Negative - Canned ODE solver no longer produces a believable result. To be honest, I'm not sure what the hell it's doing at all!
Solution: Ghetto-fy it. As in, my integration scheme is as follows:
y(i+1) = y(i) + yprime(i) * timestep;
Yeah, I know. Not exactly Runge-Kutta. But hey, whatever. Wanted something quick and dirty to make a result. It's an easy problem to solve (linear interpolation of the torque curve), and I have plenty of CPU power to just muscle it. I'm sure my other solver is failing out because of some accuracy or tolerance setting that I'm too lazy to fuck with at the moment.
To a degree this might be nice, in that instead of setting a time span for integration I can go one more step and calculate distance, and have the solver cut off after a certain amount of travel. Ultimately that's what I'm interested in for doing straightaway sims.
Here's the result though, with the following parameters. It's a little goofy under 3000 crank RPM since I have no dyno data, so I filled in some BS numbers (engine is pretty much stalled at that point!). By "Engine Thrust" it's thrust at the tires, coming from the engine. Obviously with the data below 3000 RPM being crap anyway, the 0-60 time isn't even worth looking at.
- Car weight: 1000 lb
- Drag model: Tuned to generate 400 lbf at 120 mph (arbitrary numbers)
- Final chain sprocket reduction: 3.250
- Rear tire OD: 22.6"
- Shift point: 11,000 RPM
Next up.. I'll have to clean up this solver and add the distance output and solution limit, then do the same for a braking sim, then start building the actual lap solver.
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