Suspension Phase I - Scope Definition

So after my first round of mod/maintenance, I thought I would be good for awhile. Unfortunately, upgrading the motor mounts (Rennline Adjustable w/sport inserts, race inserts had too much nvh) and getting the like new Pilot Super Sports mounted that came with the car revealed how tired the stock suspension was. So I went with my first impulse and bought the used KW V3s for sale in the classifieds before they got away. So now I need to come up with a plan (I know it's supposed to be the other way around.) I've read alot of great posts from Vandersmith(whose build I idolize), Alpine, and dporto but can't seem to wrap my head around what the scope for my Suspension Phase I should be. My goal would be to refresh/upgrade any of the components that would require an alignment in a single phase while keeping the cost at a minimum. I'm looking for recommendations on both parts and recommended brands that I should include when I install the coilovers. My '99 C2 Couple is a Daily Driver that I will be using for Track and PCA AutoX (maybe eventually SCCA). I'm a beginner/novice level for DE. Thanks! Brandon

A complete set of powerflex poly bushes is a great way to tie all your suspension upgrades together . The stock bushes are often overlooked , and well they are crap. They degrade over time relatively quickly and stiffer suspension and swaybars only puts more stress on a soft stock part . These cars have multi link suspension so there are lots of bushes to wear out. Poly bushes really improve the handling and steering and last years longer than putting new stock bushes in There are other brands , elefant racing are really high end , I went with powerflex because they are made in the uk ( not China) , they were used in the CSR car, are DIY or small shop installable and I was able to get a package deal from larkspeed on a whole set .they even had fair shipping to Canada . http://www.larkspeed.com/category/view/POWERFLEX Powerflexusa has a site and pelican sells them too Your top mounts are probably gone too

Hmmm, a slippery slope it is! As you're probably starting to realize, there are a bunch of components (all of them actually) in the suspension that are interactive. So, ideally you need to identify ALL the components that need replacement prior to beginning the work - otherwise you start to "chase your tail" so to speak. Just replacing the shocks/struts/springs MAY be ok (Those KW 3's are really nice!), but I'd be sure to really check everything out before doing it, so you don't have to keep going back in to change out different parts... Good luck

I'm really happy with my h&r swaybars , German made quality , reasonable cost , great performance

If you plan on lowering the car with the KW's, I would look into a bump steer kit. My car came with PSS10's and I think I'm getting some bump steer. I can't say for sure because I don't know what the stock steering felt like.

"If you plan on lowering the car with the KW's, I would look into a bump steer kit." ^This^ It's not just for feel either - depending on how low you go, you may not be able to get the camber and toe adjustments within spec. without the bump-steers (adjustable tie rod end links)...

Bump steer kit which can also be found integrated into aftermarket adjustable toe links if you plan on lowering the car 2" or more. Besides being able to adjust toe back to specs, it will save your tires. Sway Bar kit is nice if you track at higher speed tracks with wider turn radius. I believe the KW3 already comes with tophats? You can also upgrade to either Elephant racing control arms or GT3 control arms. Doing this can minimize caster changes under load and keep your handling more consistent at the limit. From a value/budget proposition, I would get sway bars first if you plan on doing DE/trackdays. OTOH, those might not really be a big priority if you just do auto-x's. The most important thing is to make sure all your stock bits aren't worn(control arm bushings, tie-rods, ball joints, etc) and you have a good aggressive alignment(x74 or GT3 spec). Then you can start experimenting with your tire pressures to get the most out of your new setup. I recommend these as a prerequisite.

+1 on Powerflex mention. Really great product and quality. We have them for your 996 here: http://www.pelicanparts.com/catalog/...pg4.htm#item27

OK, great information. It's a lot to process The KW's do come with the top hats I believe (see below). So here's what I'm understanding: - Adjustable Front and Rear toe links will allow for full adjustment to compensate for lowering the vehicle - Sway bar (such as H&R Kit) is the next best bang for the buck for track days - Powerflex bushings can revitalize the control arms Is that right? And I can wait until later to worry about camber plates, dogbones, drop links, thrust arms, and other pieces that I don't really understand yet? Are there other bushings that need to be checked besides control arms if I get the adjustable toe links? Are there bushing for the tie rods also or do I just need to replace those? If so, what brand would be recommended for my application? Sorry for the basic questions. Suspension remains a mystery to me but I'm hoping to understand it by the end of this process. Thanks!!!

