With our dedication to oversteer strong, we soon found that Project Evo IX still didn't rotate as well as we wanted, even during simple road testing. Looking for more life from the rear end, we added a 24mm adjustable Hotchkis rear anti-roll bar (allowable under section 15.7 with a bushing change). The Hotchkis bar is a cheap buy that slots into the stock location with ease. We did, however, have to drop the rear muffler and one rear lower control arm to gain enough room to wiggle the stock anti-roll bar out of place.
The Hotchkis bar is hollow, which saves a good deal of weight versus a solid bar of the same diameter, and is adjustable with three different mounting holes. The outermost hole is about 10 percent stiffer than stock, the middle hole 27 percent and the innermost hole 47 percent stiffer. We chose the innermost.
At the same time, we also took the opportunity to maximize the rulebook's allowances and added a rear tower bar. Section 15.2, C allows strut bars that cross left to right on the upper or lower suspension mounting points only. No additional holes may be drilled in the car's body, but interior trim panels may be cut to fit the bar. This means that multi-point bars, such as those offered by Works and Cusco, are not allowed in SP. Our choice was the beefy, one-piece, two-point rear tower bar from Carbing. This provides a direct connection between the rear towers and, because it's constructed from hollow aluminum, comes with a weight penalty of only a few pounds. The Carbing bar also does its job with ease, providing a perfect fit and a more solid rear end. Also, it has no hinges or multi-part construction around which the bar itself could flex.
With Project Evo IX buttoned up and ready to go, we cranked the rear shocks to full stiff and hit the test track to see how our autocross prep performed. From a baseline of 0.88g on the skidpad when completely stock, Project Evo IX blasted through our figure-eight course in 25.16 seconds and averaged 0.93g in Street Touring trim-with the Bridgestone RE-01R tires. In Street Prepared trim, with the Toyo R888s, the car reached the magical 1g mark. Even more impressive is the 24.55-second time through the course-which puts it squarely into Ferrari territory-while still using a stock 4G63. The super-sticky R888s also shine under braking, stopping from 80mph to a standstill in just 177 feet-42 feet shorter than what a stock second-gen S2000 can do. This would have placed Project Evo IX fourth in the braking test at last year's USCC.
Already displaying significant speed with an impressive figure-eight time, Project Evo IX could be even faster in SP trim with a more consistent resistance to understeer. Through the course, the front end proves to be skittish on turn-in, with a knife-edge balance between 'on the limit' and violent, shuddering understeer. Get it just right, though, and the car is amazingly fast, although there's still an improvement to be made when entering turns. We're reluctant to try any massively large rear anti-roll bars, out of the fear that Project Evo IX will then start to lift the inside rear wheel during cornering (lifting a drive wheel during steady state cornering is never good), although different alignment settings and a stronger rear limited-slip differential is something we've been looking into. Remember, with an Evo, there's no such thing as too much oversteer.
By Joey Leh
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