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    997.2 Turbo Suspension: Mr. W. Rohrl “digs” our Bilstein mods?

    Going through the recent review in my favorite US car mag, Excellence Magazine, I couldn't help but notice that comments from Porsche engineers, and the changes to the 997.2 Turbo’s suspension, very much parallel the ideal of the suspension mods that a number of us have done to the first generation Turbo. 

    In summary, the changes are as followed:

    1. Stiffer rear spring
    2. Stiffer anti sway bar: Front bar only for cars without PTV, front AND rear for cars with PTV. (I think I have an explanation for this. Ask if you want to know.)
    3. Stiffer rear bushing to "control lateral movement." Although I don't know which bushing they are talking about here, reading this one almost brings tears to my eyes. Smiley I mean, this is deep into after-market US-style modding! This has got to involve the rear toe control arm here, I think.
    4. PTV: Reduces understeer (increases oversteer). I assume this would improve the rear end's "rotation" into corners.
    5. PTM: More gradual change and more rear bias; in essence the car behaves more like a RWD car in corners. Yes the word “drift” was mentioned! (I have some misgiving about this particular change, reducing front traction in a daily driver with 500 hp. Faster at the track yes, but is it safer?) 

    Since my wife is preparing Thanksgiving meal soon, this post can’t be too detailed. Smiley I’ll have more quotes to add, but for now, I am glad that PAG appears to be receptive to scathing reports on how soft 997.1 stock suspension was and how the stock alignment has too much understeer.

    Judging from the numbers, the 997.2 Turbo appears to be right in between stock 997.1 and Bilstein as far as spring stiffness is concerned. Surprisingly, the rear spring is now progressive (Not sure I like this; but there are numerous other changes and I am not about to question Porsche engineers’ decision!). The car’s mission as primarily a daily driver with occasional track time is maintained.
    If I have to take a guess based on reading alone, this would be my prediction: With respect to handling, the 997.2 Turbo has more oversteer (from PTV and PTM) and will feel a touch stiffer/tighter than stock 997.1 Turbo. It is however not quite at Bilstein Damptronic level and this mod might be as alive for second generation as for first.

    Happy Thanksgiving to US readers, and anyone having turkey tonight ;-).

    >>>>>>>>>>>>>>>>>>> 

    Source: "Web research" LOL plus Excellence Magazine. For comparison, GT3 rates are posted, but do note that GT3 is around 300 lbs lighter than Turbo. Anyone with more info please correct as needed. 

    Stock 997.1 Turbo:
    Front: 206
    Rear: 457 Linear 

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

    Bilstein Damptronic for 997 Turbo
    Front: 285 Linear
    Rear: 570 Linear
    Helper springs 115 front, 145 rear (don't count towards rate).

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

    Stock 997 GT3:
    Front: 257
    Rear: 600

    --

    Regards,
    Can
    997 Turbo + Bilstein Damptronic ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )


    Re: 997.2 Turbo Suspension: Mr. W. Rohrl “digs” our Bilstein mods?

    interesting,thanks!


    --
    Dedi La vita è troppo corta per non guidare italiano.....

    Re: 997.2 Turbo Suspension: Mr. W. Rohrl “digs” our Bilstein mods?

    Nice sleuthing Can!


    --

    track vid

    0-300kph

    chasing a 997GT2

     

     


    Re: 997.2 Turbo Suspension: Mr. W. Rohrl “digs” our Bilstein mods?

    Andrea and eclou, thanks. Eclou, long time no see!

    I should give "a little" credit to eclou: "Modder extraordinare" who was first with documenting the Bilstein and alignment change that many Turbo owners have subsequently used.

    Up next: PASM change in the gen. 2 Turbo.
     

     


    --

    Regards,
    Can
    997 Turbo + Bilstein Damptronic ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )


    Re: 997.2 Turbo Suspension: Mr. W. Rohrl “digs” our Bilstein mods?

    Source: "Web research" and www.wikipedia.com.

    First an amateur-level review of how PASM works, for those who don't lalready know. Any correction is appreciated.

    A coilover consists of
    a. spring and
    b. shock absorber.
    Conventional wisdom is that for a particular car with a particular goal on a particular road or track, there is one ideal spring rate. So first one chooses the spring, then one fine tunes by adjusting the damping force.

    Both the spring and the shock absorber affect how "stiff" (I am trying to keep things simple here) the car is. Conventionally & ideally, to make car stiffer, one uses spring with higher spring rate.
    However, another way is to use shock absorber that have variable damping force; the damping force is changed by activating an internal valve inside the shock absorber. For example with Bilstein, the valve opens in the Soft setting, allow fluid to escape faster to a second chamber, and therefore the shock absorber resists less, therefore less damping force.

