[jetbill]

*Edit: Changed the name of the thread, as I go through getting the new car dialed in for Sebring track duty (mostly PCA DE instructing with several students in the car) and the need for Autox FTD’s stickers) I’m logging some experiments as an early adopter of a new platform...(and in an attempt to not "ruin my car"...)

Stock vs KW HAS
Both spring front and rears of the stock and KW face-to-face dimensions at static ride heights are compressed to approx 4.00" and 8.00" (F/R), spring lengths are 8.5/11.0 (F/R) so you can look at values at the displacements at 4.50" and 3.00" respectively as starting rates with spring characteristics of linear front and progressive rear for both.

Note the tuning philosophy provided by KW, specifically in the front is a softer than stock (stock 260F/960R - kw 200F/900R+) spring coupled with a higher than stock rate bump stop, compared to stock which appears to be a higher rate spring with a slightly lower rate bump stop. This explains a bit of loss of steering "sharpness" experienced by what appears to be a 30% rate reduction from the stock rate. It also explains why the car bottoms out on speed bumps on my mid-pipe (with just a slight drop). Unless you are lowered so low, you are into the exponential function of the bump stop.

Might be good for some who like their cars really low(?), but not for me.

In summary - a total of 11mm front and rear drop is acceptable assuming maintaining the factory balance of front to rear bump stop engagement.

Interesting data points..
-TUV cert in kit denotes front as a progressive spring characteristic and rear as linear, data below shows the opposite.
-At rim centerline to fender measurement of 14.75", KW bumpstop starts its engagement.
-At a respectable Front ride height of 14.00" already 0.75" into the bumpstop.
-In the rear, 14.25" provides 14mm of clearance (shock body to bump).
-Minimum drop setting in the manual of 13.94" in the rear can not be obtained without extra parts. 30mm coil spring spacers in the rear were required, as the highest KW HAS setting was still too low and was engaging the bump stop 8mm at static ride height.
-40mm "A" dimension in KW manual provided a ride height of 13.25" (too low).
In summary for those that have this issue, for (whatever reason recommended by KW) to add this spacer at the owner's cost (not replace spring), I'd recommend a 15mm coil spacer that is manufactured by KW.
-1" drop provides a final Front camber rating of 2.2-2.4
-Bump stop lengths:
Front:
Stock- 75mm PUR model 22727110 DE (BMW model 3130 8091402-01)
KW- 64mm (consistent with KW TUV cert) PUR model 652 10 526

Rear:
Stock- 65mm PUR model 227271 10 DE (BMW model 3353 6859769-01)
KW- 54mm (consistent with KW TUV cert) PUR model 652 10 957

[mzcp]

Did you retrofit EDC on M2 before? I followed your posts. Glad to see you here

[mike@x-ph.com]

Thank you for sharing

[jetbill]

Originally Posted by mike@x-ph.com

Thank you for sharing

Originally Posted by mzcp

Did you retrofit EDC on M2 before? I followed your posts. Glad to see you here

Yes sir.

Originally Posted by mike@x-ph.com

Thank you for sharing

Absolutely sir.

[jetbill]

Some new fun things. Made an adaptor out for 7075 to encapsulate the stock OEM bearing to adapt a standard 3" ID Eibach coil spring. Certainly would help with clearances for future camber plate development as the inner shock tower has some serious limitations with its "stiffening rigids".

Some lessons learned here, planned to use a helper/tender with the 6" long spring but the KW perch doesn't allow for enough adjustment up or down to allow for a desired ride height.

Things to look out for is enough spring travel to prevent spring bind, a longer spring would be beneficial but not doable unless you want stock ride height.

A 3" ID spring was required as opposed to a standard 2.5" ID as the KW perch is much larger than my last Dinan HAS, were I was able to interchange standard 2.5" coils. I started with a 400lb spring, ignoring any frequency calcs or flat ride requirements, surprisingly there isn't much pitch with the progressive rear.

Further research would be required in analyzing spring block heights and various rates to develop the right combination to be used with a tender or helper, a 250-300lb 8" might work with no helper if there was more adjustment on the KW perch.

At the lowest setting on the KW perch using a 6" 400lb spring I was able to achieve exactly a 1.00" drop from stock ride height.

[jetbill]

Interesting similarities between the A90/91 Supra OEM top hats and the G80.

Vorshlag would be my first choice when it comes to replacing the OE top hats with Camber Plates, there's a few other good one's out there but from my last experience Terry and Jason give great service and support when needed to the community. I'd be interested to what becomes available in the near future.

Below are the stock G80 top hat with an image from Vorshlag's Supra plate.

Has anyone tried any of the Supra camber plates that have become available on the BMW G8X platform?

[Seedster2]

Thanks for the research. more pics of the dog!

[beachBmmr]

Originally Posted by jetbill

Interesting similarities between the A90/91 Supra OEM top hats and the G80.

Vorshlag would be my first choice when it comes to replacing the OE top hats with Camber Plates, there's a few other good one's out there but from my last experience Terry and Jason give great service and support when needed to the community. I'd be interested to what becomes available in the near future.

Below are the stock G80 top hat with an image from Vorshlag's Supra plate.

Has anyone tried any of the Supra camber plates that have become available on the BMW G8X platform?

Soon…12/1

[rmeitz167]

Glad this is where we are heading this early on this platform. Keep up the good work!!!

[mike@x-ph.com]

Originally Posted by rmeitz167

Glad this is where we are heading this early on this platform. Keep up the good work!!!

+1

[NashvilleM2]

Thank you for sharing this! This is very informative and explains why I am having a loss of steering feel. A write up like this would be great for the MSS kit as well.

[sebaflex]

bump! Curious of what setup you ended up with.