KSport Coilovers: All About 'Em
 

been considering coilovers for awhile now. looked at PSS9, JIC Cross, KW, H&R, D2 Racing, and KSport. i have finally decided on the KSports.

i'm posting info on how / why i arrived at my decision, what options i've chosen, what i expect, and finally, what happens when i get them.

the PSS9 seems to be the defacto standard coilover for our car. their standard spring rates are a little soft for what i do with my car. they also use metric spring ID's, which is a bit of a PITA when looking to upgrade w/ aftermarket springs (it is doable, though, without much trouble). i'm of the opinion that if they are valved for 260/370, they will be undervalved for springs in the 400/500 range. they're a reasonable bargain, but i'd have to factor in an additional $300 or so for springs and $400 or so for camber plates or GT3 lower control arms. that puts the total cost at around $2,600, which is getting a little pricey. additionally, i'd need rear toe links to correct toe / camber for lowered ride height. that's another few hundred bucks. bilstein does have a great reputation; dampers can be rebuilt in the US and revalved if the customer desires. turn around time is a few weeks. the last thing i don't really like is that height adjustmet is done w/ spring perch.

JIC Cross look great to me. they come w/ camber plates and i can choose my spring rates. additionally, their standard spring rates of 7kg / 9kg (400/500) is what i will put on my car. height adjustment is independent of the spring perch, which is nice. price is $2,600; comparable to the PSS9 total for my application.

KW look great & i hear good reviews. the thing i don't like about them is that height adjustment is done by the spring perch and total lowering for the variant 2 is only up to 1.5". when you lower the car, you are reducing total suspension travel. running really low means perhaps hitting bump stops a lot. additionally, the front spring rates are progressive, which i don't want. the rear rate is only 285lb, which is even less than pss9. these don't look to be agressive enough for my needs. $1,900 / set.

H&R have a good rep. their units are nice. the street version is ride height adjustable. the RSS version is ride height adjustable w/ stiffer springs and valving. neither have camber plates. both adjust height via the spring perch. $1,700 for the street; $1,800 for RSS. i vetoed these based on lack of adjustability, no camber plates, & spring perch height adjustment.

D2 Racing look pretty cool. they appear to be essentially JIC Cross clones with a few differences. hard to find a lot of personal testimony about them. i contacted the company for some info. they did get back to me, but ultimately did not provide the information i was looking for. their US presence is lacking. ultimately, i didn't feel comfortable with them; too big a risk.

finally there is KSport. they come with camber plates up front and rear pillow ball mounts with three camber settings. this is GREAT because it's possible to correct camber / toe for lower ride height. this means no need for rear toe links. they are available with any spring rate the customer wants. the KSports come w/ infinitely adjustable damping (compression / rebound adjust with one dial). ride height adjustment is independent of spring perch, so full suspension travel is maintained even at lower ride heights. they appear to be JIC clones. they are servicable in the US (arizona); rebuilds are $100 per corner with a turnaround time of about two days.

they have received a lot of mixed reviews and some customer complaints. people tended to love the performance, but some people said they didn't fit the car or that the seals blew prematurely. one thing i realized very quickly is that a lot of people didn't install them or adjust them properly. one guy bought them for his 996 and said they were too long. he clearly didn't understand that total length is adjustable. others have used the spring perch to lower the cars to the point where there was no real travel left in the damper. this caused the shocks to bottom out, leading to an untimely demise.

another thing i found out: two years ago, the company was bought out. they admit to LOTS of problems with their early units. new ownership has taken the company through TuV approval and ISO 9001 certification; this is good stuff. i contacted the company on multiple occasions. response times were quick and information satisfactory. i requested shock dyno plots for my dampers; they communicated to me that they would provide them with my shocks.

ultimately, the JIC are what i would choose IF the Ksports weren't so damned cheap! they're $1,000 SHIPPED with dyno plots and springs of my choosing. considering the headway they've made in the last couple of years AND the fact that they will service them quickly and cheaply in the US, i'm willing to take the risk.

as for spring rates? my car is street / track, so it has to be livable on public roads. i don't mind a stiff ride, but i don't want it to be jarring. the boxster spec racing guys use 450 / 500. my thought was that there would be a bit of understeer inherent to these choices. this was confirmed by a guy on a BSR board who lowered his front rate to 400 & promptly knocked half a second off his lap time. i went w/ 400/500 (7kg/9kg). this, incidentally, is the standard JIC choice for our cars.

i should have these in a couple of weeks. when i do, i'll post install photos, setup notes, and initial street driving impressions. in early september, i'll be at the race track and will post track results & lap time changes. cheers.

