The generator matrix

 1  0  0  0  1  1  1  0  1  1  1  1  0  0  0  X  1  1  1  1  1  0  1  0  1  1  0  0  0  0  0  0  X  X  X  X  X  X  X  X  X  X  1  1  1  1  1  X  1  1  X  X  1  X  1  1  1  0  1  1  1  1  1  1  1  1  0  1  1  1  1  1  X  0  0  1  0  X  X  X  0  1  1  1  1  1
 0  1  0  0  X  1 X+1  1  0  1  X X+1  1  X  1  1  0  1  0  1  X  1 X+1  0  X X+1  1  0  0  1  X  1  1  X  1  1  0  1  X  0  1  1  0 X+1 X+1  0  X  1 X+1  X  0  X  1  1  0  X  X  1  X  0  1 X+1  X  1 X+1  0  X X+1  1  1 X+1  0  1  1  0  1  1  0  X  1  X  X  0  X  0  1
 0  0  1  0  0  0  0  X  1  1  1  1 X+1  1  1  0  X  X X+1 X+1  X X+1  X  1 X+1 X+1  X  1  X X+1  1  1  X  X  0  X  X  X  0  1  0  0 X+1  0  1  X  1  1 X+1  0  0  1 X+1 X+1  1  X X+1  1 X+1  0  1  0  0  X  X  1  0  X  1 X+1  0  X X+1  0  1  0  X  1  1  1  X  X X+1  0  1  0
 0  0  0  1  1 X+1  X X+1 X+1  0  X  1  X  1 X+1  1  X  1  1  X X+1  1  0  X  0 X+1  X  1  1  0 X+1  X  0  1  0 X+1  1  X  1  1 X+1  X  0  0 X+1 X+1  0  X  1  X  1 X+1 X+1  0  X  0 X+1  0  X  X  1  1  0 X+1  1  0  1 X+1 X+1  1 X+1  0  X  X X+1  1  0 X+1  1  0  1  X  X X+1  1  0

generates a code of length 86 over Z2[X]/(X^2) who´s minimum homogenous weight is 84.

Homogenous weight enumerator: w(x)=1x^0+142x^84+86x^88+26x^92+1x^128

The gray image is a linear code over GF(2) with n=172, k=8 and d=84.
As d=84 is an upper bound for linear (172,8,2)-codes, this code is optimal over Z2[X]/(X^2) for dimension 8.
This code was found by Heurico 1.16 in 12 seconds.