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Ground Control Coilover Kit Install

43K views 174 replies 14 participants last post by  mazda3az 
#1 · (Edited)
I have one of the first GC coil-over kits for our cars, and am in the middle of the installation. I say "middle", because I ran into an issue I need some feedback on.

I think many of you are familiar with the design concept of these; a threaded sleeve that slides over the shock body, with an adjustable height large nut to set ride height. I bought the set designed for use with the Koni yellow shocks. Apparently I am the first customer to put these on a Gen 1 car; they are advertised/designed for the "2010+ MS3".

Got everything out and off, ready to go, when I noticed that at the top of my Koni yellows, the round retaining "nut" is about 1/16" larger than the shock body, thus 1/16" larger than the sleeve that needs to fit underneath it.

My years of experience fixing stuff like this says to simply file the item down to the required size. Do you agree? I see no way to get this sleeve where it needs to be otherwise.

A related question is this....... These Konis I bought used, and are likely about three to four years old. Are the newer Konis available now designed such that this retaining "nut" at the top of the shock body is now the same size as the shock body, thus no filing/grinding necessary?

The instructions mention only cutting off the original spring seat from the shocks, nothing about filing the top of the shock nut.

Experiences, opinions, and related expertise appreciated about this.

Thx......
 
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#94 · (Edited)
Ground Control Coil Over Kit Summary

Let's summarize. I'm doing STF "on the cheap". I've used mostly used or cheaper versions of the necessary parts, in seeing what might be possible.

First, start with a 2006 Mazda3 Base 2.0 3i. No options except A/C. I'm not a heathen.:roll:

Here's a summary to date.

  1. Started out with cut front MS3 springs, MS3 rear springs (already had these), with the big rear Hotchkis rear bar off my H Stock car. Free.
  2. Claimed a used set of Konis Sports from my H Stock car, that had been previously used by a guy from Wisconsin a few years before that (around $200).
  3. Bought from Tire Rack a set of 7x15 wheels for about $420. Maybe someday will find a cheap set of 15x7.5's......
  4. Next bought a used, short Corksport intake ($100).
  5. Added a set of used ProKit front springs ($120) with the rear MS3 springs (same rate, MS3 springs were taller). Added the Ground Control beta front camber plates at this same time (gratis).
  6. Next installed a Magnaflo cat-back muffler system. Discounted price ($425).
  7. Now I just added the Ground Control coil-over kit ($429). Not free, but cheap. Will run for the first time next weekend at AZ Motorsports Park (AMP). Fingers crossed for a good result. 400# front/525# rear. Will try the big HK bar set on soft position....I think.
Not bad, eh? Not as expensive or fancy as some other efforts out there, but essentially I have all the basic stuff.

My results have been (with the above equipment), I feel, pretty good. My average Pax Scores are usually 960 to 980 against a local crew that typically has three or four past or present National Champs or high Nationals Class placers affecting top Pax every weekend.

At our last few events we've had Joe Austin (HS/STF), Brian Peters (FS/STR/others), Fred Zust (XP) Clint Child (STX), Britt Dollmeyer (ESP), Jay Balducci (STR), Dave Rock (STR).......every darn event weekend some of them show up! Give me a break.:a:


Anyway, my next challenges will be to address adjustments to the above setup.

  • What rear bar to use?
  • Are these starting spring rates in the ballpark?
  • Starting at zero toe front and rear (I used to run +1 turn of toe out in front). Will that work?
  • Is the ride height OK; up down, or just fine?
  • Do I need the rear camber arms installed (also here, bought them used too).
Anyone with any opinions or advice please do share your thoughts.


Thanks........ (Go Denver!!!!)


 
#95 ·
Sounds like the mini. Swift springs, bilsteins, camber plates and a rear bar. :)

Coilovers are nice but not always needed. You'll be shocked how well you can dial in what you have :)
 
#96 · (Edited)
Adjustability

Coilovers are nice but not always needed. You'll be shocked how well you can dial in what you have :)
Hope so.

I know that just adding a neat part does not always result in a performance gain. I had some amazing success with the ProKit/MS3 spring combo, and am a little concerned that the balance will be hard to recover.

I did this mainly for the adjustability factor. Now all I have to do is learn how to accomplish that!:chuckles:

(It appears that Denver is not listening to me......)
 
#101 ·
That setup should make the car really fun to drive! Everything looks good for a base setup. Spend some time dialing in shock and bar setting to your liking and you should be fine. 7.5" wide wheels would be next on my list as well.
Thanks!

It's feeling quite perky on the street. Looking forward to this weekend. Not sure the OTS yellow Koni rear shocks are enough for the 525# rear springs.

