Project Silvia’s Girlfirend Part 2: Making it Handle



Two important tips when using these Mazda3 rear end links in this kind of application:

1: Mazdaspeed3 end links use a larger, 10mm stud on the upper ball, requiring the holes in the end link to be opened up slightly. (The 8mm stud on a standard Mazda3 is uncomfortably loose in the sway bar hole, on the other hand). Many aftermarket sway bars have their holes drilled with some kind of very hot technology. I can't remember if Progress bars were using plasma cutters or lasers at this point, but the heat from either one hardens the metal around the hole, so it will laugh at your puny drill bit. You have to open up this hole with a file…

2: The loss of adjustable end links is not as bad as you think. When you get to the step in your setup when you want to install the end links, bolt both links securely to the bar, then just lower the control arm stud into the arm. If the If you're lucky, both with touch down at the same time and you won't have to adjust anything. Most likely, though, one will land on the control arm and one will hover over it a bit. Stack washers under the floating end link until they both touch down at once. Voila! Adjustable end links for everyone… You have to do this with the car sitting on the ground and the suspension loaded as it will be when you're driving (even with a driver in the seat if you really want to get anal about it). Adjusting end links at full droop is meaningless.


Another rattle prevention trick is to wrap the top of the strut housing with electrical tape before installing the coil-over sleeves. There is always a little clearance between the sleeve and strut body (so you can slide it on!) and without this tape taking up that slack, the shifting suspension loads can sometimes rock the coil-over sleeve back and forth, causing little kerpop noises.


The clearance here is generally very small, so you have to adjust the number of laps you take with the electrical tape accordingly.

Naturally, none of these little things were the source of the KERPOP noise. I’m almost embarrassed to admit what the noise was, considering it took me a year to find the damn thing. In the end, it was just a dry polyurethane sway bar bushing sticking and releasing. Before this I'd never heard a sway bar bushing make a KERPOP noise without also making eeh-eer-eeh-eer noises every time the suspension moved.

Anyways, a tip for tracking down mysterious noises: use your fingers. The only way I was able to track this down to the sway bar bushing was by placing my hand on the sway bar when the noise happened. I could feel the bar move when the noise happened.

I want that year of my life back…

Speaking of bushings: if it were up to me, the front suspension bushings would all be replaced with heim joints, the rears would be a mix of heims and Nismo rubber, and the rear subframe bushings would be locked out.  Sarah has spent enough time in Project Silvia to know she doesn’t want to listen to differential gear noise all the time, though, so the subframe bushings are still in place. As for the heim joints, those were nixed too, in favor of something with more noise and impact sharpness isolation. Up front, that meant Nismo rubber lower control arm bushings for more direct steering response, and the tension rod bushings were replaced with these mysterious polyurethane bushings I found in my garage.


Before trying to press in poly bushings, I always soak them in boiling water. The durometer usually changes quite a bit with temperature and this makes them quite a bit easier to work with.

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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