Time tracking is available in Pixie via an integration with Clockify. However this just saves the time entries against your user. You still need to assign them to a project to be useful for reporting purposes.
Unfortunately at this time Clockify does not allow assigning of time records to specific projects via Zapier, so each of the records needs to be manually assigned to a project. However there are a couple of Zaps that can make things easier. Click the links below to copy the Zaps into your own Zapier account.