MX Bikes Official Forum

Mods => Bikes => Physics => Topic started by: PiBoSo on September 04, 2018, 10:35:12 PM

Title: Alta conversion
Post by: PiBoSo on September 04, 2018, 10:35:12 PM
Steps to convert the Alta to make use of Beta9 electric engine support.

1. open the file MX2OEM_2018_Alta_Redshift_MXR.cfg

2. go to the "engine" section.
2a. add
electric = 1
This tells the physics that there is no fuel tank, no idle and no engine stall.
2b. the "stall" section is still used to make sure that engine braking goes down to zero at zero rpm.  Example:

stall
{
RPM = 500
torque = 0.1
}

2c. "IdleThrottle", "IdleRPM", "FuelRatio", "shiftRPM" can be removed.
2d. the "Clutch" section must be removed to tell the physics that the engine is direct drive.
2e. the real engine primary ratio, "Ratio0", is actually 19, 67  :P

3. remove the "fueltank" section, and replace it with:

batterypack
{
Capacity = 5.8
}


4. remove the "gearbox", "autoclutch" and "shifthelp" sections.

5. go to the "driveline" section.
5a. delete "SecondAxisInertia".

6. "data" in "tyres" is not used anymore.

7. save and close the file.

8. open the file sfx.cfg

9. the "starter" and "gearbox" sections can be removed.

10. save and close the file.

11. all done, but you can also delete the files "engine.wav", "p_mx.cfg", "p_mx_f_midsoft.tyre" and "p_mx_r_midsoft.tyre", because they are unused.
Title: Re: Alta conversion
Post by: Asdrael on September 04, 2018, 10:43:10 PM
Great, thanks! I'll do it for the next OEM update.

Two small things:

batterypack
{
Capacity = 5.8
}

Is this a random number or what we should use for a standard Alta?

Quote2d. the engine primary ratio, Ratio0, is actually 19, 67
Ok I admit I found 3.53 and thought 'fuck it 20/70' is good enough :p
Title: Re: Alta conversion
Post by: PiBoSo on September 04, 2018, 10:48:25 PM
Quote from: Asdrael on September 04, 2018, 10:43:10 PM
batterypack
{
Capacity = 5.8
}

Is this a random number or what we should use for a standard Alta?

According to the official Alta data, the real bike uses a 5.8 kWh pack.
Title: Re: Alta conversion
Post by: Asdrael on September 04, 2018, 11:36:10 PM
Ok, I tried fast. You could have said it was going to be more complicated than that :p

My conclusion: there is a flywheel issue linked to the engine. Is there an other parameter that needs to be tuned compared to a ICE? I haven't touched wheel inertia (obviously) nor anything else that I could see...
Title: Re: Alta conversion
Post by: 𝖙𝖋𝖈 on September 05, 2018, 12:12:34 PM
Thanks PiBoSo for taking the time :)
Title: Re: Alta conversion
Post by: Asdrael on September 05, 2018, 07:41:49 PM
Figured it out, engine inertia. 0.001 feels like a proper value.
Title: Re: Alta conversion
Post by: PiBoSo on September 05, 2018, 09:17:24 PM
Quote from: Asdrael on September 05, 2018, 07:41:49 PM
Figured it out, engine inertia. 0.001 feels like a proper value.

The bike is direct drive, so the engine inertia is added to the rear wheel.
Problem is, it also affects the gyroscopic forces, while it shouldn't.

Lowering the engine inertia is a workaround, but 0.001 is not a proper value.
Title: Re: Alta conversion
Post by: Asdrael on September 05, 2018, 09:37:18 PM
Thanks for the update. The "full electric" with the 0.001 inertia and modified engine braking doesn't feel too bad actually. A bit toy like, but the behaviour is really fun.

I guess we'll have to wait for a fix to get the proper inertia value in then.