It seems odd that you are doing all this in a substitution rather than iterating over the results of the match, e.g. while ($text =~ /$re/g) {...}, particularly given that you are already resorting to some complex activity including an e modifier. However, you could do this in a fell swoop by capturing the entire block you want to reparse, and using a sub-regex in list context w/ the g modifier to return the full list:

    $text =~ s/
          (.+?)            (?:\s*\n)+
      ((?: \d+ (?:\sPSI)? (?:\s*\n)+ ){4})
     /push @r, [ $1, $2 =~ m|\d+ (?:\sPSI)?|xg ]/esgx;
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If I were the maintenance guy that followed you, I would not think friendly thoughts when I saw that.

You could get something a little more maintainable by explicitly expanding your {4} terms:

    $text =~ s/
          (.+?)            (?:\s*\n)+
      (?: (\d+ (?:\sPSI)?) (?:\s*\n)+ )
      (?: (\d+ (?:\sPSI)?) (?:\s*\n)+ )
      (?: (\d+ (?:\sPSI)?) (?:\s*\n)+ )
      (?: (\d+ (?:\sPSI)?) (?:\s*\n)+ )
     /push @r, [ $1, $2, $3, $4, $5 ]/esgx;
[download]

    my $sub_re = qr/ (\d+ (?:\sPSI)?) (?:\s*\n)+ /x;
    $text =~ s/
          (.+?)            (?:\s*\n)+
      $sub_re
      $sub_re
      $sub_re
      $sub_re
     /push @r, [ $1, $2, $3, $4, $5 ]/esgx;
[download]

None of this changes the fact that you have a fundamental obfuscation by using a substitution instead of a loop.