Crown

(This thread is a continuation of my first Bilstein thread: http://www.rennteam.com/forum/thread/449462/Bilstein_B16_Damptronic_A_Must_For_The_Turbo/page1.html )

 
Recently my car underwent what most likely is its last major mod ; one that involves to me the "final frontier" of suspension tuning, stiffer springs. Obviously, I don't think mine is the only way, or the best (never think so about any of my car's mod, well except maybe the Cargraphic exhaust LOL) , but it is extremely satisfying and I would like to share the experience. If you have tried a combination that's different from mine, no question I would like to know about it. Hopefully we could all learn something new.
The setup was done by Tom, of Lucent Motors in West Los Angeles. Lucent is a small shop in Southern Cal that is better known among the GT3 and racer crowd. Having a professional advises & test drives your car is probably the most important step in all suspension setup. 

--

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

--

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

GT's posts on this topic, reposted from another thread:

Can this is exactly what i wanted to do with my tt and trust me when I say that it is possible and then some. It involves though a lot more than just changing shocks and sways. I can elaborate on the subject as much as you guys want but it is possible to get within 95% of GT3s cornering at tight corners and same if not more in high speed corners (+ the endless power/torque of course). The main issue is weight and also the suspension components that the tt has that are geared towards comfort and.. electronic interference!

The moment you eliminate those rubber bushings the car changes completely, you dont even need the PSM button on, I literally lapped on a dump/wet silverstone with corsas with PSM off and lever lost the car with 670hp/850nm. The car is a lot more stable, the PSM comes on a lot less, so does the PTM for that matter. You are right regarding the springs but you ll find that if you take off weight (GT2 seats, Dymags, titanium exhaust, lithium batery, pccbs) then you come close to GT2 weight and the damptronic springs feel stiffer as well. I have no roll in my car even on track conditions. And the dymags have eliminated understeer tremendously.. (do you have lsd?)

___________________________________________________

GT, thanks for the valuable input. Very interesting and makes sense that weight reduction make springs feel stiffer.

To borrow the terms from my audio hobby, roughly, very roughly:
1. Micro-dynamics: For example, replace stock with after-market toe control arm, upper control arm, drop link, etc., with stiffer bushing (metal instead of rubber), to reduce geometry/alignment change under load.
2. Macro-dynamics: Spring, damper, anti-sway bar, tire wall stiffness (cup versus street). Components that affect and control traction and weight transfer; namely, body roll, dive, and squat.
While both 1 and 2 changes are beneficial, we've identified the main "problem" with the turbo as EXCESSIVE BODY ROLL and felt the best way to address this is with stiffer spring.

As far as spring rate change, yes, Lucent feels it's critical to increase the FRONT spring rate. The rear rate could be kept the same depends on how your car behaves; if it understeers, increases rear spring rate or stiffen rear sway bar, etc.
I initially wanted to use 450 front, 100 above the 340 based rate, but the tuner thought this was not enough and suggested adding another 100, effectively making a 1:1 front:rear split. 565 lbf-in front, 565 lbf-in rear.  Judging from the result so far, he is absolutely right. But... as mentioned, I would love to see if someone tries some other rate, for example 450, and reports the result.

BTW, although Bilstein would not tell me *officially* how high I could go before revalving becomes absolutely necessary, reading between the lines, it's either 20% or 150-200 lbf-in, whichever is higher. LOL. So at least, theoretically, we are at the limit or very close to it here. But I'll talk more about this later. Remember the wild card here: Ours is a PASM system with 2 very different dampening rates.

--

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

And then, when you're done, go back out to the canyon with your GT3 buddy and do some more back to back to back swaps and hurry back to share your thoughts once again

Slow In, Fast Out

I was also concerned about under-dampening, particularly on the rebound side (I'll discuss why this is so later), but the car is showing no sign of softness or bobbing on undulating roads. Traction remains excellent.

--

Regards,
Can

I noticed that you cared not a whit about the sound pollution you're causing, or even - much more importantly - about the sound quality of the meagre stereo system you have installed in your red chariot.