Starting with the heavy HK rear bar on soft. Might be too much bar. If my back end passes my front end Sunday I'll know for sure. :chuckles:

Despite naysayers, I favor my Ground Control camber plates. *I* feel with them I have about -3.5 degrees negative camber in front (lowered 1.5"), and at only $145 for the set I'm very happy. Not adjustable, but very simple, and will work with the larger diameter stock-sized springs! They are due out this month. One piece hard aluminum.

If anyone knows of affordable 15x7.5 wheels, let me know. This car is really shaping up nicely.
 
#104 ·
R & R Front Shock Struts

On a related note, on two Mazda3's now, I've gone through the drill of removing and reinstalling the front struts. IMO, what a pi** poor design.

The two bolt method I've seen on so many other cars is so much easier to work with.

That said, what have you folks here found as an easy way to get the old strut/shock out of that clamp? I've had to often resort to a bottle jack to get the shock body moving out of the bottom.

Then, when installing (even with mucho grease), get it in and started, all aligned, put pressure on from a floor jack from below, and still usually have to whack it with a hammer (from the side) to get it to go all the way in.

Is this how it is for you guys too, or is it just me?

That was another reason I didn't cut the lower spring perches off for the GC install, I wasn't confident I could get the damn things back out later without the bottle jack pushing it out.

Suggestions?
 
#105 ·
Then, when installing (even with mucho grease), get it in and started, all aligned, put pressure on from a floor jack from below, and still usually have to whack it with a hammer (from the side) to get it to go all the way in.
That was pretty much the method I used when doing front struts on my brother's 3. I'd also be interested in hearing if there's a better way. I'm not looking forward to doing it again on my Focus.
 
#106 ·
I've heard of using a pry bar or claw hammer being used to spread the assembly slightly. We'll see next week when I do my struts.
 
#108 ·
My method is easy. Take the bolt out of the strut take the bolt off the swaybar and the steering knuckle then beat the ever loving shit out of the upright until it falls off of the strut.

There are very few things I can't take apart with a big ass sledgehammer.
 
#112 ·
There's a tool for VW's that'll probably work. Their struts mount the same way.

Why is everyone so afraid of a hammer? With the wheels off and a hammer it takes literally 10-15 min max to remove both fronts. :)
Nothing wrong with hammering the uprights. That's how I shock balljoints loose.
 
#114 · (Edited)
Update on GC Coilovers

Thought I'd share how things have gone so far.

Four events, three different venues. Even though I'm winning locally, I was before these springs too. After the fourth event, assessing comparative raw times against my benchmark drivers, I'm seeing..... no significant difference so far. Time to adjust a few things.

My first Rivals were almost slicks, new set now installed.

I was thinking/anticipating a nice jump, but not yet. My (older used) rear shocks appeared to be on last legs (Koni Sports), so I bought two new MS3 Konis. Also removed one more bump from bump stops (may have been hitting).

Had the rear shocks set before at H Stock position (full stiff), thinking that may have been wrong, so now at +1 turn from full soft. Seem to handle the 525# rear springs well on street test bumps.

I have 300# front springs ordered, but will not have time to install before this weekend. That's OK, don't want to change too much at once.

Quick test runs on a couple of safe street corners seem to feel better balanced. Hoping for more event situation rear rotation. I have a two day event this weekend at Marana Airport (large site).

Will report back.:bigsmile:
 
#115 ·
GC Front Camber Plates

Guys,

I spoke with Jay today at length about why the delay in producing these for our Mazda3's. Apparently the hangup is that they are looking for a way to make these adjustable. Apparently some requirement for "World Cars" that changed the design of the front strut housings is complicating things.

They are working on this concept occasionally, not daily.

All I know.
 
#116 ·
Guys,

I spoke with Jay today at length about why the delay in producing these for our Mazda3's. Apparently the hangup is that they are looking for a way to make these adjustable. Apparently some requirement for "World Cars" that changed the design of the front strut housings is complicating things.

They are working on this concept occasionally, not daily.

All I know.
Thanks for the update. I was hoping I might be able modify a set for use on the Focus. I got tired of waiting, so I started building my own.

 
#119 ·
Spring Rates

Well, I had the 300# springs on the front for a couple of days, and had to pull them off. In the 6"x2.5" spring there is not enough travel to prevent coil-bind. Yep, found out firsthand. 7" springs at the 300# rate might work, but I went back to the 400# front springs.

Will be putting some 700# springs on the rear, and will likely move the 525# rear springs to the front.

With the Ground Control setup it is very easy to change springs quickly. You do have to take care when lowering the car after jacking to make sure the springs seat correctly.
 