    I would say all modern cars that have a cockpit switch to change the suspension character on the fly, from Lexus to Ferrari, use this technique: change the damping force to affect stiffness. Although changing damping force alone is not as "good" as changing the spring and adjust damping force, it is obviously 1000% more doable and could be done on the fly, with a flip of a switch.

    Incidentally, there is another way to change damping force, and that's by using magneto-rheological fluid in the shock absorber. This is the system used by, among others, Chevrolet in the Corvette, Ferrari in the 599 and apparently in the 458 Italia, and Audi in the R8. (I predict next generation 911 would be using this; particular now that Porsche and Audi  is one happy family again. Is it?)
    Also incidentally, magneto-rheological fluid is also the technology in the Dynamic Engine Mount option of 997.2 Turbo.

    Up next: the "problem" with Porsche PASM generation 1.

     


    --

    Regards,
    Can
    997 Turbo + Bilstein Damptronic ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )


    Re: 997.2 Turbo Suspension: Mr. W. Rohrl “digs” our Bilstein mods?

    Does anyone know if the engine weight between the 997.1 and 997.2 are the same?  I think this would also influence the rear end characteristics in relationship to the increased rates.


    Re: 997.2 Turbo Suspension: Mr. W. Rohrl “digs” our Bilstein mods?

    bbywu:

    Does anyone know if the engine weight between the 997.1 and 997.2 are the same?  I think this would also influence the rear end characteristics in relationship to the increased rates.

     I think the 9A1 block is around 40 lbs (20kg) lighter than the GT1 block.


    --

    73 Carrera RS 2.7 Carbon Fiber replica (1,890 lbs).  Former: 73 911S, Two 951S's, 996 C2, 993 C2, 98 Ferrari 550 Maranello


    Re: 997.2 Turbo Suspension: Mr. W. Rohrl “digs” our Bilstein mods?

    bbywu:

    Does anyone know if the engine weight between the 997.1 and 997.2 are the same?  I think this would also influence the rear end characteristics in relationship to the increased rates.

    Good point; I see what you are thinking. If indeed total weight of rear is lighter, than the increase in spring rate is even more evidence of PAG's admission that gen. 1 spring rate is too soft.


    --

    Regards,
    Can
    997 Turbo + Bilstein Damptronic ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )


    Re: 997.2 Turbo Suspension: Mr. W. Rohrl “digs” our Bilstein mods?

    The "problem" with Gen. 1 PASM

    When PASM was first released, it was considered the way of the future by many. A one-size-fits-all solution: Soft on street, firm on track, system changed on the fly. The perfect suspension.
    However, complaints started to come in, specifically about the objective response and subjective feel of the firm setting. One typical such complaint is in the first post of this thread, from a chronic "whiner" Smiley:

    >>>>>>>>>>>>
    http://www.rennteam.com/forum/thread/449462/Bilstein_B16_Damptronic_A_Must_For_The_Turbo/page1.html .
    My impression of the stock damper is that Normal is too soft, and Firm has poor bump management, causing the rear wheel to lose contact with the road when there are bumps at high speed. Mid corner high speed bumps literally cause the rear to walk/shift sideway.
    >>>>>>>>>>>>

    In addition, the Firm setting subjectively gives the car a VERY harsh and jittery ride and character. Turning on Sport Mode, and turning off the PASM Firm setting became a ritual for a lot of owners. While the Firm setting might have given better track numbers than the Normal setting; it is far from perfect and clearly could be improved upon.

    Up next: Why does the Firm setting act that way, bad?


    --

    Regards,
    Can
    997 Turbo + Bilstein Damptronic ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )


    Re: 997.2 Turbo Suspension: Mr. W. Rohrl “digs” our Bilstein mods?

    I had one of the first 997 and I skipped the PASM. Call me a visionary Smiley


    --
    There is no try. Just do.

    Re: 997.2 Turbo Suspension: Mr. W. Rohrl “digs” our Bilstein mods?

     you are my favorite source of suspension info, keep the great info coming and thank you so much 


    Re: 997.2 Turbo Suspension: Mr. W. Rohrl “digs” our Bilstein mods?

    Pentium, to this day, there are still some "crazy people" who think, for example, that the simple suspension of 996 GT3 "feels" better than 997 GT3 PASM. This is simply a subjective observation of course, and has nothing to do with objective track times, but it is extremely interesting nevertheless.

