RotaryRush

Hey guys, I am thinking about purchasing either the Tein Type Flex, which I have heard a lot of good things about on hear, or the Ksport Kontrol Pro coilover set, which I have not seen any comments about.

I do a lot of street driving as well as SCCA AutoX racing every month, and about 1 track event a year.

Are the Ksports a good quality Coilover that improve the handling, and has anyone had any problems out of them or complantes?

does either kit come with the adjustable camber plates?

Red Devil

I'm not at all familiar with Ksports. Do you have link to their information?

edit: are you talking about Koni?

Fanman

Is that kind've like K-Fed singing ?

HERO

iTrader: (3)

Knight Sports?? the Japanese company??

Red Devil

Kleggspeed?

RotaryRush

thanks for the url. they do not seem like a very big company, but may be very good quality. they do have a D1 GP 350Z that is in quite a few events but i don't think it is one of the top competitors.

dsmdriver

iTrader: (3)

You might want to research suspensions a bit more before you purchase if you think an RX8 needs camber plates.

Red Devil

RX-8
(SE3P) 03-up CMZ11-KP $1400 10/560
5/280 Incl. Front & Rear Top Mount

Very stiff spring rates in the front at 560 with comparatively much lower at 280 in the rear.

Also saw they are monotube, 36 way adjustable. They sound interesting, I'd like to hear a review also.

scsi

i have looked into Ksport coilovers for my 240. i have come to the conclusion that they are absolute crap. ive heard a few success stories, but more often i hear horror stories. first of all, quality control doesnt seem to be a priority for them. among horror stories include bent and/or leaking struts. dont waste your time.

if you're seriusly thinking about those coilovers, then perhaps consider megan racing. a friend of mine had them on his old S2000 and he liked them. and from other owners ive only heard good.

i have tein flex right now on my 8, they seem fine so far, but just a warning, they dont go low, or at least not the rear.

RX4life

i know quite a few 240 owners with them.. they are well worth the price for what you get.. but i have heard 50:50 stories in regards to performance and durability

AlTitaniumCar

I second the notion for the Megan Racing setup- I had them on my WRX and LOVED them. PM me if you want a good price on them (I know some people at Megan)

Kart Racer

I dont mean to jack this thread....but i might be convinced on the Megan racing, they seem like a great price! Does anyone know how they work with the RX-8?? Is is a kit solely designed for the car, or generic coliovers made to fit?

arr ex eight

bump...i'm curious about this too

Red Devil

There is a forum member that has the Megan coilovers...if you do a search you'll surely find his feedback.

AlTitaniumCar

I'll give my sponsor a call today to see what he says about the setup and I'll also get a price quote for you guys. You'll most likely have to PM me about the price though- I wouldn't want to go around throwing numbers up though, since I'm not a vendor here, so I don't think I could do that...

gh0st

they can be had for less then that!

AlexCisneros

seems Ksport has two versions of the coilovers... The second is their "race only" version. The spring rates are a mystery however.

Anyone want to be a guinee pig?

TerenceC

Wow, I haven't check this forum for a while because I had dealing with the bad luck I have on my 8(driver's door got kicked, rear-ended) and there are so much more info now.

Anyway, I ordered the K-sport 2 weeks ago but they said they are back ordered and my spring rate request will delay the arrival. I should get it next week hopefully. I requested to change the spring rate frt 8kg/mm and rr 5kg/mm from their standard 10kg/mm and 5kg/mm. (1kg/mm = 55.88lb/in)

I was also considering the Megan Racing too but my thinking is if they design the coilover with spring rate of 12kg/mm frt and 10kg/mm rr, I'm not sure they know what they are doing(unless they were designed for drifting). Remember the stock front to rear spring rate bias is 2.8kg/mm frt and 2.0kg/mm rear.

I didn't actually done any measurement for the motion ratio for our 8 yet. But just by looking at the design, seems the rear is more like .90 while the front is more like .65 and the weight disturbution is about 50/50. So I would expect the front to rear spring rate will be bigger than other cars like Miata or most Honda. ie our 8 will have the front spring rate much higher than the rear in order to get the ideal(or close to ideal) wheel rate.

I autocrossed my 8 few times in stock form and found that it slightly more oversteer than I like. So from the stock front to rear spring rate ratio 2.8/2.0 = 1.4, I estimated a 1.5 or 1.6 will be good for my taste. So I went with 8/5 = 1.6. I know I might have went too far, I should have ordered 9/6 = 1.5 instead. Oh well, I will see how it turns out I can always buy new springs but seems like there is no more autox event(except the slush series) to try them out.

