How to Use Whatever Rear Spring You Want

[P71Nero]

Hello, I have a 2013 Lincoln MKS EcoBoost I've been using as a track car. Mechanically almost identical to a Taurus SHO. The adaptive suspension the MKS is equipped with may have a sport mode, but it's not suited to this kind of use. My shocks were all either on their last leg or completely dead, so I ordered some of the BC Racing DS Series coilovers. Their default rates are 6kg/mm front, 8kg/mm rear. 8kg/mm seemed much too soft for the rear though, as I had taken measurements of the rear control arms and found that the motion ratio was 0.578. With this, I found the rear spring should be at least 12kg/mm, and I decided I wanted to use a 14kg/mm spring.

The problem is, BC doesn't have options for the rear rate. The rear springs are not a conventional spring design. I ordered the coilovers from their site with the 12k rear spring and I was told they only had an 8k that would fit the car. So I went with that, and looked for a way to adapt a linear coilover spring to the rear. I discovered that the 350Z uses a rear spring of the same dimensions in BC's kits, but they also have an option to get the 350Z coilovers with a lower spring perch for linear coilover springs. These perches can be ordered separately (D-17-LSA), so I ordered them along with some 7" 14k Swift Springs.



They do in fact fit the car and seem to work perfectly. I haven't track tested the car yet with the new setup yet, and it still needs an alignment, but if I do ever need to change rates in the future I will now be able to use whatever rate I want for both front and rear.

[bpd1151]

Interesting and an outstanding, creative way to achieve your goal by mix/matching.

Please report back and let us all know how your experiences are with them. Track, or motoring around off the track.

Sent from my SM-N986U1 using Tapatalk

[P71Nero]

I plan on track testing the car this Saturday at Streets of Willow. I just added some more transmission cooling as the PP Trans cooler by itself wasn't cutting it. I also just got the car aligned to -2.8 camber in front and -2.0 in rear, zero toe. The settings the BC coilovers were at from the factory seemed way too stiff. I ended up turning them to full soft then turning the fronts up by 2 clicks and the rear up by 4 clicks. The ride quality is similar to the MKS sport mode now but body roll is enormously reduced as well as brake dive. My previous personal best at this track was 1:29 while on stock suspension and 275/40R18 Nitto NT555 G2s. I will be on 275/40R18 Goodyear Eagle F1 Supercar 3s for the upcoming event.