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YOUR RESEARCHBilstein B6?s and springs?
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Install row c4s kit w/ koni adjustable dampers
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I just bought and installed the RoW C4S kit w/ Koni adjustable dampers from Carnewal (Belgium).
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Suggestion
Anytime the car is lifted and lowered and the tech/user doesn�t check spring seating, it�s a liability that the spring could be precariously positioned.
Leading evidence: 'Install row c4s kit w/ koni adjustable dampers' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check spring seating' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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I ran B6/H&R sport springs for years with no issues.
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Suggestion
Anytime the car is lifted and lowered and the tech/user doesn�t check spring seating, it�s a liability that the spring could be precariously positioned.
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Suggestion
Any idea why could�ve changed from 200 miles ago when the spring was loose?
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Check spring seating
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Suggestion
Anytime the car is lifted and lowered and the tech/user doesn�t check spring seating, it�s a liability that the spring could be precariously positioned.
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Suggestion
The Ohlins are on my short list to replace my OEM (95k miles) so I'm just trying to get as much info for my use cases (which includes driving the 996.1 cross country and back).
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Suggestion
I�ll note too, the car can�t tell how much preload is on the spring until the shock hits the end of travel (that might set ride height on a coil over, but that isn�t what we are talking about with B6 vs B8).
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When I called Bilstein they said I could use H&R Springs or OEM springs, so I used H&R. I ran B6/H&R sport springs for years with no issues. I actually liked the setup a lot. Only went to coilovers when I went to 18 inch wheels.
Hey guys, I'm new to the brand and recently purchased a 2002 Carrera Cabriolet. I'm in the middle of updating the struts/shocks (Bilstein B6 kit from FCP Euro) and am running into an issue. According to the options sticker in the maintenance manual, this car did not come with the M030 option but I'm finding a discrepancy between the OEM strut and the Bilstein one. I have about 1-1/4 inch difference between the two struts. I can't torque down the top nut because it bottoms out before I can tighten it down and the spring is lose in the assembly. I'm currently waiting to hear back from FCP Euro to see what they say.
My guess is that one of the previous owners lowered the suspension at some point and that's why the B6's won't work with the springs I have. I might need to order new springs that'll work with the B6's. OR, I'm doing something completely wrong.
Here are the part numbers of the old parts on the car.
-Front Strut: 996 343 041 18, don't have P/N for the spring but the color identifier is GREEN/RED on the bottom and ORANGE up top
-Rear Shock: 996 333 051 22, don't have P/N for the spring but the color identifier is GREEN/RED on the bottom and BLUE up top
I've added some pictures with measurements. One of the pictures also shows the order of all the components when I assemble it. Maybe I'm doing something wrong.
As I mentioned, I'm in currently communication with FCP Euro but I figured I'd ask here to get your thoughts.
Thanks!
Spring colour markings are listed in the parts catalogue, available as a pdf on porsche.com
Look them up to see which option code they belong to and then search for the amount of lowering they provide.
It could well be that the springs and dampers are M030, retrofitted to your car (I read here that those shocks were black, just like standard dampers) and the B6 require stock springs to provide the necessary pretension to seat them properly under all circumstances.
B8 would be suited for shorter spring in the old Bilstein nomenclature.
Thanks for the information. I wasn't aware of those parts catalogs. I ended up looking at the catalog for both the U.S and ROW, and it looks like these part numbers are for ROW M030 sport suspension. Looks like I'll need new springs that will work with the B6 shocks.
Thanks for the help!
I�m not so sure about this. FCP Euro says the RoW shocks are B6, so you�d think they�d physically work with your RoW springs.
I just bought and installed the RoW C4S kit w/ Koni adjustable dampers from Carnewal (Belgium). They have the Konis painted black to look like the original B4s. They�re a pretty well known Porsche shop.
To my surprise, the Konis are the exact physical dimensions as the B4, so I ran into a similar problem as you where my front RoW M030 springs are loose in the spring carrier when not under load.
I went ahead and installed them, just made sure the spring was located properly when lowering the car back to the ground and I�ve been driving for a few days with no issue.
I think the B4 and the B6 are the same physical dimensions too, and the Koni, so it�s weird that 2 reputable shops are saying the B6/Koni shocks are compatible with RoW springs.
The B6 strut and the one I removed from the car are not the same physical dimensions...I provided pictures of the measurements on my original post. I'm also not a big fan of the idea of the spring being loose until its under the weight of the car, and I'm not able to properly torque the top nut because it bottoms out before I can tighten it.
According to the international parts catalog, the old struts/shocks are for the ROW M030 suspension, which my car does not have. I have provided all the part numbers and pictures to FCP Euro to get their concurrence on this...hoping to get an answer tomorrow.
Something else might be the problem.
Look at your pictures - the distance from where the small washer sits on top of the shaft (the smaller diameter portion of the shaft) to the very top of the shaft is the same for both struts - about 2.5�. You should be able to torque the bolt regardless of the spring.
The stack from that beveled portion of the strut is what I�m suspicious of. Should be the small beveled washer, the large bowl shaped washer, then the rubber spring seat, the strut mount bearing seated in the metal housing, then the strut mount, then the other bowl shaped washer, then you strut nut/washer or nylon nut.l like you have it laid out.
