thanks; M8 x 1.25. odd thread choice since you can get neither flanged nuts or 10.9 grade hardware with that pitch. not sure what their rationale was there....

They probably got a really good deal on the bolts!

So, will you use washers or what?

I need some guidance on this one.

definitely use flat washers. BTW, my KSports will arrive today. i don't think i'll get a chance to install them tomorrow; slammed with work. i'm out of town from tuesday -> labor day; i'll probably install them on tuesday the 2nd. i'll take lots of pics & do an installation write-up.

Great thread! I have been tossing around some ideas too as the left front is creaking now. However, I don't track it (yet) but I do take it on long drives and should get myself to an AX to give it a try. I really don't want a stiff ride either, so the PSS9's might be the best choice albeit a little pricy. Maybe the M030's would be better suited for me? I see Suncoast has the kit for $1088 so that is more doable for me.

How are the KS's for comfort?
Chris

The KSports are very tolerable at the softest setting. I just recently reminded myself of how much range is in the settings. I had been running them pretty stiff because of a couple of AX's, and yesterday set them back to full soft. What a difference! At full soft, I'd say it's only a bit stiffer then stock. At full stiff, the car is like a go kart, and my wife gets a bit queasy.

I find my Ksports very uncomfortable even at the softest setting.

I was thinking today as I was shopping for the 14th time today preparing for the storm.

Yes I am staying...In Baton Rouge.

Do you guys think that part of the reason I am so unhappy is because I am running 19 inch rims with 30 height tires?

I am going to get the softer springs mentioned earlier.

the 19's have a LOT to do with it. good luck with the weather!

If I went with a higher profile tire would that help?

But, I think I may get rubbing issues if I go taller.

I just need a 996TT to daily drive and save the Boxster for the weekend!!

Gary, I think that's a great idea. TT for the DD, keeping the box in the garage for sunny weekends and track use.

Of course, you'll need to do an engine swap on the box so it doesn't feel so pokey compared to the TT.

I would have to do more than an engine swap ;)

Maybe swap in a 3.4 and put a TT kit on it??
Nah...I keep telling myself I am on the last leg of mods, and then I buy her a garage mate to mod.

ksport photos
 

Insite-

Please post pics of ksports installed on boxster with out the tire.

I have 19's installed on my boxster and need to know more about clearance issues. Barely clearing stock set up. 2mm or so from the bottom of spring perch (fronts) and 2mm from rear strut.

OMFG you are my twin! I promise I am done after this.

ok, i WILL be doing my installation tomorrow. i will measure clearances with my OEM suspension and also with the coilovers installed. i will take lots of pics and do an installation write-up. i imagine i will be tweaking things for a couple of days to find the right setup; i will have it all laser aligned on monday.

on the 18th, i will take it to the track & do a comparison write-up to M030. i will also have an opportuninty to compare back to back the ksport setup and PSS9 setup. more to come......

they're in. took about six hours total. right now the ride height is a little high; i'm going to give it a day of driving to settle and then lower it to around M030 up front and a bit lower than M030 in back. i have not played with the damping at all yet; currently they're all at full soft. the ride is actually pretty comfortable.

i'll try to post an install DIY this weekend. one thing of note: the reason they left the helper springs off the rear struts is that they interfere with the wheels. no matter; there is no slack in the spring at full droop, so the helper isn't really needed back there.

ok, took the car to get it aligned yesterday. i couldn't get the numbers i wanted with the top mount settings i used. for now, i'm going to recommend leaving them in their center positions like they came from KSport.

another note, the rear helper springs WILL fit and allow reasonable ride height without interfering with the wheels. i recommend using them.

still trying to find the 'right' street setup. the adjustment knobs DO have 'clicks'; there are 36 of them. i think running the front around 30 and the rear around 24 gives a reasonable street / performance ride.