I think you should make an effort to install a Burmester or Classe or Krell system, and then try to listen to some high quality chamber music while you're floating along some beautiful Santa Clarita mountain road at 95 + mph. If you can't discern the difference between a Mozart sonata and a Beethoven symphony, then I think you should buy a Panamera and dump your little red boxcar. The quality of your life, not to mention its longevity and the affection of donut-loving friends, will dramatically improve!

aGrant:

I was also concerned about under-dampening, particularly on the rebound side (I'll discuss why this is so later), but the car is showing no sign of softness or bobbing on undulating roads. Traction remains excellent.

--

Regards,
Can

I noticed that you cared not a whit about the sound pollution you're causing, or even - much more importantly - about the sound quality of the meagre stereo system you have installed in your red chariot.

I think you should make an effort to install a Burmester or Classe or Krell system, and then try to listen to some high quality chamber music while you're floating along some beautiful Santa Clarita mountain road at 95 + mph. If you can't discern the difference between a Mozart sonata and a Beethoven symphony, then I think you should buy a Panamera and dump your little red boxcar. The quality of your life, not to mention its longevity and the affection of donut-loving friends, will dramatically improve!

 Euh?

Someone had a bad weekend...

FFaust:

And then, when you're done, go back out to the canyon with your GT3 buddy and do some more back to back to back swaps and hurry back to share your thoughts once again

Sure. IMHO "comparative testing" is a must in all evaluative processes, whether it's audio, camera lenses, ECU mods, exhaust systems, or suspension mods. For example, in high-end audio circle, a reviewer could wax eloquent for 10 pages about a pre-amp and it may not mean squat to his readers. However, the moment he writes "compared to this other well known Conrad Johnson pre amp..." is the moment everyone thinks "ahhhh."
Without the GT3 test drive, I would not have had any idea that the gap between Bilstein and GT3 is still that large. GT3 really and truly annihilates my Bilstein Turbo, and to be fair 99% of any other sports cars, in tight twisty roads. I would encourage everyone to drive a GT3 once just to see what the ultimate in Porsche 911 handling feels like. It's a one-dimensional track oriented car but is without peers in this one dimension.

The benefit is that, since I bought my Turbo 2 years ago, for the first time now, and I've never said this before, I am content with all aspects of my Turbo, be it handling, power, sound, or ride comfort compromise.  And I've done enough "comparative testing" of other cars (list includes F430, Ford GT, Porsche GT2 & GT3, Corvette, Lambo Gallardo (most capable competitor!)) to feel my happiness is justifed.

Hi Sci Frog, Arthur (aGrant) is a friend of mine from the LA Porche club. He is frequently here to poke fun at me as his concept of the best 911 is the complete opposite of mine.

--

Regards,
Can
997 Turbo + Bilstein Damptronic "Stage 2" ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )

Before I get into the specifics, please let me emphasize again that what follow are merely my amateur-level observations, or suggestions for topics that you should read up on and discuss with your professional tuner. They are not meant to be technical guidelines. And of course, as always, constructive :-) professional advices are welcome.  

--
 

Regards,
Can
997 Turbo + Bilstein Damptronic "Stage 2" ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )

cannga:

For example 400 front - 600 rear for a street car, 600/800 for a track car, and 1000/1200 for a track car that will loosen your denture fillings and that you tow to the track.

Roughly, depending on the weight of the car of course, but I would say that somewhere around 550 front, 750 rear, tuners and "people" (based on web research LOL) consider the car no longer daily-driver friendly.

 

These statements were made with the assumption that a Bilstein street oriented damper is being used.

If you use for example a track oriented Moton damper, then those rules of thumb above may no longer apply 100%. What happens is that with a track oriented damper, the bump and rebound dampening forces are set for much stiffer springs in mind. I don't know the numbers but very likely at least the rebound dampening force would be much higher than Bilstein's. That being the case, a 400/600 setup might be soft enough for street use with Bilstein, but too stiff with Moton.

The moral of the story is that multiple parameters interact in suspension setup, and my discussion is merely very rough pointer for which direction you should be heading (if you are new to this). The other point is that while Moton is technically a superior coilover, it is very much a debate whether Moton is better than Bilstein for a street oriented car. I frequently am asked if I picked Bilstein because of the cost. The answer is yes and no. It costs less, but if you are setting up a car that is being used as a daily driver, with occasional track time, it is actually the "best" IMHO.

