailing out and releasing the clutch. This is a limit on the data the TCM receives from the ECM and cannot yet be worked around.
The DTC that appears is a P0746 and the thresholds for this need to be raised to accommodate the RPM above 8192 using these maps
You can also disable P1725 to force the TCM into using the tach for engine speed instead of engine speed received from the ECM directly.