#120 ·
GC Coil Over Experiences

At last weekends event I bought some 700# 6"x2.5" springs from a friend. Between run groups I installed them. The first set of runs were on the 400#f/525#r springs, the second set was on 400#f/700#r springs.

Took about two minutes to change the springs BTW.:chuckles:

Amazing difference. Great. Car handles slaloms significantly better, turns in more crisply, and demonstrates to tendency to have the rear rotate in a controllable manner.

Was going to put the 525# on the front; shelving that idea for now.

:peace:
 
#128 ·
At last weekends event I bought some 700# 6"x2.5" springs from a friend. Between run groups I installed them. The first set of runs were on the 400#f/525#r springs, the second set was on 400#f/700#r springs.

Took about two minutes to change the springs BTW.:chuckles:

Amazing difference. Great. Car handles slaloms significantly better, turns in more crisply, and demonstrates to tendency to have the rear rotate in a controllable manner.

Was going to put the 525# on the front; shelving that idea for now.

:peace:
I am tempted to up the rear spring rate on mine and see how it is, now that I've got a baseline and some seat time on the current setup. Plus, my current rears springs look to be progressive, I'd like to try stiffer and linear. One question, the current springs I'm running are flared, meaning that one end is 2.5" ID and the other is over 3" I.D. like oem to fit down in the lower control arm/trailing arm. Are you using a 2.5" I.D. spring on both ends? If so, any issues or things I need to be aware of?

Here's my current rear spring on the right:




On the car:

 
#123 ·
Wow. Those are beautiful. It looks like you moved the strut mounting point in and aft from the normal position. Is that needed to prevent a change in caster, like you mentioned in your post? Or did I interpret that statement wrong?

"My goal was to position the strut rod in a way that would get me the most negative camber without sacrificing caster, and vice versa."
 
#124 · (Edited)
Homemade Camber Plates

Very nice and well done. Very good quality and engineering.

Thanks for sharing your design. Pretty sure it's beyond my skill set.:wink:

Guys, please direct comments and questions on this project via the Focus site.
 
#125 · (Edited)
Alignment, Springs, and Tire Temps

Another "truth" I think I learned this past weekend, is that my infrared tire temp gun is nowhere close to being as accurate as a real tire temp probe.

I just got an AccuTech probe Pyrometer from Summit Racing, and used it last weekend. Got consistent temp readings from run to run, which did not happen (for me) with the infrared temp gun.

Fronts ran (inside to outside) typically 116/120/116'ish at 40#, so I dropped to 38#. Very even then. This with -3.5 degrees camber, zero toe, and the 400# springs. These were 225/45/15 BFG Rivals.

Rears ran about 86/88/90 degrees with the 700# springs, 42# pressure, zero toe and -2.5 degrees camber.

Want more rotation? Up rear tire pressure. Sorry, but with these tire temps I'm keeping that rear camber.:winker:

Very impressed with this GC coil-over setup, especially with how easy it is to change F & R springs when needed.
 
#126 ·
How long are your runs, how long do you have after a run before you can measure the tires? I don't know Rivals, I'm under the impression that other tires get hot to the point of greasing if you abuse them enough on back-to-back runs.
 
#127 · (Edited)
Tire Heat

How long are your runs, how long do you have after a run before you can measure the tires? I don't know Rivals, I'm under the impression that other tires get hot to the point of greasing if you abuse them enough on back-to-back runs.
This was near Tucson, AZ, on airport asphalt. Course was about 6/10 of a mile, all second gear. No rev limiter involvement.

Ambient temp Sunday was 60-78 degrees from my morning runs to my second set of "Time Only" runs. During our summer I water my tires, did not today; too cool.

Finish the run, 30 yards back to grid, measure tire temps, within 20-30 seconds after a run. Had a good 7-8 minutes between each run.

Course map and results here: http://www.azbrscca.org/

I was in the 56-57 second range, four runs.

At no time did they "go off" or get greasy. No drop off from one run to the next (as I had with my 2008 H Stock Mazda3S on Dunlop SS's).

This is my second set of Rivals, on purpose.:chuckles:
 
#134 ·
I have pretty much the same kit as Scott. The piece that drops in the lower control arm is REALLY simple. It's basically just a 2-3" long tube with a spring seat welded halfway down the tube. Half the tube sits down in the hole on the LCA and the other half is meant to keep the spring somewhat centered. The kit came with a rubber spring isolator that also works to center the spring. Sometimes G.C. doesn't like to sell pieces like this unless you buy the whole kit, but it might still be worth a phone call.
 
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