A makeover for motor racing? Revolutionary! (9)
I believe the answer is:
firebrand
'revolutionary' is the definition.
(thesaurus)
'a makeover for motor racing?' is the wordplay.
'a makeover' becomes 'rebrand' (I can't justify this - if you can you should give a lot more credence to this answer).
'for' says to put letters next to each other (I've seen this in other clues).
'motor racing?' becomes 'fi' (FI resembles Fr, Formula r).
'rebrand' after 'fi' is 'FIREBRAND'.
Can you help me to learn more?
(Other definitions for firebrand that I've seen before include "One who stirs up trouble" , "Agitator" , "Rabble-rouser" , "Energetic person often fomenting trouble" , "Troublemaker" .)