Revisiting the Suspension Setup

After a week or two of driving and letting the springs settle I decided that running without helper springs was going to drive me nuts. There were just too many little clunks here and there anytime you drove over a bump in the road (plenty of these in NY/NJ). It was also a total pain every time we'd jack the car up and having to make sure the springs seat properly when we lowered the car back down. Despite me not wanting to have to remove and reinstall the shocks, I really had no choice so I ordered a set of Hypercoil 2.5" ID 4" free length helpers and Eibach 2.5"ID spring spacers (couplers?).

Hypercoil 2.5" ID 4" free length helpers with
Eibach 2.5" ID spring spacers - 7/7/2015

Since I had to take the shocks apart to install the helpers, I thought I'd double check my setup. After pouring through my notes and blog entries for Bumblestook, my target spring rate difference of 100lbs wasn't going to work (theoretically of course). Assuming the Bridgestone RE-71R generally behaves like a previous generation R-compound tire and that I'm running a square 255 setup versus the 295/315 stagger of Bumblestook, my target should be more like 150-200lb difference front to rear.

Springs removed - 7/8/2015

To achieve this, I decided to replace my rear springs and go from 750lb to 650lb (leaving the 850lb springs up front). I think this will help keep the rear more stable and add some mechanical grip as well as more compliance to bumps and undulations. This would also allow me to up the rear sway bar setting from full soft to 3/7 stiffness and give me room for fine tuning later. The front sway bar is staying at 5/6 stiff.

Hypercoil 650lb springs and helpers installed in the rear - 7/17/2015

It turns out that my front springs were 2.25" ID so my 2.5" helpers weren't going to work so I ended up ordering new 850lb 2.5" ID 7" Hypercoil springs for the front so I can give the old ones back to Rad.

Hypercoil 850lb springs and helpers installed in the front - 7/17/2015

I reset the ride height back to a stock-ish 14.5" but I'm hoping it'll settle to around 14" over time or I'll just adjust it a few weeks after I've gotten some miles on them. I took it out for a good test drive and I'm very happy with the results. No more clunking. Everything feels solid. The damping is perfect and I think the 650lb rear springs is the ticket. Just the right amount of stiffness while the 850lb fronts gives very fast and responsive turn-ins (still miss the AP1 steering rack though in Bumblestook).

There's still some work to do before I can take her out to her first event but she's getting there. I'm basing my initial setup from years of driving S2000s and my driving style using Bumblestook as the reference but I won't know for sure if the formula works until my first event. I'm hoping it'll at least be within the ball park so I won't have to make too many major adjustments.