In my car, two settings were tried, 565/750 and 565/565. At 565/750, the rear was loose (oversteer), and the car was quite bumpy on imperfect LA surface streets. Not only 566/750 makes the car not usable for a daily driver, my tuner thinks it not safe for someone with my low-leveled driving skill.
Lastly, I misspoke earlier ,  the final frontier of suspension tuning is spring AND tires, not just spring. A 565/750 rate would require more traction and wall stiffness from the tires, as cornering speed/force with the stiffer spring **WILL** be much higher and would/could overwhelm street tires. In other words, a very high spring rate requires Michelin Pilot Cup, with its stiffer wall and better traction, to replace my Michelin Pilot Sport 2, with its soft side wall and poorer dry traction.
--
 

Regards,
Can
997 Turbo + Bilstein Damptronic "Stage 2" ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )

While we are on the topic of spring and tire: It is often said "better" tire is the single most cost effective suspension mod one could do to a car. While there is much truth to this, the issue is much more complicated than just buying the most "aggressive" race oriented tire. One must pay attention to the importance of matching a tire with an appropriate spring rate.
In other words, although it's been done, one should not take a track oriented tire like Michelin Pilot Sport Cup and put it on a soft suspension like that of a stock Turbo to improve handling. The grippy, but also very stiff, cup tire will "overwhelm" (I'll talk about this later) the soft suspension. Likewise, it's not necessarily a good idea to put street tire onto a car like the GT2. The stiff suspension will overwhelm the tire.

A race oriented tire like Michelin Pilot Sport Cup (aka R compound tire, aka DOT approved race tire) has these 2 important characteristics that makes it different from a street tire like Michelin Pilot Sport:
1. Grippy rubber to improve traction.
2. Stiff internal construction, stiff sidewall, and as a result high lateral stiffness.
While #1 is obvious, 2 must be recognized, and is the current topic of discussion. The interesting thing to remember is that while the rubber of a race tire may be softer, the tire itself is actually stiffer. This is how a race tire could withstand the much higher lateral force involved with cornering at high speed.

Why would a stiff tire "overwhelm" a soft spring? In this scenario, the higher grip and high lateral stiffness of the tire will allow higher cornering force. The car WILL take corners at higher speed. But... what happens then is that the spring cannot handle this higher lateral force and the suspension will lean and car will roll excessively as a result. I believe Walter Rohrl mentioned this in a recent discussion of modification to the 911 the he's going to race at the N'ring: As full blown race tires are installed on the 911, stiffer springs must be added as well.

--

Regards,
Can
997 Turbo + Bilstein Damptronic "Stage 2" ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )

 I think you're ready to take your car to the track now.

Doug

Houston, Texas USA 

997TT ...RUF550

TT Gasman:

 I think you're ready to take your car to the track now.

Sure. But not just at the track; the car now "hugs" any corner like it's a long lost girl friend. From the decreased body roll, it "dives" into curves at a tremendous pace, one that's simply beyond the reach of the softer spring setup. Stiffer car yes -- in fact at border of acceptability for a daily driver, but quite fun AND most surely quite satisfying.

In fact the tuner thinks adding r compound tire will be the final "equalizer" to competitors at the track. But I have to live with it daily, and it does rain in Southern Cal, so maybe I'll do this during the summer only.

--
 

Regards,
Can
997 Turbo + Bilstein Damptronic "Stage 2" ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )

cannga:

While we are on the topic of spring and tire: It is often said "better" tire is the single most cost effective suspension mod one could do to a car. While there is much truth to this, the issue is much more complicated than just buying the most "aggressive" race oriented tire. One must pay attention to the importance of matching a tire with an appropriate spring rate.

 

Tire discussion from someone with a little more credibility.  Panorama, 2010, WR being interviewed about the 997.2 Turbo:
>>>>>>>>>>
Question: How about with a full racing tire on the Nurburgring?
Rohrl: OK, that will be faster but my experience is that if you put a slick tire on a standard car, then the suspension is too soft. You get too much rolling, because you have too much side force. Then you have to also change the suspension. That's our experience even on the GT3. As soon as you put slick tires on, you must also increase the spring rate.
>>>>>>>>>>

I do believe however that in the case scenario of putting R compound onto stock Turbo, the car WILL be faster even if stock suspension is not altered -- stiffer and stickier tire does this. The point here though, I think, is that it's not a "perfect" match until you stiffen the springs as well.

