Here is the full list of all 13 Car Tehc achievements.
Complete 20 jobs
Make 500 horsepower car
Max out every part of the car and do a dyno test
Paint a Car Blue
Buy every garage upgrade
Buy a shelf.
Order 10 funnels at the same time
Sell $2500 worth of items
Remove all the parts of a car and try to drive it
Don't give a name to your garage
Delete 20 e-mails
Steal a part and cancel the job
Earn your first money.