i am having some issues with wierd bounciness on the street. i decided to run some calculations to figure out why. turns out i'm having some issues with harmonic amplitudes due to the combination of spring rates i chose. usually, this is a non-issue, but since our cars are rear weight biased, it becomes an issue. i will start another thread on suspension design and link to it here. i will post shock dyno plots and setup analysis in that thread.

my installation notes for the rear are complete; i have to break it into multiple parts since i'm limited as to the size of document i can post. i'll put it up in just a minute. i hope to have the write-up on the fronts done shortly.

here are the install notes for the rear. FYI, M030 RoW ride height puts the front fenders 25.25" off the ground and the rears 25.75" off the ground. i set mine up to be 25.25" front and rear. 1" of adjustment at the coilover equals 1" of ride height change.

here are the instructions for installing the fronts.

Um, I have matched my spring rates to yours. Should I use the ones that came with the set instead or what?

My control arms will be in next week and I need to get this all sorted out before I send the car to the mechanic or I'll be in for a lot of extra time and costs to get it right.

Thanks for all your help here and experimenting in advance of my installation, by the way!

insite,

Thanks for posting the pdf's showing the procedure from start to finish. I know that it was a lot of work to put together and I just wanted you to know how much I appreciate your effort.

I did note that the strut is not adjustable for ride height independent of the spring perch like you thought in your original comparative analysis. Is this something that is just not available on the 986? It does not seem that any coilover systems offer this. Would the absence of this feature lead you to go for a different brand (ie the PSS9) if you were doing it again?

did you get the 400/500 setup, or the 300/400 setup? i thought you traded out your rear springs for 7kg.

i'll try to explain the harmonic issue i'm talking about. when we design suspension for a car, one of the first things we do is to choose the natural frequency of the suspension. this is the rate that, if undamped, the car would bounce up and down at. higher natural frequencies make the car respond faster while lower natural frequencies make the car respond slower (and they make it more comforable).

the natural frequencies for road cars tend to be in the .5 - 1.3Hz range. street / track cars and some formula cars tend to be in the 1.3 - 2.0 range. high downforce formula cars are over 2.0. these frequencies are determined by the spring rate.

we actually want to choose slightly DIFFERENT frequencies for the front and rear axles. the reason for this has to do with how the car reacts over bumps. if the frequencies are the same, the rear of the car is at maximum height when the front of the car is at minimum height. this excessive pitch / dive is felt as bounciness at lower speeds. ideally, we want the rear frequency to be about 10% - 20% higher than the front.

the frequency is based on the motion ratio of the suspension (this is the distance the wheel travels compared with the distance the shock compresses in the y direction), the SPRUNG mass, and the spring rate. for our cars, the motion ratio is about 1.43. if i assume a 3000lb car with 100lb unsprung mass per front corner and 115lb unsprung mass per rear corner, then the sprung mass at each front corner is about 600lb and each rear corner is 680lb. the springs i received are 7.0mm/kg (392 lb / in) up front and 8.7 mm/kg (486 lb/in) in back.

this works out to a frequency of 1.76 up front and 1.85 in back. this is a difference of only 5%. the car would ride much better on the street if this were greater than 10%.

FYI, the stock KSport frequencies are 1.53 and 1.88; this is a 23% difference and is too great.

the softer spring rates i recommended (5.3 / 7.0) would work out to 1.53 and 1.66, an 8% difference.

usually this problem isn't so tough to overcome; the rear biased nature of our car means we have to compromise: the best spring rates for balance (under/oversteer) aren't necessarily the best for ride quality

if one uses the 5.3kg stock KSport front springs, they'd want a rear spring rate between 403 lb (7.2kg/mm) and 440 lb (7.9kg/mm) for a 'flat' ride.

if one were to use the 9.0kg rear springs (mine showed up as 8.7 rather than 9.0), they'd want a front spring rate between 322 lb (5.8 kg/mm) and 360 lb (6.4 kg/mm).

no problem! thanks for the feedback.


it is not available on the 986. the strut receptacle on the wheel knuckles isn't large enough to accomodate the required sleeve to allow this feature. this ommission alone would NOT be sufficient to cause me to seek out a different brand (since nobody has them).

