NOS

[MirceaKitsune]

I think an awesome new feature for vdrift would be a nitro system for cars. It's one of the things I liked most in the Need for Speed series, and imo it makes racing games much more fun and interesting (as well as strategical, since you decide where and how much NOS to use during a race).

The way I imagine it is all cars starting with full NOS at the beginning of the race and using it where they believe is best. It could be either non-rechargeable or the drift points you score can give some nitro back like in NFSU2, if that would be a better idea. The menu should allow disabling this at race setup, so it can be turned off in races where it's not wanted.

Just my own thoughts, I'd like to hear more opinions and if anyone else supports this idea even for an optional feature. I'll try looking into it once I can get SVN to compile, though I'm not so good when it comes to heavy code. Hope this can be added to vdrift in some form

[fudje]

The only difficult thing about implementing happy gas in a racing simulator is that it responds different depending on the setup of the engine.
The way VDrift works at the moment, we specify the following things about the engine:

- Torque Output
- Mass
- Rotational Interia
- Fuel consumption (kinda' - ish)

In order to implement NO5, we'd have to either
- Fudge the figures, "this system is setup to provide this must power boost perfectly according to this engine speed," which isn't very simulator-ish (and makes specifying NO5 pressure completely surreal)
- Start messing around with air:fuel intake ratio figures (and makes specifying NO5 pressure somewhat complicated)

It's not quite like implementing overdrive gears or turbochargers (although it's a bit like implementing turbochargers).

OTOH as far as I'm aware every racing game produced so far that does things like NO5 has been a pure arcade game, so we'd win on:
- No one would likely notice if we did it wrong
- Coolness factor (Imagine this: Initiate drift by asking for a low pressure nitro boost at the right time).[/i]

[MirceaKitsune]

I see. I initially thought NOS could be implemented by just increasing the acceleration of the car while used. Maybe NOS could be specified as an overrider of engine options in each .car instead... like Torque output +2, Mass +4, etc.

But indeed, I don't think anyone would notice if NOS didn't boost over quite perfect values. I still believe the feature would be awesome... especially during drifts like you said Imho it would be nice to try the best possible way of doing it and seeing how that looks like.

[MirceaKitsune]

I decided to attempt implementing this myself. So far I coded the base system (the rest is not ready yet) and would like to know if it's good till now. It works by boosting the Clutch Torque... that seemed the best way to me.

Patch links: http://www.mediafire.com/?zijlj5yz2ux or http://upload.ps/vlbwqrci4ll7/VDrift_NOS_v1r1.rar.htm

Important: The current patch only includes the car settings for the 360, so only test with this car as others won't work for now. To test the patch, do the following:

- You must be checking both the data and engine from SVN. Apply the data patch to the data and the engine patch to the code.

- From the menu, go to Options -> Controls -> Assign Controls -> Car Controls and assign a new key for the NOS keybind.

- Go back and start a practice game. Make sure 'Enable NOS' is ticked on and choose the 360 as your car.

- While driving, press the NOS key to get boosted, until the NOS runs out. NOS is displayed in the lower-left corner of the screen above the RPM bar.

If this feature is accepted, the remaining things to do would be:

- Add the carinfo properties for all cars. Will be doing that first thing.

- The two most important eye-candies; A NOS sound and flames coming out of the exhaust pipe. I don't know how to do either of the two myself.

- Give the NOS tank a position and weight.

- Make the HUD indicator a bar. It's currently just text for testing... I can do that if the patch will continue.

- At a later time, teach bots how to use the NOS and when. But imo that can done another time.

[NaN]

Hi, I have never seen N2O being used circuit racing. But I see the fun factor.

I'd love to have some details about nitrous oxide injection. What I've found is:
N2O is injected to increase the oxygen saturation allowing to burn more fuel. So I think it should scale the engine output torque.
Wikipedia says the power increase is up to 1.5 times engine power. But it surely depends on the thermal/mechanical limits of the engine.

About the car parameters:
What is the usual N2O bottle/tank size 1-10kg? If the tank mass is about 10kg. Its mass contribution/position can be neglected.
Liquid N2O density is constant(should be somewhere about the density of liquid nitrogen 0.8g/ml). I think we don't need it in the parameters file.
What are realistic nos-boost values(1-1.5 or more)? Should the user be able to regulate the boost amount in game?
What does the consumption depend on? Should it be proportional(boost-value) to fuel consumption?

I am not sure what you mean with "NOS sound and flames coming out of the exhaust pipe".
You can observe a so called Back-fire on racing cars caused by incomplete combustion during deceleration/gear shift(suddenly closed throttle). The unburnt fuel ignites on the hot exhaust pipe. I'd love to see this effect in VDrift.

[NaN]

I found some more info at http://www.mre-books.com/sa50/sa50_7.html
They state that the N2O/Fuel ratio is about 5:1.

My proposal for N2O parameters is:
[ nos ]
power = 74570 # power increase in W (100hp)
capacity = 9.07 # N2O tank capacity in kg (20lbs)

So how long does the tank last?

Fuel flow rate in kg/s (otto cycle: efficiency = 0.35, heating_value(gasoline) = 4.14E7Ws/kg):
fr = power / (efficiency * heating_value) = 0.005kg/s

N2O flow rate in kg/s (N2O/Fuel ratio 5:1):
nr = 5 * fr = 0.025kg/s

nos_time = capacity / nr = 350 seconds nos time for +100hp using a 20lbs tank

[MirceaKitsune]

Got the latest version of Vdrift last night, and remembered this. Is the code still usable with the latest Vdrift repo, and has it been adapted and bug fixed so far? I remember there were plans for such, but no news for a while. Would be sad if all the work got lost, and I'd still love to see this feature. Please let me know about this, and I hope it might be merged in a future version

[NaN]

I'll push the code into a branch for people to try.

[NaN]

NOS code is in master, enabled by default, control is left shift. I've added a GAS and NOS indicator to the right hud bar.

Simulated are fuel and nos consumption. Fuel consumption is calculated from engine efficiency and fuel heating value(should be a fuel-tank parameter eventually).

Code:

[engine]
...
nos-boost = 80000
nos-mass = 5
#nos-ratio = 5 #optional N2O fuel ratio
#efficiency = 0.35 #optional constant engine efficiency
#fuel-heating-value = 4.5E7 #optional in Ws/kg

The CO has got a 5kg 80kW kit for testing.

[MirceaKitsune]

Wow, thank you very much! Can't wait to try it once I get another compiled build Thanks kindly for adapting and committing that code!