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      12-26-2012, 05:26 AM   #23
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Quote:
Originally Posted by italyix View Post
My calculations were based on matching the front 500lb spring with a rear of 600lb using a rear coil over set up, given a motion ration of .83 for the rear.
Ah, I misread your orig post - I thought 600 was being used in the stock location, and 1200 was being used in the coilover location...

So you are recommending a F/R 500/1200 lbf/in setup for a R spring mounted in the stock location (i.e., control arm mounted)? I do not know of a single person running that spring combo on a street or dual-purpose setup using Motons, Ohlins, JRZ, AST, or MCS dampers - are you running, or did someone recommend, this spring rate combo?

I'm currently running F/R 500/800 on JRZ dampers, and previously 600/800 on Moton dampers, R springs mounted in the stock location for both setups.

Last edited by M3SQRD; 12-26-2012 at 05:36 AM.
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      12-26-2012, 11:45 AM   #24
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if the car is gonna be used mainly for street, im running the JRZ RS dampers with 450/650 F/R swift springs, i love the way my car rides and handles.... but with occasional track days, you should run a little stiffer springs, like maybe 650/850 F/R...
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      12-26-2012, 01:50 PM   #25
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I would recommend to use Motion Control as we have had experience with Ohlins and JRZ suspensions on our race car and customer cars. MCS also has just released their new non remote reservoir single adjustable coilover.
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      12-27-2012, 01:59 AM   #26
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why you donnt consider kw clubsport ? its. cheaper
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      12-27-2012, 08:05 PM   #27
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Quote:
Originally Posted by M3SQRD View Post
Ah, I misread your orig post - I thought 600 was being used in the stock location, and 1200 was being used in the coilover location...

So you are recommending a F/R 500/1200 lbf/in setup for a R spring mounted in the stock location (i.e., control arm mounted)? I do not know of a single person running that spring combo on a street or dual-purpose setup using Motons, Ohlins, JRZ, AST, or MCS dampers - are you running, or did someone recommend, this spring rate combo?

I'm currently running F/R 500/800 on JRZ dampers, and previously 600/800 on Moton dampers, R springs mounted in the stock location for both setups.
After reading the sticky in this section, and I quote: "The solution to the Type Three rear suspension compromise is to convert the rear to coil-over. By putting the coil spring around the damper, the motion ratio goes up from 57% to 83%, drastically reducing the leverage on the subframe. It increases the load on the body where the spring mounts, but the leverage is much less than on the subframe mounts. Also, because the action is more “direct”, the spring rate is much lower. If you want the rear rate to be a good match to a new, higher rate 500# front, then you can use a 600# coil-over spring, delivering a rear wheel rate of just over 400# that will work nicely. To do the same using the stock spring location would call for an unhealthy 1200# spring."

Although the above calculates a rear spring at a little over 400lb, it is actually around 500lb (600*0.83 = 498lb)

This would complement the front 500lb nicely.

Sway bars then can provide more "spring" when you need it (cornering that is)
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      12-27-2012, 09:20 PM   #28
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Quote:
Originally Posted by italyix View Post

Although the above calculates a rear spring at a little over 400lb, it is actually around 500lb (600*0.83 = 498lb)

This would complement the front 500lb nicely.

Sway bars then can provide more "spring" when you need it (cornering that is)
If you list numbers then perhaps you should do the math correctly:
Wheel rate = spring rate * motion ratio^2 so for your example...
600*0.83^2 = 413 lbf/in

Good luck finding any reputable shop/vendor that builds/races e9x M3s that would recommend running F/R 500/1200 lbf/in spring rates with the rear spring in the stock location
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      12-27-2012, 09:43 PM   #29
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Quote:
Originally Posted by M3SQRD View Post
If you list numbers then perhaps you should do the math correctly:
Wheel rate = spring rate * motion ratio^2 so for your example...
600*0.83^2 = 413 lbf/in

