downmix prefader with Cubase 8

I would like to export my tracks prefader (pre eq … pre-everything!) as mono files.
Is there a way to do that or have I to manually bypass processing in mixing view ???

Not sure you can render directly pre fader/inserts/eq. You might be able to fudge it with render in place or bounce in place then manually copying the new rendered files out of the audio folder.

But simplest method probably is to save project, reset the mixer (removing FX and EQ and zeroing all faders) and then do a batch export.
After completion you can get back as you were with file menu/revert or just reload the previous saved version.

no need to switch off all plugins: bounce selection (in the audio menu) will do the job. ( be shure to select the events you want to bounce first). choose “replace” in the next popup.
If you want a new clean project with just these files: use “backup project” (in the file menu), be shure to set it to copy just the currently used files in the next popup.

and/or convert stereo files to 2x mono in the pool;