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[Brian]

How does increasing the engine power increase cars speed, is it not limited by the gearing? So that for example 5,500rpm will equal the same speed whatever the engine power?

So you can increase the cars speed by increasin how much it revs?

Am i being thick?

Equal length driveshafts help lay the power down, but out of interest how would this be done in a fiesta where the gearbox is not central?

[heeman10]

As you probably know...the force acting on things in air (drag) increases with the square of the speed. I THINK I'm right in thinking the formula's something like this:

Drag = 0.5 x cross-sectional area x density of fluid x Drag Coefficient x the square of your speed in m/s

The fluid here's air (1.225 kg/cubic metre), and I'm sure you could work our your CSA if you were that bored!

So when you travel at higher speeds, the drag really starts mounting up, and the force you need to drive the car forward has to equal the drag at that speed, to maintain the speed you're travelling at. So if you give more power, you can overcome this drag. If you add 10bhp, it may give you a small increase in top speed, but like I said before, when you speed up, the drag gets significantly harder to combat, so you need serious rises in power for considerable top speed increases. Easiest way is to streamline the car.

You're right about the gearing. 5,000rpm in 5th is the same speed whatever power you have

[FezzR]

You're right about the gearing. 5,000rpm in 5th is the same speed whatever power you have

as long as the gear ratio is the same

[Brian]

yeah, so if you power up the car it increases its ability to reach higher revs by overcoming drag

suppose that makes sense now cheers

[heeman10]

as long as the gear ratio is the same

Fussy baxtered! One assumes we're talking of the same gearbox when one mentions the above

[xrsi]

only way to do get equal length driveshafts would be to get it so that the gearbox was centeral! OR HAVE ONE WHEEL STICKING OUT THE ARCH!

neither would be practical! or a very good idea really!

[FezzR]

as long as the gear ratio is the same

Fussy baxtered! One assumes we're talking of the same gearbox when one mentions the above

yea but the way u said

5,000rpm in 5th is the same speed whatever power you have

is slightly misleading cos more often than if u have more power u have different ratios

[heeman10]

yea but the way u said

5,000rpm in 5th is the same speed whatever power you have

is slightly misleading cos more often than if u have more power u have different ratios

*tut* *sigh* Some people eh?!

[df908]

Drag = 0.5 x cross-sectional area x density of fluid x the square of your speed in m/s

You left out coefficient of drag (cD) there...

[heeman10]

Drag = 0.5 x cross-sectional area x density of fluid x the square of your speed in m/s

You left out coefficient of drag (cD) there...

Yep, was just testing ya! Surprised FezzR hasn't moaned about that bit yet I'll edit it back, let's hope he didn't see

[FezzR]

Drag = 0.5 x cross-sectional area x density of fluid x the square of your speed in m/s

You left out coefficient of drag (cD) there...

Yep, was just testing ya! Surprised FezzR hasn't moaned about that bit yet I'll edit it back, let's hope he didn't see