Had to wait for quite a while to get my hands on one of high flow hotends thanks to being out of stock all the time.
But I saw that as a good signs as it means people buy them…
For me the flow rate was not really the reason for trying, it was the overall print quality I saw in the examples of others users.
But of course we all want to know…
I used this flow test but once it just completed with no issues at all …
Replaced 10 blocks of the model, starting from the second with higher speeds.
Starting with the block 10 speed and then going up by 14mm/s as the original.
Means instead of adding 10 to the result to get the max flow it was 20…
The layers turned ugly at a flow rate (as measured on the model and translated) of 42 - that’s basically twice of what I dared with the original…
Of course the result couldn’t possibly be true as I must have messed the model up somehow…
But the thing really does it THAT fast…
Next on the list was a retraction test with a glow filament that always is a pain.
For that I had the flow rate down to just 14 so with the E3D I dared 20 out of the box.
Not a single block of the hotend, same for the extruder.
And that without reducing the retraction speed from the default profile.
Quite impressive to see that sometimes manufacturer claims are actually true…
I thought my P1S does a good job in terms of surface quality.
But after honing in the E3D it is a difference like day and night.
My previous printer wasn’t bad but the P1 much better and with the E3D in place the step up is similar.
That is how our machines should print out of the box…
So far, even if I try hard, I can’t find anything to complain, except that the installation was a bit of a hassle thanks to their tight tolerances and the wires being a bit thicker than on the original.
As there are of course those who go only for speed - how much faster are prints now?
In theory I should be able to print as fast as the speedy mode now…
Reality though is a ‘female dog’ 
I tried a 50% scale print of a Groot planter.
Sliced with the standard profile and smooth variable layer height the print time as calculated to be 2h52.
That is with the old max flow rate of 21.
With the flow rate set to 39 the print was supposed to be completed in just 2h52.
Hmmm…
Ok, no worries, activate the fast speed profile you created earlier - 2h52…
Layer time is good, so how about disabling the slowing down things?
Finally things got faster - 2h51… LOL
Thing is that in the slicer preview I could see that the print speed changed from just over 200mm/s to over 450.
Will have to check one day what Bambu messed up here to make sure things won’t print as fast as they should…
Tried again with a much simpler model, lots of combined infill and just plain 0.2mm layers.
And there I got a half decent improvement, mainly for the infill.
When I printed it however the difference became obvious - the head was flying around…
Despite that it all came out even better as with the original nozzle and it’s matching profiles.
Based on those factors I would say that IF the model allows for it the E3D does provide a great boost.
Sadly it seems that even if you increase all speed related settings by let’s say a factor of 1.6 or 1.7 the complexity of a model still ruins the possible gain.
Assuming Bambu did not mess everything up:
The more tiny print moves there are the lower the actual speed gain.
I guess this is mainly related to the K-factor and acceleration calculations.
Even if the previe states a print speed of over 450mm/s: This seems to be the MAX speed possible for that layer.
So it might be just a fraction of the overall layer, like some nice strait wall section.
The biggest gain I noticed in when printing in vase mode with a thick wall of 0.75 or more.
Here the quality of the hotend and the much higher flow provide a real gain that is noticeable.
A simple cylinder or plain vase with large enough diameter will max out the flow rate eventually.
If you print a lot with a 0.6mm nozzle and the flow rate actually IS limiting for you then the Obxidian will definitely be worth the investment.
For the 0.4mm size the benefits are not that universal in terms of speed gain but the better quality already made me pre-order the 0.6 - to hopefully became available here before xmas LOL
In case you wonder about TPU:
I only had a little bit left but the max flow rate could only increase from 7 to around 12 - TPU still prefers to be printed slow…
