Hey everyone!
I wanted to give back to the group a little after not finding too much information about Eibach's new lowering spring kit. The point of this post is to share some information and pictures with the group in case anyone is in a similar situation comparing options. I poked around on the interwebzzzz and looks like there were 3 popular options out there for springs: H&R, TechArt, and Eibach. After doing my research, it looks like these drop the car the most, the middle, and the least. I have a few other toys (heavily modified 996 turbo, mildly modified 997 c4s, panamera e-hybrid and a heehaw truck), so I wasn't looking to get too crazy, but the OEM ride height was just killing me! I have PDCC and PASM, and love the OEM features so did NOT want to go to a full blown coil-over setup. I have coil-overs on the turbo and 997 and know the slippery slope that comes with it. I'm sure I could spend 10x as much and get a nicer setup, but I doubt this car will see any HPDE events (ok...maybe 1 hehe) so I wanted to stick with just springs and retain the factory shocks for PASM. I have the DSC sport module, and absolutely love it as it makes the car much more comfortable in normal mode and a bit grippier in sport. In a perfect world, whatever option I went with would do a few things for me:I ended up choosing Eibach because of their reputable brand, and i've used their springs / sway bars on other cars and been extremely pleased with their results. I've used H&R products before, but their springs for this car was too low for my liking. If you were wanting a more track focused setup, they may be a better option. The Techart kit looked great, but decided to go with Eibach as they lowered the car THE LEAST of the 3, and I was a hair more comfortable with the brand. I'll do my best to break this summary down into a few different sections so it's easier to digest. If you want the TL;DR, just scroll to the bottom now. If you want a ton of information, and pictures, keep reading.

THE BEFORE:
So let's start with how the car sat before I started. My build is a 991.1 S with PDCC and PASM. While I do enjoy getting in and out of steep driveways without cringing, I've driven lowered cars for decades now and the ride height was killing me, I think you can see why. The wheels are factory sized 20s, and run the factory size tire.







The Install:
I'm not going to go through a massive step by step, since there are tons of other links / DIYs for that, but thought I'd give my 2 cents on the install in hopes that the next person attempting to do this has. If this isn't for you, just pay a shop, and skip to the review section If you've done suspensions before, this isn't any harder. My best recommendation is to take a ton of pics as you go, of how everything goes together or comes apart in case you get stuck. I have a 2 post lift in my garage and wouldn't consider myself a talented tech, but the install took me a night to do solo with the appropriate tools. The fronts went extremely quick, I left the top hats where they were, and used the 21mm Schwaben strut nut socket to undo the shock from the top hat after unplugging the PASM connector. YOU WILL NEED this tool to do the fronts, though the rears you can get by with using a regular 19mm open ended socket. Schwaben offers a 19mm strut nut socket for this, I bought one, and it showed up 2 days after I was done installing the suspension...so go figure! I guess I have one for the next time I do a set! I unbolted 10mm brake line bracket, the sway bar end link (I have the PDCC option which may look differently than yours) and the bottom bolt/nut holding the shock in and lowered the carrier . After taping off the front fender, the shock compressed down far enough to gently slide the old spring out and the new spring in. The top hat bent back on and the shock went back into the top hat. ONE WORD of advice, is to make sure the rubber carrier which has two notches in it which fit inside the top hat. I had to loosen things up and twist this into place after I took the photo like a dunce...don't be like me, don't be a dunce






here is the correct orientation:





The rears took a bit more effort but still weren't overly difficult. The three 13mm nuts are easily accessible from the rear by folding the rear seats down and lifting the carpet / removing the foam. If you've installed a DSC sport controller (which I can't recommend enough) you know where these are. No special tools are needed to get to these bolts. I used a bottle jack to compress the spring and used some heavy duty zip ties to help compress the spring. I'm honestly not sure if this was absolutely necessary to remove, but certainly helped on the re-install b/c the shock clearance. There is an ABS sensor that should be unplugged as it's quite tight removing the shock. I marked the eccentric bolts, loosened one nut, and unbolted the lower arm to be able to pull the shock assembly out. I used a spring compressor to compress the spring, and remove the top 19mm nut while using a 9mm socket to hold the strut. This is where the Schwaben 19mm strut nut socket would be used but wasn't necessary...it would make the job easier however. Just like the fronts, there are notches in the foam that matches up with the notches for the top hat bolts. Make sure these are seated flush when you put everything back together.



