    In as much as PASM is simply an extension of how a shock absorber work, that is, even non-PASM shock absorber works by having holes that allow the fluid to escape under force, then above observation is basically criticism of tuning dampening force without changing spring rate, IMHO.

    cayenned_ksa, thanks. Fascinating stuff, isn't it? Take everything I write with a grain of salt though. I am only an amateur.


    --

    Regards,
    Can
    997 Turbo + Bilstein Damptronic ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )


    Re: 997.2 Turbo Suspension: Mr. W. Rohrl “digs” our Bilstein mods?

    Cannga you're the man. I just hate to do free beta testing for ANY manufacturer/company.

    At that time the 3.8l engine and PASM were brand new technologies for Porsche. I skipped both and never regretted. Also Porsche it's well known for their small incremental steps and always the 2nd time they make bigger improvements. I can't wait to see the 2nd generation PDK gearbox and the 2nd generation DFI engines.

     

    And one more thing: I drove the hell out of that car (997 Carrera) for 4 and a half years on Romania's roads (2004-2008), all day, all season. Almost 90.000km in total. Of unbelievable beautiful but also extreme bad roads, full of potholes. An experience which I probably never repeat Smiley because I am getting older and these days I have the tendency to minimize stress in my life Smiley

    That car was built as a tank as far as I am concerned. So, the "everyday" 911 will ever stay in my heart as #1 even compared with my Scuderia.


    --
    There is no try. Just do.

    Re: 997.2 Turbo Suspension: Mr. W. Rohrl “digs” our Bilstein mods?

    I'd like to see a show of hands of the number of people who selected Bilstein Damptronics (or any variation of Damptronics ie TechArt, TPC, etc.) simply because they are compatible with PASM.  How many of us would have selected a different suspension setup if it weren't for the issue that 1) our cars are built with a PASM controller which needs to be turned off by Durametric or PIWIS and 2) we'd have a stupid dead suspension button that doesn't do anything on the console.

     

    If none of the 997TTs had PASM, I think we'd see better variability in suspension setups than what is currently available.  I wanted to go with Moton Clubsports with external reserves.  But that requires shutting off PASM, and having a component of the car disabled/hacked so that an alternative suspension could the used.  What do you all say?


    Re: 997.2 Turbo Suspension: Mr. W. Rohrl “digs” our Bilstein mods?

    I actually agonised over this for a some time and the moton clubsport seem like a pretty good option. I was thinking of using softer springs to have a setting that works well in the city while turn into a trully setup with a few clicks. Problem is i was nor conviced after talking to a few testers that this would work as the recommended springs for those motons are quite a bit firmer than the damptronics. Not to mention that setting them up with a "bespoke" spring would be a nightmare.. So is stayed with them since I already has a massive improvement by changing all the other suspension components that cause all these geometry changes and slack under load that unsettle the turbo under cornering. I am pretty sure though that more a more track oriented use the motons would night and day compared to the relatively simple Damptronic design..

    Re: 997.2 Turbo Suspension: Mr. W. Rohrl “digs” our Bilstein mods?

    ^^^^I fully expect these intelligent "challenges" to the factory setup from fellow Porsche nuts!

    Having said that, in PAG's defense, I also know we on the forum are at the fringe of normality , and that PAG cannot please everyone. The Turbo being an all-around car, they have to pick a certain setting and system that sells cars. PAG did do a hell of a job, considering the 997.1 Turbo, with all the necessary requirements of a daily driver, at 7:52 at the 'Ring is still the fastest manual 2+2 in the world until now.
    I am just glad that the car is made to be adjusted, be it alignment or coilover setup, to each individual's use. This is a fact that I did not realize when I first got into the Porsche "club." (Anyone new to this: IF there is something you don't like about your car's handling, be it Cayman or Boxter, 997 C2 or C4: Don't settle for stock; talk to a good Porsche shop about ADJUSTING the suspension. A Porsche is meant to be adjusted and modded. Smiley)

    As for PASM, I didn't think I would ever like it... until I got the Bilstein. Done correctly, PASM is good and functions as intended on this daily driver: Normal in daily drives, and Firm when the occasion arrives, with a "creamy" ride and no jittery sensation even in Firm mode.
    But yes, sometimes I do wonder if PAG had decided to bypass on PASM for 997,  what a one spring, one dampening rate system would feel like. As mentioned, some "crazy people" are still critical of PASM and its electronics (artificial?) "interference."

    Up next: My "theory" on why stock Gen. 1 PASM Firm feels so bad and what makes Bilstein Damptronic PASM a hugely more successful solution.

