Acceleration times simulation with Excel and MATLAB

[nvpF1crazy]

I'm trying to decide the rear sprocket size by finding the acceleration times based on tractive effort curves. I've used Excel to generate my data and made a MATLAB script to do some numerical integration part.
Just to check if I'm on the right track I entered dyno data from an older FSG event and got realistic times( 4 to 4.5 sec). But it shows that the car will end in 4th gear after 75m! I think I need to account for the engine inertia during every shift to get that sorted. How is that taken into account?

[nvpF1crazy]

I'm trying to decide the rear sprocket size by finding the acceleration times based on tractive effort curves. I've used Excel to generate my data and made a MATLAB script to do some numerical integration part.
Just to check if I'm on the right track I entered dyno data from an older FSG event and got realistic times( 4 to 4.5 sec). But it shows that the car will end in 4th gear after 75m! I think I need to account for the engine inertia during every shift to get that sorted. How is that taken into account?

[Crispy]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by nvpF1crazy:
But it shows that the car will end in 4th gear after 75m! </div></BLOCKQUOTE>

That does not sound unreasonable. Some teams use lots of gears, some only use a few. On a good accel run, we are at our revlimit in 4th as we cross 75m.

I don't think you need to include engine rotating inertia to pick reasonable gear ratios. I think doing a good job of dealing with engine inertia is more trouble than it is worth.

[PBjore]

Yeah I agree, Engine inertia is overkill to calculate hopefully you will be off power short enough during a shift for it to be insignificant.

We were in third gear crossing the finish line doing about 105km/h@3.83 in Italy this year (Chalmers formula student). So for us with a relatively high power car it worked good with a quite high gear ratio.