Pics & Review of My Bilstein PSS10 Lowered Red Turbo by cannga

9 minute(s) of a 307 minute read

I updated my un-official spring rate table to include TPC Tractive as well as two track oriented cars from forum members Webspoke and pwdrhound (pls PM me if you don't want me to list it). Again this is just for fun and to give you some idea.

Pay attention to the 200-300 front to rear spring rate difference in nearly all 911's. An AWD car tends to understeer so softer spring rate in front (and softer front sway bar setting, wider front tire, etc.) helps to reduce this understeer. This is particularly important for advanced drivers at the track because it improves cornering traction. If you are beginner-level like me :-), a little understeer is not a bad thing and in general is considered safer in amateurs' hands.

3. Spring Rates Summary: Spring rates are the heart and soul of the suspension system, they tell you the intention of the car/vendor: Is this going to be a street car or is this gonna be a track star :-)? Note that the damper also contributes significantly to how the car feel: a Bilstein PASM with 400/600 springs will feel completely different from a JRZ with 400/600 springs with adjustable bump/rebound settings. This is because the damping forces in the 2 coilovers are different, JRZ has damping forces designed for heavier springs and for more vigorous requirements of track use. Also other factors such as constructions are different; one example: Bilstein re-uses the stock's top mount/bearing which has rubber parts to soften the blow, JRZ to best of my knowledge does not - anyone pls correct me as needed. So although the spring rates give you some important idea, the bottom line is you won't know until you actually drive the car.
Source for spring rates below: Very extensive web research (ie no guarantee whatsoever of accuracy :-) ) and Excellence Magazine. GT3 rates are posted for comparison, and do keep in mind the GT3 is around 300 lbs lighter than Turbo, meaning if anything the Turbo's springs could/should be even stiffer than GT3's. Also, 997.2 Turbo's engine is lighter, making the increased spring rate noteworthy. Anyone with more info please correct as needed.
Spring Rate Unit conversion 100 lbf/in = 17.5 N/mm

Stock 997.1 Turbo:
Front: 206 lbf/in
Rear: 457 Linear

Stock 997.2 Turbo
Front: 206
Rear: 514 Progressive (342 initial, 514 final)

Bilstein Damptronic For 997 Turbo
Front: 340 Linear
Rear: 565 Linear
Helper springs (no contribution towards rate) 115 front, 145 rear

Bilstein Damptronic in my baby, 997.1 Turbo (stiffer springs than Bilstein OEM)
Front: 448
Rear: 600

Ohlins Road & Track For 997 Turbo
Front: 400
Rear: 685

TPC Tractive DDA for 997 Turbo
1. Road & Track version with 343/628 (60/110 n/mm) springs
2. Intermediate version with 457/742 (80/130 n/mm) springs
3. Extreme track version with 571/857 (100/150 n/mm) springs

KW V3 For 997 Turbo
Front: Progressive, unknown final rate, possibly around 300
Rear: 970
For 997 GT3: 285 front/ 970 rear
For 997 C2S: 230 front /740 rear

Moton/JRZ For 997 Turbo (starting min. rates, stiffer if needed)
Front: 500-600
Rear: 700-800

Stock 996 GT3:
Front: 225 Linear
Rear: 550 Progressive

Stock 997 GT3:
Front: 257
Rear: 600

Moton for 997 Turbo from poster Webspoke
Front 750
Rear 1000

JRZ Pro for 996 Turbo from poster pwdrhound
Front 1400
Rear 1500

Here are some technical data of Bilstein Damptronic coilover for anyone interested:
Front: Helper 80 lb/in spring rate, 60mm length; main 340 lb/in rate, 151.5 mm length; ID 70mm for both helper and main springs.
Rear: Helper 80 lb/in rate, 60mm length; main 565 lb/in rate, 200 mm length; ID 70mm for both helper & main.

6-21-2016

Bump for 8th "anniversary" of my Bilstein installation. Time sure flies.

The car has had a few problems with leakage over the last few years (both Turbo's, engine coolant, wing, clutch - you name it, my car has leaked it), but the suspension has stayed reliable, knock on wood. Of course the car corners like a bat out of hell :-), precise, tight, firm, with virtually no body lean, and I love taking it through mountain roads.

Still a daily driver and still a long term keeper, especially with both kids now in college.

7-24-2016

Came across something interesting relating to what I wrote above, 8 years (!!) ago. This morning I was looking at a 991 Turbo S review and lo and behold guess what they are writing:

http://www.caranddriver.com/comparis...turbo-s-page-4
The Turbo S will surely be accused of being soulless and inert. We might have leveled that accusation once or twice ourselves.

I should point out that Porsche is more than capable of making cars that stir the soul (GT2/GT3/GT4); it's just Turbowas unfortunately always meant to be a grand-touring type of car. That's why the exhaust whines like an electric hair dryer and the suspension is so "comfortable" (nothing wrong with this - that's what it's meant to be). And why exhaustand suspension are among the most common mods for our beloved Turbo.