     


    --

    Regards,
    Can
    997 Turbo + Bilstein Damptronic ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )


    Re: 997.2 Turbo Suspension: Mr. W. Rohrl “digs” our Bilstein mods?

    bbywu:

    I'd like to see a show of hands of the number of people who selected Bilstein Damptronics (or any variation of Damptronics ie TechArt, TPC, etc.) simply because they are compatible with PASM.  How many of us would have selected a different suspension setup if it weren't for the issue that 1) our cars are built with a PASM controller which needs to be turned off by Durametric or PIWIS and 2) we'd have a stupid dead suspension button that doesn't do anything on the console.

     

    If none of the 997TTs had PASM, I think we'd see better variability in suspension setups than what is currently available.  I wanted to go with Moton Clubsports with external reserves.  But that requires shutting off PASM, and having a component of the car disabled/hacked so that an alternative suspension could the used.  What do you all say?

     

    It seems a rather odd question.  On one hand you say our choice is limited BY PASM and you don't want to turn it off (dead suspension button) but on the other hand you say you want something else if only we didn't have PASM. 

    The answer is:  Simply turn off PASM as if you never had it in the first place and install what you feel is best for you.

     


    Re: 997.2 Turbo Suspension: Mr. W. Rohrl “digs” our Bilstein mods?

    ruf_turbo: 

    It seems a rather odd question.  On one hand you say our choice is limited BY PASM and you don't want to turn it off (dead suspension button) but on the other hand you say you want something else if only we didn't have PASM. 

    I don't understand your point.


    Re: 997.2 Turbo Suspension: Mr. W. Rohrl “digs” our Bilstein mods?

    To understand the problem with gen. 1 PASM, some assumptions and guess work will be necessary, as the technical numbers are not all available (and if they are, I may not be able to understand them anyway Smiley). Nevertheless, I think I'll come close to the truth. As usual my warning to please take this amateur-level discussion with a grain of salt  and anyone feels free to correct me as needed. 

    Remember that the coilover has 2 parts, the spring (absorbs the bump) and the shock absorber (dampens the oscillatiion). While they serve different purposes, together, these two components (and the sway bar, but that's not a variable in this discussion) determine the stiffness of the suspension. We now have 4 different settings to compare:
    Stock Turbo:
    1. Stock PASM Normal = Soft Spring + Dampening Force A
    2. Stock PASM Firm = Soft Spring + Dampening Force B
     Bilstein:
    3. Bilstein PASM Normal = Stiff Spring + Damping Force C
    4. Bilstein PASM  Firm = Stiff Spring + Damping Force D 

    *****We know the stock springs are soft, relatively, because the rates have been published. We think that they are TOO soft because drivers have noted the excessive diving, squatting, and roll of the stock car. So... this is the first "problem" with gen 1 PASM: the stock springs, relatively speaking of course, are too soft for this car. 

    *****While we don't know the exact values of the dampening forces, and for the sake of simplicity won't go into rebound vs.compression dampening, we could deduce the followings. Whatever A is, B is much, MUCH, bigger than A. This is true because when drivers go from A to B, the change in suspension feel is huge. The Turbo becomes an impossibly stiff and jittery car. So stiff and jittery that most "normal" people never drive the car in Firm mode unless the road is glass smooth. The kind of road that doesn't exist, for example, in a major market for the Turbo, the US.
    As a result the car in Firm mode likes to go airborne when it hits a bump, and when this happens in a curve, the rear of the car would literally walks sideway Smiley while airbonre due to centripetal force unoppsed by tire friction (personal observation LOL).
    By using spring that is too soft, and by trying TOO HARD to create a difference between Firm and Normal, the engineers have to jack up B to such a high number that very little compliance is left in the suspension system. 

    So... what do the suspension systems of  the new Turbo and Bilstein Damptronic have in common (hence the title of this thread)? 2 things: stiffer springs (and/or anti sway bar), and appropriately reduced dampening forces. 

    *****By using stiffer springs, Bilstein is able to keep D at a stiffer but still reasonable value and still well matched to the spring. In other words, C and D are much closer together than A and B, and therefore, neither C and D is too far from the one "ideal" dampening force for the spring -- it's a better match. We know this to be true, without knowing the actual values, because that's what the derriere dyno tells us . With respect to ride and handling, C and D feel much closer to each other than A and B. In fact, when I first installed the Bilstein, I initially had trouble telling the 2 modes apart and thought there was some problem.
    What most likely happens is that the stiffer spring allows conservative and appropriate dampening force for the Firm setting. The result is a stiffer, more sporty car, but with vastly superior ride and compliance in the Firm mode.


    --
     

    Regards,
    Can
    997 Turbo + Bilstein Damptronic ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )


     
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