--
 

Regards,
Can
997 Turbo + Bilstein Damptronic "Stage 2" ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )

Finally took the car out for a real test drive, first time since the front spring was changed. With some sadness ;-), I've now come to realize after 2 years of fun and learning, my days of modding the Turbo is coming to a conclusion. The car drove extremely well and is finally at a point of aggression/comfort compromise that I consider acceptable.

The road to redemption was Mulholland Highway (article on wikipedia). For those not familiar, Mulholland is a mountainous road in Los Angeles, where past road racing is stuffs of legends. Nowadays, because of traffic and cops, it's no longer the best car road in Southern Cal and I normally go elsewhere; but... as the pictures show, it is still a fascinating drive.

Admittedly the car is now at the edge of acceptability as a daily driver. On a scale of 1 to 10 for stiffness, if stock Turbo is 1, and GT3 is 10, then stock Bilstein Damptronic would be about a 4, and my Bilstein Lucent Stage 2 takes the car to about 7 or 8. It is at a level that my wife might think a tad too stiff as a passenger, but my Porsche club friends will find just perfect, for example.

The current setup has Bilstein Damptronic coilover with a single change, the front spring is now stiffer and ratio front to rear is 1:1, 565 front/565 rear. The GMG anti-roll bar is set at full soft front, medium stiff rear. Camber is -1.1 degree front, -1.6 rear. Toe is .01 degree front (essentially no toe), .16 rear. Tires are Michelin Pilot Sport (Pirelli Corsa R compound is next). Tire's pressure differential readings are -1 front, 0 rear (the front is softened relative to the rear).

For a daily driver, my baby's behavior in curves is now exemplary. Compared to the original Bilstein (which itself is world better than the soft stock car), it takes corners as if on rail, with body roll much more in check and much less wallowing. No way around it, it is simply a more fun and very satisfying driving experience.
Oh and btw, it also is more liable go airborne when it sees road bumps it doesn't like . Minor detail - LOL. Stiffer is indeed nearly always "better," but as in all suspension matters, nothing comes free and it's all a compromise.

Sorry I only had my cell phone with me so only bad quality pics this time. I got the aerial shot from the web (not taken by me).

--

Regards,
Can
997 Turbo + Bilstein Damptronic "Stage 2" ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )

Just a few pics of where I drive. You are now looking at the home turf of Steve McQueen and James Dean , Santa Monica Mountain and Mulholland Highway (click here to see map).
I went there again a few days ago because next week, summer shoes (Pirelli Corsa) go on and I would like to have some more experience and memory with these tires. 

A drive here could be exhausting, depending on how long and the level of driving. As you could see, a car adapted to this road requires minimal body roll -- something I've not been entirely happy about with my otherwise excellent stock Bilstein.

Even with Michelin PS, the car is now an absolute "twisty monster" ("cookie monster," got it? LOL). Its corner entry speed is night and day faster and makes me grin. Of course, it is not as comfortable, but I will gladly take the trade-off, any day!

From mountain looking down to main road.

--

Regards,
Can
997 Turbo + Bilstein Damptronic "Stage 2" ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )

GT:
Can did you experiment with different sways? My tuner changed my GT3 solid sways to hollow sways (for extra clerance) and I just realized how huge of a difference a sway can make in roll.. (even comparing 2 different sport sways). With these hollow aftermkt sways there is so much roll and I ve been trying to find if there is sth else wrong with the suspension, trying different ride heights, geometries etc only to realize that the softer sways effectively tripled the roll! With GT3 sways at setting 2 front, 1 rear there was hardly any roll with corsas on fast road conditions with stock B16 damptronics.. For track 2 and 2, or 3 and 2 respectively did the trick for very quick laps without any roll at the limit of the tires. Given I am running fairly aggressive -1.8 deg f/r its a pretty good compromise for mixed use (but not perfect..)

