Apr 22, 2014 update to the Nissan 350Z project car

Some Special Arms for Our Special Z

Our Z was getting closer to having a proper suspension. SPC front upper control arms would provide much-needed adjustment for fine-tuning the handling.
The SPC arms (left) had much larger metal sleeves than the stock arms, raising the ratio of metal to non-metal in the bushing. That's a no-no in SCCA Street Touring.
When you have a dad with a sweet lathe, building some Delrin bushings is just a bucket of fried chicken away. Your machine shop may not work for chicken, but these were simple bushings, and labor should be reasonable if you decide to go this route. The Delrin stock was under $50.
Our replacement bushings are nice and legal, with no more of a metal to non-metal ratio than stock.
The SPC arms feature sliding and offset balljoints to make camber and caster adjustments easy.

Our Nissan 350Z project car is competing in the Street Touring Ultra category in SCCA autocross. As per the rules, we’re allowed to install substitute control arms to facilitate suspension adjustments that OEM parts don’t provide for. Our 350Z has no provision for camber or caster adjustment in stock form, so clearly some aftermarket arms would help us out.

But the SCCA has a rule about bushing composition that meant we’d have to be careful when installing our new arms.

The SPC upper front arms we chose are exceptional. They feature slotted camber adjustment and an offset balljoint that allows for additional caster. Unfortunately, the installed bushings aren’t SCCA-legal. Under the rules, we couldn’t increase the ratio of metal to non-metal in the bushing, and the large metal sleeve in the SPC bushings did just that.

Our solution seems a bit extreme, but we don’t want to face the wrong end of a protest later this year: We pressed out the supplied bushings, built a set of our own bushings out of Delrin polymer, and used sleeves that maintained a legal ratio of material.

Our new SPC arms are now in place, awesomely adjustable, and legal for the coming season.

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View comments on the GRM forums
David S. Wallens
David S. Wallens Editorial Director
5/1/14 8:57 p.m.

Who's that handsome guy making the bushings?

JG Pasterjak
JG Pasterjak Production/Art Director
5/6/14 5:30 p.m.

I found him in the woods drinking beer.

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