Turns out what you need to get the drag racing achievement is a well tuned Satsuma with the racing carburators, nitrous oxide and slick tires which are not fun to drive with on the shitty dirt roads for obvious reasons. It takes a while to break when you're going 100 km/h on the dirt, the car just keeps sliding for a little bit.
I was kind of scared of the nitrous oxide injectors because I read it can blow up your engine really easily if you fuck it up, but it was surprisingly easy to set up, way easier than the carbs the injectors are attached to. All I had to do was get the engine up to running temperature, up the pressure on the bottle to about 950 psi and flick the switch with the car running, then I took the screwdriver to the distributor and it was making that funny noise it shouldn't make, so I think I ended up delaying it by scrolling in one direction until it stopped making noise. The car felt less like a monster when accelerating but that's not necessarily a bad thing, with it tuned like that I can spend more than a second in 1st gear and when I want speed I just flick the nitrous. I read that using nitrous oxide is really not good for daily driving so now I have a less angry engine and an angry switch for using in drag racing and rally racing. I'm excited to try the rally racing with the nitrous, it really makes a difference in acceleration, like even more than a well tuned carburator, though it'll wear down your engine parts faster, especially the headgasket. though now I know what to look out for when the headgasket's ready to go, the car starts putting out a worrying smoke from the engine bay. Running with nitrous was only scarier than it seemed at first to me, you just don't flick the switch when turning it on or else boom and you don't overuse it.
edit: forgot I recorded the 17.8something seconds attempt, so here's the video! I think there's some waiting at the start that can be skipped until the other guy arrives.