Very interesting. I am surprised that GT3 bar is that much stiffer -- I mean I expect it to be stiff but the GT3 is also what 300 lbs lighter?

I often said anti roll bar is the most mysterious component in our cars. The main problem I see is for business reason, no one releases specs, so the critical information of how much stiffer each bar is, **compared to stock**, is missing. There is enough confusion without trying to tune the car in a blind fashion. I want the reference level!

Enough ranting -- sorry.  No I have not experimented with different bars. The one I have is GMG, and just so happens this company does release specs:
GMG Front Bar: soft setting is 15% stiffer than stock, middle 25%, stiff 35%.
GMG Rear Bar:  soft setting is 30% stiffer than stock, middle 45%, stiff  60%.

Which anti roll bar are you using to replace the GT3 bar? Is it H&R? I believe that GMG is stiffer than H&R, but I don't know how it compares to GT3's.

I

--
 

Regards,
Can
997 Turbo + Bilstein Damptronic "Stage 2" ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )

An update on what probably is the final mod to my Turbo's suspension system: Tire change from stock Michelin Pilot Sport (a street tire) to Pirelli Corso (R compound street legal race tire). Talk about ending with a bang.

Before the change, I was silently very skeptical of how much the difference the tires would make. I just had a hard time imagining how a different rubber could bond so much better to a street surface that is so imperfect. Well it has been a complete eye-opening experience; the tires truly and really, stick like crazy glue.

Not that I am such a particularly fast driver (a recent chase of a semi professional driver in a GT3 made that abundantly clear - those guys are crazy  ), but my pastime is to race uh drive the car in canyon roads around LA, and the main problem with Michelin Sport is that as my baby becomes stiffer and comes into corner faster and faster, it starts to do 4 wheel power slide more. With the Pirelli cup tire, it's now back to the way it should be: my skill  is the limiting factor, not the tires, more or less. The bothersome rear-end lateral movement/twitchiness if I pull a WOT too abruptly or too early exiting corners, is now completely eradicated. The car sticks as if held down by the hands of God (or Buddha).

Regarding the 3 points of concern before I switch the tires:
1. Stiffness: Not that big of a difference at all. Maybe a little stiffer, but not a night and day difference, and most definitely not a deal breaker.
2. Noise: Again, surprisingly, hardly any difference. Maybe the cup tire is a little more noisy, but again not much and not a night and day difference.
Think of how the tires are different, then maybe my observation will make sense. The R compound tires do have stiffer wall (stiff and noisy), but the stickier rubber compound AFAIK is actually softer and more quiet. The net effect is when you go over a bump for example, the car jumps more, but the noise is a more subdued thump.
3. Wet performance: I've had a couple of moments of "holy sh*t" with these tires on wet spot - not with this car, but with a GT3 with Michelin PS Cup. I live in a rather hilly/mountainous area, and when it starts raining here in LA, there is no question I will switch back to the regular street tire, Michelin PS2. The danger with wet roads, and/or cold tire, is real.

In short, for dry road and once properly warmed up, I recommend these tires very highly. I guarantee that if you haven't had them before, it will be nothing short of a revelation. I have Pirelli Corso, but of course the Michelin PS Cup is also good. When the Corso wears out, I plan to try Toyo R888 http://www.racetire.com/products/toyo_r888.htm, heavier in weight, but lighter on the wallet (ha-ha), and supposedly outstanding stickiness.

--

Regards,
Can
997 Turbo + Bilstein Damptronic "Stage 2" ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )

Can,

I have the Michelins PS Cup tires on my Turbo at the moment and have loved the grip they provid once properly warmed up, but I've put some miles on them already and they are starting to loose some grip, i have my 15,000 kms service coming, so i'm planning on changing them and was wondering what you think?  My friend's got a GT3 and is running on the Pirelli corsa's and he is also looking in need of a tire change, we are trying to figure out what tires to buy.... I loved the Michelins and he loved the Pirellis, but we both wanna see if there is somethign better out there, the Pirelli's are about 300 bucks cheaper for the set, so it's not that much of a difference.  Should we look into the Toyo's?

regs,

Moser

^^^Moser, IMHO Michelin PS Cup and Pirelli Corsa are still the gold standard. I am only experimenting because I drive my car daily and if I am to pay $$ for these tires, I want to make sure that *I* could feel the difference, not just my wallet.

