Ground Control Spring Coilover Kit REVIEW

Anyone go with a 400/600 spring combo?

e60cs5 wrote

My fronts are 370 instead of 440 and I think the rears are 600 instead of 650. Not sure where I left my receipt.

Just call Jay and talk to him - he'll help you dial it in the way you like it.

He also added some rubber boots to my end links so they could be greased and wouldn't attact dirt. I think it ended up costing me like 50 bucks extra or something like that -but I'm happy not to have any noise issues from the get go.

Some have complained about the joint and the need to grease it every once in a while. Jay knew I was sensitive to (noise) and made a few changes.

Can you post a pic of the rubber boot for your end link???...would like to order also since I just got kit today.

STALKER wrote

Anyone go with a 400/600 spring combo?

I think 440 and 370 are the only options. I went 370 and either 600 or 650. I also have the akra evo - so that was taken into account.

mact3333 wrote

Can you post a pic of the rubber boot for your end link???...would like to order also since I just got kit today.

Just call Jay. He'll send you what you need.

e60cs5 wrote

I think 440 and 370 are the only options. I went 370 and either 600 or 650. I also have the akra evo - so that was taken into account.



Just call Jay. He'll send you what you need.

mact3333 says he is running 400 spring on the front.

Hey guys, what exactly is the black plastic cap on shock tower inside engine bay???...I am assuming its the electronics for the EDC??...will the street camber kit fit there with that plastic cap there?

I've stayed quiet for a whie about this subject and I am ready to chime in today.

The OE shocks are designed and valved for relatively soft springs. When you double or triple the spring rates without revalving the shocks are going to be severely under damped. This will affect the transient motion of your suspension and affect the cars stability and traction.

If we can all simply get stiffer springs to make our cars handle better, why would race teams spend a few grand on each damper?!

rldzhao wrote

I've stayed quiet for a whie about this subject and I am ready to chime in today.

The OE shocks are designed and valved for relatively soft springs. When you double or triple the spring rates without revalving the shocks are going to be severely under damped. This will affect the transient motion of your suspension and affect the cars stability and traction.

If we can all simply get stiffer springs to make our cars handle better, why would race teams spend a few grand on each damper?!

I am not sure how true it is, but Jay from GC essentially explained it to me like this - stock M3 suspension has soft springs, short travel and stiff bumpstops, so essentially you are riding bumpstops on any significant bumps or when weight transfer puts the car on bumpstops. Stock shocks can handle somewhat stiffer springs with softer and/or more progressive bumpstops to keep the whole system close to shock specs. I am not an expert, but this seemed to make sense to me.

Anyway, my GC setup works very nice at the track - front is perfect, better then I expected to have on stock shocks, and rear is slightly bouncy only under extreme acceleration on uneven surface, but that happened to stock set up as well.

I like what Ridzhao just said. Im not an expert, but those spring rates look pretty high for an oem shock. I def dont think edc will show any difference between the 3 settings. This really stinks for me. I dont think Dinan is enough, GC looks to be nice if they made matching shocks to go with it. Sometimes i see in the aftermarket, certain things always lead in one direction>KW v3.

jimmy ny wrote

I like what Ridzhao just said. Im not an expert, but those spring rates look pretty high for an oem shock. I def dont think edc will show any difference between the 3 settings. This really stinks for me. I dont think Dinan is enough, GC looks to be nice if they made matching shocks to go with it. Sometimes i see in the aftermarket, certain things always lead in one direction>KW v3.

Being that I don't have the equipment, time or knowledge to verify the settings, I have to believe in Jay's and Ground Control's assessment. Thus far, they have proven to notch.

jimmy ny wrote

I like what Ridzhao just said. Im not an expert, but those spring rates look pretty high for an oem shock. I def dont think edc will show any difference between the 3 settings. This really stinks for me. I dont think Dinan is enough, GC looks to be nice if they made matching shocks to go with it. Sometimes i see in the aftermarket, certain things always lead in one direction>KW v3.

KW V3's are a mediocre solution from everything I've read and from those I have spoken to that have owned them. Service and warranty are issues too.

