Turbo shot discussion and thoughts

So after i was tired with the traditional shot 1:2 ratio 9 bar 30 seconds ( nothing bad just not my preference)

I have been pulling turbo shots for a few weeks now

Also tried Pressure profiling but thats for another post

I would like to share my findings and results and see whats your opinion

My set up is: dimmer modded espresso machine + OPV

K6 Kingrinder (automated using a 3d printed stand and a motor)

I started with Kenya SL28 score:85 beans medium roasted

Roasted 15 days ago

I tried 18g and 16g and compared them

My first try was at 18 grams , 55 out

In about 20 seconds

Reading 6 bars of pressure

Result was good, but a little sour (repeated 10 time)

Then i tried 16g in , 50 out, took about 16-17s in average

In same grinding setting, it tasted much more balanced

The weird thing is , once i grind finer and reach 20-22 seconds

The shot becomes much more sour(which is weird because u except it to be bitter)

I think it has something to with particle size

At courser grind there is more even extraction thus making a true turbo shot and avoiding channeling

And i also tried slow feeding ( tastes much better but less consistent because i was slow feeding the beans by hand giving inconsistent shots, i will how ever 3d print a auto slow feeder)

I love to see how you dial your turbo shots and whats your thoughts on it?