I recently forked a small github project to work on an open issue regarding the program's execution speed. I've achieved a substantial speedup, and I'm ready to submit a pull request.
However, the upstream has shown very little activity in the last 2-3 years. There is a backlog of unaddressed issues and PRs, and I have some doubts that the owner would be receptive to my work in any case. So I'm inclined to put my fork aside and set up a brand new, independent repository for this and future work. (This would not be a complete rewrite, so I'd add my name and the present year to the copyright line and otherwise leave the license intact.)
Is it advisable that I reach out to the upstream owner before doing this? Should I choose a totally different name for my project, or would the same exact name or a small variation be appropriate? Finally, in reaching out to people who showed an interest in the original project some time ago, should I communicate in private, or would comments on the upstream's wiki or issues page be acceptable?