aleok

iTrader: (1)

i'm trying to deside if i want a full coilover kit or d-specs and springs. i want a pretty slammed look. i'm already on 350z s-tech (1.2-1.5 in) and its not enough. ( have a G35)

My friend told me that coilovers have to be rebuild ever year or so. what does that mean? what does it consist of and how much does it cost?

Main questions is what would last longer coilovers or tokiko s-specs with tanabe gf210 (something with a drop around 2"), for just simple daily driving and no tracking?

is it worth paying twice as much for the coils, just to have height adjustabilty???

Z1 Performance

iTrader: (564)

your friend is wrong quite honestly

as to what will last longer, all depends on the road conditions and how you drive on them

only you can answer for yourself if coils are worth it - to some they are, to others they aren't.

Define your goals and your budget first, then go from there

aleok

iTrader: (1)

well i am on a budget, and there no track here, so i drive pretty easy, and only take some turns fast, rarely.

i don't know how much i would adjust the height, since i'd have to re-align the car even time...

dkmaxitus

iTrader: (5)

i gotta say though that your O'ahu roads suck. you should factor the ride quality in as well. for what you're describing i would go with the tein flex w/ EDFC. perfect for your daily driving with the easy adjustability for your fast turns coming up. ask puni_sher is you can take a ride in his car.

EDIT - never mind i just now seen that your on a budget. if you buy this set up brand new it would prabobly run about $2k +/- where you buy from.

aleok

iTrader: (1)

yea and the flex's are way too stiff

Z1 Performance

iTrader: (564)

you've answered your own questions then - coilovers are NOT for you

Get yourself the D spec setup, or, my own preference, Koni Yellow's with a set of Tein S Tech, or Hotchkis springs, and you'll be a very happy camper

636Racer

iTrader: (1)

It's not soo much the coilover as a whole, but the spring rates, and the spring type (linear vs progressive) that come with the coilover. He might benefit from the KW coilovers with progressive springs.

aleok

iTrader: (1)

why KW? there not much info on them. but i hear a lot of people don't like them because there progressive springs. i really liked the oem sport tuned feel, i want the ride to feel like the spring rates are between 300 and 400 ish.

636Racer

iTrader: (1)

Progressive rates arent a bad thing, but not the preferred choice (usually) for someone who tracks the car.

KW is an exceptional brand, I've seen them in a couple of porsches that road race here.

Z1 Performance

iTrader: (564)

yep -very high end units, used on alot of Euro cars.

Progressive is fantastic for the street, and yes, they even work well for typical track days (note, a car you take to track days is vastly different than a track car).

Nevertheless, if you do not plan to adjust the height, then there is no point in getting coilovers - get a proper strut/spring setup.

A car cannot "feel" like its riding on a spring with a rate of "X" lbs - how the car feels is, by nature, tied to the spring rate, and the valving of the damper. You cannot compare a spring rate of "x" on one brand of coilover to a spring rate of "y" on another. The compression and rebound valving, as well as your particular tire choise, will determine how the car "feels"

Gsedan35

iTrader: (10)

Let us please draw a line of distiction between progressive springs that change rate suddenly as in via coil bind and what that means in aggressive driving let along in a track enviroment and a spring that changes rate via coil diameter change where it does not change rate suddenly. Two totally different animals. The KW's are progressive by coil diameter changes, NO COIL BINDING!

Of course the other method to make a progressive rate spring is via wire diameter change, haven't run into one of those yet.


As I have posted before


Their is more to progressive springs regarding the compromise on performance for ride quality. Progressive rate springs are a bad idea for aggressive driving for several reasons. Soft initial compression of the springs allow the car to roll more on turn in, then the momentum built up by this roll hits the firmer part of the spring. This puts a heavier load on the outside than linear springs because the linear springs would not have allowed as much roll in the first place. And most progressive springs don't have "seamless" transitions in rate. They change rate in significant steps as active coils bottom on each other. A sudden change in spring rate, while at the traction limit, can result in a nasty slide. And further still, a progressive spring has two or more rates on one spring, right, that's what makes them progressive. ...let's assume that for the first 3 inches or three coils, the rates are 250lbs per inch and that for the next two inches, the rate is 350 lbs per inch. Therefore, when at rest, suspension will be compressed on the 250lbs spring section, and the next inch of movement will be in the 350 lb per inch range.

Now let's use the same scenario......a corner is entered and the outside spring is compressed one inch and the inside spring is extended .75 inch...rememeber the rates!

Now you encounter a bump in the corner...and since you are currently using the outside spring at a rate of 350 lbs per inch and the inside spring rate of 250 lb per inch... and the suspension is compressed the additional two inches....what happens to the spring rates? Since they differ, the chassis rotates around the roll axis... and the vehicle attitude changes/rotates differently than when in steady state cornering! Its motion becomes slightly skewed since to offset the bump deflection each spring must work through a different spring rate! If you were to then hit another bump, the attitude would change again...and so forth. All of these things of course would not happen with linear springs.