There is one key parameter that is not emphasized enough when comparing tires: weight. I have noticed that less expensive tires such as Bridgestone (IIRC) and Toyo could be quite a bit heavier than the Michelin/Pirelli counterparts. For example the weights for the 3 cup tires are as followed:
Michelin Cup: 20/27 lbs front/rear
Pirelli Corsa: 21/26
Toyo R888: 25/31 
Additional  9 lbs front and 9 lbs rear is a lot of weight. This weight gain is especially bad as it comes at the outer border of the wheel, hence increasing angular momentum of the wheel even more than weight gain at the center. We've had discussion in the past regarding how higher unsprung weight will affect: braking, acceleration, ride, and handling (anyone interested look up precess and gyroscopic effect too - Grin). This is not a trivial matter.

To counter the above argument, there is a racing concern in the US who owns and  tunes a Porsche Turbo, and they use Toyo and say that it is fine. Actually loves it.  Essentially that has made me curious to the point that I almost want to try the Toyo. In addition, the cost in the US for set of 4 tires go like this: Toyo around $1400, Michelin around 1800, and Pirelli around 2300. Now you could see my incentive, someone who is about to have 2 kids in college (in the US, this could mean up to one 911 every year ).

If you are not burning through tires, I would suggest you stay with Michelin and Pirelli. For me, the issue will come down simply to this: Is there a difference, and more importantly, will I be able to feel the difference at my amateur level of US street driving? And even more interesting, is it possible for the Toyo to be better in aspects other than weight? What about noise? In short, I have not made up my mind and might just stay with Michelin/Pirelli based on weight issue alone.
BTW, you may only need to change rear tires only as rear wears much faster than front.

 

Regards,
Can
997 Turbo + Bilstein Damptronic "Stage 2" ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )

Thanks Can!

I'm probably gonna try the Corsas, I've never tried them and have gone through 2 sets of Michelins, i would also like to compare the two makes, but its weird, our pricing is very different over here, the M SC will run about $2600 for the 4, while the Pirelli's will run about $2300 just like the US, and the Toyo's about $1600.  It seems our lovely Michelin dealer is making quite a mark up. I think it's time to try something new and stop iflating the michelin dealer's wallet!  :) I'll keep you posted on my experience between the 2.....

Moser

Moser you're very welcome. Re. price, what variation; I smell a rat. And rich tire dealers.
BTW, during my informal research, the top 2 are Michelin and Pirelli, with seemingly (totally "informal" guys, no flame pls) more people like Pirelli. Other than the price, I love my Corsa in all important parameters: stickiness, low noise, low stiffness (for street driving).

Here is my informal tire weight ranking, courtesy of Tire Rack's Tires for Porsche 997 Turbo (it's a little late for me so pls pardon and correct any mistake):

Michelin Cup:                     front/rear   20/27 = 47 lbs
Pirelli Corsa:                                         21/26 = 47
Continental Extreme Contact DW:     21/28 = 49
Michelin PS2:                                          2/28 = 50
Continental SportContact 3:                22/28 = 50
Pirelli Rosso:                                         22/29 = 51
Bridgestone RE050A:                          24/31 = 55
Toyo R888:                                            25/31 = 56
Bridgestone RE11:                               27/31 = 59

Definitely "food for thought," and a weight difference of 24 lbs, such as from Michelin/Pirelli cup to Bridgestone RE11, cannot be ignored IMHO.  Even more "food for thought," a Turbo with iron brake and RE11 will have what, close to 60 lbs. more in unsprung weight than one with PCCB and Michelin Cup?
I am surprised that in my reading of tire comparisons on various forums, I've not run across anyone mentioning this extremely important parameter of avoir du pois. Does no one CARE about precession?

--
 

Regards,
Can
997 Turbo + Bilstein Damptronic "Stage 2" ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )

cannga:

I am only experimenting because I drive my car daily and if I am to pay $$ for these tires, I want to make sure that *I* could feel the difference, not just my wallet.

