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

21 minute(s) of a 612 minute read

4-11-2015

One more pic to whet your appetite :-). The central portion is perforated, similar to Ferrari's and other high-end steering wheels, for good reasons (more grippy, etc.). For those who bought the Turbo used and with high'ish mileage, keep in mind in well-used Turbo's, the leather of that steering wheel is no longer what it used to be when new. With time original steering wheel's leather has worsened considerably: became "hardened"/stiff (used to be supple) and very slippery. A change to this Techart wheel does a large part in making the car feel new, all over again :-). 

Look guys, just do it. Don't think of it as an $1800 mod, think of it being *ONLY* around $900 more than the alternative LOL, to get you a seriously better steering feel, hand made in Germany by a highly reputable German tuner. Lastly, as mentioned, I am a very picky person (extreme OCD type really :-)) and I don't say anything is great unless I have considered all the pro's and con's. No con here.

OT: Chris are you back, though you sold your fantastic low mileage Turbo?

Hi, congrats on your new car. Not only I have a slightly different suspension (my Bilstein is not the Techart version and doesn't have the front lift feature), I have no idea what the road you described is really like, and what your car feels like, so following are my best guesses.

1. The answer is no, the "travel" of the Bilstein shock should be normal and very similar to stock assuming you have set it up correctly and did not LOWER the Bilstein beyond spec. In general I would not advise any lowering beyond 1 inch or so, from stock height. To best of my knowledge, the risk of too much lowering is that you would hit the internal bump stop - and that would be quite an adventure at speed, in the curve. Go here to see how to measure car height and see how much you have lowered from stock: https://www.6speedonline.com/forums/...ml#post2758673. Please measure your car and let me know what numbers you are getting - once you know where to measure, it takes 5 minutes, literally.

Assuming your car's setup is otherwise correct, the tires are good (what tires are you using?) and not over-inflated (should be about 32/38 psi "cold" in 70 degree F weather), I would add that when road surface is imperfect, all bets are off and speeding would cause problems regardless of what suspension you have. Pardon me if you already know this, but in case you are new to a 911: more so in a rear engine 911 than in any other car - slow in fast out is the order of the day, even for professional drivers. I agree lifting throttle at high speed in mid curve is something that would require an underwear change after.

Whether you should de-tune the car to stock suspension only you could decide. But let me warn you that once you have tasted the stiffer Techart Bilstein, going back to the the soft stock suspension may make the car feel like a ponderous and lazy grand tourer. (The suspension change, for me, is THE single most important mod for 997 Turbo's.)

2. Having listened to quite a number of Porsche Turbo exhausts, IMHO and in my experience all exhausts have a resonance at low RPM, if you are an audiophile with good ears :-). It sounds like engine lugging and you would also hear it with the stock exhaust, around 2200 to 2600 rpm. This low rpm resonance is a problem not just in Porsche, but across several car makers if you google the topic (Toyota Highlander has it LOL - looking to buy this for my son and can't help but have a chuckle reading people losing sleep over it.). My thought on this topic: An engine, any engine, is simply not meant to be driven at 1500-2000 rpm.

Why this resonance is never a problem with several Turbo owners? At least, in a manual car, we drive our car at 3000 rpm to keep the car in the sweet torque range and therefore inherently avoid the problematic 2000 rpm range. Also possibly unconsciously we keep the gear that will maintain 3000 rpm to prevent the resonance. So... the result is that in normal driving, it is not a problem. As for automatic Turbo's, I do not have any idea - have never driven one.

BTW aftermarket exhausts with the least resonance are likely to also be on the quiet side, relatively. It likely would have very little of the extremely satisfying low V8 frequency rumbling. The good thing then for quiet exhausts is lack of resonance, the bad thing is if your personal preference (no right or wrong) is for a louder, more sporty sound, it might be too quiet of an exhaust for you. My Cargraphic for example has resonance at 2400 rpm like the stock exhaust, but it also absolutely, positively sings, loudly, and is perfect for me for the past EIGHT (!) years while passing stringent California smog test. So keep your excellent Capristo and enjoy it! BTW to hear it best, have someone else drive the car with you standing on the sidewalk (exhausts sound better - the full frequency range and loudness - when you are outside the car), or take your car into a tunnel, lower windows and sunroof, and listen to the firework. Hope this helps.

I like it that you are using all top notch components in your car. May I suggest also the Techart wheel. Please TRUST me I didn't expect it at all but the muscular Techart wheel transforms the subjective steering feel. A new steering wheelalso makes the car feels new LOL.

With street tires like Michelin PSS, 32/34 psi cold (meaning you measure before driving the car - before tires heat up) is LOW for the rear tire. I would think 32/38 are more in line with recommendation. In fact I am surprised your TPMS did not show alarm warning at 34 psi rear?

IN GENERAL and with a street suspension, the rear of 997 Turbo tire should be about 6 psi higher than the front. This is primarily because of the rear weight bias of 911 rear engine platform.

2-15-2016

If you haven't done so yet use tire gauge with digital readout. I could sense differences in street driving feel with as little as 1 psi change. Also note that reading from the car's TPMS could be off by as much as 1-2 psi when compared with a reference tire pressure gauge (Tpms tends to read LOWER than actual btw, ie good tire gauge reads 33, tpms reads 31.). I use a good quality Longacre tire pressure gauge.