Progressive springs can be made to work in very limited conditions where the parameteres are well known, like a specific road course where telemetry is constantly giving feedback to help select the right rates.

Z1 Performance

iTrader: (564)

While I agree in theory, I've drive a ton of sports cars, on a track, and on the street, ranging from a 350Z to a 911 Twin Turbo, using Eibach Springs (which are Progressive). These cars will outhandle what anyone can realistically achieve in street driving conditions, and are also very well suited for a typical club type track day. Yes, they are not what you want on an all out race car, I'd agree, but for the typical street car, that even sees a few track days a year, they will work very well.

It's another example of how theory and practical reality don't always coincide

636Racer

iTrader: (1)

So KW doesnt make their coilovers with progressive rate springs? What Gsedan35 is writing makes sense though. The rear springs on my car are wider at the base, then smaller at the top to fit the preload bracket-perch thingy, with a constant coil width. It's still considered a linear rate spring (or is it?). Though the pictures on the KW site is showing has their springs at a constant diameter, but the spring wound is much closer towards the top of the damper. Isnt that the typical construction of progressive rate springs?

I dont think aleok will ever see the track (at least not here), at least not for a couple of years...hopefully sooner. Our track recently closed it's doors for business...and we live on a fricken island, and this sucks. our island is plagued by crappy roads and pot holes gallore. take a vacation to Oahu..you'll see why.

In my experiences, linear rate springs kinda sucks in our conditions. The RM/A8 on my car have linear rates, 10 kg/mm(f) and 8 kg/mm(r). On the track - they're great...though it could use some higher rate springs in the rear, or convert the rear with the same rated springs (ie. Buddy Club, Stance) - at which I am going to do. On the street - raised the ride height, lessen'd the preload and, softening up the damping helped a bit. It's tolerable in most conditions, but bad bumps make the car bouncy. I've riding my motorcycle a lot and havent paid much attention to figuring out a better medium for the street...one of these days, I will.

aleok, if anything...if you dont like fiddling around with your suspension rates too much, or would like to keep them at a minimum, go with Z1's suggestion with a good spring/strut shock setup and, still play with the damping rates atop the strut/shock. You'll get a pretty mean drop with 350Z GF210 springs and 350Z D-Spec shock/struts, still have a sporty feel to take on the Uninversity on/off ramps; with enough comfort to drive across our sh*tty roads. but, if you want coilovers...any of the good ones will do. It's personal preference. They're fine if you set them up to your liking.

Gsedan35

iTrader: (10)

They will work well for the individual that isn't so much concerned with performance. And I'll site history, we have seen over time, many Eibach owner's bail out of the springs and go with Hotchkis or RSR because they were not happy with their Eibachs on the track. Progressive springs that have wide rate spreads that begin below at or barely above oem rates are simply not going to deliver the same driving experience as a linear setup that starts at and stay's at a higher rate. Turn in, will be less sharp and predictable, more brake dive, more squat, weight transfer management will be poorer. I can see a progressive spring setup that doesn't have a large rate spread or change rate by coil bind, but even those are for me.

Z1 Performance

iTrader: (564)

I understand what you're saying - but we're repeating ourselves

He has a street car....he will never notice a progressive vs linear spring on a street car. I've previously posted that yes, for an all out track car, you would want a linear spring for the utmost in handling, but he does not have an all out track car, or even an occassional track car - he has a street car, and as such, a progressive spring can offer a good balance of lower height while maintaining a comfy ride.

But now we are far off topic of what the original poster reqeusted

aleok

iTrader: (1)

no no, its all good. this is all very help information.

i'm thinking about the buddy club coilovers and the tokiko d-specs w/ tanabe nf210 (350z). i don't think i would change the height around THAT much. maybe for a show or for just a change in apperance. but forking out the extra 7 or 800 just for that idk.

g35sedan- can the d-specs take the load of such a dramatic drop?

636Racer

iTrader: (1)

Dont worry man...this has happened to me before...it's pretty useless.


If you opt for the 350Z d-specs, I would gather that they would. Though, I'm not too sure if the 350Z d-specs have a short shaft length when compared to the G35 d-spec shock/struts.

Z1 Performance

iTrader: (564)

you are going to be far happier with d specs than with any coilover IMHO

aleok

iTrader: (1)

^ why? i don't even know if any spring i get is going to allow me to drop as much as i want.

Gsedan35

iTrader: (10)

The D-specs can take the load, the springs in the kit are 375/375, the shocks themselves are valved for up to 450lbs.

Buddy club coilovers are pretty far removed from your desire to have a setup that "feels like 300lbs-400lbs spring rates", the HKS RS is much more inline with what you want to end up with. Also Tein CS comes to mind.