just make some crack, i.v is dirty
That's one of the most shortsighted things I've heard on this site in a while. What the fuck do you mean by "dirty"? How is i.v. "dirty"? Why do you make a jab like this and not state the reasons for your opinion? Asshole.
Coolio, there is a slight difference. Crack is broken down with an acid to be injected, thus turned into a type of salt. Cocaine powder is generally cocaine hydrochloride.
Crack broken down with vinegar is cocaine acetate. Broken down with citric acid, it's cocaine citrate. Broken down with vitamin C, it's cocaine ascorbate. Each salt has slightly different pharmacological properties when shot.
I have only injected cocaine hydrochloride, so I could not tell you the difference. If you search on this site, you will find some references about this and people's opinions on the differing salts. However, it might be hard to find, and the information is neither satisfying nor complete so you might not find all the information you want on the subject. The differences are subtle too.
I believe that you feel the taste of an injected substance in 8 seconds, and the high in 10 seconds. I'm not exactly sure, but if someone could time their experience and let us know, that'd be cool. Also, I think it would depend on the substance and where you injected. Obviously if you shoot in the right arm the time is going to be spread over a much larger period than if you shot in your left arm, or even, theoretically, your neck. I imagine shooting in your neck would actually be quicker than smoking and you probably would have trouble taking the needle out. For that reason plus the obvious reasons, I wouldn't recommend trying this.
I would rather IV coke.
On another note, I didn't think a speedball was that great. I think I'd rather IV the substances separately. I just found the experience extremely intense. It was rather costly though, and nothing that great. You can get as much euphoria and content with just using each substance alone.