I've received a couple of emails asking about what I've done to my car so far, so below is a brief summary of my first "phase" of modification. The "phases" are my own opinion/concept and obviously not the only way, but... for anyone new to this, I would suggest a similar approach. Add mods in steps so you could evaluate each change along the way and back out when NVH becomes too much.
The changes of the first phase are conservative, well known, yet enough to totally transform the car; sheep turning into an agile and angry wolf, so to speak. Of note, last weekend I arranged to have a "calibrating" drive to compare my modded Turbo against a stock Turbo. There is now no doubt in my mind about the improvements and the necessity of modding the stock car's suspension.
Phase 2 are perhaps for the more adventurous. Please remember that each step of the way, you are likely trading handling prowess for ride stiffness and noise; nothing comes free. How far you would like to take it is the beauty of owning a Porsche 911: Up to you!
There is a Phase 3 obviously (Motons, Rear Upper Control Arms, cup tires, more aggressive alignment settings, etc.), but I'll skip it for now. No plan to go that far.
Phase 1:
1. Bilstein PSS10 Coilover with a height drop of 10 mm.
2. Street GT3 alignment, meaning a change of front camber from -.4 to -1.2.
3. GMG anti-sway bar, set to middle stiffness (holes) both front and rear.
Phase 2:
4. Tarett Drop Link
5. Rear Toe Control Arm with Bump Steer
6. More aggressive alignment: front toe out, rear toe in.
7. Corner balance, once happy with all the changes.
Below are some reasons why each step is done. Important to know I think. If something is not to your liking, you'll at least know why and what to tell your tuner.
1. The Bilstein Coilover is the main reason for the car's improvement; you are basically buying Bilstein's concept as to what the Turbo should be like. A drop of at least 10mm, at most 25 mm is recommended (read thread for details why). My tuner didn't measure exact ride height so all I could go by is measuring fender height on my own. My car's mid fender height has dropped about 10-15mm.
2. To reduce understeer. Negative camber improves grip of the tire in corner-improving its corner performance. As grip of front tires improves relative to rear, understeer is reduced. -1.2 is a conservative change. Note that here, we are keeping the rest of the alignment parameters (toe, camber, caster) the same as stock. Only front camber is being changed.
3. To reduce body lean; happens to make steering less flabby. The GMG Anti-Sway Bar has 3 stiffness adjustment levels (3 holes) and is supposedly 30 to 70% stiffer than stock. I use the middle holes front and rear and assume that this means 50% stiffer than stock (?). I've tried a different setting --soft front, stiff rear-- to reduce understeer, but did NOT like that at all. So I am back to middle front, middle rear.
4. To reduce sloppiness in effect of sway bar; necessary for corner balancing. Again, nothing exotic we are doing here; this type of link (length adjustable, with metallic instead of rubber joint) is used in Cup cars and (IIRC) GT3RS. In addition, if you want to corner balance the car, a length adjustable link is needed so that you don't preload the sway bars. I'll post my impression of this change when I come back from vacation.
5. Rear toe link, as mentioned, more than one tuner has mentioned to me that this is the most cost effective and beneficial mod to the rear suspension, without risk of adding NVH.
6. To reduce understeer & improve turn-in response. Front toe-out "encourages" the initiation of a turn and therefore improves turn-in response. The disadvantage is the car may wander a bit on straight line cruising. Rear toe-in reduces oversteer.
My tuner is recommending this as the next step, just a touch toe-out front, a touch toe-in rear. He says the car will feel more aggressive and I will love it.
7. Perhaps not needed for amateurs and not sure if I could tell its effect. But having it done would make me feel good.
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