the front spring KWs are:
Its a 40Nm Spring with a 10Nm Helper

 

Thanks, very interesting. This gives the spring rates of 228 front/750 rear, which is strangely unusual. As mentioned above, Porsche OEM suspensions and Porsche tuners tend to use spring rates in the range of 300 front/500 rear for street cars, or 400/600 & 600/800 for more race oriented cars. Basically, typical 911 rear spring rates tend to be 200-300 more than front; in case of this KW setup it is 500 more.

This soft front/very hard rear bias of KW is consistent with why you had to dial the front damping up so much; you are compensating for that soft spring rate with the damper (which only works for a narrow range). IIRC, a Turbo owner here with KW reported his car dove front down with braking, which is also consistent with a soft front spring (the rear spring rate of KW for Turbo is even odder, around 1200).

KW is an excellent company but there is something odd about their Porsch spring setup; it doesn't seem right. Unless I am missing something (damper rates help to equalize the higher spring rate but 3x is too much to overcome); this seems like an unbalanced setting for 911. Instead of increasing front damping, I would think using stronger front spring as being a better solution. The spring rate is the most important parameter of the suspension; damper is for fine tuning only, not to grossly influence stiffness.
If you can't get the KW to work out, one option is going back to the 20mm OEM sport chassis and use softer tire like Michelin PSS, with lower tire pressure say 1 psi less than recommended (minus 1 on TPMS), and see that would work.

 

Hi Can,
you are on the money Id say. Ive been tossing around the idea of going back to OEM, hence keeping the MSS as spare ATM. Hard to calculate if the softer sidewall stiffness of the MPSS and reduced pressures will give me what im looking for, Ill have one last shot with KW and see where it goes then if not good, back to OEM.
All Aboard?
:-)
ps Id be very interested in 997TTMeister findings too.

 

wow what a great night tonight.
I have added 1.30 camber at front and 6deg toe out, car feels VERY ALIVE,
also bobbing has reduced with full hard setting on rear bump.
things are getting almost to my dream car.
wow toe really makes the steering alert 6deg out might be a lot i wonder if 2deg is enough to engage the tyre or if 6deg makes engagement even quicker?
this is felt from 60-70kph upwards and very engaging at 100kph plus.
i want this feeling at 40kph! more toe? 12deg? :-)

 

^^^Glad things are working out better for you. Regarding slight front toe-out: Yes especially with our 4WD Turbo, a slight toe-out in front makes for wonderful improvement in steering/turn-in response.

I have never had more than -.03 of front toe-out so I don't know what happens beyond. Do keep in mind you are trading in straightline stability for improvement in steering/turn-in response - there is no free ride. Car becomes more twitchy and tire wear suffer with too much toe out setting.

Not for "scanners" of course, but anyone wondering about this just take a look at the alignment chart on first page of my Bilstein thread. This slight front toe-out setting is my tuner Tom of Lucent's family trade secret :-) and I really hope he doesn't mind my posting it; I am making him more "famous" in So Cal anyway so I don't feel too bad about it . Kidding aside, remember alignment change is a big part of suspension tuning; it's a big part of why I enjoy driving my baby Turbo so much!

 

Yes tyre wear is not an issue as the front are always still healthy when the rears are gone. :-)
yes, there was a little more skip/dance on undulation holes in the tarmac in straight line but nothing concerning. Yes its a trade off i agree. Your 3deg might be where ill go if all that is required is just "loading" the tyre rather than the amount.
What speeds do you really start to notice your 3deg change happen?

I spoke to the KW guy, yes he agrees the spring rates for KW - Porsche are unusual, the reason is their dampers are far more complex with the valving and do alot of work. I agree they are outstanding in terms of comfort v performance. You can wind them up till nothing moves and theres still no jarring on potholes in the road. Impressive. I do although suspect a millisecond delay in response with them, but this also adds up with the latest fast car laps at Nurnberg having slightly more "sponge and give" to create smoother and larger tyre patch contact and grip.
I can throw full accel launch on corners with potholes and the rear just feels beautifully dampened and rubbery soaking up any jarring to the chassis. Also the rear side walking that Porsches do under hi speed long bends with undulations is reduced dramatically with the firmer rear spring.

I am about to take a turbo Gen2 manual today for a few days. The one i took a week ago had pdf which had no instant connection at all. way to much delay. unbearable disconnection from the road.
I notice you would prefer your gen1 to a gen2? can u explain why Can? Love to hear your thoughts.
lots of questions there for you today mate!
thanks
Scanners.

 

997.2 overall is the newer, better, and faster car. 997.2 versus 997.1:

Engine: Controversial and I am actually 50/50 as to which engine is "better." 997.1 has famous and proven GT1 race bred engine, the so-called Mezger engine. 997.2 has newer engine without true dry sump. I was suspicious at first but considering the stupendous times that 997.2 TTS has put up, and that this new engine is going to be in new GT3, I would be happy with either.
For those with extreme high power mod and use old automatic transmission, I believe 997.1 is better. For rest, I think 997.2 is better.

PCM: 997.2 is better period.

Exhaust: 997.2 sounds better: warmer and a little louder. But still very wimpy and still need after-market exhaust.

