CTSVLSX

I've been following this thread and the one on cadillacforums and decided to chime in!
I have the KW3's installed on my car (full list of mods later in sig after i set it up)
It seems very .. bouncy.. especially under power, the rear moves around too much, and I'm triyng to pin down what is causing it.

Great info from Fuzzy!

How does it feel with the higher lb/in springs vs the ones that came with the KW set ?

I have a Gforce setup on my rear (the 9" IRS).

Car is a completely different beast than it was before, however it's still too bouncy.. That's the last thing I need to dial in to get it right

Sssnake

Fuzzy,

Any more updates? I will be pulling the trigger on this mod very quickly. Currently when I get on the gas the rear is squatting too much and front gets light. I also have the "walking out" effect with the GC setup.

Did you actually weigh the corners or just assume? The reason I ask is I want to get actual corner weights for my car as I have changed the weight distro quite a bit. Purchasing scales seems out of the question as the ones I saw started in the thousands. Any suggestions about where I can come up with actual corner weights?

BTW - Excellent thread! These are the types of threads that make me feel confident in spending a couple of grand.

FuzzyLog1c

iTrader: (4)

I will have updates in the next few days. I'm still tuning the front end. Are you still running the stock subframe bushings? What are your spring rates?

I estimated the corner weights I presented earlier based on the stock CTS-V spec sheet, and my Excel spreadsheet notebook where I track the weight of each incoming and outgoing part, as well as its cost and any installation notes that occur to me. There are places that will actually do corner weighing--I haven't looked into it yet, though. Too many mods left.

Sssnake

Spring rates 550 F and 600 R and I have the Revshift Blue subframe bushings.

garrettg

iTrader: (1)

Can you verify what I had read in another thread in that you are running compression at the max turns from tight aka least amount of compression resistance possible? I haven't turned mine out that far, is it obvious when you get there and is this the ticket for handling potholes and other bumps at slower speeds? I am trying to get my car move civil at near stock ride heights with the kw v3 setup using 500/629 spring setup.

FuzzyLog1c

iTrader: (4)

Your spring rates don't make sense. Where did you get a 500/629 spring setup?

Changing the compression and rebound dampening settings on the KW Variant 3 only modifies the slow speed valving on the shock, which only comes into play if movement is less than about 1" per second. Depending on how big and how deep these potholes are, how inflated your tires are, and how fast you're hitting these obstacles, you may not be on the right path to solving this problem.

And I'm not sure I would want to tune for potholes--I'd rather tune for more normal road conditions and drive around the potholes.

garrettg

iTrader: (1)

I bought the 629 rear because I wanted more ride height than the stock kw v3 spring provided. I have a trailer hitch installed and a sub in the trunk. For the front spring again to achieve close to stock ride height and to keep 275/40's from rubbing too much decided to go with a longer spring so I choose a softer 500 rate. I can get there with the stock kw spring but the preload it takes doesn't leave much for suspension travel. I am trying to obtain more comfort than the stock 400/400/fe4 setup. I may be completely wasting my time I don't know but I know I would like a softer ride at this point. The ride on the highway is fantastic my issue it with bumps and pot holes at really any speed. Back to the question, I had read you ran the least compression possible in the kw shocks. Are you doing that because you want more compliance over crappy roads or some other reason?

FuzzyLog1c

iTrader: (4)

Your logic for your spring rate selection makes zero sense. You were having rubbing issues, so you bought a longer, softer spring? What?

VeryWhiteDevil

iTrader: (9)

did you say trailer hitch?

if you don't like those KW3, I will trade you my ground control FE2 setup garrettg.

garrettg

iTrader: (1)

The height of the front bumper is more of a concern than rubbing from running 275/40 on the front. The rubbing is rare and can be dealt with next set of tires with smaller section width. I wanted to try 275/40 square setup to see how it was. The softer spring is an attempt for comfort. I can switch out springs all day long just looking for comfort settings on the shocks over rough streets in the city. If going back to stock is best option given my goals then that is what will happen. Been on kw v3 for 25k bought the 629 rear spring right away. The softer longer 500 front is a recent experiment. I didn't post here to catch flak about spring selections just trying to make the wife and upcoming newborn happy so I don't end up with a slushbox 5 series.

garrettg

iTrader: (1)

Yes for towing sport bikes, its not a big deal v does fine I posted pics of it last year. If somebody could adapt the mr shocks from V2 to the V1 would trade my kw v3 for that in a second.