7-30-2016

Tire Weights

In motorsports, if there ever could be a reasonable generalization, it would probably be about weight; "weight is the enemy of goodness." The idea of lightness is king is particularly important where the weight is unsprung and rotational force is involved. In other words, better to gain weight at the frame (sprung) than at the wheel (unsprung), and better at the wheel (unsprung, inside) than at the tire (unsprung, outside). Angular momentum is proportional to radius - tire is the worst place for you to gain weight as it is furthest from the center of the wheel.

Note that while we know that unsprung weight is bad, whether anyone could feel say a 10% difference in weight - I leave it up to you to decide. The number in bold are the weights of one front plus one rear tire.

Michelin Cup (R comp): front/rear 20/27 = 47 lbs
Pirelli Corsa (R comp): 21/26 = 47
Continental Extreme Contact DW: 21/28 = 49
Hoosier R6 (Race tire, not for street, 315/30-19 rear): 22/27 = 49
Michelin PS2: 22/28 = 50****
Continental SportContact 3: 22/28 = 50
Pirelli Rosso: 22/29 = 51
Bridgestone RE71R: 24/30=54****
Michelin Pilot Super Sport: 25/30 = 55
Bridgestone RE050A: 24/31 = 55
Hankook Ventus V12: 24/32=56
Toyo Roxes R888 (R Comp): 25/31 = 56
Bridgestone RE11: 26/32 = 58
(If you think there is not much of a difference. A Turbo with iron brake and RE11 will have close to 60 lbs. more in unsprung weight than one with PCCB and Michelin Cup!)

https://www.6speedonline.com/forums/...ml#post3815659

8-8-2016

It's here:
https://www.gmgracing.com/store/gmg-...ay-bar-ki.html

If above is not available, other popular choices from reputable companies are H&R and Eibach. Tarett also makes one. Hope this helps.

nacelle, thanks for the nice comment.

8-31-2016

I have no experience with TPC DSC so can't comment but there have been many excellent reports from users on the TPC DSC. There are 3 options that I could see, depends on how hard core you want to take this car, how advanced of a driver you are, and if $ is an issue:

1. If this remains a city car and lowering is not a good idea, then TPC DSC. Keep in mind that you are still stuck with the ho-hum shock absorber and springs of the stock car - the TPC DSC merely modifies the brain the controls them.

2. If this is eventually going to be a car that is involved in "serious" track speed type driving or canyon carving, and $ is an issue, then I would vote for coilover only. Why? For advanced level suspension tuning, sooner or later you will have to replace the stock shock absorber and very soft springs, meaning, you *will* need a new coilover. If you change to coilover, the need for TPC DSC becomes less critical, and you do not need TPC DSC at all if you are going to use non PASM shock absorbers such as Ohlins, KW, JRZ, etx. (Not common but there have been people who felt the need to move on to coilover after TPC DSC.) You save $ 1k+.

3. If $ is no issue, then both Bilstein coilover and TPC DSC! (As mentioned, don't get TPC DSC if you are planning on non-Bilstein, non PASM coilover.) All IMHO and hope this helps.

9-9-2016

Hi, the following setting, the so called GT3 street alignment, has been used by many. Essentially the key is to max out front camber at -1.2, and set rear camber at -1.6. Next if you are bothered by the lazy steering response of the Turbo and want to improve turn-in response, set slight toe-out in front.

Has had it in my car for many years: very stable, not jittery, and tire wear is minimal.

3-22-2017

From this post: https://www.6speedonline.com/forums/...ml#post3333907

There are two places you could get springs that fit Bilstein: Hypercoil and Swift Springs. The springs you want to look for is 70mm ID, 6 inches long front, 8 inches long rear. The process is very easy and cheap - labor should be around 300-400 per axle.
Swift Springs: http://www.swiftsprings.net/products...r-springs.html
Hyperco: http://www.hypercoils.com/PDF/70mm.pdf
Currently my car is set at 448 front/600 rear - versus Bilstein's 336/560.
The front spring is Swift Spring part # Z70-152-080: Internal Diameter 70mm, free length 152mm=6 inches, spring rate 8 kgf/mm=448 lbs/inch.
The rear spring is Hypercoil part # 8P0600: Internal Diameter 70mm, free length 8 inches, spring rate 600 lbs/inch.

3-23-2017

The mechanics and function of Techart Bilstein is obviously way beyond my knowledge/experience, so really the only thing I have to add is that for spring rates, I probably would vote to err on the conservative side at this point, such as 336 front/560 rear, same as the stock Bilstein rates. 650 rear may be too stiff still.

Stiffer suspensions are extremely fun on smooth curvy roads and the track, but once you have bumps and potholes, all bets are off.

Good luck and hope things will work out well for you. Update this thread once all is said and done.