GT4RS PDK Gear Ratios Published
 

Some additional technical specifications have been posted over on the Porsche Newsroom.

Thought there'd be enough interest in posting a dedicated thread for discussion. Once it winds down I'll combine it into the main thread for archival purposes.

As published the GT4RS reaches max speed in 7th gear:

3.75 2.38 1.72 1.34 1.11 0.96 0.84
Reverse gear 3.42
Rear-axle gear ratio 4.17

Here is the GT4 PDK for comparison:

3.91 2.29 1.65 1.30 1.08 0.88 0.71
Reverse gear 3.55
Rear-axle gear ratio 3.62

Here is the GT4 Manual Gearset:

3.31 1.95 1.41 1.13 0.95 0.81
Reverse gear 3.0
Rear-axle gear ratio 3.89

Attached is the full tech spec bulletin

Looking forward to these ratios in my Spyder RS!

It'll be interesting to see what the speed in gears will be on a comparative basis.

If you know the wheel diameter there are calculators that are pretty close.

So not only all 7 gears were revised but also the final gear ratio...

Really nice ratios, with closely spaced gears.

Looks like a snappy combination. The PDK GT3 has the same ratios except for the final drive is 3.97 compared to the GT4RS 4.17. The GT4RS should be quick! :rockon:


https://cimg0.ibsrv.net/gimg/rennlis...b73bbecec6.jpg

It's the same GT3 engine so not surprised that it has the same gear ratios. I'm hoping PDK Sport will have as violent shifts.

Probably....plus you get a final drive a bit higher than the GT3 (faster acceleration)

It has a higher final drive ratio ...... shorter 20 inch tires (27") on the rear instead of the GT3's 21s (28.5") ..... and is lighter than a GT3. Yes, it should be really quick.

Some calculations comparing the ratios. The peak acceleration numbers in each gear I calculated assume zero drivetrain loss and perfect grip, neither of which are true of course, but are useful for comparison at least.
https://cimg8.ibsrv.net/gimg/rennlis...b2f041dbcf.png

Damn, significant difference.

Yes, Spyder RS will do nicely with this :corn:

It’s great that the GT3 has the same 1st-4th gear ratios regardless of manual or PDK.

Hopefully Porsche can adapt the GT3 manual gearbox for the Spyder RS. If it doesn’t fit, just leave out 5th and 6th. I don’t need them.

That wont happen...check the other thread were it's explained why any 911 gearbox wont work on the mid-engine platform.
Can they revised the gears of the current mid-engine platform transmission? Yes they can but then it brings the issue of that transmission capacity...in the manufacturers eye, not aftermarket.

I knew you were a true believer in there, somewhere. ;)

Another way to look at it; my biggest complaint with the non RS gearing is the 1-2, tho the two fuel econ gears in the non RS car's PDK are also an annoying nod to fuel econ requirements.

The drop at an 8k RPM 1-2 shift for the 4RS is 364 less than for the 4 M6 and 392 RPM less than for the 4 PDK -> it'll drop you less out of the power when tooling around. I'll find a dyno plot to further make my point, but max power is pretty much at redline, and there's a torque bump at 5.5kRPM or so which makes things even more noticeable. I've found the 1-2 to be similar in some other cars I'm familiar with, and theirs didn't bother me, so this could be more that the engine is peaky than the 1-2 is extra long, but IMO it'd be nicer to have a 1-2 that's more tuned to the engine.

In a drag race, what matters is power * time and for the GT4 engine, the 4RS is PDK is going to do this better than the GT4 PDK, at least for the GT4 power curve. I'll run the numbers at some point, but I bet it's worth at least a time average of 20hp applied.

The RS ratio stack is more what I'd expect in a performance car, and would like to have seen it in the GT4.

Maybe there is a performance benefit to the extra long 1-2, like being able to stitch together corners without upsetting the car, but esp for the PDK with smooth and lightning fast shifts, it's not intuitive to me.

https://cimg8.ibsrv.net/gimg/rennlis...594b52fb0b.png