is it a series of clicks, or is it just a single "clunk"? does it do it while you're turning?

if it's a series of clicks and only happens once in a while, it's likely to be clutch chatter... do you abuse your clutch/race? your friction disk may be damaged or warped, your flywheel may need resurfacing, or your pressure plate has broken/weak springs or may be defective.

if it's a single clunk or click, check your radius rods. my right side radius rod has come loose on me before at the LCA. just dropon some loctite and tighten down the bolts.

if it happens at launch and turning, it's a CV joint going bad... check the rubber boots on the axles for tears and thrown grease, replace axles as necessary.