Did you purchase new strut mounts?
I might be reading this wrong, but what you mentioned is exactly what I have in the picture that shows all the components in order. That's the exact order I disassembled the old strut. I ordered the entire kit from FCP (22046123KT), which include the new mounts.
The other thing I've read, and its noted in the FCP site, the B6 are designed to be paired with the OE factory springs. For the lowered springs, it should be the B8's.
Again, first time doing this and I could be missing something.
You should be able to torque the top nut, it shouldn�t bottom out regardless of the spring. Something else in that stack must�ve changed I would think because the dimension on that portion looks the same on both struts.
The springs will definitely be loose on the front under droop, I�m seeing the same thing on my car. But that top nut should torque down.
Around 17:30 in this video is a good sanity check for how to reassemble that stack:
You Tube
Yup...at this point I've watched that video 10 times, making sure I'm assembling correctly. I agree that the top nut shouldn't bottom out, but it does. I'll see what FCP tells me when they get back to me.
I also reached out to Bilstein, but haven't gotten a response.
Man that�s weird, sounds like you�re doing everything right. Please report back with what you hear because this is thoroughly confusing, especially when FCP states the RoW M030 kit utilizes the B6 damper!
https://www.fcpeuro.com/blog/the-def...996-suspension
RoW M030 springs, identified by the colour coding matches the catalogue info, are stiffer and to achieve the 20mm(?) lowering, they are shorter than springs that offer NA or RoW ride height.
As such, they require either the OEM M030 shocks or Bilstein B8 to have sufficient pre-load remain at full extension.
The fact that they are loose when combined with B6 proves it and it also proves that the internet info on that combo being possible is wrong.
Stock, B6 (and B4) dampers require the springs that provide stock ride height, be it North American ride height or the 10mm(?) lower RoW ride height, as they are long enough to maintain sufficient pre-tension at full extension.
OP's foto shows the differences in extended length between the two.
Generally speaking, a spring with too little preload can become unseated and rub against rim flange or worse, against tyre sidewall, possibly puncturing it.
@AeroF16
It not having happened yet says very little.
Apart from that safety risk, the car will be underdamped. Can't see a reason for such a combo on a Porsche, really.
Understood but, why would a reputable and well known shop like Carnewal sell a kit like this then? That was my surprise when I received the kit but I ignorantly assumed it would work because of who I was purchasing from.
http://www.carnewal.com/products/996...ith-Koni-Sport
I should add, the springs on the front of my setup aren�t so loose that they would escape the lip of the spring carrier at full droop, but they aren�t fully seated against the strut mount either, just some slip in between.
Not sure what to think of it now honestly. I didn�t think it would present a safety concern when installing as they would at least be contained in the carrier, I was just worried they might rotate a bit and not be 100% aligned in the carrier.
Well, I just got off a call with FCP and they said the B6's work with both stock U.S height springs and ROW M030 springs. As
@AeroF16
stated, the spring is not so loose that it'll move out of place.
I'm in the middle of the install and inserted the through bolt from the sway bar link and the mount nuts and the spring is no longer loose. I'm going to move forward with the install based on what FCP told me. I'm planning to take it to my local Porsche indie shop afterwards to do tires/alignment, and I'll run it by them as well.
Thanks for the help guys!
Well, glad you got to a solution you�re happy with!
Can you elaborate on the bolt your talking about, after which the spring was no longer loose?
The sway bar end link on my C4S bolts directly to the spring carrier, not sure how that would affect the spring preload. Or are you referring to the strut mount bolts being torqued down that got rid of your slop in the spring?
The sway bar link bolts through the strut carrier and tightens the strut in place. Then using the floor jack I raised the entire assembly to the ride height by using the markings on the lower control arm. Then install the top mount nuts. With the everything at ride height, the spring is no longer loose.
Ah ok, yeah that is what I see in my setup as well.
I�ll have the car back in the air tomorrow. Seems all my suspension parts are settling in, as the front has dropped 5/8� so far, a little bit over each day.
Curious to see if mine springs are still loose at full droop.
To give closure regarding residual pre-load at full extension of the shock.
Porsche obviously deems it needs to be higher than the pre-load of RoW M030 springs in OEM standard ride height dampers and/or aftermarket dampers with the same rod extension length.
Sellers of these aftermarket dampers consider the spring preload of above combo to be sufficient. That's no surprise as they want to sell and have a greater market by stating that combo works.
It would be interesting to know what Bilstein and Koni say to this. I expect they will side with porsche's view as the manufacturer of the product/car, for which they 'merely supply' replacement parts. To add to that bilstein has the B8 damper family, that is explicitly intended for use with lowering springs, whereas B4 and B6 are for standard (ride height) springs. Koni had the same in the past with their sport product family. They wouldn't have that, if they didn't think it was necessary as it increases their cost.
Having said that, private individuals can decide for themselves and in case they've read this thread, they're even aware of potential side effects (noise) and risks.
Depends on the settings. They are adjustable from very stiff for track use to buttery soft on the road.
