Bc racing coilover setting ??
 

I had my coilovers installed about 1 month ago. My setup is 20x10 fr 20x11r i have the setting at 15 / 15 Ive noticed when I down shift or launch hard the front in seems to flutter from side to side and not stay planted .. whats a good adjustment to use to correct this issue???

What does "flutter from side to side" mean? Are you feeling a pull on the steering wheel? Did you get an alignment after the CO install? If not, that's where I would start first. As far as rebound and dampening adjustments go, I also started with 15/15 all the way around, and made some small adjustments from there. Also, did you set the preload on the springs per factory specs?

yes got it alignment done , im not sure how they adjusted the preload what should it be adjusted to? it just seems like the front end floats under torque load

I can't recall what my settings are now, but my friend who races professionally helped me set it up a few years ago. We put the back at around 18 and front at 23 or so for some track days. That helped braking and cornering tremendously. My wheels and tires are still stock. He wanted me to make it even stiffer but I didn't want to shake the car apart!

There are many factors that may come into play in what is "best" for the BC settings. Things like - are there suspension Mods (Bushings, Sways, etc), Tire/Wheel Combos, Alignment settings, etc. Also the specific spring rate of the BC Coil Over.
In general, I avoid any lower settings (less than 10) cause I was getting weird ride and noise results. BUT - this is specific to my car, which has the full boat suspension bushings, and BMR front and JPSS rear sway bars. I also have Moreno Camber plates which allowed be to dial in more Caster, and 22"s which add ride harshness, esp on our God Awful Michigan roads. So I wound up currently for a street setup at Front 15/10 and Rear 16/12. This gives me the best ride and handling quality, without too harsh of a ride or bouncing around on our rough roads. If our roads were smoother in general, I would be cranking up the settings.

General Info:
Rebound (Top of Strut adjustment knob) has a ton of adjustment range. This is used to tune the cars handling balance. It controls the sprung mass of the car, and settings generally effect Under and Over Steer. Increase Rear Rebound to reduce understeer, and increase front rebound to reduce oversteer.
Bump (or Bound/Jounce/Compression) adjustment (Canister or Reservoir Knob) is not as sensitive, and First 10 clicks on bump adjustment do nothing. It keeps the tire on the ground when encountering bumps, and adds grip up to the point where the car will not absorb them smoothly. So more for a smooth road, and less for rough roads.

Super soft (if you are in cupcake delivery business)
Bump (f/r): 15/10
Rebound (f/r): 10/7

Full soft (recommended street setup)
Bump: 15/10
Rebound: 15/10

Medium (track setup)
Bump: 25/10
Rebound: 20/18

Full stiff (auto-x setup)
Bump: 25/10
Rebound: 23/20

Super soft and full soft settings focus on ride comfort and maximize the total amount of road grip. Medium setup is a good compromise between road grip, overall vehicle control and transient response time. The comfort level is pretty comparable to stock. Full stiff maximizes vehicle response and control. It is far too uncomfortable and twitchy for the street.

So in the end you really have to experiment with your settings until you get the desired results for whatever and wherever you are using your ride. If you are experiencing what you call "flutter" or "floating", then try adding more compression until the ride gets too harsh.
Hope this helps.

I have the BR series so i dont think i have the bump adj where they a addon??

There is single adjustable (BR) like you have, and dual adjustable (ER) series. Obviously the BR series only allow the same settings for compression/rebound, whereas the ER's give you the ability to set compression/rebound separately, and cost about $850 more. Preload on the spring should have been set to compress it about 10mm or so to ensure there are no clunks. SO with the BR's, start at 10 clicks and go up in 2 click increments till you don't like the ride quality.