This does not belong in the psychedelics forum, expect it to be moved soon.
You most certainly can overdose on meth.
As much as a half point of pure meth (roughly 1/2 gram of street meth) can be fatal if consumed in one hit if the user has no tolerance. However there is no definate figure due to the way different people react to different things.
However, if you're banging it twice a day then expect your tolerance to have sky rocketed.
Telling us how many cc you use is completely irrelevant because this does not tell us in any way how much actual meth you are consuming.
While I cannot accurately answer your question, do not expect to continue banging it twice a day without any consequences.
Some guy told me you can't od on meth. lol, 'some guy'. That's like 'some guy' told me to use a bunch of vicks inhalers because they contained (l)methamphetamine
Please pay attention to what forum you post in. This was the wrong one for this question. Each forum has rules and guidelines at the top to help you. I'm moving this to the correct place. Thank you.