Alright guys, I've got a lot to say but I'm going to do my best to condense this into a reasonable/readable length.
First, I want to explain what my goal was with coilovers. I wanted to retain the "liveliness" of the stock car. Positive front end with a free rear end, still controllable, however with height adjustment and more high speed stability.
I'm currently running
275lb/in or 4.9kg/mm in the front
and 350lb/in or 6.25kg/mm in the rear.
The reasoning behind those rates are based off of the Eibach Pro-Street coilovers. Eibach spent a lot of time developing their suspension models side by side with the stock car. That gave me confidence that the Pro-Street spring rates would be a great starting point for my goals of retaining the stock balance of the car. @
FT-86 SpeedFactory was awesome in helping me find out that information. Prompt email responses and more than knowledgeable about the products.
To break it down, the stock suspension spring rates are:
Front = 131 lbs/in or 2.3kg/mm
Rear = 211 lbs/in or 3.7kg/mm
and the motion ratios for front and rear are:
Front = 0.92
Rear = 0.77
So stock rates in correspondance with motion ratio are as follows:
110.8lbs/in or 1.97kg/mm
125lbs/in or 2.23kg/mm
with a Front/Rear ratio of 0.88
Now when we compare that with the rates I am running it looks like this:
Fortune Auto rates in correspondance with motion ratio:
232.7lbs/in or 4.1kg/mm
207.5lbs/in or 3.7kg/mm
with a Front/Rear ratio of 1.12
Essentially meaning the front spring rates have stiffened up, which makes a lot of sense based on the fact that our cars are front engine. This makes the car much more positive on initial turn in and through the center of the corner but we'll get more into that later.
Let's take a look at the coilovers!
Front:
Front Top Hat:
Front Bearings: (These work awesome, I know that because I don't hear them!)
Rear:
Rear Top Hat:
Front Installed: I'm running the car much lower (Less Thread) than shown here.
Rear Installed:
On the ground:
To the important bits, how it drives!
At first, I drove the car and had a bit of understeer through the center of the corner as I was continually applying throttle, this is normal, but I'm looking for the rear end to be free!
So here's the setup I'm currently running and continuing to refine:
Front thread length 2inches 12 clicks of rebound (From full soft)
Rear thread length 1 1/8inches full soft on the rebound.
I originally ran the car with 2 in of thread length at full soft up front and 1 inch of thread length and full soft in the rear.
But in an attempt to free the rear end of the car up, I needed to dial the front in a bit. I've been from full soft to 20 clicks of rebound. 20 overstressed the stock tires, so it was time to back it down. After going back and forth, I decided 12 clicks felt best for me. This is also completely baring the fact that I drive differently then all of you, on different roads at different speeds. So what works for me, may not be what you run.
The rebound got me close, but I needed to shift some weight forwards to stick those front tires down. Raising the rear thread length by another 1/8in did the trick. Lucky first try. Although I will be trying different settings this weekend at the track.
This is also all based on running the stock recommended alignment specs, which are as follows:
Front:
Camber: 0 +/- 45' (0 +/- 0.75°) (Right/Left Difference: 0°45' (0.75°) or less)
Caster (Reference): 5°54' (5.90°)
Steering Axis Inclination (Reference): 15°31' (15.52°)
Toe (Each Wheel): 0°00' +/- 0°11' (0.00° +/- 0.19°)
Toe (Total): 0 +/- 3.0 mm (0 +/- 0.1181 in.)
Rear:
Camber: -1°12' +/- 45' (-1.20° +/- 0.75°) (Right/Left Difference: 45' (0.75°) or less)
Toe (Each Wheel): C + D: 0°10' +/- 0°15' (0.16° +/- 0.24°)
Toe (Total): 2.0 +/- 3.0 mm(0.0787 +/- 0.1181 in.)
As the car is setup right now (With my driving style) the car is super positive on initial turn in, (and if driven correctly), the car drives down to the center of the corner and as you start to reapply throttle, the front end tracks true and the rear end is planted. This time, more planted than stock as well as easier to maneuver through the corner if you find yourself making adjustments. Basically, like stock, but more grip and more confidence. The coilovers are simply using the stock tire more efficiently.
However, if you want to get it loose, a simple exaggerated turn in, excessive weight transfer and a stab of the throttle and it goes into a controlled slide as beautifully as it did the day it came from the factory! Thats the fun stuff!
Daily driving, the car is softer and smoother over bumps when rebound is set at full soft, and feels almost identical to the stock car with the front rebound up 12 clicks.
The guys at @
FT-86 SpeedFactory helped me through this process and it made life so much easier. Can't thank them enough for their help. Incredible customer service and great knowledge. Not much more you could ask for! They are a vendor for the coilovers, you can check them out at
www.ft86speedfactory.com
I'll post updates as I continue to refine the suspension. But for now, time for a drive!
