Coilovers. GC vs Tein vs RS*R vs KW etc.

[D1cker]

Originally Posted by Re~Mix

The specific models I was looking at brand-wise are as follows:

RS*R iSport
Tein TFlex or Flex Street
KW V3
GC Sport FRS Coilover Kit
Eibach R1 (R2 looks to be overkill?)


My goals are as follows, 1 being the highest priority:
1. Improve suspension performance vs. stock
2. Improve ride quality on normal everyday roads
3. Help make the car easier to handle on the track
4. Aid in dropping the car approximately 1".

As far as racing experience, mine is very limited and I am definitely a novice. I have no intentions to compete on a regular basis, however I do like to attend the occasional autocross or open track day. It is important to me to do this right the first time and not be kicking myself 1K, 10K, or 50K miles down the road and shelling out another $3000.

If it helps having an overall sense of my plans for the car, I intend to upgrade the suspension, sway bars, wheels, tires, exhaust and that is about it. Trying not to upset the amazing package the stock car already offers.

From this list I would take the KW V3 as well if you're primarily street driving. The GC kit was good but I still had some issues with the way the swaybar connects to it and don't really trust the way the camber plate is mounted. The KW's had a very nice ride on the street as well.

Edit: To offer a bit more information on the GC vs KW kit, the ground controls did offer better performance on track and are a better value when you take camber adjustment into account. The customer service from both companies was/is great, but ground control is easier to deal with.

EDIT 2: GC has contacted me to let me know that they have redesigned the sway bar mounting bracket to make it easier to install (my kit was one of the prototypes) so disregard my comment about that!

[xwd]

I would look at the RCE T2 setup, if they are available now. They are based off the KW dampers and most of the guys who ran them on the WRX/STi had great success with them.

http://www.racecompengineering.com/

[CSG Mike]

Originally Posted by Re~Mix

As I mentioned, my goals are in order of importance to me. I do not have the means to adjust the suspension within my own home, however a good friend has a garage and the know-how less than a few blocks away.

My driving experience to date has been lots of canyons, 2 open track days and 1 autox since purchasing the car a little under a year ago. Coilovers are something I'm looking at investing in within the year however I am not in a rush.

I agree that I should not rule out certain kits at this point and I need to establish a baseline for comparison. It looks to me as if avoiding the $1000 entry line kits is a good choice? The next tier being $2-2.5K and the final packages $3.5K and up.

Once you get to the $2.5k range, the line starts to blur.

PM sent.

[Racecomp Engineering]

Originally Posted by Re~Mix

Still shopping around for the specific wheel/tire/size combination. However, I intend to run 18x8 or 18x8.5 (square setup) with unknown tires at this point.

Tire compound is going to be the big driver in your suspension choice.

There are a lot of good options out there for coilovers and a few more on the way. A lot of crap too, but it looks like you've picked some good options. You do need to look at the big picture and think about a complete system that "works" together, and works for you and your budget. It looks like you're on your way.

- Andrew

[Re~Mix]

Thanks for all the feedback thus far, it is much appreciated.

Keep the comments coming and feel free to point me towards any reading material on the various types of coilovers options, tires, etc.

[FRS2NV]

Actually my 2 choices are KW V3 and HSD..I have owned both these BRANDS and loved them..
VAlue for your buck HSD comes on top on my list for what you pay and get for $1250...
KW run over $2000 but for everyday use i would say HSD FTW

[SubieNate]

Originally Posted by FRS2NV

Actually my 2 choices are KW V3 and HSD..I have owned both these BRANDS and loved them..
VAlue for your buck HSD comes on top on my list for what you pay and get for $1250...
KW run over $2000 but for everyday use i would say HSD FTW

I looked up the HSD thread. The fact that their rates ar 9kg/mm front and 7kg/mm rear tell me right off the bat that they don't really know what they're doing.

[GTM_Challenge]

Originally Posted by SubieNate

I looked up the HSD thread. The fact that their rates ar 9kg/mm front and 7kg/mm rear tell me right off the bat that they don't really know what they're doing.

What tells you that? Just curious. i don't see anything wrong with those spring rates. Sure, they are stiffer than some of the other kits, but I wouldn't hesitate to drive a car on those rates.

[SubieNate]

The stiffness isn't the problem, it's the front to rear balance. This car has multilink rear suspension, which is part of the reason the rears are stiffer than the fronts on all three variants of the car. Those rates look like they belong on an OG Impreza with struts all around. I think the lowest I'd want to have the rears is equal to the front rates, as in RCE's yellows. Anything much below that and the natural frequency balance front:rear is going to be screwy due to the difference in motion ratios caused by the completely different suspension layout.

