Ground Control spring kit? Anyone have this?

[disruptv]

Originally Posted by disruptv

what are the spring rates on dinan and eibach prokit?

any1 know?

Originally Posted by Radiation Joe

You will never get a good answer on this. It's really a personal preference thing. However, if you are sticking with the stock valved EDC, it's easy to say 800 is too much. The EDC rebound damping is not up to the chore of controlling an 800 lb spring. My opinion is that the 400+ lb front springs in the GC kit may be a bit on the stiff side for the EDC dampers. 500 or 600 lb springs aren't too much for the front of an e9x M3, but your dampers have to be able to control that spring.

+1

This is why I asked if any1 knew the rates on dinan and eibach springs so that if I ever go GC down the road, I could use those as a reference point...currently I have eibachs and they have been amazing

[gthirtyfizle]

They have other spring rates as well. Its a matter of what u r using ur car for.

[Lemans_Blue_M]

Originally Posted by Radiation Joe

You will never get a good answer on this. It's really a personal preference thing. However, if you are sticking with the stock valved EDC, it's easy to say 800 is too much. The EDC rebound damping is not up to the chore of controlling an 800 lb spring. My opinion is that the 400+ lb front springs in the GC kit may be a bit on the stiff side for the EDC dampers. 500 or 600 lb springs aren't too much for the front of an e9x M3, but your dampers have to be able to control that spring.

+1

The stock EDC dampers were never designed to handle such a stiff spring rate.

I would also like to advise anyone who is thinking about doing this mod about a very seriuos drawback....

You will accelerate the wear of the OE SACHS EDC struts & shocks by installing this coilover conversion kit.

And the more aggressive you get in regards to the drop and the spring rates, the faster you will wear out the OE dampers. That's just the way it goes.

Don't expect these OE EDC shocks & struts to last 50,000 miles, with the increase in spring load and the shorter suspension travel they will have as a result of this modification.

You never get something for nothing guys. There are always going to be trade-offs when you attempt something like this...

[mastek]

Originally Posted by Lemans_Blue_M

+1

The stock EDC dampers were never designed to handle such a stiff spring rate.

I would also like to advise anyone who is thinking about doing this mod about a very seriuos drawback....

You will accelerate the wear of the OE SACHS EDC struts & shocks by installing this coilover conversion kit.

And the more aggressive you get in regards to the drop and the spring rates, the faster you will wear out the OE dampers. That's just the way it goes.

Don't expect these OE EDC shocks & struts to last 50,000 miles, with the increase in spring load and the shorter suspension travel they will have as a result of this modification.

You never get something for nothing guys. There are always going to be trade-offs when you attempt something like this...

Wouldnt stiffer springs relieve the shocks of more wear??

[BarryC]

Originally Posted by Lemans_Blue_M

+1

The stock EDC dampers were never designed to handle such a stiff spring rate.

I would also like to advise anyone who is thinking about doing this mod about a very seriuos drawback....

You will accelerate the wear of the OE SACHS EDC struts & shocks by installing this coilover conversion kit.

And the more aggressive you get in regards to the drop and the spring rates, the faster you will wear out the OE dampers. That's just the way it goes.

Don't expect these OE EDC shocks & struts to last 50,000 miles, with the increase in spring load and the shorter suspension travel they will have as a result of this modification.

You never get something for nothing guys. There are always going to be trade-offs when you attempt something like this...

Just like the s/c guys - you got to pay to play.... I'd be glad to get that kind of mileage out of mine as my car will be 7-8 years old at that mileage....

BC

PS - why did you stop replying to my question regarding the DCT shifting issues?

[rzm3]

Originally Posted by mastek

Wouldnt stiffer springs relieve the shocks of more wear??

Nope. Stiffer springs = higher acceleration = higher forces experienced by the shocks = more wear and shorter life.

[rzm3]

Originally Posted by Lemans_Blue_M

+1

The stock EDC dampers were never designed to handle such a stiff spring rate.

I would also like to advise anyone who is thinking about doing this mod about a very seriuos drawback....

You will accelerate the wear of the OE SACHS EDC struts & shocks by installing this coilover conversion kit.

And the more aggressive you get in regards to the drop and the spring rates, the faster you will wear out the OE dampers. That's just the way it goes.

Don't expect these OE EDC shocks & struts to last 50,000 miles, with the increase in spring load and the shorter suspension travel they will have as a result of this modification.

You never get something for nothing guys. There are always going to be trade-offs when you attempt something like this...

The springs should be fine in the rear, as 650 is just slightly higher vs. OE (550).

The front is where I have doubts... 170% stiffer vs. OE. It's going to be quite underdamped... meaning a lot of unwanted oscillation, aka bouncing.

But I will withhold my judgement until BC's review.

[m_parade]

if I have the kw v3 can i upgrade the spring kit to my shocks and add the gc camber plate?

[Lemans_Blue_M]

Originally Posted by m_parade

if I have the kw v3 can i upgrade the spring kit to my shocks and add the gc camber plate?

No, not without changing the way the dampers work.

I've spoken to the lead suspension product specialist for KW North America, and I asked him this question about changing the spring rate on the V2 & V3 coilover kits two years ago.