Terence

PhotoMunkey

Terence,
I put the K-Sport package on last week, and went with a 10 kg/mm front and an 8 kg/mm rear rate. They didn't have a 7 kg/mm available. Like you, I figure I can go to a lower rear rate eventually.

They do have excellent valving though! I set the fronts and rears initially at their "2 turns up" street setting, but backed the fronts off .5 of a turn. Excellent ride and excellent turn-in with very little roll now. Will probably still be a touch tail-happy under hard throttle cornering, but I was used to that with my Mustang. I think that's why the spec'd out the 10/5 spring rates. Their setting probably work better than my choice for auto-x or track driving.

TerenceC

I finally had some time to install the package at Christmas time. They still sent me the wrong spring rate that I wanted, I asked for 8kg/mm frt and 5kg/mm rr but they send me 7kg/mm ft and 5kg/mm rr. I just don't want to wait any more so I just install it and see how it handle first. I also had to purchased another set of rear top mounts from Mazda because their web site was misleading me it will include the rear mount(they seem to changed it now 01/07).

At the front I undo the upper inner arm mounting bolts(2 per corner) and in the rear I undo the lower inner rod mounting bolts(1 per corner, the camber adjustment one). This made the installation so much easiler and without damaging any bushing. Don't try to push the suspension down too much hoping you can take the shock assembly out because this can easliy damage the rubber bushing.

Unlike PM have mentioned, it is possible to adjust the damping after install. There is actually a very uneasy way of adjusting the shock after you install it on the car. I found a small hole, just big enough to fit 1 finger in to turn the **** which I had left on before I mount the asembly on to the car. The front is, like PM said, is hard but doable to adjust if you have the stock tower bar in. I left all 4 adjustment tools on the shocks before I install them on to the car.

Becasue I used softer spring at the front, I need alot of preload. Without any preload(or small amount), the shock already ran out of travel when I drop the car to the ground(ie. top mount alrady touching the rubber boot). I compressed the spring about 40mm(~280kg) preload and shorten the shock body 40mm to mantain the same ride height. Now I get about 1.75 inch travel before it has first contact with the rubber bump stop. (Note: the front shock does not have huge travel to begin with, only about 2.5 inch before lowering the car to ground) At the back, I cannot really see if there are any travel because the way the stock top mount design so I just preload them with 25mm(~140kg). You will not need to preload this much if you use a stiffer spring. Just imaging if each corner of our 8 weights 750lbs and you have a spring that is rated 750lb/inch, the spring will not compress at all when lower to the ground and you will get all the travel the shock design for.

Right now, I just set the ride height same as stock so I can easliy compare the handling just from the k-sport package and also easiler for me because the alignment will roughly be the same as before.

The ride: seem very compliant for street driving (I set the damping 2 turn down from full stiff). Rear is too stiff for this setting, it seem to skip over bump rather than ride over it. I will lower the damping and see if it helps.
The handling: The steering response is alot faster than stock, go-kart like indeed. I had a '02 Miata with RB sway bars and Tein Flex(1.25" lowered) before and the steering response was only slightly better than this setup. Imagine if you put a thicker sway bar and lower ride height......... These are all street driving experience and mostly wet condition(Vancouver BC weather, what do you expect?) I have to wait until spring time to do more dry traction feel and at the limit feel on autocross event. By then I will fine tune the ride height and alignment(I expect I don't need as much neg. camber) if the handling is somewhat balance at the limit(I am worrying it will oversteer too much to my liking, I was asking for 8kg/mm spring front).
Problem?: The rear is making some noise when going over medium to large bumps. I need some time to check it over to see anything lose.

Terence

Razz1

Your better off going with a reliable company like KW.

Try the KW Variant 3's

http://www.kw-suspension.com/en/index.php

PhotoMunkey

Check the upper mount-to-body bolts, and check that the spring coils are not binding. Austin there sent me a pair of 6kg/mm springs to try, because they were out of the 5kg/mm springs normally used with the kit and they're too short! I was getting serious coil-bind and clash whenever the suspension had to move upwards or was heavily loaded in a dip in the middle of a corner. Not good.

I went back to the 8kg/mm rear springs I originally purchased (with 10 kg/mm fronts) and the ride seems okay, but a little tail-happy with the Progress Technology anti-roll bark hooked up, even on its softest setting.

