Spiderman Web Shield Invincibility?

[Fierfek]

I've read in various places on the internet that it's possible to upgrade Spidey's web shield boost so that he's completely invincible for 3 minutes.  However, when fully upgraded it's just 70% for 80 seconds.  I've given Spidey his stark armor suit with evade fully upgraded to give him an extra 13%, then given him gear that gives him 10% more, but that still only makes 93% for 80 seconds.  How do I get the invincibility for 3 minutes thing that I've read about?