existanzrx7

iTrader: (8)

Ok like the tile says I am looking for the best Fd coilover set up for $1200 and under? I know there are several brand new set ups for that price including good used sets. What I am looking for is for in a coilover set up is a nice quiet confortable ride but also aggressive when needed. Where I can take some good cornering. Please include any experience you have with a nice set up you like and or any differences between set ups. Thank you

ZE Power MX6

iTrader: (160)

I'm looking for the same thing, been debating between Tein street flex and Stance, but I'm worry they might been too harsh for just street use.

purerx7

iTrader: (61)

In that price point for used coilovers, your best bet is Greddy type s, HKS hypermax sport and Tein Flex. Please let us know if we can help in your search, all of our coilovers are backed by a 12 month warranty.

rotard7

iTrader: (6)

+1 for trustworthy vendor

Bought a used set of HKS hypermax 3 sport coils with about 5k miles on them and love em.

ZE Power MX6

iTrader: (160)

There's a sale going on for street flex, new set for a grand.

existanzrx7

iTrader: (8)

Thanks you can email pics and info on any coilovers sets you have in my price range. I would really be interested in sets with low miles thanks

existanzrx7

iTrader: (8)

Where? Thanks

ZE Power MX6

iTrader: (160)

There are some on eBay, sale run till end of April.

armans

iTrader: (2)

My FD is on Fortune Auto coilovers and I consider them very comfy, and the price was around $1200.

sctRota

iTrader: (2)

HKS hypermax's are great but our roads here aren't the best so it is quite a rough ride for me. I run showa SP's as they seem to be my most favourite street/track setup till I get something like the greddy type S

Natey

iTrader: (19)

Best? Ohlins or Penske

Good enough? Tein Flex, Stance, Fortune Auto, Zeal (I have em and love em), etc. .

For street springrates, I'd look for not more than 10K or your liable to lose some fillings.

ZDan

It's not the spring rate that causes you to lose fillings. It's the high-speed damping. "Budget" coils are guaranteed to have high/harsh high-speed damping. Better damping is *smoother* and less harsh even with stiffer spring rates.

existanzrx7

iTrader: (8)

Tein flex vs Stance Gr+ Pro?

purerx7

iTrader: (61)

+1000, people make such a fuss about spring rates when it is the damper that matters most. Having rubber top mounts can make a noticeable difference too. Been in several FDs with 16k+ spring rates that were smooth.

Natey

iTrader: (19)

OK, I stand nit picked and corrected.

Attention new guys. Pay no attention to spring rates.

existanz, I'd probably go with Stance because of the resale value. I'm sure someone either trying to sell you suspension or on Teins will tell you differently though

evo_koa

iTrader: (2)

I have k sport coilovers. Pettit now sells them. I have 12k front 10k rear, they do a custom valve setup with a rubber center piece on the strut mount. I track mine and drive it on the street, it is very smooth and not harsh at all

lOOkatme

iTrader: (19)

I am a big beliver that ride quality is highly correalated to spring rate, which in the end deals with the frequency of the car. In physics they would talk about the frequency of oscillation and this oscillation is highly correlated to comfort. I perfer to run the car around 1.5hz area. when you start to exceed 1.8hz you start getting a less comfortable ride. I attached a diagram of how people perceive the different frequencies with the comfort of the car. This is obviously with many different types of damping with different cars. There is a strong correalation with frequency and comfort. (the graph has comfort being lower and uncomfortable higher).

the second part that I did using some math and the damping calculations is to figure out the critical damping for my set up. I am running 8KG front and 6KG rear. I also think 7KG rear would be a great selection. The 7KG rear spring fits better with the flat ride rule of 10-20% higher frequency in the rear than the front.

The After all the math the critical damping for this spring rate is attached. you want to run less than this rate with the shocks. typically you want to run around 65% in the low speed area (0-3 IPS), mid high speed is around 35-45%, and continues to drop into the 10-20% range with very high shaft speeds 18+ IPS. This is a digressive curve. I have attached the critical damping and also the ideal damping, or so, for the spring rates 8KG front and 6KG rear.

I might try these valving rates with Fortune auto 510 coilovers with my swift springs. we'll see what happens.

ZDan

Please note that no one said spring rate is unimportant.

Spring rate and damping rate do two very different things. As far as ride *harshness* goes, it is all damping.

Springs are dumb, simply provide a restoring force per displacement. Stiffer springs of course change natural frequency, but have little to do with what you immediately feel when you impact a pothole or bump. Damping is the brains of the system. Cheap dampers will give something like orifice damping. Too little low-speed damping and too much high speed damping. Hit a bump and the damper will act like its locked. OUCH! But then they'll flop around under cornering/braking/acceleration.

Stiff springs with good dampers will feel somewhat "busy" as the natural frequency is high, but shouldn't feel *harsh*.

FWIW, my car is way way WAY smoother and less harsh on 13kg front 11kg rear springs with Ohlins DFV dampers with spherical top mounts than it was with 9kg front 7kg rear Tein SS with rubber isolators. I went from having to practically park the car before any road ostacle to smooovely gliding right over them. AND got much better low-speed control in the bargain. Yes, natural frequencies are higher, which I also wanted/needed for track work.

lOOkatme

iTrader: (19)

I totally agree. The damping ratio to a critically damped system is the key to the whole mix. The dampers need to match the spring rate. MOST dampers are not matched to the spring rate.

The digressive valving works great for performance oriented people. It does well because of what is called transmissibility. The exact thing you are talking about with your Ohlins suspension.

What I see for most shocks are linear valving, and linear valving doesn't do well when it comes to performance AND comfort. somewhere on the transmissibility curve you will need to give either performance or comfort up. you can set the performance low speeds good, but high speed bumps go to hell, and vice versa.

