Considering the Porsche 997 is mostly a reworked 996, its suspension changes are more revision than revolution. The same basic architecture remained, but new technologies and lessons learned translated to updates for every piece. Now, as a used model, the reworked 911 remains an analog time capsule while still providing owners with a modification platform. Whether you're looking to perform some maintenance yourself or prep for track duty, you'll need to understand the basics of how it works, so we're here to help you out. Here's the lo-down on all things related to the Porsche 997's suspension.
Porsche 997 Suspension Guide Table Of Contents
Porsche 997 911 Suspension Overview
The Porsche 997’s front suspension utilizes a MacPherson strut with a lower control arm and thrust arm to create a lower wishbone. The rear suspension uses a multi-link architecture that Porsche calls LSA (Lightweight, Stable, Agile). The LSA uses the same lower wishbone setup as the front but ditches the strut for two upper control arms and a toe arm. A coil-over-shock that connects to the bottom of the knuckle controls damping in the rear. Non-S models receive standard passive dampers, while S, Turbo, and GT models feature active dampers. As with the 996, the GT variants use a two-piece lower control arm adjusted by shims for static camber adjustment and multi-way (adjustable) sway bars.
Those words are almost identical to what you’ll find in our 996 suspension guide, and that’s because much of the 997’s suspension development involved modifying the 996’s pickup points for better crash safety and increased performance. Up front, Porsche widened the front cross-member by 30mm to account for the new track width and wheels. Out back, the LSA cross-member was widened by 30mm, the upper control arm mounting points were raised by 10mm, and the lower point was dropped by 5mm. To go along with that, revised control arms had their previous rubber bushings replaced by hydraulic-filled units.
Digging into the specific variants further, the two-wheel-drive models share the same suspension design, which differs slightly from the all-wheel-drive cars. Overall specifications like spring rates, sway bar sizes, and damper specs are dependent on the engine size, drivetrain, and chassis configuration. That lent to a nicely handling sports car no matter the model or configuration, but deciphering which components fit on which models isn’t always simple. Let’s take a look at what Porsche came up with for their first water-cooled re-do:
Porsche 997 911 Dampers
Passive (Standard Non-S)
The standard dampers fitted to the base 997 Carrera and Carrera 4 models weren’t too far off from those fitted to the 996. The overall suspension architecture remained the same, with small tweaks to springs and sway bars, so the standard Bilstein dampers underwent a slight re-valving. Twin-tube gas-filled dampers were fitted at the front of the 997.1, and gas-filled, single-tube dampers at the rear.
The updated 997.2 took advantage of the knowledge gained from the 997.1. Again, the dampers were updated slightly for different spring rates and suspension advancements. The front struts maintained their twin-tube design, while the rear shocks added a tube to join the fronts as a twin-tube damper.
PASM (Porsche Active Suspension Management)
The 997 was full of firsts for the 911, including Porsche’s first road-going adjustable dampers since the 959. Called PASM, the electronically controlled suspension can alter its firmness depending on the driver's setting and the road's conditions ahead. Although active suspension wasn’t necessarily a new idea when Porsche fitted it to the 997—Mercedes-Benz and Chevrolet both had active dampers in production then—it differed from other systems.
Porsche’s active suspension uses a bypass valve fitted inside the damper. The valve is hydraulically activated and controlled by a series of sensors and computers. The PASM computer opens or closes the valve depending on the suspension setting and the conditions being read by the various attached sensors. A more open valve allows the fluid to pass through quicker for a softer ride. Closing the valve reduces the size of the oil passage, giving the damper a firmer response and ride.
The PASM computer uses the input from various sensors along with a handful of predetermined maps to set firmness. Those maps come into play when the driver chooses between “Normal” and “Sport” settings determined by the button with a damper assembly on it (the "SPORT" button is for the throttle mapping but will engage PASM if equipped). The maps determine the valve’s openness based on set parameters, and for PASM, those maps overlap in certain places. The damper is relatively soft in the “Normal” setting, lending to a more comfortable ride. But the dampers automatically firm up when the speed increases to give the steering a safer feel. Conversely, the dampers will automatically switch to a softer map in “Sport” if bumps are detected to prevent the 997 from skipping over them and feeling too twitchy.
Small individual computers called modules use sensors to read the suspension, steering, yaw, roll, and pitch. The module that reads the vehicle’s pitch will stiffen the rear dampers under hard acceleration to minimize squat and stiffen the front dampers under hard braking to reduce nose-dive, resulting in better acceleration and braking. Quick lane changes and evasive maneuvers elicit a response from the roll module, stiffening whichever side of the Carrera needs it to maintain a flat and composed body for the best tire-to-road contact. All of those adjustments happen in fractions of a second while the driver is none the wiser.
