You had done such a nice job on the car...I'd hate to have you drive around like that. It's kinda like going to dinner with your zipper undone.

 

I went out for an hour on some back roads this morning. The car feels extremely tight and agile. The new tyres need wearing in a little but even in the wet it's hard to reach the car's grip limits on quiet public roads.

The only thing that I am a little concerned with is the stiffness of the car over rough terrain, especially when going slow.

I am rethinking my 0-10 initial assessment. I would now say normal and sport are closer to 7 and 8 with an empty fuel gauge and 5 and 7 with a full tank.

Also you have to creep over any kind of crest in the road surface otherwise you scrape your underside as you come back down again!

So I would say that my configuration is probably at the limit of daily driver usage but take it on some flat twisties and you won't stop smiling for hours!

 

UPDATE:

After the Porsche Club GB Christmas Cruise I took my car into Center Gravity to have Chris do some geometry checks (to make sure nothing had sagged/changed since the original work was done). By the time Chris had finished fine tuning my suspension around 5 ish it was down to -2 degrees C. Chris then took me out for the final road test.



We started testing break away speeds for the front and back wheels around his local small roundabout. We managed to get up to 26mph before we started to slide. A respectable value given a GT3RS with sticky race tyres on a dry hot summers day will do just over 30mph on the same tarmac.

We then went out on some bumpy b-roads and Chris certainly wasn't holding back due to the damp/freezing conditions!! We were doing some serious speed, cornering and braking. Just shows how stable/grippy these cars are even in ice-rink conditions!

My geometry is about perfect now for me. We dialled out some of the grip for high-speed track corning and made the car a little more fast-road orientated. Steering and front end grip is much more inspiring. Seems smoother over the bumpy b-roads too now for some reason.

Final measurements (winter settings with less camber for more grip on cold wet bumpy public roads)





Apparently I was at max negative camber before and so only 1/3 to 2/3 of the tryres were in contact with the ground. Great for hot track days, sucks for winter public road driving. Chris says a lot of his customers come in for winter and ask to have all their negative cambers reduced. That way they have more of a contact patch of each tyre on the road. It also means on bumpy b-roads you get less camber thrust and the car feels less nervous.
In the few 1000 miles since I had my Bilstein B16's fitted the rear had sagged by 2mm. This explains a couple of differences on my original 'final' shots and my new 'initial' shots. Apparently the stock Bilsteins on all the 997s sag like crazy so the B16's are much better at keeping the same heights over time.

To put into context here are the factory settings:

 

Fantastic write-up Chris! Well-thought out mods done right. It must feel like a totally different car now! No wallow and very sharp.

 

I've done it!! With the help of Chris I have found 997 Turbo driving nirvana for 'all-road' driving...

These were the tests we did yesterday:



Please note the REVISED PORSCHE FACTORY SETTINGS. There was some confusion over numbers Chris initially gave me, but yesterday I checked them for myself and revised my tables. This principally meant all the ride heights I was basing my initial calculations on was wrong!!

The other thing of note is that in 3000 miles since I fitted my Damptronic kit the car has sagged a LOT. This means though that by raising the car back up higher the dampeners/springs have more travel and them and the ride becomes softer and more importantly makes the wheels touch the ground more when on rough terrain GIVING YOU A MASSIVE AMOUNT MORE TRACTION ALONG WITH BEING MUCH MORE PLANTED.

The other major change I made was setting the front sway bars to full soft (note still a little stiffer than the stock bars). The allowed the front end to lean and twist more. Again this helps with traction and stability over public roads.

So the car does roll a bit more through corners but the extra compliance is staggering. The car is so much more confidence inspiring now. As Chris says in the world of geometry tuning "compliance is king"!

I would HIGHLY recommend everyone with the Bilstein Damptronic kit to go back to your tuners after a few thousand miles after the car has done most of its sagging/settling, and check you ride heights, and adjust the Bilstein's to match mine. You will be amazed at the difference! Please note that ride heights should be measured at the Porsche official locations under the car. Using fender measurements is WILDLY inaccurate according to Chris.

Any questions then let me know.

 

Insane write up bud! Thanks for doing this, it's a ton a important information.

 

congrats Alex, great job !

 

Alex,

Great review, congrats..

Where did you buy your Bilsteins? from Cargraphic?

Also, do you know technical differences between Clubsport and Comfort versions? (such as spring rates)

I would like to compare European bilstein versions to the US model.

Thanks
Emre

 

I got them from Center Gravity who are a Bilstein partner.

With regards to the versions, Cargraphic use to say that the Damptronic kit come in normal or clubsport variants...

• GA5-D598 Sportsuspension B16 damptronic, FA+RA 15-35mm CLUBSPORT/
• GA5-D581 Sportsuspension B16 damptronic, FA 25-35mm, RA 15-35mm /

I fitted the Clubsport version.


HOWEVER now when you go to the Bilstein site it says the D581's are for Carrera 4 and the Turbo you only have a choice of the D598 or the non-PASM PSS10 kit (GM5-D601).


So I guess everyone here with Damptronic kits are either running the Carrera 4 soft versions or the correct Turbo version.


Bilstein recommend a drop of 15-35mm over stock. More drop, the harsher the ride will be over uneven surfaces. I am now on -15mm and this has made a huge difference to stability and grip.


Also, everyone should bear in mind that all Bilstein's - stock or upgrades - sag over the first few 1000 miles. So you should go and get your ride height checked after the sagging has settled and raise the car back up to my current settings (or less if you want a more track set-up)

 

This is awesome next step is the Nurburgring