KW coilovers bottoming out badly

[CrisZenithBlue]

hi guys,

hoping some of you with coilover experience can give me some advice on this issue i'm dealing with.

i bought a set of KW variant 2 for my boxster from a forum member on here and it came nicely prepared with top hats installed with only 2500 miles on them. they have height and shock dampening adjustment. once i installed them and set up my desired height (which was not crazy low) and set the shocks to full stiff then dialing down a couple of clicks they seems to bottom out quite easily on the front only. when i look at the coilovers installed it seems the front spring doesnt have enough travel. the way they are designed when i lift the car the perch moves up and compresses the front spring which i think is causing the problem.

here are some photos of how it looks like now with the suspension loaded:






when i lower the car the perch moves down and i get more spring travel (i think).
i am looking for a setting where i dont have to look out for every little bump when i drive, i really dont want to loose practicality with this setup, i really like how they handle otherwise.

i've been asking around and someone recommended helper springs which would allow me to lift the car and still maintain adequate spring travel. does this make sense? i reached out to KW asking the same and what helper springs to add.

what do you guys think?

i really hope i can sort this out, i really like these coilovers they feel great and handling is awesome.. until i BUMP (BOMB) the crap out of the suspension and it feels like the car will split in half..

thanks,

Cristian

[Smallblock454]

Hi,

this looks wrong. Too much preload on the springs.

Street Performance Variante 2 isn't listed for 2.5./ 2.7 and 3.2 986 cars. Only Variante 1 and 3 (production on demand) are officially listed for these cars.

Are you shure these springs are the right ones for the car? Did you check the number on the springs?

Did you check if you put the right springs in front and back?

Regards, Markus

[rfuerst911sc]

I agree that doesn't look right at all, the height adjuster looks to be all the way to the top. Doesn't look like those are the right springs .

[thstone]

Can you post a picture of the car on the wheels so we can see the ride height? Or can you post a pic if the entire shock body so we can see where the lower collar is within the ride height range?

My best guess is that the ride height was too low. Then the pre-load and valve stiffness was maxed out in an effort to keep the car from bottoming out and when the shock valving is set a little bit softer, it goes right back to bottoming out. Again, I can't see all of the settings so this is just my best guess.

If you want to try making some adjustments yourself, then start by setting the ride right to the factory height. Then lower the car by 20mm. Then set the preload. This should be a decent starting point and the car shouldn't be bottoming out. If it does, then there is something else going on that needs investigation.

If it was me, I'd take the car to a shop that has experience in suspension setup and have them do the initial setup. Then you can adjust from there to your liking and have a known reference point to come back to.

[dijinn]

Are you sure those aren't the rear springs on the front?

[CrisZenithBlue]

hi guys! thanks a lot for all the responses!

i bought the set from a forum member who had them on his boxster and they came installed with the top hats for the boxster which only go one way. the rounded ones go in the rear and the triangle ones go in the front. i confirmed with him and i have the right springs in the front. i also checked some photos online and it seems to be right.

there is no bottom collar, these coilovers dont allow for height and spring compression adjustment separately. that purple collar you see is all i can adjust on the shock except for the dampening up top by turning a little nob.

this is how the ride height looks like right now:



note i had this higher than this by maybe half an inch to an inch and it was the same if not not worse in terms of bottoming out.

this is how the spring looks like with this ride height with the car sitting on the ground:




i just got an answer from the PO with the settings he had on his car where he didnt have issues bottoming out so i think i'll probably try those next.

it just still looks very strange to me.. the spring just should not be that compressed regardless of the height. I've also reached out to the manufacturer maybe they have some advice for me.

thanks,

Cristian

[CrisZenithBlue]

ok i found this site that sells KW Variant 2 for the Boxster:

KW Variant 2 Coilover Kit Porsche Boxster (986) incl. Boxster S - Part Number: 15271001 - Sparktec Motorsports - KW Variant 2 Coilovers


and this is the photos they have of the set (mine look like this):



now correct me if i'm wrong but the shocks with the brackets going all the way down at the bottom for abs and brake sensor cables are the rears right? (on the right side in the photo). i dont even think you can install the shocks incorrectly.

i happened to have a photo of the rear set installed where you can see the brackets:




if you look at the springs in the photo from the website they have the ones that have the same diameter from top to bottom where as the fronts have a larger diameter towards the middle of the spring. this tells me i have the springs installed correctly front to rear.

what do you guys think?
i think the problem lies elsewhere..

[Smallblock454]

Hello Crhis,

KW does definitely not list Variante 2 for 986 cars. I don't know why dealers sell this for the 986.

