Might feel a little cheat(y) but if you breed two high level Rexes and hatch the baby near the Carchar, kill it, you can drag it’s body and it’ll instantly be ready to tame. Lower taming rates will require more rexes but it’s effective.
After taming 3 carchars, this is what I have learned:
-the best way to trap these fellas is a 1x1 of metal dino gateways. You must have a bear trap in the middle of 3 gates to trap the carchar and then put up the 4th gate
-when trapped, the bastards will often refuse to eat, in order to fix this you can leave the corpse by it and simply go out of render from it. All tames must be out of render for this to work. If you left the corpse by it’s feet like I earlier said then by the time you come back the corpse will be eaten and the carchars progress will rise
-In the process of leaving and entering render to reset them, it a a must that you do this in a swiftly manner, as if you load in the carchar before you load the trap in the charcar has a large chance of meshing through your trap. I like to use a dino which can quickly elevate and dive for this
-when you have fed them enough corpses their progress bar will turn green and you can ride them, leave up the trap except for one gateway and start killing anything you see
-it is a good idea to head for highly populated areas instead of going for big kills
-elixirs do work on them so make sure you pop one when the car gets to 70% taming
-I’m not sure if this is possible with our rates yet, but if the car gets to a 99 kill streak it is very important that you roar. If you don’t and you hit a streak of 100 you will be kicked off of the car. Some dinos give a higher boost than just one, so if you feel as though you are getting to close to 100 you should roar sooner
-If you don’t get to 100% before the ten minutes is up it is much easier if you walk the car back into the old trap while you still have control of it. If you would like, you can also put up a new trap around the car while you still have control
-each time you have to feed and mount the car it’s timing effectiveness will tank. It will also fall if you take damage so make sure you don’t hit creatures with a thorn aspect like arthlos or kentros. It is also important that you negate all fall damage by jumping off of them because this drops their effectiveness as well
No trap necessary! I’ve tamed 6 now and no trap is easier than dealing with the trap. Mate high level rexes, hatch eggs, and cryopod the babies. Find Carchar, kill ALL dinos in the immediate area. At a safe distance but in sight of carchar get high level baby rex(s) out of cryopod, kill them, drag to carchar and let them sniff and eat. Number of baby rex needed is dependent upon carchar level and your server taming rates. I recommend only killing one rex at a time otherwise carchar may end up going over to your pile and eating them and that will do you no good, trust me. If on extinction I recommend luring the carchar back into the snow biome if it has ended up out in the wasteland. The random spawning of corrupted can really add another level of difficulty to this tame.
In theory, you could use a mind wipe tonic, pump most your stats into weight and kill some adult rexes at the sight to use for feeding. I haven’t tried that though so experiment at your own risk.
On Extinction they spawn regularly on the outer edge of the snow biome from the southeast to southwest corner of the biome. I’ve found them on both sides, just inside or just outside of the biome.
They take forever to raise and imprint but they are well worth it if you can get some high level breeders. They are a giga on steroids with a better turning radius, a stamina boost, and a blood rage buff that drastically increases melee and heals them faster than they can take damage. I raised 6 that started around level 150 and got them mostly imprinted. Just riding one I am unstoppable, I can handle a purple supply drop up to wave 5 and not even be close to losing the carchar or dying myself. Unfortunately I lose the drop because there are more Dino’s spawning than one person and mount can handle.
Like all big Dino’s they don’t handle fall damage well so be careful there.
If you wanna tame it really quick first feed it a baby Rex to fill its meter, now this next step is weird to many people but it's one if the best, tame a bunch of diplos breed them and only level health. After leveling no need to heal them just unclaimed and feed to charcar, this works well because the more health the dino has the higher the taming percent. Just make sure that if it is not a diplo make sure the dino you unclaimed is on passive
Level points ONLY into health. The more points into health, the more quicker you can tame the Carchar.
Next, find a Carchar, DO. NOT. TRAP. IT. It will not eat the corpses you bring if it is in a trap. It will also bug out, better to do it without one.
Now you have 2 options, use a throwaway tame or use any Dino in the area to feed the Carchar.
The best way I found, is to use an unclaimed tame that has a lot of points into health - preferably 100k.
Next, drag whatever corpse you chose to the Carchar, and WAIT for the sniffing animation. It doesn’t matter if you also walk up to it after it finished sniffing the air, it will solely focus on the corpse, make sure you run away asap though.
The more the corpse has health, the faster the Carchar will let you ride it. Please remember that.
After dragging the corpses and the Carchar is letting you ride it, you can either go around on a murder spree OR use your throwaway tames.
I used my throwaway rexes that had 100k health in them - here’s the fun part.
Instead of focusing on your Carchar munching away at the rex for 5 hours, you can whistle passive (before bringing taming the Carchar, recommend doing it before you start bringing the corpses) unclaim, then damage your tame till it is VERY bloody.
Once you did that, bring over your Carchar and make sure you are RIDING IT; manually attack your unclaimed tame, and boom. Taming efficiency goes up a bunch.
Highly recommend diplos or rexes with over 100k health as it will tame so much faster, don’t forget to damage them enough so it only takes a few bites for your Carchar!
TDLR: more health on dinos = faster Carchar taming.