About that boost gauge

First off, BeamNG 0.9 = awesome job pushing a release that is such a leap forward!

Now that the important stuff's out the way, on to the reason im writing here. Its no biggie at all and does not bother me but that boost gauge doesnt show negative values/vacuum on idle and engine braking (only applies for vehicles running other than diesel, since they dont have vacuum). It does do that when the car is revved without load and that is of course accurate. Normally turbocars run about -0.5 to -0.6bar when idling and when cruising its slightly under 0. Vacuum is often read/shown in mm/Hg or in/Hg since bar and psi only really counts for a positive value.

Just wanted to mention it

 

Psi can be negative

 

What's important, is how far the gauge goes the other way.

0 or less means your turbo ain't doing jack.

 

Yup, psi can be negative as long as the gauge that is being used is reading atmospheric pressure as 0 rather than 14.7psi (or whatever it is), then there is no issue with psi or bar being negative.

 

Reason for that is that throttle butterfly simulation is not there yet, also BOV is open when you have zero throttle, because there is no throttle butterfly, no intake manifold, so there is no vacuum that would have it's own effects on BOV and on boost gauge display.

You can think it as if boost gauge would of been hooked to pressure pipe before throttle butterfly so it does not never really receive vacuum.

With 0.9 turbos were improved quite a bit, now you don't have boost on idle like before with some cars, so driving is much more like with a turbo car, but I guess they improve things further in a future when other work required is completed.


With diesels there is no throttle butterfly indeed and turbo is spinning somewhat faster at idle too, so that is making driving bit different experience, I guess this aspect is also better simulated in a future as they get throttle butterfly simulated more accurately.

 

That is very informative, thank you. Shouldve have thought that it had been thoroughly looked into but jumped the gun. Makes sense that if it doesnt simulate the throttle body action but other details and actions of the engine, NA or force fed, petrol/gas/e85 or diesel then the boost gauge displays what is going on atm and is correct. Nice to have an explanation.

 

These two links probably will give good picture of current status, I think that with current limitations they are doing pretty nice job, especially with latest updates:
https://www.beamng.com/threads/throttle-sensitivity.37888/

https://www.beamng.com/threads/is-throttle-butterfly-implemented.35343/

In your Steam apps folder, where BeamNG.Drive is installed, you might also look into this path steamapps\common\BeamNG.drive\lua\vehicle under there is Powertrain folder and inside turbocharger.lua and combustionEngine.lua, reading those files will give bit of insight how things work and sometimes I find comments there entertaining.

Of course you can then edit files (make backups first!) to make new features or change existing ones in game, surprisingly easy for some stuff actually, it is by far more difficult to make own custom lua for a mod.

 

They do leave some interesting comments, including the commented out experimental things ^_^

 

Vacuum opens BOV (hence differently rated BOV springs for different amount of vacuum), so when you have vacuum BOV stays open and when you have throttle closed there should be vacuum, except older stuff, where BOV was shut until enough high pressure happened in pressure tubing and then bovless systems.


With new turbo tuning petrol/gasoline cars seem to be working much better now as there is no exhaust power to spool turbo at idle when throttle is closed!

From some catalog that I sourced when I did research of these new fancy BOVs:


Then new cars of course do all sorts of stuff with computers, it's completely different, like ETK 800 probably adjusts everything from compressor wing angles to wastegate by computer, too complicated for me

So we just think that pressure sensor is in pressure tubing instead of intake manifold.

 

Not only i that is into engines, turboed to be precise, i can tell

 

Great thing about BeamNG is that while of course developers like Diamondback have to balance time spent vs gains from spent time, we can slowly learn LUA and make changes to expand simulation to further than what is realistically possible for devs, however usually I manage to make only a mess, but that is why there is backups, still there is none other as good sim that is so open for adding new features.

Learning though, that is felling many times onto ground, getting up and trying to learn something from the fell or at least from sudden stop.

 

Youre an important part of Beamng, so many fun/interesting lua/mods have made it into Beamng thanks too beibg a mod tp start with. I dont have the time anymore, irl cars and engines take all my time. Been building engines and tuning them for years so its fun hearibg how Beamng or mods for ot actually simulates the real deal quite detailed.

 

Yeah, it is indeed quite hard to get 100% correct and I don't really know how much meaning it has, maybe it allows to have bit higher exhaust power at idle, but I think that faking vacuum to boost gauge might be as efficient, would there be much other effect than what boost gauge shows? But it is always nice to have simulation closer to perfection

In this new version turbo slows down very nicely, just destroyed few Sunbursts at ECA dirt roads and you really get now that effect where if you are a chicken with a throttle you don't get power, so have to push bit harder than you want, it gives thrills

 

Would a future plan of mine help at all.
I work for Pico technology. We manufacture usb oscilloscopes and do have some models plus a second version of our software for automotive use.

I was planning on throwing a pair of our pressure probes onto a 2 channel scope to log pressure either side of the boost control solenoid. This should also give a decent reading of the pressure in manifold indicating whether diverter valve opens at idle or not. Cars an EJ207 equipped bugeye WRX