The PASM system is only active in damper control, but the option package includes different springs and sway bars to suit the active suspension system better. As standard on the S models, the PASM springs are slightly firmer and sit 10mm lower than the standard passive suspension fitted to the base Carrera. It provides the stiffest OE suspension for the 997 Carreras and Turbo.
However, Porsche didn’t stop developing the PASM system and introduced the PASM Sport with the 997.2. Sport PASM, or SPASM, lowers the car a further 10mm with even slightly firmer springs. The sway bar sizes generally stayed the same, as the tweaks mostly focused on the dampers. The Sport PASM package also included a rear limited-slip differential for rear-wheel drive models—all-wheel-drive models have the LSD as standard. The Sport PASM was a very driver and performance-focused package, and because of that, it was available only on the Coupes.
Porsche 997 911 Springs
If it wasn’t already confusing, buckle up. In an effort to have all versions of the 997 drive like a 911, Porsche mixed and matched spring rates based on the driveline, engine, and transmission. The S models received slightly stiffer rates because of their extra sportiness. All PDK-equipped models, regardless of other factors, received stiffer rear springs for the extra weight of the transmission. All-wheel-drive models received stiffer front springs to compensate for the front differential.
Porsche takes their suspension tuning very seriously, and the 997 was no exception. Check out the list below for the full breakdown between generations, models, and equipment.
Porsche 997.1 Spring Rates
|Front||Rear-Wheel-Drive Carreras||All-Wheel-Drive Carreras|
|Base Suspension||27N/mm or 154 lb/in||30N/mm or 171 lb/in|
|PASM||33N/mm or 188 lb/in||33N/mm or 188 lb/in|
|Base Suspension||43N/mm or 245 lb/in||43N/mm or 245 lb/in|
|PASM||56N/mm or 320 lb/in||56N/mm or 320 lb/in|
Porsche 997.2 Spring Rates
|Front||Rear-Wheel-Drive Carreras||All-Wheel-Drive Carreras|
|Base Suspension||27N/mm or 154 lb/in||30N/mm or 171 lb/in|
|PASM||33N/mm or 188 lb/in||33N/mm or 188 lb/in|
|Sport PASM||36N/mm or 206 lb/in||36N/mm or 206 lb/in|
|Base w/Manual||43N/mm or 245 lb/in||43N/mm or 245 lb/in|
|Base w/PDK||46N/mm or 263 lb/in||46N/mm or 263 lb/in|
|PASM||56N/mm or 320 lb/in||60N/mm or 343 lb/in|
|Sport PASM||65-95 N/mm or 371-543 lb/in (Progressive)||65-95 N/mm or 371-543 lb/in (Progressive)|
Porsche 997 911 Sway Bars
The sway bars were largely carried over from the 996.2. Non-GT models received passive bars with varying thicknesses and single drop link mounting points. The GT bars are the thickest of the bunch, providing the most roll resistance, and feature multiple mounting holes for roll control adjustability. The thickness and overall diameter of the bars fitted to the various 997 models depended on their drivetrain, body style, suspension choice, and engine size. Because of that, there are more than a few to list.
Looking at the chart below, you’ll find each size broken up by trim. This is a great place to start in terms of suspension modification for more spirited driving. The 997, regardless of model, all share the same sway bar mounting points. However, larger bushings and different drop links are needed. Talk to your local Porsche independent shop for more information.
Porsche 997.1 Sway Bars
|Front||Rear-Wheel-Drive Carreras||All-Wheel-Drive Carreras||GT3 & GT3RS||GT2||Turbo|
|Manual Gearbox||23.6mm x 3.5mm||22.5mm x 3.5mm||26.7mm x 3.5mm||25.6 x 4.4mm|
|Tiptronic S||24mm x 3.8mm|
|PASM||23.6mm x 3.5mm|
|Base Suspension||18.5mm x 2.5mm||22.5mm x 3.5mm||23.6mm x 3.5mm||25.2mm x 4.4mm|
|PASM||19.6 x 2.6mm||18.5mm x 2.5mm|
|w/LSD||22.5 x 3.5mm|
|No LSD||21.7mm x 3.0mm|
The updated 997s benefitted from updates to the suspension that necessitated slight changes for each component. The sway bars are no exception, needing to be updated to take advantage of the revised PASM, Sport PASM, and new tire technology.
