I have a paper accepted at a X conference. I have been working on changes for the camera ready version. I have some results from experiments that I ran after the paper's initial submission.
Questions:
No, this would usually not be allowed. One important aspect has not been explicitly covered in Buffy's answer: bypassing peer-review.
Adding new experimental results can significantly alter the paper's contributions and conclusions, and adding them while submitting the camera-ready version bypasses the peer-review process. This is also the reason why many conferences that allow rebuttals to reviews do not allow adding new results even in the rebuttal. For example, the guidelines of CVPR 2021 state:
The author rebuttal is optional and is meant to provide you with an opportunity to rebut factual errors or to supply additional information requested by the reviewers. It is NOT intended to add new contributions (theorems, algorithms, experiments) that were absent in the original submission and NOT specifically requested by the reviewers. You may optionally add a figure, graph or proof to your rebuttal to better illustrate your answer to the reviewers' comments.
I'll guess the answer from the committee would be no for a conference because of time constraints, but you can ask. Once camera ready copy is provided any changes require time and cost and are likely reserved only for minor changes.
But you can certainly ask. You can also discuss the updated material in any conference talk you give, but it won't likely show up in proceedings.
It is possible, however, that there are two stages and the current copy is just for distribution to attendees with a later corrected/updated version done for publication in proceedings. If that is possible, the chair will let you know.
But you should also consider a follow up paper to extend the one given at the conference.
For a journal paper, the answer might be different, but it might also lead to a delay in publishing or even a new round of reviews. So, it might be best to skip it in any case.
