[evo227]

2015 EVO X MR is dead. I believe it's the battery. I want to try to jump it first. I know the positive nut is under the red top but where do I clamp the negative cable?

 

[Splattj]

Anywhere on the engine is good (if it's bare metal) otherwise, I've used a strut tower bolt in the past.

 

[chetrickerman]

You want to ground to the chassis since that is what the battery grounds to.

 

[kevin77]

See the owner's manual, section 8-2. You can download the owner's manual for your year from:

2015 Mitsubishi Lancer Evolution - Owner's Manual - PDF (338 Pages)

carmanuals2.com

Attached are screen shots of the two relevant pages for jump starting. As the others have mentioned, there are technically a lot of places you can connect the negative cable to, but the manual suggest the mounting bracket on the top back of the engine, next to the upper intercooler pipe that feeds the turbo, as you can see in the picture of the owner's manual.