Porsche 997.2 Sway Bars
|Front||Carrera||Carrera S & Carrera GTS||Carrera 4 & Targa 4||Carrera 4S, Targa 4S, & Carrera 4 GTS||GT3 & GT3RS|
|Base Suspension||24.0mm x 3.8mm||22.5mm x 3.5mm||23.6mm x 3.5mm||25.6mm x 4.0mm|
|PASM||24mm x 3.8mm||24.5mm x 3.8mm||23.6mm x 3.5mm|
|Sport PASM||24.5mm x 3.8mm||23.6mm x 3.5mm|
|Base Suspension||18.5mm x 2.5mm||20.7mm x 2.8mm|
|PASM||19.6mm x 2.6mm||19.6mm x 2.6mm||21.7mm x 3.0mm||21.7mm x 3.0mm|
|Sport PASM||18.5mm x 2.5mm||18.5mm x 2.5mm||20.7mm x 2.8mm||20.7mm x 2.8mm||23.9mm x 4.0mm|
Common Porsche 997 Suspension Problems
Common suspension issues on the 997? Those don’t really exist. At the time of the 997’s production, Porsche's suspension architecture was well developed, with all of the bumps and hiccups ironed out. The front suspension has very little rubber in it to actually go bad. Most commonly, the strut mounts will wear, leading to a light clunk over bumps. There is more rubber in the rear suspension than the front, but there is a similar lack of issues. Check the rear’s arms around the 100,000-mile mark, as that’s the general replacement interval. Occasionally, a bushing in a drop-link will wear until it makes a noticeable click over bumps. Standard maintenance is all that the 997 should need.
Porsche 997 Suspension Upgrades
While a stock 997 is one of the best-handling sports cars anyone can purchase under $40,000, it can certainly be improved. The factory alignment and suspension settings provided plenty of grip for a twisty back road but can be understeer when pushed around a track. The GT cars won’t have that understeer as they’re already the best Porsche could offer, so some upgrades won’t apply. The spring rates and damper settings can also be optimized over stock for aggressive track use. Look no further if you plan on serious track time in a 997.
Controlling the wheel placement at all times are the suspension arms. All of the arms bolt to a subframe and locate the wheel during its vertical movements. On top of that, they also determine toe and camber settings, making them hugely important pieces. The 997’s front suspension uses two arms to control caster and camber gain, while the rear uses five arms per side. The arms either use ball joints or hydraulic-filled rubber bushings to absorb the road undulation. The GT variants use more aggressive bushings than the Carreras, so their suspensions are better set for spirited use from the factory. Because of that, these upgrades mostly don’t apply to them.
One of the easiest and most worthwhile suspension modifications on a 997 is a new set of suspension arms. OE quality parts will use the same rubber bushings as the factory, keeping the suspension sporty but comfortable. We offer complete front and rear suspension arm kits with our Lifetime Guarantee that’ll completely refresh how your 997 feels and handles. Companies like Elephant Racing offer just the bushings, but that’ll lay the car up for a while, as you’ll need a press for removal and reinstallation. However, if you plan on using the 997 for street and track use, then Elephant Racing makes more sense.
Along with offering stock bushings, Elephant Racing offers “Sport” bushings. They utilize a stiffer rubber bushing for less deflection in caster and camber, giving you a more responsive feel and consistent contact patch. The only downside to these bushings is that they require a unique tool to be pressed in. Elephant Racing offers it, but it’s just another expense. A slight step up from those “Sport” bushings are Powerflex’s polyurethane units. The poly bushings are offered in street and race stiffness, allowing you to choose how much you want to punish yourself. Both the Elephant Racing and Powerflex bushings are available for every bushing in the suspension, and both offer bushings with modified mounting locations for increased adjustability.
The Carrera’s control arms are a one-piece design, whereas the GT3 uses a two-piece design. The inner bushing on the GT3 piece bolts to the rest of the control arm and uses shims to extend the arm’s length, increasing the available camber. These arms bolt onto a non-GT 997 without modification and utilize stiffer rubber bushings, providing an easy and streetable upgrade for any 997. However, the middle bushing used for the thrust arm is a different size, so the GT3 thrust arm has to be used with its control arm. The same goes for the rear suspension’s upper arms. They’ll bolt onto a non-GT 997 and provide improved suspension control at the cost of NVH and comfort.
However, if you’re building a 997 for some serious track time, you’ll want to look elsewhere. Rubber and polyurethane bushings are great for the street, but Heim joints are the top dog. Also called rose joints or monoballs, they use no rubber or polyurethane. They are spherical bearings that allow articulation with no deflection; they’re metal on metal, translating every bump, crack, and dip through the suspension. Street cars can use them instead of rubber, but tradeoffs will exist. The increase in suspension control is offset by their quick wear rate when used year-round and their increased noise.
