I know the devs are revising the Automatic transmission system to incorporate losses and making it behaving more like real life torque converter automatics but so far I haven't read revision regarding manual transmission. My idea to incorporate some delay on the gear change on manual transmission with assisted clutch mode. Currently gear change on assisted clutch manual transmission is lightning quick whereas in real life, there's a delay caused by us pressing the clutch in, rowing the gear (current gear -> neutral gear -> desired gear), clutch out. One game that got it right is NFS Shift 1. When we downshift or upshift, we can see that the transmission indicator goes to neutral before going to the desired gear. During the change, pressing the accelerator will only increase RPM but no acceleration happened, just like real life. It would also be nice that the devs add more part lists such as short throw shifter, sport/race clutch, or simply that currently available "Race" transmission reduces slip/power loss and or shifting time. This idea won't really concern people playing with racing wheel, but for controller and keyboard user it will add some realism. I hope the idea is useful and could be implemented.
A while back i made something similar to what you are suggesting with upgrades to the transmission. I made some custom flywheels which made the engine more or less responsive depending on which flywheel was selected. I could easily do the same for clutches which would have the effect of reducing shift time if you wanted.
That's a perfection right there! Any plans to make it shift faster or slower depending on what kind of transmission or clutch we are on?
Several shift time parameters can be adjusted via jbeam, so you can certainly make it slower or faster.
Will we see modifications on the clutch of cars to make them lighter and reduce drivetrain loss and improve shifttimes?
Based on mentions of how the entire drivetrain will be completely customizable, I think if it's not something straight in the stock game, it will be easily done with mods.
