Well, this may be a silly question, but after reading about the difference between horse power and torque, I better just ask:

I was at an airfield event this weekend in my GT2, which went good , as I clocked the highest speed (185,23 mph on GPS) with a F430 coming second (around 182 mph). I guess I can optimize my gear changes, and WHEN to change gear. This was the first time I did anything like this.

I got a (atm) completly stock 996 GT2 MKI. The power graph looks like this: (well, this is from a MKII, but it should be pretty much the same):



Should I try to change gears to keep the torque at maximum (i.e keep it between 3000-5000rpm until 6. gear and just keep going) If I understand torque right, this should be where I get most power to turn the wheels around? So.. I probably changed gears way too late... (my excuse are that I am coming from a 996 GT3!)

Comments?

 

Even though the torque is maximun in that (3000-5000) range the actual torque to the ground will depend on the gearing.

Slightly less torque at 6000 with much taller gearing will net you more torque to the ground in the lower gear.

You can actually calculate the torque to the ground with each gear ratios and devise a shift point from where the latter gear have more torque to the ground than the previous gear.

I could be wrong, but in our cars the lower gears will have more torque to the ground up to redline.

 

Thanks, can someone calculate this?

The ratios should be:

1st Gear Ratio 3.82:1
2nd Gear Ratio 2.05:1
3rd Gear Ratio 1.41:1
4th Gear Ratio 1.12:1
5th Gear Ratio 0.92:1
6th Gear Ratio 0.75:1

 

Here goes.

If you shift at 6500 from 1st to 2nd the rpms will drop to 6500*2.05/3.82 = 3500

In 1st the torque to ground is approx 500 * 3.82 = 1910
In 2nd the torque to ground is approx 640 * 2.05 = 1312

So 1st has more pulling power to redline.

Can anyone double check my math.

 

Sure, you just add the 5, carry the 1, multiply times 12 and subtract 48. Looks like you are right on!