Helper springs (Vorspannfedern) are in general only used to get a preload on the axle. Helper springs are completey compressed if the car stand on his wheels.

Check the numbers on springs and dampeners and ask KW of USA if these are the right ones.

http://www.kwsuspensions.com

Regards, Markus

[Racer Boy]

The springs look to be compressed nearly all the way when the car is on the ground, judging by the pictures you posted. It looks to me like those must be the wrong springs, they are either too short or the wrong spring rate.

I'd check the number of the spring and compare with what KW lists in their application chart.

[Gilles]

Originally Posted by Racer Boy

The springs look to be compressed nearly all the way when the car is on the ground, judging by the pictures you posted. It looks to me like those must be the wrong springs, they are either too short or the wrong spring rate.

I'd check the number of the spring and compare with what KW lists in their application chart.

+ 1

Chris, based on your pictures something is not right, most likely you have the wrong springs as the perches on my car are about 2-3" from the bottom of the treads on the strut.

Right now we are celebrating our 25th anniversary in Mexico, otherwise I would take a couple of pictures of the KW's on my CS for you.

Hopefully someone will post a pic of his KW's, otherwise I should be able to take some for you by the weekend.

Regards,
Gilles

PS: I am not sure if you will be able to follow Marcus suggestions, as I looked at my struts a couple of weeks ago to get their part number required by KW prior of shipping the struts to them to be rebuilt, and I was no longer able to get any P/N as all of them had faded after 9 + years, you may have to remove them (or better yet, remove all the load on them ) and measure the thickness and height of the springs before you call KW.

BTW, my car sits as low as yours..

[CrisZenithBlue]

hi guys,

i have gotten a response from KW with some instructions on how to install the coilovers but the instructions seem to be from a v3.

Markus has a point, on the KW website they dont offer the v2 for the 986 but other dealers do. my next move has been to as KW directly do they or do they not offer this set for the 986?

if the answer is no then there's my problem..
if they need the part number i'm sure i can get them, the set is pretty new and in good shape but i'll have to have the car up and it might not happen until later this week.

i'll update as soon as i have an answer from them.

Gilles i would appreciate a photo when you have time
enjoy Mexico!

thanks a lot for the help guys, i really wanna get this straight so i can enjoy my car worry free again.

Cristian

[CrisZenithBlue]

Ok so i got confirmation from KW that this is indeed the correct set for the 986 and the reason why V2 isnt offered on their website anymore is because it was discontinued at the beginning of this year. I imagine some dealers out there still have it in stock that's why you can find it. According to them Variant 1 and 3 are currently available for the 986 but V1, 2, and 3 have all used the same springs front and rear with no helpers. The damper itself is the only change in the valve adjustments and in the case of the V3 it has external reservoirs. Aside from that all 3 systems are very similar.

They said it's simply not intended to be used at the vehicles original ride height and that's not just because of the springs but because the shock itself is shorter.

Well that's good news i guess as it would have been a pain to replace everything. My next move is to play around with the settings to find the sweet spot. Luckily the previous owner who had these on his Boxster sent me the settings he had where he was not bottoming out so i'll try those this weekend.

I'll let you know how it goes.

Thanks again to all for your helpful advice! I swear i would hate owning the Boxster if it wasn't for this helpful bunch on here!

Cheers!

Cristian

[steved0x]

That sounds like a good plan, in my opinion, when you lower the car, make sure to keep the same proportion of front to back rake as what is given in the Bentley manual/service manual, which is here on the forum somewhere. The measurements they use are taken from suspension points to the floor which is kind of an awkward measurement but I think it is important. When I first installed coilovers I had the back set too high in relation to the front which contributed to bad handling and a tail happy car.

There will be a lot of jacking the car up and taking the wheels on and off, and using a micrometer to measure your height adjustment (or counting turns of the adjustment collars after marking them with a white crayon) to make sure they are exactly the same side to side.

One helpful tip is to separate the upper and lower collar by some amount, like 5 mm, and count how many turns it took to get there, then 10mm and count that, and then when you measure the chassis height and need to go up or down X mm you have an idea of how many turns of the collars to make (although it is not 1:1)

[Smallblock454]

Originally Posted by CrisZenithBlue

They said it's simply not intended to be used at the vehicles original ride height and that's not just because of the springs but because the shock itself is shorter.

Hello Cristian,

hm, i hope that works. When looking at the pictures i would say you can lower the car maybe 1 inch without hitting the tyres the fenders. But not shure if that will give enough spring travel.

Maybe you should preload the dampers also a bit more. I know that preload is not the right term in that case, but i hope you understand what i mean.

