Turbo getting stuck on high boost in rF2 ?

mantasisg

mantasisg

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On around 0.65bar my horsepower in devmode keeps frequently jumping up to equivalent horsepower that happens to be at 1.45bar. I also noticed that horsepower keeps going up when I am changing gears, not sure if it is correct, I am just beginning to study trurbos.

I have 10 setting steps for turbo, could it be that somewhere at around 4th step (0.65bar) my wastegate chokes and boost pressure build up to maximum, as then for further steps nothing changes ? I don't understand what is going on.

I use two turbos.
 
mantasisg said:
On around 0.65bar my horsepower in devmode keeps frequently jumping up to equivalent horsepower that happens to be at 1.45bar. I also noticed that horsepower keeps going up when I am changing gears, not sure if it is correct, I am just beginning to study trurbos.
Click to expand...

A few weeks ago, I also started to get into the turbo building and also for me, hybrids. I've noticed that same HP change in Mod Dev. I haven't been on that project in a while so I haven't been able to isolate if it is the hybrid, the turbo, or both that is causing it. For context, it was starting the Nissan ZEOD RC conversion.

mantasisg said:
I have 10 setting steps for turbo, could it be that somewhere at around 4th step (0.65bar) my wastegate chokes and boost pressure build up to maximum, as then for further steps nothing changes ? I don't understand what is going on.
Click to expand...

My ZEOD also had something like this. I had 12 settings for the engine mixture and hybrid mapping. No turbo adjustment. In the real car, it could fully turn off the hybrid and run on ICE only, and vice versa of turning off the ICE and run hybrid only. It had been a few weeks, but I believe I am having the same or similar issue as you with the ICE settings.

EngineMixtureIssue.png


Looking at the screen shot. The first 7 settings work as I would expect. At setting 4 or 5 (depending on your count) @ 36% power, the engine will turn off. The engine will remain off for a few of the settings. But the final 2 settings, the ICE would be at full power. As a work around, I have the minimum @ 40% or so. It doesn't fully turn the ICE off, but rF2 I do not think supports what the ZEOD is capable of. It looks like this is changed in LMU.

I'm not sure if you need to do something similar with the turbo. Have the minimum raised?
 
Your problem is on another level of complexity. I am working on 1976 BMW CSL Turbo. They barely raced it IRL, but it was insane experiment, they went crazy with boost, allowing themselves to go above 1000hp. And of course they always broke. I have read that floor got so hot from turbos, it would start melting shoes.

I try to avoid mixture settings and other table like lines. To me great difference was made by tweaking "IntakeVolumePerRevolution". It has twin turbo setup. And each turbo had intake of half the engine displacement, while I think that would be correct if it was only one turbo in use.

I think it resulted in something weird going, when boost would build up so dramatically, that you could get maximum amount of boost on close to minimum setting. For example with rapid gear shift, or if you'd rapidly lift throttle from 100% to 0% and press it fully back again. It was also working around engine damage, and fuel consumption thus heat.

When I set IntakeVolumePerRevolution too low, then I had slow steady linear power curve rising with rising rpm, with no apparent kick. And turbo inertia and friction parameter also made not as much difference then.

With correct IntakeVolumePerRevolution amount turbo friction and inertia parameters starts making expected differences needed to delay speed power curve shift, i.e. to get proper turbo lag.

It is the only parameter in engine physics, that directly refers to engine displacement, isn't it ?
 
Did you make any changes to the Compressor table? This was something that i recently discovered on how to do, but am still missing a couple things to make finding some values a bit easier. I'm thinking this would be the part that controls your turbo lag and such. Correcting this would probably fix your spiking problem. I recently wrote up a bit of a tutorial. I need to clean it up, but I'll see if I can get it uploaded soon.

I haven't figured out how to do the TurbineFlowEffects. That would be another thing that if corrected, should help a bit.

EDIT:
https://forum.studio-397.com/index.php?threads/turbo-building-tutorial-wip.82894/#post-1158388
 
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I have the same experience as you @mantasisg, lowering my IntakeVolumePerRevolution by 0.3 from 1.5616 (calculated value in spreadsheet) to 0.12616, it removed most of the extra false boost when letting go of gas, but not completely. But it also removes some of the kick from the boost.
 
Since I have originated my turbo from yours, there might be something about the rest of parameters, such as compressor table, which I haven't worked on. I did however change a lot of things. I also have twin KKK turbohargers setup. Supposedly IntakeVolumePerRevolution has to be half of the engines displacement. If there are two turbos it probably has to be a quarter of displacement for each. I also have 3.2L engine in BMW CSL Turbo with 2x turbos. When I had the value set at 0.8, then turbo felt too wild still, even wilder maybe as lag became harder to deal with. Value at around 0.6 to me turned out to be about right. I guess from there a lot of fine tuning should go for turbo inertia and friction.

It is not necessarily always nice when power goes from 500-600hp, to 800-900hp in less than a second in BMW. It is too harsh. But when power increases too softly then it hardly feels like a turbo, and there are much less blowing off and whistling sounds.
 
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