I tried playing some tapes recorded on a PD-170 on a DVX100 and it was super messed up. I am guessing that it is because DVCAM records faster? Can I make it record Mini-DV speed? The reason I ask is for editing reasons.

You can playback DVCAM on some Sony consumer models, but not on other brands.
For recording in DV go to menu, cassette symbol, rec mode and set DV SP.

if only i knew this 48 hours ago :(

If the PD-170 was a rental and you can't playback the DVCAM format on your DVX100, I suggest you borrow a Sony consumer MiniDV cam from someone. There is a good chance it will playback your tape.
Sony Canada's DVCAM support site claims the following:

3.(Q) Are consumer DV and DVCAM compatible?

(A) Both consumer DV and DVCAM are closely related, so much so that all DVCAM equipment also carries the DV logo guaranteeing full DV playback compatibility. As well most Sony DV products, except for the original two camera's (DCR-VX700 and VX1000), also have full playback compatibility with DVCAM tapes.