Vidra

I'm nearing a final decision on purchasing coilovers for the S13. I hope that someone who has firsthand experience with Ground Control could chime in with clarification.

Since Ground Control coilovers utilize a partially threaded strut housing. I forsee issues with the strut bottoming out if they are lowered significantly. I was told that this is corrected by employing a short stroke damper that was approximately 2" shorter.


Despite emailing them, I haven't received a clear answer to this question:

- Since the strut is 2" shorter, can I expect that the overall physical dimension of the coilover is also 2" shorter, resulting in a 2" lower ride height straight out of the box?

thegr8one013

Yes exactly,your car will be 2 inches lower from just the install. Are you just trying to be low or want these for road racing? If you are going for road racing you don't want to go to low anyway because your geometry gets out of whack. If you're looking to just get low you could go with your standard isr or stance or any fully threaded coilover

Vidra

The purpose of the car is mainly for street with occasional track use. Looking to drop roughly 3" over stock in the front, 2" in the rear. Definitely not going for a slammed setup, but certainly don't want more than 1" fender gap.

oewoko

I have ground controls over koni inserts on my s14. Im probably dropped a modest 2", but looks more with my slightly oversized tires, 245/40/18. I have the eibach equivalent spring rates of 6k front, and 5k rear. It's only seen the street, and I have never once bottomed out. The konis are a quarter turn from the softest, and it's very comfortable, yet firm on rebound. Not at all harsh.

I don't know how these spring rates feel on the track, but spirited street driving is hella fun.

In the process of putting Megan racing hardened rubber bushings on the arms, a la nismo.

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oewoko

Also, I'm not aware of any bolt-on short stroke damper. But if there is 1, it will lower the car however much shorter it is than the stock dampers

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Vidra

"Our main dampers are approximately 2" shorter than the originals. This allows the vehicle to be lowered and still maintain bump travel without prematurely engaging the bumpstops."

"The base kit comes with our custom valved 8641 series struts and 8041 series rears."

oewoko

It looks like this email is referring to the inserts available for the S chassis. If it is, after hacking and inserting into your OEM strut housing, it would not be any lower without the use of springs

What they are saying is their insert is 2" shorter than the original, meaning you gain 2" of suspension travel.

I actually never knew this about the inserts. Guess this is what I've never bottomed out.

I had GC's over agx's on my old b14, and would bottom out that car with also about a 2" drop, but softer spring rates too.

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Vidra

I should have specified, all of this is in reference to their complete coilover kit (part # 6065.70).

Vidra

Oewoko, do you have any spring droop front or back? I'm looking to drop 3" up front and 2" in the rear and it's looking like I'll have quite a bit of droop, especially in the rear.

I'm thinking about having Ground Control add helper springs to the rear and possibly the front as well. However, I'm very concerned with running out of downward adjustment thread on the fronts if I add another ~.75" (counting the compressed helper spring & ID coupler).

oewoko

I do. Whenever I jack up the car, the springs are off the tophats. The front is on stands now. I'll get a pic for you today

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Vidra

Just curious as to how much droop gap (in inches) you're experiencing up front (and rear too if you know).

When you take pics it would be great to also see how much threaded sleeve is available to lower the car further (if you have that in inches too even better!).

I've been very concerned about running out of shock travel and hitting the damper bump stops since Ground Control doesn't use a fully threaded coilover design. However, they told me that their dampers are 2" shorter in length, supposedly making the car ~2" lower right out of the box with the spring perches set at their highest setting. Any truth to this?

Essentially, I want to lower the car -3" and -2" respectively to stock, WITHOUT reaching my bump stops despite driving aggressive at the track. 450 lb spring up front and 350 lb in rear.

You've been a huge help so far!

e1_griego

You don't need helpers in the front -- the spring droop is fine.

If you're going the pre-built GC route I think it's worth upgrading to Koni 8610s in front (I think they charge an extra $100?).

Vidra

I am going pre-built and upgrading to 8610's up front. It's an additional $150 total now for anyone interested.

oewoko

Fyi, I saw a set on the for sale threads come up yesterday. The complete GC assembled c/o

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oewoko

This is the front. Sorry I couldn't get a ruler out. But it's about 3 inches from the spring seat to the top hat with full droop

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Vidra

Wow that is a LOT more than I was expecting up front. Can't imagine how big the gap is in the rear! Any issues with bottoming out on the bump stops?

Also, roughly how much thread is left up front to lower the spring perch further?

oewoko

Here's a couple pics with a measuring tape. 2" between the spring seat and top hat. A little less than 0.5" left on the collars. I'm probably dropped around 2", and have never hit the bump stops, which I have shortened by cutting off the lowest section.

Fwiw, people that normally go for ground control/koni, aren't doing it to be super low, but for racing.

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Vidra

Oewoko you are the man! For some reason I was thinking that you had the turn key full coilover kit from Ground Control. I see now that you are just rocking the sleeves and full length Koni yellows. This expains why you have the spring droop up front and you are almost completely out of perch adjustment.

The setup for sale on zilvia is the full turn key kit and utilizes the shortened length Koni dampers. I PM'd the seller and he told me that despite having the spring perches the entire way up (as pictured in the for sale thread) the car was still lowered without any spring droop up front.

Looks like I will be good rocking a 3" drop up front with no issues bottoming out. I'm going to still want helpers in the rear though.