Good luck finding any reputable shop/vendor that builds/races e9x M3s that would recommend running F/R 500/1200 lbf/in spring rates with the rear spring in the stock location
Yeah ty, math was never my strong point. Im not saying to run 1200lb in the rear. If one plans to match the rear spring with the front, the equivalent oem location would require a 1200lb spring to match the front, hence why a rear coil over makes sense. Now, will the towers crack? Idk, but GTS runs a rear coil over.
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      12-27-2012, 10:01 PM   #30
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Quote:
Originally Posted by italyix View Post
Yeah ty, math was never my strong point. Im not saying to run 1200lb in the rear. If one plans to match the rear spring with the front, the equivalent oem location would require a 1200lb spring to match the front, hence why a rear coil over makes sense. Now, will the towers crack? Idk, but GTS runs a rear coil over.
I'm not the most knowledgeable person on suspension set ups but idk why anyone would want to match the front effect wheel rate with the rear on the e9x M3s? Especially with the weight of the engine slung over the front axel. Im guessing thats why M3SQRD used the OEM "wheel rate" ratio (1.70:1 front to rear) of approx ~460 lbf/in Front and ~270 lbf/in Rear. Hence brings you to around a 800lb rear spring for oem locations and ~ 300lb rear spring for a coilover rear location.

I would think having a 1:1 effective spring rates on the front and the back would be really stiff in the rear.
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      12-27-2012, 10:22 PM   #31
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Quote:
Originally Posted by biggynuts01 View Post
I would think having a 1:1 effective spring rates on the front and the back would be really stiff in the rear.
Good point there. How much "offset" in spring rate would the rear require compared to the front? I ask because I used to run a 1:1 on my Evo IX (12kg springs in front and 16kg in rear to match motion ratio) and the car handled like it was on rails. Was it stiff? You bet...
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      12-28-2012, 05:31 AM   #32
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Quote:
Originally Posted by italyix View Post
Yeah ty, math was never my strong point. Im not saying to run 1200lb in the rear. If one plans to match the rear spring with the front, the equivalent oem location would require a 1200lb spring to match the front, hence why a rear coil over makes sense. Now, will the towers crack? Idk, but GTS runs a rear coil over.
The GTS also has a 4-pt roll bar with the two rear mounts attached to the rear shock towers. The M3 GT4 also comes with a rear coilover setup as well as a full cage...
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      12-28-2012, 03:09 PM   #33
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Quote:
Originally Posted by M3SQRD
Quote:
Originally Posted by italyix View Post
Yeah ty, math was never my strong point. Im not saying to run 1200lb in the rear. If one plans to match the rear spring with the front, the equivalent oem location would require a 1200lb spring to match the front, hence why a rear coil over makes sense. Now, will the towers crack? Idk, but GTS runs a rear coil over.
The GTS also has a 4-pt roll bar with the two rear mounts attached to the rear shock towers. The M3 GT4 also comes with a rear coilover setup as well as a full cage...
Thank you, did not know that.
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      03-18-2013, 06:10 AM   #34
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I'm planing to pick up a set of Nitron R3's for my GT3 from my boys here in Taiwan German Motorsports.

they seem to have very good quality i've seen these in person. should be a great choice for M3's
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      08-15-2013, 06:31 PM   #35
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Quote:
Originally Posted by marktapscott View Post
Hi there,

Quick introduction - Mark from Nitron (UK). I lurk around here as I drive an E46 M3 and its great place for inspiration!

Just wanted to note that Nitron do indeed have several service centres in the US. We intend on establishing a Nitron North America for this exact reason you point out - to support our US dealers, improve delivery times and establish local full factory support and servicing facilities.

Until that happens, there are two primary and official service centres East/West coast. I do not want to be seen promoting so I will allow those interested to contact their dealers for further details.

PS - We plan to improve upon our European race wins and our BMW Nurburgring lap record again this year with the F10 / E9X platforms....

Hope that helps - Thanks!
Hi Mark

Was wondering what kit you would suggest for my 2008 E92 M3...I want a lower stance and I autoctoss is a few times a year...but 90% of my driving is city and highway.

Can you quote me a price for here in Canada.

Cheers mate

derrick
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