Find Usable Power Curves

[63AvantiR3]

So I'm in the tuning window setting up my Pescarolo C60/Judd and bring up the power curve window. Wonderful! It only gives a low end RPM (1000) and a high end RPM (8000) with the TQ and HP lines drawn in the middle unlabeled.

How exactly should I find out where I want to keep my tach needle? I took a ruler up to the television screen and noticed that the window boundaries set up at 1000 RPM and 8000 RPM are a fixed width of 8.5 inches. I read the ruler's reading, roughly as far down the power curve as I wanted to find out.

Just for reference's sake, I eyeballed it and found out that at 6 3/8" down the ruler from 1000 RPM was the cross in TQ and HP. Now we all know where the power curves should cross when doing math (5252 RPM), I just wanted to test Polyphony Digital's integrity. Dividing 6 and 3/8 by 8 and 1/2 gives 3/4. 3/4 of the overall span, 7000 RPM (high end minus low end RPM figures), is the magical number of 5250 RPM. This is close as I'm sure the numbers don't cross at exactly the 6 3/8" mark. We can conclude that the theory works well enough.

This trick works for all other charts too. All cars don't give 8000 as the top RPM, but the black window containing the power curves is always 8.5" wide. It's possible to take fractions of distance and turn them into fractions of the RPM band and plot out a certain car's power.

The Pescarolo in question has usable TQ from 4060 - 4900 and HP is great from 5390 - 5810. Now I know not to let my tach sweep below 4000 RPM and that anywhere above 6000 RPM the engine is only making noise. Useful information to have, especially since the tach goes all the way to 7500 before the shift light starts to blink.

Annoying that P.D. didn't put more labels on the RPM chart, but cool that at least they did label starting and ending references so we, the consumer, could figure out via math where a car's power curve starts and stops.

 

[joseph dobson]

what does this mean?

 

[63AvantiR3]

what does this mean?

This means that you can set up your transmission gears to not drop your engine's revolutions below "X" RPM when you shift. It also means that you know not to wind the engine out to redline. In most cars case all the engine is good for at an RPM above where your car stops making power is making noise.

In the above example, I found that the Pescarolo/Judd has good usable power from 4000-6000 RPM. This means I should gear the car to use that range of the power band, and should shift right around 6000-6500 RPM in order to drop back into the meaty part of the torque band, or circa 4000 RPM.

Your mileage may vary, not all cars are going to be good from 4000-6000 RPM. Use the measurement trick to find out not where torque and horsepower peak, as that's documented, but to find out how much of the RPM band is useful. This trick shows you the area "under the curve" that is still usable.

 

[Ezz777]

you would have loved the good old days of GT. They used to have a combined gear ratio and power curve sort of thing so you knew exactly where each gear was going to be chagne. takes out the 'ruler' element. i have no idea why they take out all the good features. seems they sometimes loose the focus by trying to put a tad too much detail in terms of tracks to the point where some of the crucial gameplay elements sometimes are left unattended.

 

[isaac05]

and so how do you set up your tranny to where it will shift down to the good rpm zone?

 

[Ezz777]

nowadays its sort of guess work. best bet is to try different settings and see how you go. other than that you may have to resort to the ruler technique...

i do find tho that trying to get the bottoms of the lines in your gear adjustment to be at about the same height should ensure even gear changes.

 

[63AvantiR3]

Ahh yeah I do recall the sweet features of Gran Turismo. The transmission adjustment screen had a lot more detail so you could tell where everything was going to fall.

 

[Wild Cobra Z28]

So I'm in the tuning window setting up my Pescarolo C60/Judd and bring up the power curve window. Wonderful! It only gives a low end RPM (1000) and a high end RPM (8000) with the TQ and HP lines drawn in the middle unlabeled.

-----SNIP------

Annoying that P.D. didn't put more labels on the RPM chart, but cool that at least they did label starting and ending references so we, the consumer, could figure out via math where a car's power curve starts and stops.

I think you are trying to over analyze. First of all, don’t concern yourself with absolute numbers or the torque since HP is a function of torque x speed. I worry about where the peak power is. When I need to concern myself with that little extra performance, I try to get my shift points so I leave one gear at peak + x RPM and enter the next gear at peak – x RPM. The idea is to have maximum volume under the power curve at your shift points. If the curve is symmetrical, the plus and minus spacing will be equal +/- from the peak power.

By the way…. The strait sections on the torque and power curve are at 500 RPM intervals. Easy way to determine peak within 250 RPM since the strait sections do not make a true curve.

I also set my transmission differently for that little extra performance when I need it. I make it so 2nd-6th gears are at equal height at the bottom. I then change the final gear for the top speed as needed for tracks. This makes all shifts consistent to be able make the best use of the power. Works best if the TCS is not flashing in 3rd+ gear.

1) Set final to full right, or 0.500 from full right.
2) Set Auto to 1, moving it right first if near 1 starting.
3) *IF* low power car, set 1st gear full right, otherwise little effect, but may want to move toward the left. Also note that this method may be worse for some low power cars than normal autosets.
4) Set 2nd gear full left
5) Set 5th ger full right
6) Set 3rd, 4th, 6th, and 7th so the bottom of the diagonals form a strait horizontal line if joined.
7) Set the final for the various tracks. Do not disturb the other settings once set.

If you have a scientific calculator, the numbers can be calculated for the gears. Take the 3rd root of 2nd gear – 5th gear (multiplier = (2nd-5th)^(1/3)) and that is the multiplier for your gear spacing.