The KW V3 coilovers use specific progressive spring rate that is matched to the compression and rebound performance of the front & rear dampers.

You shouldn't use a different progressive spring rate, nor should you attempt to use linear spring rate as a substitute for the progressive springs that come from KW.

Not only will that void your warranty, but it will completely change the way the dampers work. The results will probably tend to be worse rather than better, since all the R&D testing was spent on perfecting the ride and handling performance of the kit using the progressive rated springs in the V3 kit.

The overall performance of the coilover kit will likely suffer as a direct result of this type of modification.

[aus]

I think Mr.5 had the spring perches changed to accept Swift springs by Harold

[BarryC]

Originally Posted by rldzhao

The springs should be fine in the rear, as 650 is just slightly higher vs. OE (550).

The front is where I have doubts... 170% stiffer vs. OE. It's going to be quite underdamped... meaning a lot of unwanted oscillation, aka bouncing.

But I will withhold my judgement until BC's review.

Will be interesting to see how this all works out. Spoke to Jay about this and his response is the OE spring really only affects 6mm of suspension travel and as you have noted elsewhere, the bumpstop becomes part of the "spring". He also said that he has used a 525lb spring with no issues on this car. Kit will be here in a week and I've got a track event the following Sat so I should be able to post some impressions for sure...

Thx,
BC

[gthirtyfizle]

Just got word for gc. Kit is shipping out today and I upgraded the shipping to 3 days so that I can have them installed by the weekend. Cant wait to get these on

[JC919]

^I'm looking forward to a review, as there seem to be two sides to this thread. Can you possibly PM me how much this system usually runs as I can't find it on a google search.

[rzm3]

Originally Posted by BarryC

Will be interesting to see how this all works out. Spoke to Jay about this and his response is the OE spring really only affects 6mm of suspension travel and as you have noted elsewhere, the bumpstop becomes part of the "spring". He also said that he has used a 525lb spring with no issues on this car. Kit will be here in a week and I've got a track event the following Sat so I should be able to post some impressions for sure...

Thx,
BC

In addition to your "seat-of-the-pants" impression, do you have any data in terms of say, lap times on a particular track with OE, Moton set ups? It would be a more objective way to compare the systems. Just a thought

[M3Alpine]

cant wait to see, im interested in this as well

[1º]

Originally Posted by JC919

^I'm looking forward to a review, as there seem to be two sides to this thread. Can you possibly PM me how much this system usually runs as I can't find it on a google search.

-

Originally Posted by BarryC

Here's some pics of my kit that will be here on 2/18:



Front strut assembly with my EDC strut:



Kit will be installed on 2/22 and I'll post impressions then. Looks very nice!

BTW - the cost was $899. Take that Dinan!

BC

Originally Posted by Jaypod

I contacted Jay today. He confirmed the kit works for non-edc suspensions as well.

Here is a recap of what the kit includes and an additional pic:

The kit comes with:

Street camber plates (that allow use of EDC wires)
Adjustable ride height conversion for the stock struts
front springs, 3 choices because they have to match stock damping. The
stock damping is pretty good however.
front sway bar brackets for strut
front sway bar end linkls (adjustable)
front bump stops

rear ride height adjustment
rear bump stops
rear ride height adjustment
rear springs, 5 choices to match front.
rear shock mounts (GC "hybrid" exclusive), allows use of EDC wires

I am really starting to lean toward this - pretty impressed

Originally Posted by STALKER

All for $899!!!!!

[gthirtyfizle]

^^ was just gonna post that lol.

I would also like to add one thing. I cant get into any details, But lets just say that this kit has been tested around a track and has done significantly well. I have very high hopes for this kit, and not cause I have purchased it, but because it sounds and looks very promising. I was ready to dish out a lot more money for a premium set of coils, and then I found out about this.. Im really so anxious to test them out. Which is y i upgraded the shipping lol.

[BarryC]

Originally Posted by rldzhao

In addition to your "seat-of-the-pants" impression, do you have any data in terms of say, lap times on a particular track with OE, Moton set ups? It would be a more objective way to compare the systems. Just a thought

Unfortunately I don't have any data logging equipment. Besides, I won't be running the same tires and the weather will be much cooler so I'm assuming there won't be as much grip even if I had the same tires.

Also I'm not consistent enough to make a fair comparison...

BC

[michaeldorian]

Originally Posted by STALKER

All for $899!!!!!

Wow, this is killer. Can't wait to read BarryC's review. I'm considering dumping my RD Sport chassis kit. I'm unhappy with the front drop and rake.

@BarryC - Can you also do a thorough review of the car's manners compared to stock on the street?

[STALKER]

Originally Posted by michaeldorian

Wow, this is killer. Can't wait to read BarryC's review. I'm considering dumping my RD Sport chassis kit. I'm unhappy with the front drop and rake.

@BarryC - Can you also do a thorough review of the car's manners compared to stock on the street?

What wrong with the drop and the rake? Too much forward?

[michaeldorian]

Originally Posted by STALKER

What wrong with the drop and the rake? Too much forward?

You can check out what I mean below. Yes, I feel that it's too far forward and a bit too low.

http://www.m3post.com/forums/showpos...8&postcount=79

[Trier Germany]

H&R stance is very similar