We've been busy these last months cranking away at our project cars with updates, maintenance and, in some instances, major teardowns. The problem with having a staff of fanatical drivers is that the cars get driven fanatically. Regardless of how well they're tuned, they still take a beating. The upside is that every failure is an opportunity to learn a little more and get that much closer to tuning each project car to its full potential.
After last month's victory over a Lotus Elise, our MR2 is back to daily commuter life. But victory comes at a price. The Yokohama A048s we mounted to take on the Elise are just too much for the street. That much grip in such a light car is really overwhelming, and the overall feel has been compromised. See, the A048s are track tires developed in Japan for Japanese circuits, which are still significantly smoother than our tracks. This means that the sidewalls are way too stiff for the MR2's soft chassis and stellar street/sports suspension. On-track, the car is always fighting to keep in balance. At ten-tenths, the car either sticks and rolls uncomfortably or rolls so much that it unloads the inside tires into a tail-slide that's nearly impossible to catch, given all the toe-out in the rear. Street-wise, ride quality is compromised again by the incompliant sidewalls. The car will also track wildly in ruts and grooves. So we plan to retire the race rubber and downgrade to something more appropriate, like Yokohama's new S.drive. This is one case where stickier isn't necessarily better.
Our XS Engineering turbo kit is also showing some wear, as can be expected with a prototype. The coolant lines could be routed better and the muffler mounting and intercooler ducting could use a little work. All simple fixes we've addressed with zip ties and duct tape. The car is also starting to ping as it nears redline at WOT. With the ignition retard function disabled on our A'PEXi Power FC, there's no way to keep the car from knocking other than to put in some high octane or back off the go pedal. But we'll be taking the car back to XS for a tuning and hardware update. It's part of the development game. Project MR2 is still the best handling and quickest car of the bunch.
Project: 2000 Toyota MR2 Spyder
Odometer: 3000 (depending on which engine we're talking about)
What we broke: A 2007 Lotus Elise Sport Package
What we fixed: The tires-Advan A048s ($772 for the set)
What's next: Fine tuning and street tires.
Rolling pylon and cop magnet jokes aside, Project SRT-4 still catches a lot of attention from our domestic-loving readers and sobriety checkpoints. With its massive braking power and lift-off oversteer, it's the closest thing to driving a front-drive race car on the streets. We've long contemplated another phase, but let's face facts, it's a street car. And even with the Quaife limited-slip diff installed, the SRT still manages to spin its tires and torque-steer into the adjacent lane up through third gear. With roughly 240 wheel-hp and 260lb-ft of torque starting at 2500rpm, any more power from a Mopar Stage III turbo would be just a waste unless you're at the track.
Instead, we're trying to play with the set-up to make it a bit street-friendlier and trying to cope with the torque-steer issues. Replacing worn tires, we've opted to mount another set of BFGoodrich KDWs-in the street-car spirit of things. This is the only car we have with competent wet traction. We also had the car fully realigned and corner-balanced at M-Workz, which specializes in race car alignment and suspension set-up. The ass-up stance of the nose-heavy car is pretty close to a 50/50 front/rear weight distribution. Alignment-wise, we brought added camber to the front, bringing it to minus two degrees, and rears to minus one degree. Toe was set to zero in the rear and just a hair (2mm) toe-in up front. The rationale was that the toe-in would add straight-line stability and help with the torque-steer. And under hard acceleration, forces acting on the front suspension would actually force it to toe-out slightly, giving us less torque-steer and reasonable turn-in. It works, and the SRT-4 is no longer the ugly duckling no one wants to drive.
Project: 2003 Dodge SRT-4
Odometer: 23,559
What we broke: The tires
What we fixed: BF Goodrich KDW tires ($500 for the set)
What's next: Leave it alone