On springs - add dampers or go coilover for my needs?
 

have a 13 BRZ with eibach pro kit on 18x8 rims and 225 width tires (will probably bump to 245 next time).

for the most part i like both the ride height and the performance of the suspension. i live in southern california where the roads are ok and very rarely will the car be in inclement weather. this is a daily driven car but i do autocross and would like to graduate to some hobbyist track driving. my big problems with the current suspension:

- ride harshness is very pronounced. i am not super experienced with suspensions but i feel that this is the result of very poor damping from the stock shocks being paired with stiffer, shorter springs giving a shorter stroke to the suspension and changing the ratio of bump and rebound. my benchmark for damping and firmness is my old volvo c30 r design which i believe had eibachs from the factory

- the car rides a little more neutral on new springs than it did stock, which is good but i do feel like it could use more grip from time to time. i would appreciate the ability to dial this in but it is not a dealbreaker if i can find a decently happy medium

- based on the stiffness of both the car and the suspension I lose grip fairly regularly on bad roads. bumps really rattle the car and there is a major tendency to lose some wheel contact and break traction which is annoying. the most popular autocross circuit in my city is in a pretty poorly paved stadium parking lot

I THINK what i need is better damping, but perhaps a change in spring rate is also in order to meet these goals. I figure adding a little bit of negative camber to the rear wheels will also eek out a little more rear grip, as long as its not so much as to disrupt launches. Price range is probably under ~$1500 or so, which means either a decent set of dampers (koni or bilstein) or a budget coilover kit (blitz, tein, hks, etc.)

- does it sound like i need adjustable height or damping?
- what is the relationship between damping rates and spring rates in terms of ride firmness and traction? i feel like i could handle an even stiffer ride so long as it damped bumps better and i didn't lose traction, but is that an inherently impossible thing to ask for?
- is it possible/advised to retain the eibach springs with the dampers from another coilover?

I know that the eibach springs with the bilstein dampers is essentially the brz sti/TS setup so i'm tempted to go with the oem+ type option, but for the price i am worried about missing out on adjustability, etc.

thanks for the input

http://www.ft86club.com/forums/showthread.php?t=9936

http://www.ft86club.com/forums/showt...highlight=ruin
^See number 2-6-7

I would be more concerned about fitment rather than ride quality

I’d contact @CounterSpace Garage or @Racecomp Engineering and ask them for an opinion and then support them through a purchase. They very freely share information here on the forum and have been a huge help to me and many others here.

That said, it’s pretty easy to go down a rabbit hole chasing improved suspension performance, especially if you don’t do a lot of research upfront and have a well defined budget and goals. For most applications, a well matched damper and spring set can go a long way and often outperform a low-end coilover, and a good alignment and increased negative camber make a huge improvement in overall grip.

There are zillions of people on the internet running the pro kit and stock dampers and saying they work fine, but on my Honda Accord it never felt right, always a bit bouncy and underdamped. This will obviously depend on the model of the car and how soft their struts are.

Also keep in mind Eibach sells dampers that are specifically made to pair with their springs... never tried them though.

My GF has a volvo c30 rdesign and my stock 2013 FRS rides firmer than that... so the fact that you have the stock struts and stiffer springs and aren't happy with the ride compared to that, doesn't surprise me. The 2013 rear suspension is fairly stiff in its stock form, have to be careful taking fast corners around here with some of the crappy potholes etc. The rear can snap around quite easily if its upset by a bad bump.

Personally i would not do coilovers for a street car, way too much headache.

Given the price range, I would suggest a set of dampers. Both brands are good. A budget coilover is not the best option and you would need to go higher in price ($2300-$2500) to get high quality damping.

We don't advertise often, but we have successfully campaigned the CSG Spec TEIN Flex A for quite some time. This would fit quite well within the $1500 budget that is being requested.

What makes you say that? Sitting 18x8 with 225s and 45mm offset.

There is a little bit of rear camber but could go for more potentially. #7 about having too much tire grip for the level of damping sounds like it might make sense. I never considered bouncing an issue because the car doesn't bounce downward too much, but on rough roads there is definitely some "upward" bump that makes it skip traction. I might have been thinking the wrong thing by wanting even grppier tires (225 pilot super sports on there now)

Define the symptoms of being underdamped in your opinion. I know the pro kit is meant for stock springs but it definitely feels like a suboptimal match.

Naturally I don't expect it to be as comfy as the c30 but I would expect coils or better damping to make it a little more tolerable and grippy

Have you looked into the MCA traction mod?
Able to "mat" it earlier in the corners.
Enables a squat.
http://www.ft86club.com/forums/showthread.php?t=112859

do you all reckon there are other mods that can help increase traction and improve damping on the stock set? i've heard adding a little camber for example can increase the stroke on the dampers and give them more travel to do their work. is this enough to be noticeable?

It's getting to be that time when a lot of the 2013 models are due for a suspension refresh. Pro kits are fine springs, but on worn dampers they won't be very comfortable (especially on 2013 dampers, which aren't as good as later models anyway).

The easy button would be to just add Bilstein B6 to your current set-up. It's a solid way to go...the Bilsteins are good. It's not a nationally competitive autocross set-up, but it will ride pretty well and perform a little better than stock.

I would at the very least inspect some of your suspension bushings and top mounts. Depending on mileage, they may be ready to be replaced too.

If you do want a significant upgrade in performance, coilovers will get you that. There are a lot of options out there with varying levels of quality and cost. Don't assume that all coilovers are always better than a good strut + spring combo. It will depend on what you're looking for out of your chassis.

Adding camber won't help add travel, but a good alignment with some negative camber from bolts, plates, or LCAs will make a massive difference in handling. Again, how much will depend on your goals.

Feel free to send us a PM!

- Andrew