I guess I should rephrase that as, "I don't think their R&D for this particular car was very good." I don't know enough about the company to make a judgement past that.

Nathan

[wootwoot]

How will the spring rates make the motion ratios all "screwy?" I thought the motion ratios were fixed via geometry...

[SubieNate]

Whoops, that's a typo. Got my terms mixed up. Meant the natural frequency. Fixed.

Basically, if the natural frequency out back is too low in comparison to the fronts, it's bad for performance. Because the rears see the bumps after the fronts, you generally want the rear natural frequency to be a bit higher than the front so that at speed the car doesn't "buck" over bumps and the whole thing settles naturally. Too much of a mismatch one way or the other and the front and rear aren't going to respond in a similar manner and the ride and performance are both compromised.

A front heavy car like a WRX or EVO has to run higher spring rates up front, both to keep the natural frequency (It drops as mass increases) and the suspension travel in check. Compared to those cars, we have much more even weight distribution. So a heavily front biased spring setup will likely understeer heavily as well as have the aforementioned frequency issues.

[GTM_Challenge]

I'll disagree here. Many, many RWD cars run stiffer rates up front compared to the rear because it reduces oversteer in the set up.

Look at the S2000 spring rates from the factory:

http://www.s2ki.com/s2000/topic/9606...way-bar-rates/

For the first few years, the car was known as twitchy, with a tendancy to oversteer a lot - same with the FRS.

Later years of the car, they used stiffer springs up front. Did the car handle worse? Not exactly. It was still praised for it's handling.

Spring rates have the same effect at sway bars do - add a higher spring rate in the rear, the car is going to oversteer. Add a high spring rate in the front, the car is going to understeer.

We will be testing out different combinations this season looking for what combo works best for us.

I will say that on my s2000, when I went from a 517lb set up all around to a 700/600 set up, the car was a lot more stable, especially under braking while at the track.

Cars that are FWD or AWD with FWD bias often run stiffer springs in the rear to get it to rotate.

[SubieNate]

Fair enough, I'm more than willing to see test results of what works best on track. I do know that one of the fastest NA cars here in Southern California is running 10k F 12k R.

Also, the S2000 is double wishbone (well, really multilink) all around so it has a completely different motion ratio calculation than our car if I'm not mistaken. Also, IIRC it's rear suspension exhibits large geometry changes as it compresses/extends which contributes to the stability "issues".

It's not just a case of RWD vs FWD. That was just one example of a case where stiffer front springs are necessary.

Nathan

[D1cker]

Originally Posted by GTM_Challenge

I'll disagree here. Many, many RWD cars run stiffer rates up front compared to the rear because it reduces oversteer in the set up.

Look at the S2000 spring rates from the factory:

http://www.s2ki.com/s2000/topic/9606...way-bar-rates/

For the first few years, the car was known as twitchy, with a tendancy to oversteer a lot - same with the FRS.

Later years of the car, they used stiffer springs up front. Did the car handle worse? Not exactly. It was still praised for it's handling.

Spring rates have the same effect at sway bars do - add a higher spring rate in the rear, the car is going to oversteer. Add a high spring rate in the front, the car is going to understeer.

We will be testing out different combinations this season looking for what combo works best for us.

I will say that on my s2000, when I went from a 517lb set up all around to a 700/600 set up, the car was a lot more stable, especially under braking while at the track.

Cars that are FWD or AWD with FWD bias often run stiffer springs in the rear to get it to rotate.

What you're missing here is that an S2000 is a double wishbone suspension car (like a miata) where as the FRS is strut in the front and multi link in the rear.

The S2000's usually have stiffer front springs, or the same springs front/rear but the motion ratio is similar in the front and back so the wheel rate is also similar (I don't know the motion ratios off hand)

The FRS has strut front suspension which has close to a 1:1 motion ratio. Therefore in the front of my car which has 10kg/mm springs the wheel rate is about 10kg/mm. The rear is multilink and has about a 0.75:1 motion ratio, which means my 12KG rear springs have a wheel rate of 9kg/mm. And some people who run the same rates front to rear would have a 25% softer rear wheel rate.

If you see a coilover with spring rates of 9/7 then the wheel rates are going to be 9 and 5.25 which shows that company doesn't really understand the car and hasn't put any development work in (save for the ad)