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      06-21-2017, 11:35 PM   #1
Mar48
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Considering a change... Ground Control Coil Overs (525/650)

Bought my Z4M this past week and drove it 1100 miles home. Absolutely love the car, however I'm not thrilled with the coil-over setup. I thought it may be a issue but over the drive it made itself clear, the setup is too stiff for me. I can literally feel every single bump in the road, and occasionally feel like I catch air on big bumps. I've had a couple S2000's with coil-overs before but neither were this stiff.

I have Ground Control Coil Overs (525 front spring rate/650 rears).

I'm considering switching coil-over setups or maybe even going back to a stock setup with lowering springs. I want a lowered car, but since I daily drive the car and the roads here aren't the greatest, I want something more comfortable.

Any suggestions?
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      06-22-2017, 11:07 AM   #2
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Quote:
Originally Posted by Mar48 View Post
I've had a couple S2000's with coil-overs before but neither were this stiff.

I'm considering switching coil-over setups or maybe even going back to a stock setup with lowering springs. I want a lowered car, but since I daily drive the car and the roads here aren't the greatest, I want something more comfortable.

Any suggestions?
Give Shaikh at Fat Cat Motorsports a call.
My FCM setup rides much better than stock and generates more grip too (336 / 616 lbs/in F/R spring rates, custom valved non-adjustable Bilstein-based dampers).

Stock suspension is comparatively harsh as well, in part due to being overdamped in rebound. The real fix for this is to get dampers with better valving.
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      06-22-2017, 09:43 PM   #3
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Thanks for the suggestion - I don't mind a lightly harsh ride as I'm used to driving sports cars with stiffer suspensions, when I test drove a Z4MR the ride felt perfect stock (to me).

I think my spring rates 525/650 are a bit stiff

Interested in getting some more opinions
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      06-23-2017, 04:57 PM   #4
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Quote:
Originally Posted by Mar48 View Post
Thanks for the suggestion - I don't mind a lightly harsh ride as I'm used to driving sports cars with stiffer suspensions, when I test drove a Z4MR the ride felt perfect stock (to me).

I think my spring rates 525/650 are a bit stiff

Interested in getting some more opinions
Too stiff for street and probably a bumpy track!

I'm not sure what the Konis can accommodate as far as lower spring rates. Maybe 450/550 or even a bit lower.

If you want to try and use the GC, I'd give GC a call. Jay (owner) or one of the staff can probably help answer questions and let you know what can/cannot be done.

If you're looking at other options search Fortune here on the forum. There are some nice setups there with digressive pistons yet street oriented.
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      06-24-2017, 09:55 PM   #5
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Quote:
Originally Posted by Finnegan View Post
Too stiff for street and probably a bumpy track!

I'm not sure what the Konis can accommodate as far as lower spring rates. Maybe 450/550 or even a bit lower.

If you want to try and use the GC, I'd give GC a call. Jay (owner) or one of the staff can probably help answer questions and let you know what can/cannot be done.

If you're looking at other options search Fortune here on the forum. There are some nice setups there with digressive pistons yet street oriented.

What do you mean by Koni's? I may be misunderstanding your response, I have GC coilovers on with 525/650 spring rates and find it too stiff/bone rattling so I'm considering all other options. Would OEM shocks with lowering springs (like H&R) ride a little "softer"?
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      06-25-2017, 07:52 AM   #6
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Quote:
Originally Posted by Mar48 View Post
What do you mean by Koni's? I may be misunderstanding your response, I have GC coilovers on with 525/650 spring rates and find it too stiff/bone rattling so I'm considering all other options. Would OEM shocks with lowering springs (like H&R) ride a little "softer"?
GC use Koni dampers.
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      06-25-2017, 02:36 PM   #7
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I was wondering that but couldn't find more info on a quick search. thanks!
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      07-02-2017, 04:08 AM   #8
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Quote:
Originally Posted by Mar48 View Post
Quote:
Originally Posted by Finnegan View Post
Too stiff for street and probably a bumpy track!

I'm not sure what the Konis can accommodate as far as lower spring rates. Maybe 450/550 or even a bit lower.

If you want to try and use the GC, I'd give GC a call. Jay (owner) or one of the staff can probably help answer questions and let you know what can/cannot be done.

If you're looking at other options search Fortune here on the forum. There are some nice setups there with digressive pistons yet street oriented.

What do you mean by Koni's? I may be misunderstanding your response, I have GC coilovers on with 525/650 spring rates and find it too stiff/bone rattling so I'm considering all other options. Would OEM shocks with lowering springs (like H&R) ride a little "softer"?
Ian nailed it.

My idea was to see if you could just swap out for lower spring rates but keep the rest of the GC coils. GC would know what the Koni valving could accommodate. This should be cheaper than other options and certainly better than (potentially tired) stock dampers plus lowering springs.
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      07-02-2017, 08:27 PM   #9
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Sure - I reached out to Jay and got some ideas from him to try to make the current setup a little more daily driver friendly. If that doesn't work I'll see what he says about lower spring rates

Thanks!
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      07-09-2017, 06:36 PM   #10
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I run 450/550 on Koni DA and find the ride to be really civil. It also helps I'm running meaty 17's.
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      08-03-2017, 04:00 PM   #11
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i run club sports and they feel so good, stiffer thanks stock but imo a much better ride , feels really well damped, the KW uses a really nice damper design.
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      08-04-2017, 10:43 AM   #12
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I just changed to KW V3s, from stock dampers with H&R lowered springs. The ride is now much more controlled and far less "crashy" over potholes and sharp bumps. The KWs are German made, stainless steel and TUV approved and are fully adjustable. I sourced them from a UK supplier, who is currently offering a 300 discount, making them very good value IMO.
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      08-04-2017, 01:54 PM   #13
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Quote:
Originally Posted by Finnegan View Post
Ian nailed it.

My idea was to see if you could just swap out for lower spring rates but keep the rest of the GC coils. GC would know what the Koni valving could accommodate. This should be cheaper than other options and certainly better than (potentially tired) stock dampers plus lowering springs.
That's the way to go! I have 500/600 springs. I'm sure GC could rework the springs and valving to be more civilized for daily use.
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