V3's Maybe OK for a drop but not recommended for serious track use.

I'd consider Moton SS (assuming all the bugs are worked out) or the KW CS if I was buying for track use. Otherwise, I can't justify the additional money for a mediocre solution.

e60cs5 wrote

KW V3's are a mediocre solution from everything I've read and from those I have spoken to that have owned them. Service and warranty are issues too.

V3's Maybe OK for a drop but not recommended for serious track use.

I'd consider Moton SS (assuming all the bugs are worked out) or the KW CS if I was buying for track use. Otherwise, I can't justify the additional money for a mediocre solution.

Moton SS were a major FAIL

MaxL wrote

I am not sure how true it is, but Jay from GC essentially explained it to me like this - stock M3 suspension has soft springs, short travel and stiff bumpstops, so essentially you are riding bumpstops on any significant bumps or when weight transfer puts the car on bumpstops. Stock shocks can handle somewhat stiffer springs with softer and/or more progressive bumpstops to keep the whole system close to shock specs. I am not an expert, but this seemed to make sense to me.

Anyway, my GC setup works very nice at the track - front is perfect, better then I expected to have on stock shocks, and rear is slightly bouncy only under extreme acceleration on uneven surface, but that happened to stock set up as well.

The stock bump stop is initially very soft until it is compressed to the limit. So yes, at the very limit the effective spring rate is high, but it is only for a very short amount of travel. It makes sense that the OE shocks are tuned to more than handle the stock springs alone, but it does not make sense to say that they can handle rates double or triple of stock.

Anyhow these are just theoretical discussions. What I would really like to see is lap time comparison. After all, the seat of the pants feel could be misleading sometimes.

rldzhao wrote

The stock bump stop is initially very soft until it is compressed to the limit. So yes, at the very limit the effective spring rate is high, but it is only for a very short amount of travel. It makes sense that the OE shocks are tuned to more than handle the stock springs alone, but it does not make sense to say that they can handle rates double or triple of stock.

Anyhow these are just theoretical discussions. What I would really like to see is lap time comparison. After all, the seat of the pants feel could be misleading sometimes.

I'd be willing to say that lap times of a GC Kit vs OE Springs would be faster based on the stiffer springs allowing faster lateral transitions .... and more camber cant be argued with, right?

A properly setup full coilover kit with some real shocks will most likely yield faster lap times then this GC Kit.

If you match the spring rates to the weight of the car and take into account suspension travel via spring length, then theoretically you can make any car faster around a road course by just changing springs.

I agree with you that double the spring rate might not be healthy for the shocks as it makes them work harder (faster) under heavier loads. But this sacrifice applies to most mods that excercise the car outside its factory limits.

Has anyone tried adjusting the ride height on their cars themselves? I would like to raise the rear a bit as it is rubbing on my new setup.

From their experience, can anyone tell me how much the suspension goes up with one full turn?

Thanks

DrC

The collars are a bitch to turn. Not sure how much each turn goes up. Don't pay someone to do it though.

SlamMan wrote

The collars are a bitch to turn. Not sure how much each turn goes up. Don't pay someone to do it though.

I can turn the fronts by hand, and the rears are relatively easy with the spanner wrench. You must have dirt or some other debris in the threads or else you are not loosening the allen screw that clamps the collar enough.

HP Man wrote

I can turn the fronts by hand, and the rears are relatively easy with the spanner wrench. You must have dirt or some other debris in the threads or else you are not loosening the allen screw that clamps the collar enough.

Yeah they're pretty easy to turn when they're clean but not after they've been on the car for a while. It's inevitable that they'll get grit and dust in the threads. Not sure how that would be prevented.

SlamMan wrote

Yeah they're pretty easy to turn when they're clean but not after they've been on the car for a while. It's inevitable that they'll get grit and dust in the threads. Not sure how that would be prevented.

can't be prevented... blow out with compressed air before turning

It seems like to get an even stance I'm needing to center the front adjustment and I'm about 3 threads from the bottom in the rear. Are you guys seeing similar?