My profile (in the logitech profiler) gets ignored, so I have deleted it.
If you have profiles for other games, that fine just leave them alone.
Try this :-
Profiler > Options > Global Profiler Settings > Select 'Do not apply profiles to games automatically' > OK
Then :-
Profiler > Options > Global Device Settings
FFB : 107% (or whatever you want)
Spring : 0%
Damper : 0%
Enable Centering Spring but leave at 0%
Rotation : 360 degrees
Enable allow game to adjust settings
In F1 2015 advanced settings, leave all sliders (saturation etc.) at the default 0%
This means that when you play
any game which does
NOT have a Logitech Profile, the above settings will apply.
For any other game, just select the profile you want to use.
The 360 degree rotation and all sliders in-game at 0%, will give you 1:1 steering with the in-game wheel in your car.
Cheers
By the way, you don't need to use the Logitech profiler at all, if you don't want to. You can just use the setting above as your Windows default for your controller. Control Panel > Devices & Printers > G27 Racing Wheel > Right Click > Game Controller Settings > Properties > Settings
But this will effect all games, if you are not running the profiler