Kevin

Right On
 

Dude,

Thank you for doing an excellent review. This sets a standard.

Ike

Sounds fantastic! Can't wait to hear more about these on the car.

Patrick

Insite,
Sounds like a good choice for your car. When i move up in class next year I will be doing coilovers/R-comps also. I am interested in your track testing with these.

One heads up if you change dampening: Several race teams have been testing off the shelf coilovers and found the dampening adjustment settings to be vague at best and completely bogus at worst. Their suggestion is simply to confirm your new dampener settings with a shock dyno to make sure they are still matched before you do your install.

How is your car running with all the new toys you put on last winter?

very familiar with this issue. the KSports don't even have detents that 'click' when you change settings; they're continuous. i will likely wind up using a 90 degree twist as a 'setting'. KSport will be providing shock dyno results to me w/ the dampers. i will verify with a local test.


running great! love the LW flywheel & spec clutch. the exhaust is awesome, & the new tranny is buttery smooth. i'm to the point now, though, where i can overdrive my suspension on the track. in the corners, i'm ready to dial in the next adjustment before the car is finished taking a set. i think w/ stiffer springs & tighter damping control i will be MUCH faster. i am betting on 1.5s minimum gain at little talladega and probabl 3s gain at road atlanta.

Insite, excellent write up. I'll be very interested to hear what your impressions are of the KSport coilovers when they come and you have a chance to install them. I've done much of the same research as you and found the low price of the D2 and KSport setups as very appealing. But I could not find any constructive feedback on their use with the Boxster. So I'll be very interested as to what you report back!

I've got the KSports on my car and I am very satisfied. The ride is stiff at the softest setting, but it's not horrible. Set in the middle, it's been great for AX on smooth courses. With the stock suspension, I was quite far off the top 10% times for our regional PCA AX events. Now, with the KSports and a set of Pilot Sport Cups, I'm in the top bunch. I even beat one of the PCA instructors in his 07 GT3 (also on Pilot Sport Cups!)The car handles flat and predictable. With all of the setting options, I'm very interested to hear about how you are running the car. One thing that I'm thinking of doing is enlarging openings on the strut towers above the adjustments. Right now, to change the camber settings, you have to remove the wheel and bottom out the spring and drop the top mount on the strut to make the change. The stock holes are too small to get to all of the allen bolts.

i'd thought about that. what i'll probably do is adjust the camber plates so that i'm at -1.2 deg camber with the struts pressed all the way inboard in the factory slots. that should give me around -1.8 at street height and -2.0 at track height. still, modifying the top mount to allow access to the set screws would be nice...

Excellent write up. Its post like these that adds value to the board. Bravo.

If you can, please post up your impression of them after initial drive or month or two after ownership with the settings that you decided to use.

Couple more questions though.

Also, did you order directly from KSport for the $1000 shipped price ? Its lower than prices I see on Ebay.

Did you end up with the Control / GT Pro / or RR version of the coilover ?

What made you pick it over the other two version ?

Gary in BR has/had them on his ride. I'm not sure what spring rate he is using but he said they are way too stiff for him and he's removing them.

What model K-Sport coilover did you buy? How in the world did you get them for $1k?

Hey, how were you able to adjust the ride height independent of the spring perch?

i'll post install notes / picks, setup notes, street impressions, & race track impressions / results.

i got them for $1,088 shipped from TCS Motorsports on EBay. this price INCLUDES the custom spring rates.



i went with the control. the RR version is just the control w/ different spring rates & valving. since you can get different spring rates for free and since the control version is already heavily damped, that's what i did. i think the RR version would be way to stiff. the GT Pro version has an inverted damper design similar to the PSS9's. i didn't go with this because i think it will be easier to adjust the damping in the trunk and under the clamshell rather than behind the wheels.

below the spring perch where the coilover is inserted into the wheel knuckles, there is a locking collar (on the front wheels, there is a locking collar on the very bottom of the strut, too). loosen the locking collars. then, twist the WHOLE strut. it will thread in and out of the wheel knuckle, making the entire strut shorter or longer. finally, tighten the locking collars. they need to be TIGHT; use a flathead screwdriver and a hammer to do this. BTW, if your struts make a knocking sound, these locking collars are loose.

how much better are these setups than M030?

how do they stack up against M030 from a bang/buck standpoint?

for spirited street driving - i would assume these coilover systems are overkill??