THE RESULTS:
First let's take a look at what it actually did. I'm sure the car is still settling, but after a few minutes drive here is where the car sits now. Eibach claims .8" F and .5" rear, though I did lower the perch in the rear so that may be a hair off. From the factory, a PASM car (not S-pasm which is 10mm lower than factory) the heights are 28" rear and 27.5" front. This is from the ground to the middle of the fender arch. The new heights after being lowered are 27.5" rear and 26.75" front, so .5" drop in the rear and .75" in the front, PRETTY CLOSE to as advertised (again, with the lowered perch on the rear shock). Since I left the top hats alone in the front, the wheel drove straight, but still wanted to get an alignment. I opted for a more aggressive front camber setting though I think that's why my front wheel looks a little tucked. Here are the before and after alignment settings I used. We couldn't pull the right rear camber in any more, but maybe after it settles I can pull it in. Another project for another day. (If anyone's in the Cincinnati area, I had a great experience with Source One Automotive (huge NSX / performance guys), and they got me all setup. Couldn't say enough nice things about that place, the owner, and workers.)




before alignment but after spring install :



after alignment :





and now...the glamour shots...








aaaaaand some light painting shots...









aaaand some rolling shots







FINAL IMPRESSIONS: Ok, so you've made it this far, nice work! So what do I think? Well.. for one, I would absolutely do it again. I'm very happy with the spring rate, and the ride quality is very similar to OEM. I can tell it has springs so bumps are a hair more noticeable, but I doubt my passenger will tell the difference. I also have the DSC sport module, so your results may vary. Temperatures here in Cincinnati currently 50-55 so I haven't pushed the car 100%, but I can tell a nice improvement in the twisties. I would say the trade off of 10% stiffer ride is worth the 15-20% better performance and 100% better looks. I can't tell if it's my eyes, but if I had to make one suggestion to Eibach, it would be to raise the front JUST A PINCH. I'm not sure if the car looks lower in the front than the rear because of my more aggressive front camber, or desperate need for spacers up front now (LOL), but other than that I'd give them a 95 out of 100. I'd definitely buy them again.

I will leave you with some final spring rates. Here is what I currently know about the 991.1 platform vs eibach vs a few others. After reviewing this data, this would make sense that my ride is very similar to what it was before, but bites a little better in the corners.
This is all sourced from different rennlist and 6so posts so don't shoot the messenger, just sharing what research i've found. All numbers are in n/mm. If you want to convert to lb/in multiple it by 5.71111111. Also 1kg = 55.997 lb/in

• Basic 991.1 Carrera Chassis: F24 / R48 (NM)
  991.1 Carrera / Carrera S PASM Chassis: F28 / R62 (what I have)
  991.1 Carrera / Carrera S PASM Sport Chassis: F33 / R108 (this is the one that's 10mm lower from factory) or
• Eibach: Front is progressive F22-32 and rear is progressive R46-70
• 991.1 GT3, 991.2 GT3, and 997 GT3-RS has rates of F45 and R120 * apparently there is some discussion on the .1 vs .2 rates as they moved to a progressive spring and lightened PASM load for .2 GT3, but for this post you get the idea
• 991.2 GT3RS is F100 / R160
• KW HAS: F44 / R100
• Bilstein B16 Damptronic full coilovers: F50 / R110
• Elephant Stage 1: F52 / R96
• H&R VTF: ???
• Techart: ???
  
  Since it seems like no one does all NM, or all LBS/IN or all KG, i thought it would be nice to make this little graph.

• 

 

Car looks really good! I don't know if I will do the same as I kind of like the stance of my GTS. I have played around with suspensions all my life as well so you never know though!

 

Thanks! I'm honestly not really sure where the GTS lies in spring rates, do you know off hand?

 

No, I do not...need to look it up.

 

Man that looks great, how’s the ride quality?

 

great. I’d say 10% stiffer. With the DSC sport controller it’s the same or easier than factory.