Related Clues:
- Additive that sponsors NASCAR racers
- Slick 50 alternative
- Engine performance aid
- Big car racer sponsor
- Additive that once sponsored Richard Petty
- Indy inits.
- Antiknock fuel
- ___ alcohol, gasoline additive
- Word before ''acetate'' or ''alcohol''
- Valvoline alternative
- Indy 500 inits.
- Brand for a gearhead
- Richard Petty sponsor
- Additive at Indy
- Unsustainable but trendy fuel source