FuzzyLog1c

iTrader: (4)

Garrett, putting aside the fact that I despise your application of the CTS-V (you really should buy a SUV), your understanding of how springs work and how wheel rates can affect ride comfort needs an overhaul. If I have time this weekend, I'll try to explain why I think you're doing exactly the opposite of what is necessary to help you achieve what you want.

garrettg

iTrader: (1)

Numbers based on your weight calculations which are very handy.


500/629 KW V3
Front/Rear Effective Coil Rate: 295.85 and 314.5 lbs/in
Front/Rear Wheel Rate: 175.06 and 157.25 lbs/in
Front/Rear Wheel Frequency: 81.49 and 84.32 cpm
Front/Rear Natural Frequency: 1.35 and 1.4 Hz

Front/Rear Bias: -3.47%

FuzzyLog1c

iTrader: (4)

Quick update: for the 674 in-lb front springs, my initial estimate of full soft compression and 50% additional rebound dampening increased (8 clicks from full hard compared) is working pretty well.

Haven't been able to really beat on the car because I need to get an alignment. Had to remove the front control arm to install new bushings. Suspect that final tuning will involve somewhere between 1/4 and 5/4 turns additional compression dampening (front and rear) to sharpen up the handling. Will report back with final-ish tuning numbers.

gangnam style

update on current settings (c/r)? alignment?

assuming still running 672f/896r

FuzzyLog1c

iTrader: (4)

Sorry, I forgot to update this thread since the thread on the Cadillac Forums had a steady trickle of feedback and questions. Still running 672/896 and have no intention of replacing those springs with something else.

I run the Addco swaybars--significantly bigger than most of the guys with the LG Motorsports setups. End link locks (as pictured in my 2013 mod hell post), Hotchkis billet race brackets, and Supra adjustable end links round out that package for maximum strength and tunability. I plan to identify my end link lengths for the benefit of interested drivers. Presently, they are cut to the following length, which I selected to provide (what I felt) was a conservative amount of clearance to the KW Variant 3 shock body:


Supra adjustable end links ($89 for a full set)

The threaded piece in the calipers is what I cut off the end of the adjustment rod. In the picture, both end links are screwed to their shortest possible length. Uncut on the right, cut on the left. As it turns out, you can modify the response curve of your sway bar (i.e.: change the amount of differential loading necessary to activate the sway bar) by lengthening or shortening the end link.

That's why every user's manual will tell you to start by setting the end links such that they drop straight down from the sway bar to the control arm (with full weight on the wheels). If you can do that, the moment load shifts, the sway bar starts to go to work because the end link was a hair's breadth away from being under tension. Most of the time, however, suspension / sway bar geometry won't let you get there.

Conversely (this is what I did by accident), if your end links are too long, movement of the suspension on one side of the car will have to rotate the sway bar so that the end links are straightened out before load begins to transfer from one side to the other. While this is great if you like to drive on railroad tracks, it sucks from a cornering perspective.


Plenty of room

Per my previous post, I tried 1/4 additional turn of compression dampening (one sweep on the bottom of the shocks) and did not like that at all. My recommendation for dampening with the 672/896 spring setup is that you want both shocks set to full soft on compression, with (IIRC--I'll check this weekend) 7 clicks from full hard on front rebound, and 5 clicks (I'm certain on this) from full hard on rear rebound. If you're running stock springs in the front, stick with the compression and rebound settings recommended in the manual for those.

Still playing with rebound--my next experiment will involve trying to dial out some interesting undulations on this one stretch of road. No other road I've driven has this problem--above 65 mph, the car doesn't have enough rebound dampening to settle before the next, gentle "wave" in the surface of the highway. Ultimately, I suspect that tuning it out would require triple or quadruple adjustable shocks (not even going to go there!), but if I can improve on this tuning, I'll share it with the group as always.

gangnam style

Thanks for the update. Appreciate it.

I was under the impression you were running miata end links or am I mistaken ?

FuzzyLog1c

iTrader: (4)

I was, but the boot on one of them cracked and the ball joint was starting to seize. These are built a little better and shouldn't have that problem.

Sssnake

Fuzzy,

Do you have a measurement for the effective length (distance from the outside of each endlink bolt) of your current endlink adjustment? I have been all over the place with mine. I have too much body roll with them cranked all the way down but too much coupling of each side when they are longer. I suspect that I need to stiffen up the springs on all four corners. The reason I am looking for the measurement of the effective length is I have the powergrids so knowing the amount cut out isn't beneficial.

Charles

garrettg

iTrader: (1)

Fuzzy,
Where are you on ride heights front and rear? I took my kw v3 setup out for now until next tire change the 275/40 front tire to something else does works fine with stock suspension setup.