In this paper we study how to attack under the self-similarity hypothesis a
perfect fluid Bianchi I model with variable G,and Λ, but under the
condition divT=0. We arrive to the conclusion that: G and
Λ are decreasing time functions (the sing of Λ depends on the
equation of state), while the exponents of the scale factor must satisfy the
conditions ∑i=13αi=1 and ∑i=13αi2<1,∀ω∈(−1,1), relaxing in this way the Kasner conditions. We also
show the connection between the behavior of G and the Weyl tensor.Comment: 15 pages. accepted in IJMP