Tom@TPC Racing

All OEM 997 GT3/RS coilovers can be installed on 997 C2/C2S/C4/C4S/Turbo with just a few adapter parts for the front. The adapter parts are:
1) Front adapter sleeves
2) Front extension cables, or extend the cables yourself
3) Front spring adapter for OEM strut mounts, or buy monoball top mounts with spring motorsport style spring hats.
4) AWD cars(C4/C4S/Turbo) require special front sway bar mounts.

Rears are all direct bolt-on using the OEM top mounts. The OEM top mounts are interchangeable.
Or can upgrade rears to monoball rear top mounts with motorsport style spring hats.
Such as this- https://rennlist.com/forums/997-gt2-...lable-now.html
Here's an image that shows rear OEM top mount(Left of image) vs. monoball with motorsport style spring hat(Right of image). I prefer the latter design because it allows for articulation as the suspension travels as oppose to "bending" the spring. But I suppose the OEM street car design is good enough for since this design on all GT street car model.

Tom@TPC Racing

There's more options now then before for electronic coilovers. The current options are OEM GT3(997.1 or 997.2 or 4.0), Bilstein B16 Damptronic(C2S or GT3 version), KW DDC, and Tractive DDA. By mid-2020 there will be more brands available.
All current options are very good upgrades for C2S. Ultimately it depends on what level of performance you are looking for as the price varies and relative to the performance level. Having a DSC to control the electronic coilovers makes a big difference in both performance and comfort because the OEM controller is pretty binary, whereas DSC uses the entire damping range based on real time load.
Not limited to, but just a few examples:
OEM 997.1 GT3/RS has ~230/580 in-lb springs
OEM 9972. GT3/RS has ~270/620
Bilstein B16 C2S has ~260/550
Bilstein B16 GT3/RS has ~330/720
Tractive DDC has custom spring rates, popular choices are 330/600(sporty and excellent ride over bumps), 390/720(sporty, intermediate to advanced track use, good over bumps), 560/840(track focused, pretty good over bumps), 670/1000(more track focused, still versatile for street)

To answer your question directly, Yes, they are all worthy of consideration as upgrade. What's best for you depends on your usage and budget. For street and mild track use you might be happy with just a DSC and a set of sway bars.

Senger

Also going to bring back an old thread. Can I do the 997 GT3 coilover upgrade on a base 997.1 without PASM?

Tom@TPC Racing

This is a good and fresh question. I have stated multiple times in this thread alone that OEM 997 GT3 coilovers can be installed on any 997 models, but never said anything about non-PASM car.
The answer is: OEM 997 GT3 coilovers can be physically installed on a base model 997 without PASM, but then there's electronics or wiring on a non-PASM car to control the stiffness, they'll be stuck on full stiff, which is awful to drive(feels rough like a dump truck).
There is a product you can buy to retro-fit the electronic control and wiring, this product is called the DSC SA(Stand Alone) Kit.
With DSC SA Kit you can use any PASM-compatible coilover/shocks such as OEM 997 GT3, OEM 997 GT3, Bilstein B4, B6, B8, B16, and Tractive.

GBX

Didn't realize that KW now has a DDC version for our cars? Is this something new? Anyone try it yet?

Tom@TPC Racing

They've been available for more than a year. Google search "KW DDC Porsche 997". My guess is the popularity hasn't caught on because these coilovers don't connect directly to the factory PASM wiring harness and they're not integrated to the car's factory CAN(Control Area Network) system. Instead they are controlled by their own controller box which has presets for the user to select. One could swap the connectors and connect them to a factory PASM car and use DSC to integrate to CAN to produce fully dynamic control.

Aclmin

I would highly recommend the DSC, with it, my .2 GT3 set up on a .1 C2 is firm but very streetable, a marked change vs the stock controller. Even running pretty low and with Cup2 tires (stiff sidewall). In terms of ‘firmness’ the .2 GT3 coilovers feel ‘similar’ to H&R lowering springs, but obviously have full damping range.

