Turbo Dismount

I did not get this achievement as Mr. Dismount. Using him does not seem to be a requirement.
The character i used was Mrs. Bumblebee.

Use the workshop level Get Eaten! While there are a few vehicles that could work, the one that did it for me was the Cool Streak. Chances of this taking a few tries seem high, and there seem to be better characters/vehicles than Mrs. Bumblebee/Cool Streak, so do some picking and choosing yourself if my solution doesn't work.

Your best bet for this achievement is Giant Palm Tree Explosion.
DO NOT USE CUSTOM LOGOS OR ANY CUSTOMIZATION. They will negate this achievement.

Continuing on from there, some tips:

• This triggered for me with Mr. Dismount on the first pose for every vehicle
• Use manual steering, it helps a lot
• Check the underside of the vehicle to ensure the stuff is all off

These vehicles, as of the Emergency Season update, have no destructible parts:
Pink Lightning, Red Hot Engine, Mall Racer, Street Slicer, Boss Throne, Whiplash

If you need help with knowing when stuff is off (it's difficult to tell sometimes,) here's an imgur album showing all vehicles - completely destroyed.
imgur.com/a/CgG4pnb

If the achievement fails to trigger, make absolute sure you have no custom logos, no custom anything. If it still doesn't, there isn't much advice i can give other than - just keep trying. It'll happen eventually, just believe ^^

I can't verify for sure whether or not this actually triggers the achievement. It's been forever since i got this, and i followed a steam achievement guide. But it sure looks like i did it~

As the achievement name implies, you need to go to the Scaramanga map. Whether or not that's a requirement, i don't know, but it's definitely the easiest way.
Change your vehicle to The Wedge. Change your steering option to the fourth one, and put a turbo pad on the third obstacle. It should look like this:

Your speed should be... let's say, around almost full. You can experiment with it.

Provided you did it correctly, it will still take a few tries. But it shouldn't take too long, and some wacky landings have worked for some people.
But, hopefully, you get a roll as beautiful as this one:

Looks about right, no?