The most common and most likely answer to this crossword clue is the 4 letter word INDY
I've seen this crossword clue in The Guardian
I
N
D
Y
More clues leading to the result INDY
- Front runner pulls out of wild motor race
- Start off nervous in this fast-paced kind of racing
- Flatulent? Heading off – that’s us, shortly
- Popular daily, vacuous newspaper in short?
- Motorsport almost dying out
- Motor race among leaders of drivers yesterday
- Virtual paper chase involving cars
- Find Yank partly involved in US motor racing
- Nervous leader tumbling in race
- Daily features suffer here
Buddy explains!

The straight part
We know that "fast-paced kind of racing" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fast-paced kind of racing = indy.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does INDY mean?
INDY noun- An independent entity.
- Independent, unaffiliated (especially not affiliated with a major organization or company).
- Cars designed to meet the rules on the Indianapolis 500 car race.