You are correct. It's been just long enough for me to forget these details. I have the 5.3's in the front and the 7.0's in the rear. I take it you don't think I'll experience that bounciness you're experiencing on the street?

I'd love to avert having this upon my first drive after installation.

it's hard to say whether you'll feel it or not. you're at an 8.2% differential with those spring rates. ideally, you'd want a slightly stiffer rear or a slightly softer front. if you want to be positive these harmonic issues won't affect you, trade your rear springs for something in the 7.5 mm/kg region.

I just checked the box and my paperwork. The ones they sent me to replace the 9kgs are 7.2kg. As it stands, my setup will be:

Front: 10.5-205 (stamped on the springs) = 5.3kg
Rear: 11-180 (stamped on the springs) = 7.2kg

I also read through all the PDF's you posted for the install while eating my lunch at my desk. Very, very helpful. Thanks so much!

are the 11-180's 7.2? they told me 7.0....

anyway, your rear frequency should be 9.7% higher than front. this is borderline; it's your call.

I asked him to double check his calculations and he said it was 7.2kg.

your initial reaction
 

Insite-

so far from what you have experienced, how are they? Have you driven a boxster with pss9? if so, how do they compare?

to give them a fair shake, i have to get them dialed in first. i will have a chance next thursday to compare my car w/ ksports side by side with a 987 on PSS9's.

i pulled my rear struts today to re-set the top mounts; when i put it on the alignment rack yesterday, my MAX rear camber was -1.3 and my MIN front was -1.8; clearly i made a bad guess!

tomorrow i will pull the fronts & reset their top mounts. i may be able to vary the weight balance on the car a bit w/ ride height to minimize the harmonic issue.

once i have the ride heights and alignment in good shape, i'll continue my testing for a few more days on the street. after the track next thursday, i'll post my thoughts.

Insite, do post the ideal positions of the tops of the struts as well so I can preset them before giving them to my mechanic for installation. Thanks!

i'm doing an engineering analysis of the ksport dampers here: http://986forum.com/forums/performance-technical-chat/18178-evaluating-designing-suspension-ksport-examined.html#post159952

there are dyno plots, evaluations of the dyno results, and discussion on damper settings here. feel free to ask lots of questions and get very technical!

the drawing below shows the two settings i tried on the front camber plates. the setting on the left is 2/5 of the way between center and the next largest hash mark. the setting on the right is dead center.

the camber range available to me using the FACTORY adjusters with the ksports set as shown are:

Left Drawing
Min Camber = -1.1 deg
Max Camber = -1.9 deg

Right Drawing
Min Camber = -1.8 deg
Max Camber = -2.5 deg

since i track my car, i have set front camber to -1.6. for a street car, i recommend a setting between -0.8 and -1.2. unless you need more than -1.7deg camber up front, leave the KSport camber plates exactly in the middle (factory setting).

usually, lowering the boxster makes it difficult to set proper camber in back and still get a good toe setting. because of this, lowered boxsters usually suffer from excessive rear camber. this is frequently corrected with aftermarket toe links.

ksport tried to provide a remedy for this. i THOUGHT i needed to use the 'less camber' setting (shown on right below) to dial some camber out. i was wrong; either by design or by accident, the center setting is pretty much perfect. i was able to get my toe in spec with as little as -1.5deg camber in back.

here are the camber ranges i could set at the concentrics on the control arms with the KSport plates in the positions shown.