Have you every calculated the Motion Ratio for the front suspension? I did the rear tonight and came up with .65 (14" pivot to shock center line, 21.5" control arm length from pivot to ball joint center). From that I calculated a natural ride frequency of 1.26 cycles per second for the 5 kg/mm spring, and 1.6 cycles per sec for the 8 kg/mm spring. I used 737.5 for the sprung weight which is simply my car's weight of 2950 divided by 4. I didn't adjust for the unsprung weight of the spindle, shock, spring, axle, and brake system. There's probably 50 lbs there at least!

If I take of 50 lbs from the 737.5, I get ride frequencies of 1.3 for the 5 kg/mm spring and 1.65 for the 8 kg/mm spring.

Now I really want to know what the front Motion Ratio is so I can calculate the ride frequency for that system too! With a 10 kg/mm spring, and very little shock travel, I'm betting that the Motion Ratio is around .5, as soft as the front feels. This might mean that Megan Racing's 12 kg/mm front spring isn't a bad choice

Generally, ride frequencies of around 1.2 are used for rally cars which have to deal with a very bumpy surface, with higher rates of 2.2 hz for moderately bumpy "street performance" rates, and 3.2 hz for ultra-smooth track-only race car suspensions.

I'll figure out the front Motion ratio exactly tomorrow

PhotoMunkey

I forgot to note that Nick at K-Sport said the proper 5 kg/mm spring is 1.5" taller than the 6 kg/mm spring. That extra free length is needed to solve the coil-binding issue that the 6 kg/mm spring has proven is a problem on my car.

My car is also a very light base 6MT, at 2950 lbs wet

PhotoMunkey

I think 7 kg/mm on the front is going to be too soft, but... the softest front spring I've seen for a coil-over is on the Tein Basics, at a whopping 4.93 kg/mm (280 lbs/inch). They, and the Mazdaspeed and Eibach performance springs, are FAR longer than a coil-over spring, so what they lose in rate, they ultimately pick up in travel. Performance coil-overs are saving unsprung weight by using shorter, heavier-rate springs BUT this approach changes the natural ride frequency of the spring. We've all seen Hondas bob-bob-bobbing down the road on too-stiff springs, with stock dampners... Do that on your car and you create a dangerous situation where you could lose tire grip as the spring cycles too many times per second. The lower the number of cycles per second, the better job the spring does of keeping the tire pressed firmly to the surface of the road.

Stock is 155 lbs/in (2.74 kg/mm) front
Mazdaspeed is 280 lbs/inch (4.93 kg/mm) front
K-Sport is 454 lbs/inch (10 kg/mm) front
Megan Racing is 682.7 lbs/in (12 kg/mm) front

TerenceC

Thanks for the suggestion, i will check if it's coil bind. But I only have very limit time now to work on cars since I moved to a house that it's hard to access the garage and with a 2-year-old to look after.

Without doing any actual check, I was just guessing the stiff top bushings and maybe lack of pre-load is contributing the noise. I also noticed the top of the shock shaft where the nut holding down the top hat is really close to the car's body. The car has a ~1" daimeter hole and the top of the shock shaft is sitting somewhere off center, so I'm speculating the shaft or the top nut actually touches the sheet metal when the suspension compress. My plan is to take the whole rear coil-over out, change back to the stock bushings and recheck everything. I forgot to put the clear plastic sheet on the right side when I install it last time.

Now, after you mentioned it, I will first go take a look to see if it seems to be close coil bind when stand still right after work today.

7kg front seems to ride very nice and a good improvement over stock. And after I preloaded the spring, it gain the travel back. I could pre-load it more to get even more. So I think the suspension travel will not be an issue if you pre-load enough(as long as you don't load more than the weight of that corner). If I can get rid of the noise at the back and if the car is balance, I will be happy.

After a month of driving with this setup, I drop the shocks all the way down to 4 turns from full stiff. I feel the compress is a little too stiff but the rebound could be a little stiffer.

So sounds like you don't have the noise from the back issue. I'm thinking maybe because I order an extra set of rear top mount for the k-sports, if there is any design different or I left off something. (If you transfer the stock rear top mount to the k-sport, you will most likely transfer everything needed to the k-sport).

I don't have a chance to measure the front motion ratio, but if you found out the back is ~.65, then I think .5 is a very reasonable guess.

thanks for all the data and suggestion.

Terence