Do you run fender liners on your race car?
 

With them on, you'd get less turbulent air inside the wheel well, and better protection from rocks and debris, without them, you'd get a bit less air pressure built up inside of them, less of a need for fender vents?

I never did. debris protection isn't much of a concern to me, and while there may be some benefit to turbulence, the sheer irritation of having to deal with those things every time I changed a fender would have annoyed the hell out of me.

I just yanked all mine out on the FB this past weekend. Did not weigh that much but they started to irritate me too.

Fair enough, thanks guys. If I decide to run them again someday, I'll probably fabricate new smoother ones.

Never had them as the car came that way.
The only odd part is picking out track rubber -- from the slit between the fender and the door.