About 5k is what I would say.
That's a lot of torque for not a huge amount of power so guessing it's turbo charged?
Alfa 4c with
low rpm turbo.
I used to drive it with shifting at ~6500rpm which is the 2nd peak and throws you right back at the 1st peak in the higher gears and slighty further back in the lowers (because of ratio selected)
Some extra things to consider...
If the event has fuel usage, short shifting a car with a flat power curve (like this one) would lose minimal lap time and save lots of fuel = less time in the pits.
Makes this car reasonably good in the 1h missions where it can be used, and I like the sound and handling.
+ Also always something to keep in mind is gear vs corner, but this makes things overly complicated to explain, but is easier to
feel once one got the hang of MT.
If it's all flat & straight like SSRX then the mathematical optimum mentioned above is correct
That one is tricky again, because
if you change gears at a particular moment/location the tyres will spin and you may lose stability or time (or both)
With the SSRX 720pp event, you have insane ampunts of power, and bringing that into acceleration requires testing the limits of traction. But this is really one exception to the game, as it doesnt include any meaningful drag-racing mode.
edit: Lancia Stratos (all tuning applied) AT / MT
red = AT
yellow = MT
This is a car that is pretty well suited to AT, making MT faster over the distance of 5kilometers straightline by
only 0.24s , but most of this difference stems from using gear 1-2-3 for just a bit longer -> so it will occure on the sprint after every corner.
Other cars will produce different delta depending on when AT will shift compared to the power curve.