I understand for others outside the car the sound from a good after-market exhaust could be quite terrifying (literally like a jet). My first traffic ticket was the first day that I had my Cargraphic. The cop was quite upset at me - "didn't you hear my siren!?"

I don't make my recommendation lightly, and the Techart wheel is recommended without reservation. Over time, the stock steering wheel's leather becomes smooth and hardened, making grip difficult and feeling not so nice. Not only the Techart wheel gives you new leather, the increased front-to-back thickness at 3 and 9 o'clock position is terrific. It makes a huge difference.

Be clear as to exactly what you want when you order the wheel - there are multiple options/variations and in my case Techart Germany had to make and send 3 steering wheels before they got it right (First one got a badge, second one they forgot I wanted the perforated leather in the mid section for better grip, etc.). It was a semi fiasco and my dealer ended up with 2 extra wheels LOL.

https://www.6speedonline.com/forums/...per-now-4.html

2-17-2016

Hi, should not present a problem at all as the install is all outside the car's cabin. Great install thread here: https://www.6speedonline.com/forums/...b-g-rides.htm

2-23-2016

Hi, very interesting but sorry no knowledge of this product. I do trust TPC, an excellent and reputable tuner, and what they have to say.

BTW & IMHO if you are that serious about improving the car's soft suspension (yes stock 997.2 Turbo feels pretty soft also, to me anyway) the next thing would be stiffer spring or coilover. Cup tire has very stiff side-wall and using a stiff tire with the very soft stock spring, while a good improvement, could be further improved, by matching it with appropriately stiffer spring. No hard and fast rule but you kinda want the the spring and the tire to be evenly matched in their behavior (not one super stiff, the other soft).

A while back Porsche was racing GT3 at the 'ring and IIRC Walter Rohrl mentioned a similar concept: road condition caused them to have to de-tune to softer tire, and as they did that they switched out to softer spring as well. If my memory serves me right.

Similarly, DSC is only software change of stock damper - there is only so much this could do, and changing the actual hardware (the damper itself + spring) would bring even more improvement. Besides "better" spring rates, just lowering the car's center of gravity is of huge benefit with car dynamics and this could only be done by actual spring or coilover change.

3-4-2016

Regarding Tractive - thanks for the explanation. Very interesting and now the cost of the system makes sense to me. www.tractivesuspension.com

Back to DSC for Bilstein: would you please explain why the number of modes is cut back to 2, from previous 3? Is it a matter of how much memory the module could hold? Memory is cheap, no?

I would think more is better, 3 to me is a good start, or even 4, as it allows user to compare the modes instantly (COMPARISON - very important for us amateur drivers IMHO) and gives more choices. At the least, it doesn't cause any harm to have more choices, does it?

3-6-2016

Some spring rates for comparison (thanks Changster and TPC/Harris) for fun, nothing else :-). Note that multiple factors, ie both the damper and the spring, and multiple other components (sway bar, drop link, etc., etc.) determine suspension behavior. That said, IMHO the spring is THE most "important" component to look at if you want to have an idea what the tuner is thinking and what his intention for the car is. I converted TPC spring rate to lbf/in - please correct me if I made any error.

When competent pro's like TPC do something, I like to learn from them. The first thing to notice is the differential between front and rear springs of Tractive DDA system. No matter what the front spring rates are, the difference between front and rear remains a fixed 50 n/mm or 285 lbf/in. This is consistent with other numbers I've seen, around 200 between front and rear.

3-7-2016

Excellent questions. IMHO (any expert/pro please correct me as needed - I don't mind):

1. Up to a point only. Two key components make up the suspension system: spring and damper. To make the system stiffer, you could stiffen dampening rate, but this only "works" up to a certain point. Eventually and ideally, you will have to go up on spring rate, and THEN tune the damper to fit that spring rate.
What happens if you do jack up the dampening rate instead of changing to stiffer spring? This is the problem with 997.1 stock system: Porsche/Bilstein engineers increases the dampening force so high in the Sport mode that the system has no compliance whatsoever. This is why it's so jittery and so un-useable, and why TPC DSC is a great solution.

2. Spring is the key of any suspension system. The 3 spring rates used by TPC is expected and nothing abnormal- see 1 above. Pro and expert tuners such as TPC would pick a spring rate, then tune the damper to fit it. Comments below are my opinions.
TPC Tractive DDA for Turbo
1. Road & Track version with 343/628 (60/110 n/mm) springs (similar range to Bilstein Damptronic)
2. Intermediate version with 457/742 (80/130 n/mm) springs (now we are talking - this takes the Turbo to GT3 level and this is where I would try if I have the $)
3. Extreme track version with 571/857 (100/150 n/mm) springs (GT3 killerKidding)

The beauty of using coilover such as TPC's Tractive is that the springs could be easily exchanged as your needs and taste change. This is no big deal and the spring costs about 100 each. You could do the same with your Techart Bilstein's springs; change them to softer or stiffer springs as I did. BTW above discussion is why I've told Changster that DSC is great, but eventually if you want to get "serious" you will have to deal with the soft spring of stock Turbo(200/450 range): by changing to either stiffer lowering spring, or to a coilover with stiffer spring.

3-12-2016

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.