This is a comparison between the cut broadcast on American TV networks (e. g. Cartoon Network or USwpix) and the uncut Japanese Version.

While other countries have not yet aired Dragonball Kai, the series was already broadcasted a few times in the USA.
In comparison to Dragonball Z you can immediately see that Dragonball Kai was obviously toned down in a few scenes:

Dragonball Z	Dragonball Kai

Additionally, many violent sequences were not even altered for Dragonball Kai, but cut out in the first place. Thus, you will hardly see any close-up shots of Tenchinhan after Nappa cut half of his left arm off. Also, you do not see Freezer's beam going through Vegeta's chest. Even the well known sequence in which Freezer massacres Kuririn is much more harmless than in Dragonball Z.


Getting ready for US-TV:
The series was censored in order to be bradcasted on US TV. The censoring reminds one of Naruto's US Version. Sometimes there are cuts which are very noticeable due to a crack in the music, while at other times they used a few tricks, e.g. by retouching things or using alternative material. Sometimes they even altered or postponed soundtracks or sound effects in order to make the cuts less noticeable.


The overall difference in time amounts to 3 minutes and 24 seconds.
(The rest of the difference in time results from differently long intros.)

4:58
Missing shot of Mr. Satan.
2.5 sec

5:39
Master Kaio tells Son-Goku he was reckless.
4.5 sec

5:46
More dialog between Master Kai and Son-Goku.
23.5 sec

6:21
Goku and Master Kaio have found a place to stay.
9 sec

7:33
When Trunks gets penetrated by Cell's attack, the US Versin contains a white screen instead.
no difference

7:31
As compensation, the subsequent shot of Trunks falling backwards is exclusively in the US TV Version.
+ 1.5 sec

7:35
Retouched blood.
no difference

Uncut	Cut

9:24
There is an old man in the car wreck and he is shoting at C-17 but C-17 does not mind being shot at. C-17 approaches the man and puts a gun to his head. He is just about to pull the trigger when he hears some noise.
(Then, the US TV Version is back in the game. The noise C-17 heard was a Ki-beam by Trunks).
48 sec

10:12
Missing shot of C-17 ducking.
The rest of the scene is in the US TV Version but due to zooming in, the old man is literally not the picture.
1.5 sec

Uncut	Cut

10:15
Due to continuity reasons, the shot of C-17 landing is missing.
2 sec

10:58
Trunks hits C-18 in the face.
The US TV Version is back in the game when C-18 crashes into the wall of the house.
0.5 sec

11:05
Missing comment of C-18.
2 sec

12:42
Due to continuity reasons, the scene with Trunks helping the old man is missing in the US TV Version. While doing so, Trunks thinks it was finally over but he then realizes it is not. Not yet.
19 sec

17:12
Cell's blood looks like saliva.
no difference

Uncut	Cut

17:56
Cell gets shredded by the Ki-beam.
2.5 sec

18:37
The shot of Master Kaio is slightly shorter.
0.5 sec

19:08
At the end of the episode, a recap with the highlights of the show is missing.
142 sec