Tarrett, RSS, BBi, and SPC offer suspension arms with Heim joints instead of bushings. Their lower control arms all use Heim joints larger than the stock inner bushings for greater durability, while the center bushing for the track arm is a solid aluminum piece with an adjustable mounting point for greater suspension adjustability. The upper control arms are replaced with stronger aluminum pieces using threaded Heim joints at either end, providing greater adjustability over the factory arms and their eccentric bolt. The track rods and thrust arms are all available with Heim joints, too. These components are not for the faint of heart. They turn any 997 into a significantly more aggressive and responsive sports car best prepared for the race track.
Porsche spent lots of time in R&D for the 997’s suspension. The PASM dampers were a game-changer for the 911 and have since become a focal point of the lineup. Owners and journalists alike praised the PASM with high regard to its adaptability, response, and overall comfort from the adaptive dampers. The standard passive dampers were given good marks, too, delivering the blend of comfort and cornering performance that a 911 should. However, when the going gets twisty, aftermarket components can improve performance. Suspension design and tech have come a long way in the nearly two decades since it debuted, and there are now some great aftermarket suspension offerings to help you achieve that perfect 997.
As you might imagine, the PASM makes suspension upgrades a little tricky. The on-board suspension computers must communicate with the dampers, and they’ll throw codes and warning messages without it. Thankfully, Bilstein was the OE supplier of PASM dampers, so they built out a catalog of PASM-compatible parts. Bilstein refers to them as the DampTronic struts and shocks for ease of reference. Each of these parts can be found on our website and carry our Lifetime Replacement Guarantee, too!
The basic damper replacements for the PASM are the Bilstein B4; they’re valved to OE spec and are direct replacements for the original parts. For slightly firmer street duty, the B6 Performance DampTronic struts and shocks. The monotube dampers retain their adaptive functionality and plug/bolt directly into the 997 to replace the original parts. The slightly firmer valving is meant to be paired with the OE springs for a noticeable but subtle improvement. If those aren’t enough, Bilstein offers the B8 Performance Plus dampers. They’re designed specifically for use with larger sway bars and aftermarket lowering springs to deliver a ride much more aggressive than factory. Non-PASM-equipped cars have the same upgrade path, as Bilstein makes the same dampers without DampTronic tech.
Choosing an aftermarket spring is where upgrading can start to get overwhelming. It’s hard to determine with so many options and opinions on the internet without experiencing them firsthand. With that said, only two companies produce the multitude of aftermarket springs: H&R and Eibach. Both companies offer springs directly through them and for other aftermarket companies like TechArt and GMG Racing. Compare the springs to one another, and you’ll find that they all offer a 25mm to 30mm drop and very similar spring rates. Differences in feel and handling quality range from owner to owner, so impressions must be your own. However, there are plenty of forum posts with owners sharing their experiences, so it may benefit you to search through them for decision-making help.
When superior road handling performance is required, and comfort is an afterthought, a set of performance coilovers is the only choice. Porsche followed that same statement when they built the 996 GT3, as they fitted it with a set of coilovers from the factory. Using spring rates far stiffer than any standard Carrera, they helped the GT3 post a sub-8 minute time at the Nurburgring Nordschleife in 2003. The lap times improved with the 997, but the same coilover suspension design remained. Along with their more aggressive valving, the coilovers featured adjustable spring perches for height and corner balancing adjustments.
Aftermarket coilovers can replace the OE springs and struts fitted to your non-GT 997 and the OE coilovers from GT models. Like the section above, several well-known and respected aftermarket companies make coilovers for the 997, each with a slightly different approach to suspension characteristics. As Porsche’s tech improved, so did the aftermarket’s ability to handle it, giving PASM-equipped models aftermarket adjustable suspension designed to work with the factory suspension computers.
KW, Bilstein, Ohlins, and AST are some of the biggest names that produce coilovers for the 997. However, Bilstein is the only company with PASM capabilities. Their partnership with Porsche allowed their B16 DampTronic coilovers to bolt and plug in seamlessly to the 997, providing motorsport-like suspension control and adjustment without massive modification to the car’s systems. The other companies listed above and a handful of smaller companies from around the globe don’t have the adjustable damper control. However, they offer manually adjustable options that provide the firm and sporty ride expected when used in conjunction with one of the various PASM-cancellation kits.
Regardless of what coilover brand you end up with, it’ll all be pointless if set up incorrectly. An alignment by a knowledgeable, motorsport-supporting alignment shop will ensure the best possible handling characteristics the coilover can offer while preventing premature wear of tires and suspension bushings.
