504

Hey guys,

I searched, but was unable to find any answers. Does anyone know at what power level the transmissions or clutches start to have issues? I searched with no success on whether upgraded clutches are available? Most PDK/DCT transmissions are limited by the clutches and not the gearbox itself. I'd like to know whether that is the case with the PDK equipped in the 981 and if there are options to increase the clutches power limit.

Thanks!

Code

Assuming the gearbox is the same as what's in the 991, I would say it could reliably handle 550HP / 500TQ (@ the crank).

504

Thanks for the reply! That was another aspect of the question. How similar is the gearbox between the 991 and 981? It seems the 991 version with upgraded clutches can handle quite a bit.

Code

The new GT2 RS can handle 700HP, but I think that version of the PDK is specific to that car. I can say with certainty that in a 997.2 Turbo with Stage2 Turbo upgrades was slipping the clutch in the PDK once it got to 600WHP. Upgrade it, and it's good for 1000+.

djm68

The 987/981 PDKs are not the same as 997/991 PDKs, though they do share some components, such as clutch packs. The Turbo's PDK is its own beast.

The clutch packs on 987/981 PDKs are the same as their NA 911 counterparts, so the clutches can handle over 400 HP. Dodson Motorsports can upgrade the clutch pack: you send them your clutch pack (to New Zealand), they cut open the clutch carrier, install new friction plates, and finally re-close the pack, though part of the modification includes making the pack easy to reopen for future rebuilds. Cost is around $9000.

DJM

504

Great, so shy of 600whp would be the limit for the stock turbo PDK. Thank you!

Awesome info, thank you so much. It's good to know that Dodson can modify the 981 clutches as well. Do you know any details on the differences other than rotation, and whether the gears themselves are capable of handling similar power levels to the other PDK's?

Code

Thanks for that!

djm68

I am not a PDK expert, just a bit of a gearbox geek. Final drive ratios are different as well as some of the gear ratios themselves; final drive ratios and gear ratios are even different with the same gearbox family, depending on the application. For example, the PDK intended for the 2.9 liter non-S cars, has numerically higher final drive (and ratios) to better allow the 2.9 to rev. In the 981 series, the 2.9 non-S PDK is also used in the GT4 Clubsport.

I do not know numbers for the gears/internals ability to handle various power levels, but unless you are planning a turbo motor for your 981, I doubt you have anything to worry about in terms of the PDK breaking from power alone. Heat is the real concern for PDKs, regardless of power level.

You'll probably find this interesting as well: https://www.cobbtuning.com/products/...-991-1-carrera

Note the high torque capability -- if you are building a high torque motor, you can increase the clutch pressure.

DJM

504

Thanks again for all of the info. I appreciate you taking the time to fill me in.

I should have been a little more clear in my original post. The transmission will be adapted to a Turbo Honda K20 engine in an MR setup. The K20 engine is great, but the transmissions are known to be a weak point. It will be adapted to run a Porsche transaxle, and I'd like to run a PDK box. The car currently makes 390whp but will likely have the boost turned up closer to 500-550. It seems like that might be right at the limit of what the PDK can handle.

djm68

Oh, this is extremely interesting! MR = MR2? If the car is very light, keep in mind the tires are likely to slip vs. breaking the gearbox.

DJM

504

NSX and pretty light! Hopefully the weight and lower torque of the turbo 4 make doable.