'better' has to consider application. for spirited street driving, the RoW M030 is perfect, IMO. it's even great for autocross and some track duty.

the reason i'm stepping up to a full coilover system is that i'm now able to drive beyond the capabilty of the M030 on track; the car doesn't react as fast as i can input steering corrections. additionally, this full coilover type of setup gives me more adjustability so i can dial in one setup for the street and a much more aggressive setup for the track.

it all boils down to rate of weight transfer. the M030 transfers weight in a nice progressive fashion; it's quick enough to allow a nice, sporty feel but compliant enough to really soak up bumps and irregularities in the road. the real difference with the KSports come from the increased spring rate and corresponding increase in compression and rebound damping rates.

spring rates are generally noted in force / distance. let's say i hit a bump in the road that causes a 1G force on the front left spring / damper. let's say that the static weight on that corner is 800 lb and that the bump causes an additional 800 lb force on that wheel. if my spring rate is 200 lb / in, that corner will compress by four inches. the damper will control that rate of compression and corresponding rebound. 4" is a lot of distance and will allow slower accel / decel as the chassis reacts to the bump. this is comfy. now say i double my spring rate. now, the same bump will be soaked up by only 2" of travel. if the dampers are valved in an equivalent manner for the spring rates, then the time used to accel / decel the damper is cut roughly in half. this means that the damper will feel as if it absorbs less of the bump and translates more of it to the chassis / passenger compartment. remember that in physics, 'impact' is defined as a change in momentum over a change in time. since we're halving the time, we're doubling the impact. quality dampers can mute the effect on the passenger compartment, but this will still certainly be less comfortable.

at the track, though, if i enter a corner with the stiffer springs, i get less motion, less body roll and a faster reaction time from the chassis. since the grip available on a tire's contact patch is proportional to the weight on the tire, i will have more time at peak grip in that corner (since the weight transfered there sooner) & the car will set faster, preparing to receive the next driver input earlier.

it's all about trade-offs. ultimately, my personal preference at this point is to increase the on-track capabilty of my car at the expense of street comfort. a compromise between the KSport and M030 would be the PSS9. they use progressive rate springs & lower absolute spring and damping rates. they are still great on track, but much more comfortable on the street. my personal preference here, though, was to surpass the PSS9 in spring rate & valving. additionally, progressive rate springs are nice for the road, but they translate into inconsistent handling at the track. a linear spring rate is more ideal in that setting.

man, i'm long winded today......

a little more info.....pls
 

Insite, U R awesome. Sell me that car!

Im looking into the same thing, and eagly await your results just like everyone else. However, i also ask for a little more info.

Where are you getting these, and which ones exactly? Dont they have different lines?

Ive been lookin, but have not put pen to paper in a proper eval as u have.

Thx.

TJizzle

i got them here: http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=140247438327

i contacted the seller ahead of time with regard to custom spring rates. so far they've been great w/ communication following the sale. because of the custom rates and the fact that most shops don't have these on the shelf for our cars, it will probably be 2-3 weeks before i receive them.

With shocks, the devil is in the details. Anyone can make a coilover by taking a shock, adding some mounts and putting a spring around it. Its the shock that matters, especially its rebound control.

I have heard nothing but bad things about JIC. KSport sells the same basic unit for a whole slew of cars. They look cool but no one serious uses them on track or auto-x.

I would much rather get a system that was made by a shock manufacturer of repute like Moton, Bilstien, Koni, Boge, Penske, etc. I think you will find that a $1000 KSport system is worth $1000 and not a penny more.

Serious shock engineers admit that shock development and tuning are one of the last black arts in motorsports. I'd purchase from a master magician, not an ebay deal of the day.

Regards,
Alan

agreed!


on the contrary, i've heard a lot of GOOD things about JIC from various PCar owners. the only complaints i've heard tend to be about ride harshness; they're a bit more track than street. as to the assertion that 'no one serious' uses them on track? depends on what you mean by serious. if you mean 'competes for money', then of course you are right. if you simply mean 'serious enthusiast', well that's debatable.

do you honestly think we wouldn't all rather have Motons? apples and oranges, sir. they are $5k a set WITHOUT springs, camber plates, etc. ditto for JRZ. koni, boge and penske do not have applications for our cars. that leaves bilstein, JIC and the JIC clones. custom valved bilsteins would be nice, but again, $$$ is a consideration.


master magicians don't make much for the boxster. they certainly don't make anything that fits within a DE budget. for someone who competes to win, it might make sense to blow $8k on a 4-way Moton setup. for the rest of us, not so much. i believe the JIC design to be a good one. i also believe that the taiwanese will reverse engineer and improve upon this and similar designs. i also believe from having spoken to KSport USA about the direction their company has taken in the last couple of years that they will provide a fine product & great support at a bargain price. it's a gamble, but a calculated gamble.

Insite, I just bought the same set from the same people on eBay! What a small world.

I did not request the special spring rates, so what do I do now?