I’ve now done a few track days in my NB, on both occasions it’s been quite a hot day with temps in the high 20’s and the car has got very hot (peaked at 111°C 
). Half way through the day yesterday I removed the aftermarket grille I’d fitted and temps dropped by about 5 - 6 degrees.
I’ve got a new upgraded rad on order but I’m in two minds about whether to refit it. What’s the consensus on fitting a grille to a track car?
If it’s solely a track car, I’d do without unless you’re wanting good looks awards ??
Not too fussed about looks, it was more about protecting the radiator.
If you’re worried about potential rad damage from stones etc on-track, I’d fit some fine chicken wire to the back of the bumper aperture.
You’ll get maximum airflow through, and have better protection for the rad than a standard type grille. That’s hopefully a win:win !
I have a makeshift one, tbh i think your at more risk of damage on the road unless someones kicked gravel on the track. Im at snet on the 14th ill let you know if removing it makes a difference to temps
This is a good advice 
I’ve always run with a grill on and never noticed particularly high engine temps in my NBFL even after a couple of touristen fahrt laps of the Nurburgring in my NBFL where the brakes were definitely running hot at the end of the second lap.
If you are doing trackdays where they have gravel traps, ie most UK circuits, I’d have thought it worthwhile having something a bit nore substantial than chicken wire in case you are the unfortunate soul who runs out of talent and or real estate and ends up ploughing nose first into one of these things at unabated speed.
Might save you the cost of a radiator on a day where embarrassment will already be sky high. Of course I hope that never happens and that you enjoy many miles of on track motoring in good health for decades to come.