This is my guide on how to get the My Summer Car achivement "Greased Rust" to get Greased Rust you need to have a drag race time of under 17 seconds.
In order to get a fast time you need to strip EVERYTHING off of the car. Doors, fenders, hoods, lights, passenger door, all of the exterior items must go. In the end you should have a car with only a seat, engine, brakes, and fuel.
Okay, so you need a fully upgraded engine with the racing carburetor, you will also need the N2O setup with a full bottle. You need your distirbutor timing set to 11 or when it stops ticking when the N2O is on. The carburetor should be set to 13.1 A/F ratio. I used the 3.7 final gear ratio, you should use the highest and get better times. You will also want to have slick tires in the front and rally tires in the back. Also, one final tip, try to have ~30% gas in the tank, it will help trust me.
When you reach the yellow line and see the four yellow lights put the car in neutral and keep it revved up. When the three orange lights turn on, put the car in 1st and engage the nitrous. Then keep driving and shifting then (hopefully) when you reach the end you got the achivement.
Hopefully you got the achivement you can seeking advice for. If you didn't get it the first try, keep trying at it. I spent an hour trying to get the achivement and want to help those who also having issues.