Project Silvia’s Girlfirend Part 2: Making it Handle

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Liberal application of the magic Loctite goo to both the bearing and the bore solved the problem. I only ever had to do this to one hub. The other one never made the noise, so it may have have been machined by a more experienced child.

Coil-Overs:

Now, onto the big players in the handling game. We were looking for something that would give a reasonably comfortable ride, but still have good enough body control for track use, while still penny pinching. All these qualities seemed to co-exist in Dan Barnes' E36 project car he had built for European Car magazine. His TC Kline coil-overs were based around rather pedestrian (a.k.a. affordable) Koni single-adjustable sport dampers. Of course, the BMW kit had been custom valved and dialed in by TC Kline, but at least is showed the potential of that simple shock to play the street/track game. 

Since S13s are a little short on front suspension travel, we didn't want to just start with Koni Sport replacement struts up front. Instead, we had Ground Control make some strut housings that shifted the mounting ears higher on the strut, lowering the car about an inch before any suspension travel is consumed. The shot on the right shows approximately how much higher the ears are mounted on these strut housings. The upright is hanging where it would line up with a stock strut.

Ground Control added their own custom-valved Koni insert. At the rear, the fork-style lower mount forced us into using Z32 300ZX rear shocks. The only real problem with this is that Koni decided to save about $10 on this application by not putting an external adjuster on the 300ZX rear shocks. To make rebound adjustments, you have to remove the shock, compress it all the way, and then engage a hidden tab between the piston and foot valve inside the shock that lets you rotate the adjuster. Doing this requires a pretty comprehensive tearout of the interior panels in the back of the car. Painus in the anus…

 

 

Every time I set up a suspension I like to assemble it without springs and see where the tire will end up with the car compressing the bump stop. With the fenders off, it was clear the shorter struts were doing a good job of letting us use all the available compression travel. Here you can see we started with 235/45-17 takeoff tires from an EVO IX. EVOs come with incredibly good tires from the factory, so this seemed like a good idea at the time. More on that later.

 

One reason for this travel check is to see what the tire is going to eat up under full compression. As with Project Silvia before it, this wiring harness needed some minor repositioning.

 

 

If there's any question as to the value of looking for all the compression travel you can get, and making sure the bump stops are the cushy, self-damping urethane foam kind, here's a shot of Project Silvia using every last millimeter of compression travel at the bottom of the corkscrew at Mazda Raceway Laguna Seca. Travel is key…

 

 

The mounting bracket on Ground Control's strut housing extends farther up the strut than the stock bracket. This is a great way to improve the stiffness of the strut housing, but it caused some wheel clearance issues with our wide 17″ wheels. Project Silvia's Girlfriend runs SSR GT7 wheels (on clearance when we got them, and long out of production now) in 17×8.5 +35. As you can see, this leaves paper-thin clearance between the inner rim and the extended strut bracket. We acutally tried running like this for a while, but under hard, bumpy cornering there was enough flex somewhere in the spindle/wheel bearing/wheel assembly to let the rim contact the strut and actually cut a chamfer onto that corner of the wheel rim.

1 comment

  1. Trying to do this same GC coilover setup on my S13 with rear z32 knuckles for that OEM+ type ride all these years later. I have already had to step up from the original 7” 250lbs rear springs to 8” 250lbs which are still at the top of the threaded collar on the yellow KONI with not enough clearance between fender & tire. Currently about 1.8” of clearance between the rear fender & tire which still doesn’t seem close to the early pics of this project car. Do you recall if you had to use longer springs on the rear like I am (about to move up to the 9” 280lbs spring next in order to hopefully have a better range on the threaded collar)?

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