Aesthetically coilovers make a big difference too.

Senger

I'm glad I had a good question haha. I figured it would bolt up, but questioned how it would operate without PASM. Is this a worthy upgrade over buying a different set of coilovers such as BC? The car currently has H&R springs, I'm assuming GT3 or BC would be a solid upgrade compared to springs, right?

Tom@TPC Racing

I already said in my previous post that without the electronics to control OEM GT3 coilovers they'll be stuck at full stiff which is not pleasant to drive.
If you don't plan on getting the electronic and leave the OEM GT3 coilovers "unplugged" then they won't work as intended, therefore in my opinion its not "worthy".

Senger

I was referring to installing the DSC to have PASM with the coilovers.

Tom@TPC Racing

Sorry I misunderstood the question. In that case, using the DSC SA kit to control OEM 997 GT3 coilovers or any other electronic coilovers is a worthy mod. We even use DSC SA kit in 997 GT3 Cup cars!

Senger

Good to know, thank you. How much adjustability do you get with the DSC and what all can you adjust?

Tom@TPC Racing

Before I answer your questions, first let me apologize to the OP for going off topic from the original purpose of his thread, and second, this is "Broken Record Alert" for those who have heard/read the same info over and over again on this forum and other forums.

Answers:
DSC adjust individual damper in *real time based on g-force. For example, during braking the front compression will stiffen relative to the amount of g-force to minimize nose dive which makes car more stable during hard braking. Below is an example screenshot from the DSC software showing the G-force table. The blue highlighted cell indicates straight line braking at 0.8g. The command shown at 0.8g braking is 95% compression to the front to reduce nose dive(prevent overloading front tires), while the rear is at 90% rebound to reduce rear lift(making the rear end more stable and more effective rear braking)


Same with cornering, when cornering G-force is present the commands are to stiffen the dampers to corner more flat. Here's an example, same car, same driver, same track, same afternoon. The driver is familiar with his car and this track, the only change the DSC. The lower image shows by the driver's muscle memory the same car is flatter at the same corner at the same pace. Since the car is more planted the driver can potentially get more speed.


Each cell in the G-force table can be adjusted by the user down to a fraction of a percent. DSC does come reprogrammed so that users don't need to start from scratch. Adjustments can be made by the user based on how the user wants the car to feel. DSC spent a lot of time and effort in the development to such extent that 95% of the users(some are even highly experienced pro race car drivers) likes the DSC standard program as is.

Beside G-force, other inputs that can be adjusted by the user in a Porsche 997 to change damping commands are Brake Line Pressure, Throttle Angle, Steering Angle, Vehicle Speed. All of these tables are in the DSC software.
The word "adjust" by the user in this context means setting the parameter for the event to happen. Literally DSC "adjust" the commands to each damper in *real time while you are driving. The DSC algorithm has proven to superior to even the most recent 991 GT3 RS and GT2 RS in comfort and performance, there are many positive reviews and videos that can easily be found by doing a search.

Of the many videos, here's one that's fun to watch, starting at 1:35 in this video, Mike Levitas, the developer of DSC, sums up what DSC does in a few words in a fun and upbeat way-

*real time denotes DSC electronics processes data in real time, the dampers' reaction time is 7 to 100 milliseconds depending on type of damper.

d9m13n

Tom, Im heavily considering going this route with my 997.1 C2 as the secondhand market seems to have a lot more GT3/RS coilovers for sale than for a base Carrera. Is it still possible to purchase the front sleeves from you if I do end up pulling the trigger on a set of aftermarket coilovers?
Cheers,
Jake

moralman

Hi Tom,
You were mentioning this:
4) AWD cars(C4/C4S/Turbo) require special front sway bar mounts.

What and how do you acquire the special mounts? Currently running a 4S with GMG sways.