I'm curious, how bad were the motor mounts? I actually went and ordered a set after seeing yours. I'm used to a lot of NVH though.

You might as well do ball joints since the control arms are coming off. I just hit 120k miles on my chassis, so it sounds like I'm in the same boat as you. I'm just waiting to finish all of my PM on the motor before focusing on the suspension.

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At 4K it was tough to talk over so pretty bad. BUT, I don't think I had them installed properly, even after calling Rennline to verify. So that might have been some of it. There is a new thread on the other site's 997 forum that details the installation pretty well. With the blue (sport) inserts (and proper installation) the 4K mark is still very noticeable but in a pleasing way. If it wasn't my daily driver, I probably would put the reds back in.

"drop links" aka swaybar end links, you may or may not need when you do the swaybars. People often misunderstand it's use which is to primarily remove preload off the swaybars when you lower a car past a certain point. I don't know how much you plan on lowering it, but you can always go the scientific route and wait until you lower the car and it settles and see if you have any preload on your endlinks before unnecessarily purchasing them. If you're serious about track days though and considering you got some good CO's, I would make sure you get a proper alignment and corner weighting after you install everything to get the most out of them.

I was referring to a full set of suspension bushes , all of them , not just control arm bushings .in a multilink set up that's a lot of bushes by the time you've done the subframe , link arms etc. http://powerflexusa.com/9119961997-2005.aspx

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Got it. How long did it take you to install the whole kit? How many pieces required a press? Thx!

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How do you know if you have pre loaded end links? I just want to drop it enough to increase handling a bit. The look isn't that important to me. I also remember reading that the MKII had lowered the front end more than rear to increase down pressure. Would want to mirror that if prudent.

Im in the same boat as you. I was recently reviewing my suspension on my 99 so I can replace or improve whatever is needed for my needs. I want the car to handle like new, or if possible with a low cost better than new. I was looking at the EPS control arms but they change the functionality of the suspension not necesarilly for the better. The only review I found was on a Boxster forum. http://986forum.com/forums/general-d...m-upgrade.html So right now Im leaning towards replacing all my bushings to the powerflex bushings but im worried it will made the ride very harsh. Any thoughts?

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Looks like dporto went with the EPS fronts/polybushings and was pretty happy with them... https://rennlist.com/forums/996-foru...-good-eps.html

OK. Looks like I can install the coil overs to X74 height and align to X74 spec without having to add additional pieces. That would be awesome and allow me to upgrade the suspension progressively. I will look at going to poly bushings while I'm at it. Thanks for everyone's input and help.

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With your car on level ground, loosen bolt holding end link on the side of the swaybar. You should be able to push the bolt through the swaybar hole with your thumb. If you can't and have to either jack up the carrier or pound it through with a hammer, you have preload. This is a good strategy. Even at x74 height though, you might scrape your front bumper if you have a Aero bumper from time to time.

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I don't know what Moe Monney is referring to, but yes, I replaced mine with the EPS control arms. I did them and the coffin arms before I did the struts (the ball joints were squeaking like crazy) and top-mounts. They definitely stiffened up the feel of the front end, and cleared up some of the squeaking. As I found out shortly after, my struts and top-mounts were shot also... All fixed up now though

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I just went and read the thread in the Boxter forum...According to the dissenting opinion, The Powerflex bushings (straight bushing w/steel sleeve) will get you roughly the same result as the Poly Bushings in the EPS control arms (depending on the hardness of the polyurethane) . In his opinion he also states that theoretically, the Poly bushings will actually give you a softer ride with less precise steering due to deflection of the bushing as opposed to the ball/socket design of the OE arm. I can say unequivocally that the EPS arm is stiffer/more precise in MY CASE, as mine were worn out... I can't comment on how a new OE arm would perform in comparrison as I haven't experienced it.

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Well it definetly helps having your opinion since you have experienced it first hand. I'm still considering the EPS control arms. I'm going to make a decision today. Right now I'm leaning towards poly bushings all around on all parts.

FYI, I went and talked to our local Porsche mechanic/racing expert who will be doing the alignment and corner balancing. He said for what I was doing, corner balancing was overkill but that he would do an alignment for me that would work well for street and track. He also said that he could do it with just the coilovers, but that it would be alot easier if I installed the rear toe links as well (as recommended here.) So I'm going to get a set of Torque Solutions off of Amazon and install those when I do the coilovers.