A good matched digressive curve can accomplish performance and comfort together, or be a good mix. a high percent critically damped low part gives very good traction and grip and comfort, and then it needs to transition to a very low percent critically damped for high shock shaft speeds. Pick a good spring rate with a flat ride and you reach nirvana.




I am going to try and explain the graph a little for everyone. in the upper right of the graph are the critical damping ratios. 1 is critically damped, .5 is 1/2 critically damped, etc. The graph shows the transmissibility of bumps per the different frequencies. transmissibility is the displacement of the sprung weight vrs. the bump that gets hits. so if you have a 1 transmissibility and you hit a 4" bump, the sprung weight moves 4". The best performance is having the wheel on the ground as much as possible, it also creates a smooth ride. so before the sqyare root 2 of the resonant frequency you want a high critical damping value, something like .7 or so, after the square root 2 of the resonant frequency you want a .2 critically damped damper. this looks like a digressive curve when plotted with a shock dyno. There are calculations you can do with motion ratio's selected spring rates given the springs frequency, sprung weight, etc that can get you in the ball park of what ideal might look like for damping. they typically are digressive curves. Linear curves are ok, but they give somewhere. Some shocks dyno's I have seen show rediculous valving for the spring rates selected. They can be overdamped, and what not. All these on the curve are considered "underdamped".

I am an engineer and I wanted to understand why the hell my car didn't ride well at high speeds. First was the spring rates were 12KG front and rear, the car didn't ride well because the rates were high and correalted with high frequencies. it has a flat ride (rear higher frequency by 10-20%) which is important for ride quality, but the frequencies are really high. Combine this with pretty high damping and its no wonder the car likes to skip over bumps at high speeds. The key is the valving is not enough down low, and too much at high speeds. I am going to run 1.5hz or so springs and striving for a nice comftorable, aggressive street car. running higher rates will be great on smoother roads, but we have a ton of crap in colorado for bumps, joints, etc and I want a smooth ride. will update if I get those coilovers. I also notice that running a little higher % critically damped in the rear makes the car feel a little better as well. for my car since I run higher spring rates in the front might mean the same damper setting front and rear.

ZE Power MX6

iTrader: (160)

lOOkatme, what coilover are you running? Did you get them with 8k/6k and proper valving?

lOOkatme

iTrader: (19)

I am running the 8kg 6kg springs but I am running them on ARK coilovers which came with the car when I purchased it. The coilovers have linear valving like most other coilovers on the market where they are not optimized for the springs. they aren't horrible, but they definitely need less damping on high speed bumps.


I am looking at getting custom valving done through fortune auto for their 510 series shocks. I think they will be able to provide something that is really good for what I want. If I decide to purchase them and run them sometime this summer I will update everyone with the valving I chose with the shocks and give good feedback on how the car rides.

LargeOrangeFont

iTrader: (7)

I did Fortune 510s on my FC, and am very happy with how they turned out. My only advice is to go with your gut on the spring rates. I went with the front rate they recommended, and softened the rear slightly going 1kg/mm softer than their recommendation. I since have dropped the rear spring rate another 100lbs, roughly 3kg/mm total (this where I had thought it should be in the first place) and the car is really really good now.

Skip the Swift spring upgrade option until you have your spring rates dialed in. You don't save any money buying the Swift springs from Fortune anyway, so you might as well keep the stock springs and have another set to play with.

lOOkatme

iTrader: (19)

I spoke with Terry at auto fortune. I am not sure what spring rates the coilovers come with stock, but it seems a lot of people like running stiff springs on these coilovers. I was telling him about running my 8/6 and he was surprised by how low of a rate I am running Looks like a lot of people like running really high rates, I mean if you have downforce and need it, go for it.

What rates did they have stock? Looking at their shock dyno they must be running 10KG + spring rates to match that shock dyno otherwise the shocks would be "aggressively" valved for a 8KG spring. basically the lowest setting or two would be fine for a 8KG spring. 6KG would be very aggressive.

I already have my springs, I bought swift springs from a few other forums used for 60 shipped and 80 shipped for each set. now I am just hunting for shocks that can match these bad boys well.


My current set up is 8/6 with stock sway bars. the car is 25" front and 25.5" rear. The car rides pretty firm. its not rough but its not a "silky smooth ride". The left to right transition is very good. I am running 285/30/18 tires all around on 18x11.5 wheels. When I get on it the car does squat good but its got grip. it feels great. It does squat a little under very hard braking, exactly what I think it should do and it grips very well. I can't imagine running much stiffer springs than this on the street. Hell, I think I could get away with a 7KG front and 6KG rear even.

Just a bit of info for others reading.

LargeOrangeFont

iTrader: (7)

For the 510s they give you whatever rates you want and valve the shock accordingly. They have a worksheet you fill out and give you the spring recommendation from there. I'm at 671lb (12k) in front and 400lb rear now. They suggested 10k and I went with 9k. It was ok like that if the track was smooth but the car hopped around a bit on rough sections of the track. It is a track car but it rides better than my old coilovers with 8k/6k springs.

I am running PAC springs. Basically the same deal as swifts (lower coil count and lighter weight) but cheaper.

j9fd3s

iTrader: (3)

i have found the same thing. empirically. we all had FC's a few years ago, and the best riding one was not the low mile stock one, or the softly sprung cheap shock car, but the stiffly sprung $$ damper car.

although i must say, we've been road racing for more than a decade and the Ohlins we switched to this season were eye opening, it handles right, AND it can soak up big bumps without getting upset, but it also seems like it rides nicely. most shocks can only do the handling