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Discussion Starter #1 (Edited)
Can someone help me understand this
The following came from a 2014 technical specs document.
Which one is the one for pdk? is it the one with ( )?
Also to make a shorter gear ratio does that increase or decrease the number below?

981 base model gear ratios.JPG

[TABLE="class: NormalTable"]
[TR]
[TD]Transmission[/TD]
[/TR]
[TR]
[TD]Manual transmission[/TD]
[TD]6-speed[/TD]
[TD]6-speed[/TD]
[/TR]
[TR]
[TD]Automatic transmission[/TD]
[TD]7-speed PDK[/TD]
[TD="width: 200"]7-speed PDK[/TD]
[/TR]
[TR]
[TD="width: 200"]Ratios (PDK in parentheses)[/TD]
[/TR]
[TR]
[TD="width: 200"]1st[/TD]
[TD="width: 200"]3.67 (3.91)[/TD]
[TD="width: 200"]3.31 (3.91)[/TD]
[/TR]
[TR]
[TD="width: 200"]2nd[/TD]
[TD="width: 200"]2.05 (2.29)[/TD]
[TD="width: 200"]1.95 (2.29)[/TD]
[/TR]
[TR]
[TD="width: 200"]3rd[/TD]
[TD="width: 200"]1.46 (1.65)[/TD]
[TD="width: 200"]1.41 (1.65)[/TD]
[/TR]
[TR]
[TD="width: 200"]4th[/TD]
[TD="width: 200"]1.13 (1.30)[/TD]
[TD="width: 200"]1.13 (1.30)[/TD]
[/TR]
[TR]
[TD="width: 200"]5th[/TD]
[TD="width: 200"].97 (1.08)[/TD]
[TD="width: 200"].95 (1.08)[/TD]
[/TR]
[TR]
[TD="width: 200"]6th[/TD]
[TD="width: 200"].84 (.88)[/TD]
[TD="width: 200"].81 (.88)[/TD]
[/TR]
[TR]
[TD="width: 200"]7th[/TD]
[TD="width: 200"](0.62)[/TD]
[TD="width: 200"](0.62)[/TD]
[/TR]
[TR]
[TD="width: 200"]Reverse[/TD]
[TD="width: 200"]3.33 (3.55)[/TD]
[TD="width: 200"]3.0 (3.55)[/TD]
[/TR]
[TR]
[TD="width: 200"]Final Drive Ratio[/TD]
[TD="width: 200"]3.89 (3.25)[/TD]
[TD="width: 200"]3.89 (3.25)[/TD]
[/TR]
[TR]
[TD="width: 200"]Clutch diameter[/TD]
[TD="width: 200"]Manual: 240 mm (dual-mass flywheel).
7-speed PDK: 153/202 mm[/TD]
[TD="width: 200"]Manual: 240 mm (dual-mass flywheel).
7-speed PDK: 153/202 mm[/TD]
[/TR]
[TR]
[TD="width: 200"]Body[/TD]
[TD="width: 200"]Monocoque lightweight body in a combination of steel and
aluminum[/TD]
[TD="width: 200"]Monocoque lightweight body in a combination of steel and
aluminum[/TD]
[/TR]
[/TABLE]
 

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Shorter gearing (more revs per given speed) means higher numbers, just like taller gearing (less revs per given speed) means lower numbers. It's backwards. But notice this: PDK has shorter gearing (higher ratios) than the manual, BUT a lower final drive ratio. Therefore, for the overall ratio of each gear, you need to multiply both figures. Go ahead and do that to avoid confusion. As a side comment, I remember reading PDK has the same ratios on all 981s, so you might want to check on that, since 7th would be waaaaaay too tall for the 2.7. I think it's even too tall for my GTS. The good news is at least on my GTS, even 6th is taller than the manual (74mph vs 72), so you could just use 6th. Hope this helps.
 

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Discussion Starter #5 (Edited)
OK will the following gear ratios be a minimal improvement or more aggressive short gear ratio for a 2.7 pdk cayman?

0.962 - 26:25 - 6th
1.100 - 30:33 - 5th
1.286 - 21:27 - 4th
1.550 - 20:31 - 3rd

Photo Mar 23, 12 21 27 PM.jpg

Just noticed that 5th and 6th gears are slightly shorter but 3rd and 4th are just a bit taller for the pdk thats if I am looking at it right.

Stock Gear ratios
981 base model gear ratios.JPG
 
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