The roads in my area can be pretty bad so I was sore from the bumps after long drives. The car handled like it was on rails but just too stiff for me at my age.
The Ohlins suck up EVERYTHING!! I have adjusted them twice and may do so again.
Thanks. The Ohlins are on my short list to replace my OEM (95k miles) so I'm just trying to get as much info for my use cases (which includes driving the 996.1 cross country and back).
100% agree...
Been rebuilding dampers & suspensions for longer than I care to admit. Off road, dirt track, scca, dunes, sports cars, dirt&superbikes, Ax, drag. you name it I've learned from some of the best in various industries. Might not be an expert professional, but know enough to tell you a lose spring at any point in suspension travel is wrong.
IMHO & experience, No suspension should ever have the spring go lose at any time in full suspension travel, ever. Thats one reason they make helper springs and limit straps. If you can't dial in the spring length to correct full drop preload, those will still allow correct travel in the correct applications
Don't listen to those that tell you different, its incorrect.
Some suspension setups use a big thick c-clip type washer to lock in the top spring mount. Only thing holding in the clip in is preload. If that clip ever came lose the spring would dislodge and suspension would drop.
What I'm trying to say is, all suspensions need some, even if its just a little preload at full suspension extension...
If you don't need a spring compressor to remove/replace your struts spring, either you're a wild man shop danger or not enough preload in your setup.
Hmmm, how did that happen..? Was it a oem Porsche spring ? Never seen a 996 bust a spring. suppose it does happen....
I see your points and I'm hope to hear back from BIlstein themselves. Reached out to them a few days ago and haven't gotten a response yet. I'll make sure to provide an update when I do.
Here are two videos of drivers side installed. One with the assembly fully extended and one at ride height.
Honestly im just not comfortable with it. To me there needs to be some preload at full extension. I�m just going to ordered new springs, if nothing else, just for the ease of mind.
Mine aren�t quite that loose but my shock mounts are different than what yours look like, so maybe that�s the slight variation.
I agree that it�s definitely not an ideal situation and, if I knew this prior, I would not have bought this combo.
That being said, I�ve put about 100 miles on mine in the last 3 days or so and I have zero concerns about this becoming a factor while driving. I understand that it could, but I think it�s very unlikely for how I drive and use the car, so I�m leaving mine for now. Car drives great, no noises or clanking or rubbing or anything.
If it becomes a factor, I�ll put my stock springs back on as they are in very good condition.
The B6/Koni and lowering spring combo is so common - why haven�t we heard more about this issue? My guess is, most people have no idea because they have a shop installing the parts. And unless you are tracking the car or driving like Dukes of Hazard, I�m not sure in what scenario your suspension would travel that much and cause an issue.
In order to try to understand this, I looked at Bilstein's International Catalogue (excludes US). Adding to the confusion, they say the B4 is the OE replacement for the RoW M030 setup. And their cross reference part numbers match the PET for RoW M030.
Bilstein International Catalogue
yeah at this point I have no idea what to believe�.earlier I stated I was going order new spring but I haven�t. The springs in rear shocks have zero movement at all. I�m going to run it by the shop when I take it in for alignment.
If they confirm it�s incorrect I�ll order the springs and swap them out.
IIRR, Porsche oem uses the B4 in many different configurations, all called B4. Its all depending on suspension type. Standard USA suspension, sport suspension USA m030, ROW m030. All those different B4 have different specs but are 'B4' shocks....
So I jacked up only my drivers side of the car yesterday, both front and rear tires fully off the ground and in full droop.
Reached in to look at the front RoW spring and it now has plenty of preload and no play in it. I have done nothing mechanically different other than drive about 200 miles.
Any idea why could�ve changed from 200 miles ago when the spring was loose? I did all the control arms up front and new strut mounting hardware, could the rubber bits just be settling?
With only one side of the car off the ground the sway bar is preloading the lifted wheel. So the compression on the passenger side is lifting the drivers side (preloading it) through the sway bar.
If you want to see what the preload is, lift both fronts or both rears off the ground at once. I am curious, as I have US M030 car with newish B6s and I would like to put RoW springs on it.
This may be a good illustration of how often the spring would unload even in a track or hard-driven setting� if one wheel is heavily loaded, and sway bars are present, both will still be loaded. To have a spring unload you need to unload the spring and the sway bar - as you just demonstrated, you need the whole axle off the ground. One caveat would be, if you aren�t running sway bars, you can fully one spring (I have built droop limiters for a track car not running bars�). The other caveat is, if the shock travel were shorter, while the spring would have more preload, the sway bar would appear much softer when the shock reaches the end of its travel (end of shock now rolling with car body), so in roll, the car with the long shock will have a more progressive sway bar rate past what would be the short shock end of travel. I�ll note too, the car can�t tell how much preload is on the spring until the shock hits the end of travel (that might set ride height on a coil over, but that isn�t what we are talking about with B6 vs B8).
Regardless, it is still preferable to always have the spring captive in the strut. Anytime the car is lifted and lowered and the tech/user doesn�t check spring seating, it�s a liability that the spring could be precariously positioned.