Hi Can, thanks for sharing your tire experiment impressions  As those R-compounds are very temperature sensitive I am wondering how you get the neccessary heat into the rubber on your daily drives ?

Regarding the Toyos: they are way too noisy for road driving IMHO.

Though personally I would not use R compounds for road driving (PS2 are better performers in 90% of all road driving IMO + less expensive) I'd go for the Pirelli Corsas: in terms of "sharpness" at the limit they are somewhere between PS2 and MPSC and they work a bit better in the wet compared to the MPSC, though still noticeable worse compared to the PS2.

public roads: Porsche 987 S Seal/Cocoa, toll road  : Porsche 997 GT3 Arctic/Black

Porsche-Jeck:

 

 As those R-compounds are very temperature sensitive I am wondering how you get the neccessary heat into the rubber on your daily drives ?

Regarding the Toyos: they are way too noisy for road driving IMHO.

 

It actually has worked out very nicely. I found that with the cold R compound tires I've not had to drink as much coffee in the morning.

Kidding aside, I use TPMS to pace how I drive and does not test my luck until temp has gone up a couple of degrees. This is street driving, not all out track test, so 2 degrees are enough to get me to "reasonable" territory.
For example, car would start out approx. 27/33 cold when I leave my house, witin 5-10 mintues, I am up to 29/35, and by the time I arrive at work, toasty and perfect at 31/37. The only problem I have had is in the Turbo, the TPMS would alarm low pressure.

Roads around my house are hilly/mountainous type, so there is no question I am switching back to Michelin PS2 when it starts raining here in Southern Cal. BTW thanks; as always I value your input.

--
 

Regards,
Can
997 Turbo + Bilstein Damptronic "Stage 2" ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )

 For me, the issue will come down simply to this: ... What about noise? In short, I have not made up my mind ....

 Considering the cacophony produced by your red monster, I'm amazed that you consider noise from tires a factor. Perhaps it's because the transient intermodulation distortion (TIM to the uninitiated) is so un-Krell like? And why is it that you are irked by a few measly pounds around your wheels, while well tolerating donut-devouring denizens with mass much greater high above the center of gravity, in your passenger seat?

^^^ Arthur, I "resemble" that remark!

--

Regards,
Can
997 Turbo + Bilstein Damptronic "Stage 2" ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )

cannga:

The result? 

Handling: With stiffer front spring, the Turbo corners as if on rail, at higher speed, and in a deeply satisfying manner.
...
Steering: This is, above all, the biggest and most pleasant surprise: Turbo steering has become much firmer and direct, instantaneous in its response and therefore much "purer." This is the first time that I am happy with the Turbo's steering, to me one of its weakest points. I would have traded anything for this gain alone. The steering is now outstanding.
 

Enough of tire digression, now back to the nitty gritty of how this stiffer spring update was done. To convert a front/rear spring rates of 340/565 to 565/565, the easiest way of course is to buy a new spring for the front with rate of 565 lbf/in.

With the Bilstein Damptronic coilover, this switch is made difficult because Bilstein uses 70mm id (int. diameter) spring, very much a non-standard size -- don't ask me why, even Bilstein reps admit this is a pain in the derriere for customers. In the US, 70mm is only found with a few vendors such as Hypercoils http://www.hypercoils.com/Catalog.aspx . But then... not only you have to find the right id, you'll also have to find the right length, etc., etc.
Now you know why not many people have played with the spring rates of the Bilstein coilover, even though the ability to exchange springs *easily* is supposedly one major advantage of a coilover system.

My Porsche shop's solution is simple, surprisingly so: To increase the front rate to 565, the tuner merely bought an extra set of Bilstein's rear spring and installed it in the front.
(He actually tried 2 combinations, 565/750 versus 565/565, and very quickly decided that the higher rear rate is too hot to handle -- oversteer from stiff rear rate -- for an amateur and too harsh for street driving.)
Please also note that as we stiffen the front spring, we also change front sway bar setting to full soft to prevent too much understeer. The point is that when one starts messing with spring rates, the car has to be tuned by someone who is greatly familiar with high speed driving and suspension tuning, and who understands the limited skills of an amateur client.

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.

--

Regards,
Can
997 Turbo + Bilstein Damptronic "Stage 2" ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )