Suspension Changes on the 996

There are several suspension threads in the 996 forum every day, which is understandable because the stock 996 suspension, at least in the U.S., is unacceptably soft and the ride height is unacceptably high. Before you start purchasing and installing expensive and complicated modifications, though, you really should think about how you use your car, and what your goals for the changes are. First, before you do too much at all, you really should consider determining whether your current setup has been aligned properly for your driving habits. Carefully observing tire wear and temperatures, preferably with a probe pyrometer, can help in this regard if you are unable to describe properly the handling characteristics you observe to your alignment shop (which is not at all uncommon, particularly for newbies), including both static and transitional handing characteristics (e.g., at turn in, from turn in to apex, at apex, and from apex to track out). http://www.racerpartswholesale.com/long12.htm Here is a link to an outstanding article on how to use a probe pyrometer: http://www.longacreracing.com/articl...ter_Tips_p.htm Keep in mind that if you merely take the car to a Porsche shop, or even an independent shop, and say "give me an alignment," they will just put your car in factory recommended ranges, which may not be personalized for your style of driving. By contrast, you may find that a proper, personalized alignment is sufficient to address your particular concerns, and that further modifications are unnecessary. Obviously, a great shop can be helpful in determining the proper suspension alignment for you as well. The factory sport kits are always a safe bet for improving the handling, but they lack adjustability. http://www.carnewal-europe.com/cpx_p96079.htm There are several well proven aftermarket kits that offer adjustable ride height and dampening settings. I personally went with the PSS9s and GT3 adjustable sway bars, which gives me adjustable ride height and nine dampening settings, although I keep my car on the penultimate stiff settings all the time. http://www.carnewal-europe.com/cpx_p96095.htm You can also get aftermarket systems that allow even more adjustability (e.g., motons, ledas, etc . . . ), but you need to be sure that you have the skills to set up such a complex system. It certainly is not impossible to adjust these systems properly, but keep in mind that a mal-adjusted adjustable system can be far worse than a non-adjustable system that is designed for the car, or even an adjustable system that has fewer variables. Ride height is crucial. If the car rides too high, as the stock 996s in the U.S. do, then too much air can go under the car and interfere with high-speed handling characteristics. If you make the car ride too low, then you will scrape too often, which could lead to significant damage, or eliminate too much suspension travel which can lead to very nasty handling characteristics and bump steer. Be careful when you go real low. If you do lower your car (even if you do not), you should consider installing the factory engine protection plate. Mine has saved my pan several times. The protection plate is inexpensive and incredibly easy to install/remove. There really are no downsides to this mod, so you should do this. The plate is roughly the same size as the oil pan, and it sits about 1/2" below the pan itself, so it really doesn't impact engine temperature significantly. http://www.carnewal-europe.com/cpx_p96021.htm Good tires that are specifically designed for your style of driving are crucial. Do your homework. Also remember that your car was designed with a specific rim size in mind. Putting on a set of 22" dubs may look like the bomb, but they likely will lead to adverse handling effects, not to mention an increase in unsprung weight, which is the very worst type of weight you can add to your car. Stick with factory rim sizes, and remember that even where you have a choice between 18" and 19," the 18" may actually handle better. Although there are several great aftermarket rims, keep in mind that Porsche rims have always been great choices. For example, the 18" Carrera lightweights are incredible, and they can be snapped up from buyers who have sold them to slap on a set of Gucci dubs. http://www.carnewal-europe.com/cpx_p96031.htm Finally, you can consider aerokits, which have a significant impact on handling, albeit at speeds well above the legal speed limits in the U.S. I personally would stick only with kits that have been extensively tested in windtunnels, so I personally avoid all kits that are not OEM or Ruf. Keep in mind that the kits are frequently "systems" that require the installation of all components in that system. For this reason, you do not want to install only the rear wing without also installing the front splitter that is designed for use with that rear wing. Failure to follow the designers recommendations can lead to nasty high-speed handling characteristics. I personally went for the Porsche factory aerokit for the +'02 Targa/cabs/coupes, which you can see in the attached pictures. It is a two part kit with a lower rear wing (which is beautiful) and a rubber splitter that snaps into slots under the stock '02+ bumper, which you retain. The front splitter cannot be seen unless the car is up on a lift, but it has a very big impact on the aerodynamic characteristics of the car. Before I installed the kit, my car felt light or skitterish above 110 mph. After installing the kit, the car feels planted all the way up to 140 mph and above. Of course, you do lose a little of the top end with an aerokit due to increased drag, but the improved high speed handling is well worth the minor top speed loss. Another option is the MKII aerokit, which basically makes standard '02+ C2s look like a GT3. http://www.carnewal-europe.com/cpx_p96076.htm Before you start modding your suspension, I highly recommend that you read a book entitled "How to Make Your Car Handle" by Fred Puhn. http://www.amazon.com/gp/product/091...Fencoding=UTF8 Although it may appear to be dated, the information is extremely useful and still valid. It will help you understand the impact of various changes you are considering, which may help in the decision making process or setup process. Autocrosses and skidpads can also be helpful for determining how your car is handling. The good news is that the steering geometry and setup for the 996s are outstanding, and the 996 arguably is one of the best handling modern production cars once you depart from the stock U.S. springs and ride height. They are lightening fast on the track and extraordinarily foregiving. The cars let rookies get away with murder, and yet reward good driving in spades. For most drivers on this forum, including me, it is difficult to reach the limits of the car. Most work on the track focuses on the limits of the driver. Good luck and be sure to get to the track with your 996. Life is too short not to contract the track addiction. To give you just a little glance into the track experience, I have attached some pictures of me in my '02 996 Targa at Watkins Glen. Since those pictures were taken, I have stopped using my 996 on the track, and now use a 1984 150 HP normally aspirated 944 race car. I switched cars so that I could learn how to momentum drive, which is really how you should drive all cars. Quite simply, the 996 is so incredibly capable that it is harder to learn to drive well in a 996 than it is in a low HP, non-electronically assisted (and also without ABS) car like a 944, because you have to drive so much harder and so much faster to reach the limits of a 996, which is where you learn the most. I have also started wheel-to-wheel racing, which I think is much more comfortable in a car that I could walk away from without crying too much. The last picture shows my '44 racecar. So, when you pass lowly '44s at the track, show them some love and respect because they just might be better drivers than you are even though you are going faster.

Very nice write-up. I have a question about the engine cover. My thoughts are that any covering on the engine compartment would negatively impact the cooling which is already a problem in hot climates like here in So. Fla. PS, I always liked the word penultimate and you used it well

WOW you said something intelligent Nice write up.See I knew you went all about breaking *****.

Thanks Mitch. On the 996, the engine cover plate is relatively small and it only covers the area of the case. I seriously doubt it will have any significant impact on cooling. I have run in very hot temps with the plate, and cooling wasn't a problem. I was thinking that I could tweak the post and we could maybe sticky it to the top of the forum. I was also thinking that we could do the same for RMS issues. Since this is the 996 forum, carbon fiber may be a candidate as well This might eliminate, or at least reduce, some of the more commonly repeated threads.

It's all fun to me.

TD, Fantastic write-up. Very interesting and useful information. It deserves to be pinned for all to view on first modding their cars. Make that two

Great Job Todd! I agree with others, this should be a pinned item.

Do they make those springs in pink?

Great write-up! This should definitely be made a sticky...

TD- Nice and useful write-up for one who considers him/herself a newbie in many 996 things (that would include me). OT, I wholeheartedly agree with Mitch and your use of the word penultimate. Additonnally, you should change the word "de" to the word "du" in your sig (ma�tre du temps perdu).

Thanks and you are right. I speak so much Spanish now that je parle Francais comme une vache Espanol . . .

Je suis Francais pero hablo espanol tambien (seguramente como una vaca Francesca!) OK, back to topic.

