Looks like I have enough spare parts to build a fully working second 3D printer 
Only the Airtripper Extruder is from my current system. Although the frame is only 4mm acryl it prints really well : xy-jerk ist currently set to 180mm/s :-), acceleration to 20000 or so. Now Ill have to tune my z axis steps/mm (I’m using a cheap 28byj-48 with belt) and print all the parts again for my main printer
With that jerk setting, you’re running at constant speed – no acceleration at all. Which is fine at somewhat low speeds but isn’t a good idea at high speeds. What feedrates are you using?
I tried to print at 90mm/sec, wich made my printer shake like hell 
but no missed steps and almost no overswing on the edges. The problem of this prototype are the 4mm acrylic walls, they bend and shake alot. At the moment I reprint all parts at ‘only’ 60mm/s so I can rebuild my main printer with it’s 8mm walls, and then I can test how fast I can really go. This prototype has a broken hotend mount, so it tilts from side to side wich results in a movement of the nozzle (about 0.5mm) when changing the direction, independent of the speed.
Dry movement tests allowed a max speed of 250mm/s with jerk set to 180mm/s and acceleration set to 15000 so far.
Jerk in this context is how much the velocity is allowed to change at corners without using any acceleration ramping. So your acceleration setting basically isn’t doing anything because your jerk is so high. Jerk higher than feedrate means no acceleration whatsoever. Extremely high accelerations mean something very similar – the velocity change happens so fast it’s practically instant. So you’re basically just operating without any acceleration.
…and operating without acceleration is fine if you want to do that, but just keep in mind that there’s no such thing as a 180mm/s jerk when your feedrate is 60mm/s. The limit may be 180, but the actual jerk can’t be higher than your feedrate. And likewise, the printer won’t do any acceleration when your jerk setting is that high, so saying 20,000 mm/s^2 is meaningless. It could be 1,000,000 just as easily.
On some further thought, some firmwares may allow jerk up to 2x the feedrate… Some always slow to a stop at direction reversals and some don’t.
@Ryan_Carlyle thanks for the nice explanation. I already know all that, but it’s a good idea to have it written down all together. I cant print faster than 120mm/sec, because my cheap chinese hotend wont keep up. Going from 60 to 90 I have to increase the temp by about 15° (220 to 235, printing with ABS), at 120mm/s I need to go up to 240°, and even then, when printing solid infill or top/bottom layers, my extruder starts skipping steps or, worse, bends and crushes the filament in the 5mm between the extruder gear and the fitting to the bowden tube.