Top speed of some cars is limited.Any ideas?

[mynameis66]

Hi there.
Heres a question for those in the know.
Why do some cars,rally cars,Grb road cars like the Lancer,struggle to top 180mph when tuned to 600pp? I tried the Isle of Man time attack car with its engine swap,upped the weight/dropped power to meet the 600pp limit and it only just tops 180mph..Is it something to do with diff settings,ive tinkered with the gear ratios but no good.Ive also tried with very little rear downforce but doesnt seem to make any difference.Hp is around 600 with weight 1400kg so nothing too dramatic there.Most other cars with the same weight and power easily go faster on the main straight.
If there is a post somewhere on here can you point me in that direction? 👍

 

[Famine]

I tried the Isle of Man time attack car with its engine swap,upped the weight/dropped power to meet the 600pp limit and it only just tops 180mph..Is it something to do with diff settings,ive tinkered with the gear ratios but no good.Ive also tried with very little rear downforce but doesnt seem to make any difference.Hp is around 600 with weight 1400kg so nothing too dramatic there.Most other cars with the same weight and power easily go faster on the main straight.

Without seeing the settings it's hard to say, but cars stop accelerating for two reasons:

• They run out of gears
• They run out of power

The power required to accelerate increases by a cube of the increase of speed: if you want to increase top speed by 5% (say, 180mph to 189mph) you need to increase the power by 16% (so 600hp to almost 700hp). But if your gearbox won't spin that fast it doesn't matter how much power you put into it.

Also be aware that you need the power to be at the right engine speed. If you've got the 'box set so that your 189mph arrives 2000rpm after (or before) the engine hits 700hp, you won't reach it.

 

[Tornado]

On top of what Famine said, the reason for that happening is aerodynamic drag at higher speed.

That looks like a bit of a wind sock to me no matter how low you adjust the downforce.

 

[mynameis66]

Many thanks. 👍