Left Drawing
Min Camber = -1.1 deg
Max Camber = -2.2 deg

Right Drawing
Min Camber = -0.6 deg
Max Camber = -1.3 deg

for street cars and light track duty cars, use the center (left drawing) setting. if your car is strictly track & you use R-Comps and want more than -2.2deg camber in back, then use the third setting that is not shown (slid all the way up in the drawing).

on another note, i think i have found the 'trick' setup for my car. i was having harmonic issues between the front and rear because of ride frequency interference. i decided to try and correct this a bit by running the rear ride height a little higher than the front. currently, my front ride height (measured to the fender) is 25.00" and my rear ride height is 25.50".

this seams to have calmed the bounciness a bit. also, i set the dampers to my 'calculated' settings (24 up front, 27 in back) and got it aligned properly. it feels pretty comfortable.

i haven't had a chance to get aggressive with it yet in this configuration; i'll leave that to tomorrow.......

countdown to track day: T minus 6. weather outlook? 82 and sunny. :cheers:

Thanks for the additional information you have posted.

What is your conclusion about spring rates and settings? Or are you at a final conclusion yet? I am seriously considering ordering these and want to get it "spot on" the first time.

I am looking for a great street performance and occasional ax setup.

Thank you insite.

Another fine in-depth analysis by a skilled driver with a well tuned Boxster chassis for all of us to see. Penske has been doing this stuff forever on all their competition suspensions but they keep the results under lock and key. Nice to have our own forum race tuner who clearly understands that getting your suspension dialed in requires math, measurement... and testing. Definitely not a bolt-em-on-and-go proposition. It looks like you are getting close to hitting your ideal numbers. The car should feel great. Thank you again for sharing.

I found the ride height differential very interesting. Something Porsche figured out a while ago that I would not have guessed. Have you compared dampener performance at different operating temps? We wrestled with this doing prototype suspensions on motocross bikes. Shock fade was a big problem on early long travel systems during a hot day at the track.

Insite,

can you help me better understand the monoball uppers you posted pics of?

Are these FLAT plates that mount to the stock shock mount for the Boxster?


I'm HIGHLY concerned you are running flat plates in the rear of your car.. as this can cause the shocks to BOTTOM out. The Boxster mount is XX inches taller than any flat plate mount we have. We tried the flat monoball plates from the 996's in 2000 or so.. and had to RAISE the ride height to keep the shock from bottoming out INSIDE the tube.


I know you have the super whammy shocks that adjust ride height independant of the spring perch (from what I gather) so maybe the flat plate works well??


B

these replace the factory round strut top mounts. they are indeed flat monoball plates.

the application for the boxster does NOT use a setup w/ ride height adjustable independant of the perches (i was mistaken); most of their applications allow independant adjustment, but not for the boxster.

i'll have to take a pic friday when i put my street pads back in; KSport chose a very short shock body for the rear to deal with the problem you're talking about. the shock body is actually matched to the monoball plate, so it works well. at a fairly racey ride height, the shock still has a few inches of compression travel. additionally, these dampers have internal and external bump stops (although i don't ever really hit them).

i'll post some more info on this when i have a chance. i need to figure out in what increments KSport offers spring rates; at that point, i'll post a couple of combinations that won't have any harmonic issues.

the ride height thing is interesting indeed. i figured i could shift the weight around a bit w/ ride height since it's the sprung weight that matters for purposes of harmonics. i figured i'd try the M030 solution: 1/2" higher in back. works like a champ.

as for shock fade? i'll know on thursday. for those interested, here's some background on what Topless is referring to: dampers absorb kinetic energy. this energy has to go somewhere; that somewhere is heat. when the dampers heat up, the fluids inside change visocity and the gasses inside increase in pressure. this causes the damping charicteristics to change with temperature. in some dampers, this effect is pretty dramatic; the car won't handle.

thursday, the high at little talladega is only supposed to be around 82; they'll still get a good workout. i'll post my findings after my testing day.

Pics would be great! Your comment about the car having harmonic issues threw up the red flag for me :) then the flat plates..

Have you "zip tied" the shock shafts to find out much travel you are currently using on the street?




B