I noticed the Asobo Airbus has the speed above 10.000 feet set to 320 knots and in the FBW Airbus it’s set to 290 knots.
I like the 320 knots but I can’t seem to change the 290 to 320. I see it on the performance page… but I have no clue how to get rid of it or how to fill in another value.
So how is this speed calculated (it’s actually always the same) and how to change it?
It depends on how you setup your INIT page and your Cost Index etc. 290 and 320 indicated airspeed is pretty much a moot point on cruise. The problem with 320 knots after passing 10.000 feet is that you’ll have trouble climbing because the aircraft is focusing on keeping that high speed rather than climbing speed. You could climb a lot faster on the lower indicated airspeed than a higher one.
After passing a certain altitude, indicated airspeed would be useless to see anyway, since you’ll be switching to mach mode, and that True Airspeed and Ground Speed would be more important than indicated airspeed on cruise.
Nah, that’s what I have been doing. But then you can’t sip a cup of - non virtual - coffee and look out of the window, without spilling the coffee when that overspeed alarm strikes.
I did experiment with the cost index, but it still stuck to 290. I’ll try a really high value next time. See how fast it’s willing to go if I put it at 999 
At 10000ft and 320kts you are far away from exceeding Vmo.
You can’t climb with IAS to higher altitudes than ~FL300 without exceeding Mmo.
At the crossover altitude you must switch from IAS to Mach.
E.g. the crossover altitude from 320kias to M.77 = 25500ft
That probably won’t work since the FBW A320 only has the cost index range of between 1-100 (maybe 0, but I haven’t tried it). And it also won’t help the fact that FBW team hasn’t really implemented the Cost Index simulation. So no matter how high or how low you set the CI, it performs the same. Hahaha.
As for the Overspeed Alarm, the latest Development version has the overspeed and stall protection feature implemented, so you won’t have overspeed alarm since the aircraft will automatically work on the pitch and thrust to make sure you don’t go overspeed or stall.
" The Mach number is the ratio of the speed of an object to the speed of sound. In aviation , the mach number is the ratio of the true air speed of the aircraft to local speed of sound, which can vary due to atmospheric conditions, air temperature and density. Mach speed is often used with a numeral, i.e. Mach 1, Mach 2."
Max. cr speed is Ma .82. Ma = v / c. c ≈ 331,5 + (0,6 · ϑ). ϑ at 36000ft (ISA Standard atmosphere) is -56.5C → c = 297.6m/s. So at 36kft your TAS could technically be v = Ma * c = 244m/s or roughly 464kts TAS.
Now TAS is quite a bit higher at that altitude than IAS (That’s what you see on your PFD). Maximum IAS (Ma .82) at the ALT is about 270kts (may vary depending on actual local conditions).
Bottomline: If you were flying 320kts IAS at say 36000ft you’d be flying trans- or even supersonic causing structural damage to the only slightly swept wing (and possibly even the wing root, I don’t work for Airbus so I don’t know).
So during climb you can adjust the climb speed to whatever you like. But during cruise the issue becomes moot anyways.
Sorry peeps, I was bored 
Guys! (and maybe girls!)
The question was simple. The Asobo Airbus does it. How to get the FBW to do it?
So we can’t cause it’s not implemented!
Took a while, but now I have the answer
This is the wrong question to ask.
FBW isn’t some indie developer doing this out of hobbies, they’re passionate programmers who are supported by numerous real life A320neo Pilots and Engineers, and they have a workflow that for every feature or new update or modification that they need to make, must be supported by official technical documentation.
So if Asobo can do it while the FBW can’t… There’s a good reason for it. Probably because Asobo isn’t realistic and it shouldn’t be able to do it. This goes the other way around too. If there’s a behaviour that the default A320 exhibits that the technical documentation says otherwise, they will adjust the aircraft according to those documentations.
I’ve flown FBW for so long that I just learned to go with it. In FBW team I trust. And whatever change or feature they added or removed, it’s for a good reason to make it as closest to the real aircraft as possible.
I do realize all that. The 320 knots isn’t maintained all the way and it slowly drops down the higher you get. That was always the case, also in the Asobo Airbus. So that isn’t the issue.
I just like some top speed when hitting 10.000 feet. Should be my choice, not some baked in value. After that the computer systems will make sure I don’t get into structural damage.
I’ll wait till they implement the Cost Index thingie.
On a side note that doesn’t really relate: I’m really getting bored with that Airbus. I realized a while back I like Boeing better, but there’s at this point in time not really a choice. The Asobo Boeings aren’t a joy either. The Airbus seems a fine flying machine, so this is really just a personal preference, but I guess I like to have a little bit more control when I want it.
It’s a fine question to ask.
It just requires a good answer.
Lol, you think pilot has a choice in choosing their climb rate and just pick whichever airspeed they want? If I have a choice, I would set my climb rate to 1000 knots, break the sound barrier, so I can get to my destination a lot faster… But I don’t have a choice, aerodynamic physics won’t let me. We have to take into account Passenger, Payload Weight, total weight with fuel, the center of gravity, the fuel consumption, G-Forces, everything else needs to be calculated into the “proper” value to ensure you don’t damage their aircraft from overstressing it. And even this is oversimplifying it.
Airbus and Boeing has very different philosophy. Airbus has a lot of onboard computers that calculates and do the proper flying for you. If you’re the type of person who prefers manual handflying and direct control over the aircraft. Airbus philosophy isn’t for you. There’s a lot of safety protection in place in an airbus to make sure you don’t fly it the wrong way. For example, FBW airbus has an anti-stall protection, meaning you can’t stall the aircraft under normal conditions. Similarly, it also has an anti-overspeed protection. As soon as it’s detecting any form of imminent danger of stalling or overspeeding, the aircraft computer does its thing to compensate and avoid it from happening from managing the nose pitch, controlling thrust, everything is done automatically to make sure you stay in one piece.
For boeing, the protection in place is designed to warn you as a pilot that a danger of stalling or overspeeding is imminent so you are aware and make the corrective actions. So the difference is, for Boeing they tell you things so you can correct them. For Airbus, they correct it for you.
To oversimplify a summary, if you want to fly the aircraft, go with Boeing.
If you want the aircraft to fly you, go with Airbus.
Well, in a fully implemented Airbus simulation, it wóuld be my choice, as an independent pilot not bound by some airliner. I can change it through the cost index. From what I gather, after diving into it, it seems a simple calculation between fuel cost and fuel consumption.
Nothing crazy about that, if I decide I have enough money to waste some fuel
So let me have my 320 knots. I’m not asking Mach 2! Just 30 knots more… come on…
Then switch to selected airspeed by pulling the knob and set to 320 knots. You can even set it straight to 320 knots as soon as you take off under 10.000 feet. What’s the problem?
There is no problem.
Just that this forum seems by now less efficient than youtube.
Lesson learned.
Great way not to learn anything.