A beefier set of sway bars is required to fully dial out the vagueness and understeer of the stock suspension. Porsche’s OE set of M030 sway bars are thicker than the base suspension and are non-adjustable, making them a set-and-forget option, great for a streetcar. They pair very well with the Bilstein B6 dampers and stock springs for a light suspension upgrade.
The OE GT-variant sway bars are the next step up in performance. The front and rear bars are thicker than the non-GT bars, providing reduced body roll and improved turn-in sharpness. On top of that, the bars have multiple mounting holes. Moving the drop links to different positions on the bar stiffens or softens its torsional rate, allowing more or less roll as desired. Their adjustability makes them great for the track or autocross, where different locations require different suspension settings. These bars pair well with a set of dual-purpose coilovers like the B16 DampTronics. However, depending on the model, alternate sway bar drop links may be required.
As with the other suspension components, aftermarket bars are easily accessible. Among others, H&R, Tarret, and Eibach offer sway bars in various sizes and adjustability. Several aftermarket sway bar options are cheaper than the OE Porsche stuff, making them more enticing for a smaller budget. That said, you should end up with adjustable drop links for the aftermarket bars, too. The drop links are what connect the sway bar to the suspension. They are a specific length from Porsche to set the sway bar at the right angle for maximum roll control. Lowering a 997 will change that angle; the best fix is adjustable drop links.
It is worth noting that the 997 does suffer from bump-steer at both the front and rear when excessively lowered from stock. If you decide to slam your 997 or even lower it more than 1” or so from stock, it’s worth looking into bump steer correction kits for your car. The GT3 suffers from this even at factory ride heights to some extent, and there is a large amount of stability and control to be had by making these simple upgrades.
The several aftermarket companies that make adjustable suspension arms will also offer tie-rod ends with an adjustable pivot point to eliminate the bump steer produced from extreme lowering and increased caster angles. Changing to these tie rod ends requires an alignment by a shop that understands how to adjust the ends to eliminate the bump steer. Motorsports-related shops will be the best place to do so as competition-only cars are all that run the adjustable tie-rod ends.
Porsche 997 Suspension Service Intervals/Maintenance
Suspension components don’t necessarily have a set service interval, as the roads and conditions they’re used on are the most significant factors. Typically, the strut assembly components are good for 80,000 miles; any more than that, the car will benefit from a new set of dampers. Check the dampers for leaks every 15,000 miles or so; they don’t usually fail, but regular exposure to rough roads will shorten their lifespan. You’ll notice a clunking over bumps, and the car will feel like floating down the road; the steering response will be vague and imprecise.
All of the suspension arm bushings will be good up to around 100,000 miles. The rubber in the bushings will crack and separate from the metal surrounding them when they start to go. Once they need replacing, you’ll experience a twitchy feeling throughout the car, especially during spirited driving, and a rattling or creaking. Look to change the bushing material if you plan to drive the car more aggressively regularly.
Porsche 997 911 Suspension Torque Specs
Here are a few of the most common torque specs you'll need for a DIY job. Failing to tighten bolts and nuts to their specified spec can lead to damage and a potentially fatal incident.
- Porsche 997 Front Strut Pinch Bolt/Drop Link Nut - 85Nm or 65 ft-lbs of torque
- Porsche 997 Front Lower Control Arm Inner Nut - 120Nm or 89 ft-lbs of torque
- Porsche 997 Lower Control Arm Ball Joint Nut - 76Nm or 56 ft-lbs of torque
- Porsche 997 Thrust Arm Inner Nut - 160Nm or 118 ft-lbs of torque
- Porsche 997 Rear Upper Control Arms - 110Nm or 81 ft-lbs of torque
- Porsche 997 Rear Control Arm & Toe Arm Eccentric Bolts - 100Nm or 74 ft-lbs of torque
- Porsche 997 Toe Arm Ball Joint Nut - 76Nm or 56 ft-lbs of torque
- Porsche 997 Front Strut Mount Nuts - 31Nm or 23 ft-lbs of torque
- Porsche 997 Sway Bar Bracket Bolts - 23Nm or 17 ft-lbs of torque
- Porsche 997 Rear Sway Bar Drop Link - 65Nm or 48 ft-lbs
With all of this info, you’re ready to tackle your 997’s suspension. If there's anything that you'd like to see added to this guide, or if you have any questions, leave them in the comments below. And, if you'd like to see and read more, check back here often and make sure to subscribe to our YouTube channel.
Car and motorsports-obsessed writer/editor for FCP Euro's DIY Blog. Constantly dreaming of competing behind the wheel or searching for another project. Owner of a turbo Subaru Forester and a ratty Porsche 914, neither of which are running.