As far as MLB is concerned, the longest losing streak in 23 games held by the 1889 Pittsburgh Alleghenys (soon to be Pirates) and the 1961 Philadelphia Phillies.
The longest losing streak is 23 games in a row by 95-96 Grizzlies and 97-98 Nuggets.
That would be his current losing streak of 104 races.
Michael Waltrip had the longest losing streak before winning at the Daytona 500 in 2001.
Pittsburgh pirates at 18 straight and counting
New Jersey Nets with an 0-18 losing streak
The Chicago Cubs 2008 longest losing streak was 6 games between August 30 and September 6.