Help to turn race, getting stream of invective (8)
I believe the answer is:
diatribe
'stream of invective' is the definition.
(I've seen this before)
'help to turn race' is the wordplay.
'help' becomes 'aid' ('aid' can be a synonym of 'help').
'to turn' shows that the letters should be reversed in order.
'race' becomes 'tribe' (I've seen this before).
'aid' backwards is 'dia'.
'dia'+'tribe'='DIATRIBE'
'getting' acts as a link.
(Other definitions for diatribe that I've seen before include "Vehement criticism" , "Bitter critical attack" , "abusive outburst" , "critical speech" , "A prolonged piece of invective" .)