Did they say how low they intended the car to be?

Concerning the setup. Because the springs are progressive the method steved0x suggested won't work perfect, but it's a way to go.

There is lots of infos on setting on youtube and the internet. Always recommend to take a look, because this is not an easy thing if you want to do it right.

Regards, Markus

[jakeru]

I had a car (race-prepped custom shocks) that "topped out", and when it happened, it was absolutely brutal - almost enough to knock the wind out of you over certain bumps at freeway speed! So I do agree not to overlook the possibility of the shock "topping out". Although the ride height picture you posted seemed to show a fairly low ride height to my eye, so it's hard to know for sure that's what's going on, but who knows, but maybe those shocks really are designed to be run at a really low ride height (or, maybe they're just poorly designed - always a possibility with aftermarket products, especially compared to genuine Porsche high-quality parts!)

You might measure the deflection from max extension to normal weighted ride height, and make sure the deflection is reasonable. I'd look for 2" mininum. If too short of a distance, the shock will "top out" - where you run out of extension travel before the spring are close to unloading, which causes a sudden acceleration. In my case, I remember it being most noticeable driving at high speed when you go over certain elevated highway joints that caused the surface to suddenly drop. On working shocks, you don't think anything of it, with topping out shocks, it becomes a section of roadway to consider avoiding. Topping out shocks are not good for handling, too. In my case, car dramatically handled better after redoing the macstrut housing design to place the shock at a more better, more centered position. Hope that helps - good luck!

[steved0x]

It looks like they can be set from a range of .8" lower up to 1.5" lower according to their marketing. You probably have seen these, they contain the minimum and maximum acceptable range of adjustment for the spring collars. These are for the v1 but since KW said that v1-v3 all use the same springs, these settings should be the same across all 3:

V1 instructions http://www.kwsuspensions.com/extras/docs/BBXQ/10271001-eah68671001.pdf

Edit: I found the V2 setup instructions and they appear to be identical:
http://www.kwsuspensions.com/extras/docs/BBXQ/15271001-eah68671001.pdf

They probably use the exact same strut body, springs, collars, etc, with the only difference being the adjustment capability for the damping.

It looks like you can use the dimensions for "A" to set the coilover in the approved range and then you can use "B" as a check. Or you can pick you desired "B" setting and map it to the proper part of the range of "A" to get you close to your desired setting as a starting point.

[Van914]

Nice job Steve!

[CrisZenithBlue]

thanks guys! and Steve thanks so much for taking the time and providing such insight! I'll be playing around with it this weekend, i'll do as much research as i can so i am prepared. will let you guys know how it goes by the end of the weekend!

[CrisZenithBlue]

alright so i lowered the car by about 0.7 of an inch and while it sits low i havent really had any issues scraping except if it's a very deep ramp and i'm not trying too hard to clear it. best part is NO MORE BOTTOMING OUT. moving the perch down by lowering the car gave it some much needed travel in the spring and i can confidently glide over anything without butt puckering

i made sure i was within specs per KW. i will post the exact settings and some photos when i get a chance but here's my dilemma: i would have liked and i think i have to get the rear lower (it would still be within spec on the KWs) BUT when i move the perch low enough on the shock, with the car off the ground and suspension not loaded, the spring doesnt seem to be tight/compressed enough on the assembly. i can kinda move it up and down a bit and that's worrying. as far as i know about coilovers the spring has to be tight enough so that you have to use a bit offorce so rotate/spin it (while on the assembly) but in my case it moves maybe 1-2 mm up and down when i have it at the ride height i would prefer. I cant leave it like that can i? right now it's on there good but the rear is a bit too high. i havent checked if front-rear difference height is still within spec like Steve pointed, otherwise my tail will be happy but just by looking at it i can tell the a$$ is too high.

do you guys think that even if the spring moves a bit, once the suspension is fully loaded it would be fine? i know while sitting it would be fine as the spring compresses but what about in driving conditions when maybe the back lifts a bit? i dont want to have the spring spin or rattle or cause damage.

as Marcus was explaining, that's what helper springs are for but i have no idea if i can put helper springs on these.

as always looking to hear any thoughts or advice you guys might have.
also, the car drives really well, it's just flat and smooth in the corners, grips like crazy and feels more planted all around.

thanks,

Cristian

[CrisZenithBlue]

also, i'm thinking of adding some very minimal spacers on both the front and the rear to stick the wheels out a bit more, it would look better with the car lowered. i havent checked but seeing how the wheel is a bit tucked under the fender now would bringing it out more make it rub on the inner liner?