Buncha rubbish On a serious note, I found the PSS9's a bit soft for the track, even at the stiffest setting.

I know Chris runs with X73, and for some reason I'm leaning that way... tired of the C4S looking like a monster truck. BTW, Todd very nice write up. Rob

Nice work Todd. Now if only we can get some more 996 guys to the track. Make that your next mission. ;-) -KJ

I'll go! Actually I just wanted to complement Todd on taking a shot at this. Nice write up. I'm a big fan of Puhn's books. Dated but very valuable. I love the diagrams. I'm curious about your comments on using tires temps to set up your car. I'm not sure what they are going to tell you about a combo street/track car. They will undoubtedly say you don't have enough camber on the track and you have too much on the street. Isn't that sort of the nature of the compromise. Just like your springs are certain to be too stiff on the street and too soft on the track. I just responded to a PM question on spring rates where I pointed out that the optimal street rates are probably around 200-400 lbs and the optimal track rates are 1600-1800 lbs. Optimal street camber is something like -.5 f/ -1.6 r while optimal track camber (depending on your tire) is something in the -3.5 f/-3 r. Again, it's hard to find a compromise in settings that far apart. Anyway, I certainly support your efforts. Maybe we should develop a test where drivers answer 10 questions and we spit out the right suspension and alignment settings. I'll start: 1) My springs are just right if: a. My family loves to go on long rides every Sunday b. My spouse refuses to get in the car and is threatening divorce c. My eyes vibrate too much to read street signs 2) My camber is just about right if a. my car pushes like a grain truck but I get 30k miles out of a set of Pirellis b. TireRack is demanding I fill out a credit app and sign over my house as collateral

Thanks for the kudos. My answers are as follows: 1) c.; and 2) b.; Of course you are correct. However, even on the track, different setups may be appropriate for (1) different drivers (e.g., super aggressive negative camber is only necessary/appropriate for drivers who really push their cars . . . those who don't will just prematurely wear their tires out without benefiting from the extra negative camber) (2) different tires (e.g., hoosier slicks that love super aggressive negative camber vs. Toyo RA1s which like a little less); and (3) different tracks (e.g., lots of straights vs. lots of corners). In other words, it is always a compromise. My point is simply that drivers need to get a handle on the single most important component on their cars -- the tires -- before they start spending the $$$$$$$$$ on making major changes that may or may not have the intended impact. Watching cold/hot pressures and, better yet, temps at the cords is the best place to start. Your tires will tell you when they are happy, even if you have to decide when you want them to be happiest (e.g., track vs. street). I just know that as a novice, I had no mental framework to even begin approaching the issue of how my car handles. I am just trying to create an intro guide to help newbies dive into the water of learning about the right away to approach the issues, or at least the way I think is most correct. And KJ, I am ALWAYS trying to get people to go to the track Junkies naturally become pushers . . .

Very helpful and thanx for taking the time.

Some day when I pay off my car I will join the track crowd.

Don't wait. PCA Potomac's High Performance Driving Clinic is next weekend. I hear there are still spaces open. This is a nearly zero risk to your car event, and it is a prerequisite to doing other Driver Education events with the Porsche club. There is zero reason not to do this. So, first, make sure you are a PCA member. If not, go to www.pca.org and become a PCA member. Get your membership number and expiration date. Second, go to www.pcapotomac.org . Find the activities pull down menu, then do to Driver Education, and then to "registration." Go in, fill out the registration information and register for next Saturday or Sunday. The HPDCs are one event. Third, call OG Racing www.ogracing.com and rent a helmet. You must have a helmet, but no point in buying it until you are ready to start doing this on a regular basis. Don't worry about shoes or gloves at this point. Fourth, provided you get confirmation that you have been accepted, show up next weekend at Summit Point Raceway and prepare to have the time of your life. Even if you never get addicted to track activities, the exercises you will do will help you on the street, and you will fall even more deeply in love with your car than you probably already are. TD

And this is the reason why people need to learn about suspensions. The PSS9 system has a damper and a spring. Changing the damper rates is not to "stiffen" the supension. The spring rate should be changed. The adjustments on the damper are to change the rate of change of the damper. Of course it is not that simple and increasing the settings of the damper will make the suspension stiffer because for example, if you hit a bump, the impact lasts for a finite amount of time. Increasing the damper will allow for less change in the damper over time, thereby making the suspension "stiffer" but that is not how to "stiffen" the suspension. Use the dampers to tune the car to the specifics of the track and your car.

i agree that pss9's are too soft for the track. maybe some retailers should start offering the kit w/ different spring rates. i think the valving on the stiffest setting can handle more spring. possibly increase the main spring by 40% and make the tender spring stiff enough for daily driving duties not just to compress and retain the assembly. anyone tried the H&R coilover kit? how about a cup car setup w/ slightly softer springs?

IMHO the PSS9s are fine, I would even say great, for dual use cars. IIRC, they are not marketed as a full out track setup. If you are focusing solely on the track, then why not go to Motons, http://www.motonsuspension.com/index...tem=featuresms , or JRZs, http://www.jrzsuspension.com/index.php?race , et al. . . .? I also wonder what changes in the ride height of the PSS9 setup does to "perceived" stiffness. IIRC, Eli's setup is a little higher than mine. I wonder if that could make any difference. JimB . . . oh JimB . . . ????

motons and jrz's are much more expensive. if we're heading that way, why not just go w/ ohlins http://www.ohlins.com/pdf/productnews/porche.pdf http://www.ohlins.com/cgi-bin/dbsok/...l?category=car i'm just looking for a cheap way to upgrade an already good product. springs are cheap. i'm not a fan of lowering the rideheight just to compensate for the spring rate. it *may* up the rate, but at the price of clearance. at best, it's a bandaid approach. while not looking for a full blown race setup, i think most people that live w/ pss9's (and track the car) would not mind having the spring rate upped by 35%. those that do not, are probably jolly as hell with the way it is. anyone got factory specs on the gt3rs spring rates? that would be a good starting point

Yes, }{, I found your observations at VIR to be interesting. I am tempted to let you drive my car to see if you think the same about mine, but then I quickly snap out of it. Do you know whether Eli has the GT3 sways? Perhaps that could make a difference. http://www.carnewal-europe.com/cpx_p96006.htm I know that some say sways are "cheating," but Puhn's book is very interesting in that he explains that it is better to have springs that are as soft as possible, and that many people make the mistake of going too stiff, which is not to say that you are not correct. Before I read Puhn's book, I had the impression that ride height and sway bars were mere "bandaids," but now I do not really think that so much any more. Of course, we are talking about a system, so you can go to extremes for everything, but I no longer am inclined to default immediately to the "buy stiffer springs" solution, although that may be where you need to go ultimately. I haven't experienced the feeling that the PSS9s are way too soft, but then again I am sure that spring rates become much more noticeable as you move from street tires to R-compounds, and then again to slicks. If your tires are the first thing to let go, then you will not be loading your springs to the point that you notice a lack of sufficient firmness. I agree that you can definitely go too low on ride height, as I mentioned in my original post, but so long as you are not excessively bottoming out, hitting the bump stops or overly compressing the springs, I cannot see how lowering ride height is a bandaid. Seems to me like it would be one of the first things to consider since it is free, at least once you have already installed the PSS9s. Now, I haven't paid close enough attention to Eli's 996 to see whether it actually is higher than mine or not, so that might be irrelevant here. I just remember thinking to myself that both his and Tuffy's are higher than mine. IIRC, ASG did the corner balancing and alignment for both, so that would make sense. I knew exactly what you meant by the springs, but I think that the PSS9s are more of a "package" solution for a Daily Driving/occassional track usage. If you are more serious than that, I think that there are other potential solutions that might serve your needs better.

When you install the Bilstein PSS9's in the 996 I was told that you need to re-use some existing pieces. What are those pieces?? Does anyone know??