The largest prime factor of $X^{3}+2$ was
investigated in 1978 by Hooley, who gave a
conditional proof that it is infinitely often
at least as large as $X^{1+\delta}$, with a
certain positive constant $\delta$. It is trivial
to obtain such a result with $\delta=0$.
One may think of Hooley's result as an approximation
to the conjecture that $X^{3}+2$ is infinitely often
prime. The condition required by Hooley, his
R$^{*}$ conjecture, gives a non-trivial bound for
short Ramanujan--Kloosterman sums. The present
paper gives an unconditional proof that the largest
prime factor of $X^{3}+2$ is infinitely often at
least as large as $X^{1+\delta}$, though with a much
smaller constant than that obtained by Hooley.
In order to do this we prove a non-trivial bound for
short Ramanujan--Kloosterman sums with smooth modulus.
It is also necessary to modify the Chebychev method,
as used by Hooley, so as to ensure that the sums that
occur do indeed have a sufficiently smooth modulus. 2000 Mathematics Subject Classification:
11N32.