KSport Coilovers: All About 'Em

[insite]

Originally Posted by Boxsterund914

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.

no problem! thanks for the feedback.

Originally Posted by Boxsterund914

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?

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).

[RandallNeighbour]

Originally Posted by insite

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

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.

[insite]

Originally Posted by RandallNeighbour

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.

[RandallNeighbour]

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!

[insite]

Originally Posted by RandallNeighbour

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.

[RandallNeighbour]

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

[whitespyder]

Insite-

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

[insite]

Originally Posted by whitespyder

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.

[RandallNeighbour]

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!

[insite]

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!

[insite]

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).

[insite]

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).

[insite]

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.

[Boxsterund914]

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.

[Topless]

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.

[Brad Roberts]

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

[insite]

Originally Posted by Brad Roberts

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?

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

Originally Posted by Brad Roberts

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??

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).

[insite]

Originally Posted by Boxsterund914

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.

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.

[insite]

Originally Posted by Topless

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.

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.

[Brad Roberts]

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