Automatic Gear Box: 997.2 with PDK is vastly superior to 997.1 Tiptronic. For high power suspension mod however, Tiptronic is proven and is quite robust. OTOH as mentioned, with the stupendous times put up by PDK 997.2 Turbo S, do most people really need to modify ECU in this car?

Suspension: 997.2 is better. PASM gen 1 in 997.1 has a design flaw: Normal is way too soft, and Sport is way too hard. PASM gen 2 in 997.2 is revised and take less extreme approach; the 2 settings are closer together and the Sport setting is more compliant. The reviews of 997.1 suspension was not very complementary and Porsche did change a few things between 997.1 and 997.2: stiffer bar, harder spring; **small** changes though.
As you will notice however, the 997.2 suspension is still very soft and suffers from too much front/back and side/side weight transfer. 997.2 would still benefirt greatly from after-market coilover or lowering springs for me.
IMHO the soft, luxurious suspension of 997.2 is still its weakest point.

For me "dream" scenario is the 997.2 with the Mezger engine.

 

997.2 has the PTV (Porsche Torque Vectoring) option.

 

Having taken the 2x 997.2 turbos out over the last week, these are my thoughts.
PDK.version
yes turns it into a monster with launch, bit of a party trick though, not much use in normal daily driving. A non involving car with so much delay from the pedal to the road.

Manual version,
awesome hydraulic clutch, and tuning for an effortless gear shift and total package of suspension, what can i say but superb on every level. Bravo! Only thing i didnt like was when I gave it the "goose" it got loud real quick. I like to be stealth.

Getting back into my 997.1CS2 Sports chassis LSD. I felt more involved, lighter, go cart, feeling every change in the steering/throttle etc. Very surprised at how happy i was with mine apart from how heavy the clutch now felt. I guess my glee was in the 0-30kph range where everything is so instant around town , roundabouts/corners etc. its either the gearing or the normal aspirated instant torque at those speeds in my humble 3.8 with tune and hi octane 98ron fuel.
After all the testing I then drove a Gen2 C2S in manual, clutch was lighter than mine but no where near the lightness of the turbo, It had amazing front end grip in pasm sport
and really felt great all round apart from the tendency to rev down slowly off throttle. This made shifting very easy but no where near as involving in throttle manoeuvres. hmmm.
In conclusion, yes the turbo manual is for me in the future but no manual sounds sad seeing the Gen2Turbo has such an easy setup..
Im all about instant power/thrust at low rpm, like a "harley" so for now im getting that in my CS2, i just want a lot more of it!
Anyway just my thoughts. Now onto more de bobbing work.

 

I should mention all that the KW rep is saying here is that they are compensating for the soft spring rate with higher damping force as I've previously suspected.

While I don't want to simplify an incredibly complex topic, the basic essential is that there are two components/forces at work in determining overall "stiffness," the spring and the damper. You could compensate for softness in spring by increasing either compression or rebound damping, but ideally this is not the way it should be done. The primary parameter ("heart and soul") of the suspension is proper spring rates, then damping forces are used to fine tune. This is the same reason that I think extreme settings (all the way to one end or the other) of damping forces *could* be signs of imbalance in the system.

I don't believe KW's dampers have any more "complex" valving than other shock of same category (Moton, Bilstein Club Sport, JRZ, etc.) with independent bump/rebound adjustment, either high speed or low speed (speed refers to speed of the shock shaft, not of the car). I could be wrong of course, but I don't think so. All shock absorbers work on same basic physical principles and there is no "weird" science or manipulation that I know of.

Whether any of above is related to the bobbing I have no idea. But a last ditch effort if other things you try don't work IMHO would be to try spring rates that are typical in OEM and other after-market suspensions for Porsche: spring rate that is about 200 higher in rear than front, like 300 front/500 rear, 400 front/600 rear, etc.

 

thanks Can, you make perfect sense.

 

Hey Geoff,
how are you fairing with the KWV3 install?

 

Hi again Can, i have found some interesting Wheels that will reduce my current wheel weight by 30pounds total. What effect do you think that will have on the my car? many thnx Scanners

 

Unlike nearly all other suspension mods, where ride and handling are trade-offs: improved handling almost always means worsened ride, reduction in wheel weight is the rare exception, the only time where a mod improves both ride and handling. Reduction in linear momentum is the explanation for better ride (linear motion of the wheel - up and down on the coilover), while reduction in angular momentum (rotational momentum of the wheel spinning) explains the better handling and steering, and braking, and acceleration.

Therefore wheel weight reduction is IMHO an unconditioned positive move - very rare that a mod has only advantages, but wheel weight is the one!
Actually, there *is* one negative aspect. Weight reduction does affect the wheel strength and how it is prone to bending and damage. In fact the best one that I know of, BBS F1, has specific and scary warning about wheel damage and, IIRC, something about not using it on the track (!). (Anyone please correct about BBS F1 as needed; I remember seeing the warning, just don't remember whether it was street or track that is not recommended.)

I am curious, what wheel is this that reduces weight by 7.5 lbs per corner?!
1. BBS F1?
2. Oz?
3. Carbon?
4. Magnesium?
Make sure you weigh the wheel when you get it - actually weigh it. I don't trust manufacturers' claims.

 

BBS RI-D

19x8.5 et53 - 7.4kg
19x11.0 et63 - 8.0kg

Thnx Can. What you think of these?