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Project Car Garage

Musical Tires

Jay Chen
Jun 1, 2007
Photographer: Edward Loh
0707_sccp_01z+2006_subaru_wrx_2003_nissan_350z+car_wash Photo 1/6   |   Project Car Garage

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.

0707_sccp_07z+2000_toyota_mr2_spyder+front Photo 2/6   |   Project Car Garage

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.

0707_sccp_06z+2003_dodge_srt4+front Photo 3/6   |   Project Car Garage

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

0707_sccp_03z+2006_subaru_wrx+soap Photo 4/6   |   Project Car Garage

Our 2006 Subaru WRX has been around for almost a year, although we haven't officially done a project car installation on it yet. It's just about ready, though. We've finally found the suspension we're ecstatic about and set up the chassis to perform brilliantly on the street and for light track duty. We're also planning to do a geeky intake shootout and install Cobb ACCESSport tuning hardware.

But the car ran into a snag. Or, more specifically, second gear. At a recent track test session, the car suddenly refused to shift into second. While we're hard on cars, something this new shouldn't lose a synchro so quickly. It felt more like the shift fork slider was jammed. The only way to find out was to pull the tranny and crack it open. Not something we like doing on an all-wheel-drive car.

Mark Dibella, our mechanic and owner of MD Automotive in Westminster, California, helped us disassemble the tranny completely. As we suspected, gears and synchro were all in pristine shape. Bathed in muck and oil, we found large pieces of debris. It was a chunk of this spacer/washer that had got into the second gear slider, preventing us from pushing said slider and moving the fork all the way over.We scoured the gearbox, but couldn't figure out where the debris came from until we looked at the center diff. How we managed to break the center diff on street tires and a stock engine beats me, until I recalled a certain editor-in-chief-who shall remain nameless-mentioning the WRX getting towed. Assuming the nice impound people were considerate enough not to flat-bed the car, this might have damaged the center diff.

0707_sccp_04z+2006_subaru_wrx+spacer Photo 5/6   |   Project Car Garage

The bits we did manage to find looked more like an archaeological pottery study, but was actually one of the spacers keeping the spider gear in contact with the ring gear. It's still hard to imagine how a piece of steel that thick got demolished, chewed up and spat out without other weaker parts breaking first. This also explained why the WRX would completely wash out in our figure-eight test as we rolled onto the throttle.

We called South Coast Subaru to look for a parts number diagram for the center diff. It doesn't exist. We'd have to suck up the $400 (good guy price) for a whole new unit, which, miraculously, they had in stock. That, and a couple other cosmetic parts that were broken over the last year, totalled $700, minus labor. One deeply uncomfortable credit card receipt later, there we were at MD, putting the car back together.

We have some last bits of testing before we send it back to Subaru, hoping the company might overlook the fact that we've managed to destroy yet another of its cars. We're already dreaming of the new STI five-door.

Project: 2006 Subaru WRX
Odometer: 23,000
What we broke: The mirror, the center diff, our wallet.
What we fixed: Just the mirror ($250) and diff ($400).
What's next: Intakes, Cobb ACCESSport and tire testing

0707_sccp_02z+2003_nissan_350z+soap Photo 6/6   |   Project Car Garage

Call it the battlewagon of our project cars, but this thing just won't die. Despite being tyrannized by a supercharger, burning oil, and 80,000 miles of wear and tear, the original VQ just keeps pumping-even with over 6000 miles since the last oil change. Why are we hell-bent on destroying our Z? Because we can. Well, the engine, at least.

Although it hasn't seen a project car installation in over two years, Project Z is still driven or drifted every day by our insane drift-monkey editor. We just can't find a good enough reason to change anything that wouldn't compromise the awesome car that it is. It's just that good. But new plans are afoot for us to get a thorough spanking. Project Z is getting ready to take on the new Corvette Z06 at a track battle. It's going to take a new built engine with Jim Wolf twin turbos to hit the magical 500hp number, plus some serious brake and cooling work to keep the car alive and on track. But we know a good car when we see one, and domestic or not, the Z06 is a supercar-so we're not holding our breath.

While we're waiting for the oil cooler and new radiator to come in from Stillen, the new low-compression VQ block is being put together at Violent Racing Technologies in San Diego, California. We also took the time to replace the bald Falken RT-615 tires with Yokohama's new Advan Neovas, quite possibly the stickiest and most capable non-R-compound performance tires available today. We opted to change the original 275s all round set-up in favor of a staggered 255-width tire up front and 285 in the rear. While the car was great at low speed, using a 275mm-wide tire in front meant the car would oversteer at high speed. And with the power and grip that Project Z has, that typically meant speeds of over 90mph.

The new rubber and set-up has taken care of this high-speed balance issue without inducing too much low-speed understeer. It also seems to amplify the car's significant mid-range. We used to worry about tire spin and impressing Formula D judges with the throttle pinned at 4000 to 4500rpm. Now we just exalt in glorious grip, titillating traction and rapid forward motion. Usually, we're tippy-toes careful with Project Z's tail-out personality, but the staggered Neovas have turned the Z into one of those cars that just forces you to drive like an asshole.

Project: 2003 Nissan 350Z
Odometer: 80,000
What we broke: Falken RT 615s to their steel belts
What we fixed: Yokohama Advan Neovas ($1250 for the set)
What's next: New turbo engine and some coolers.

By Jay Chen
85 Articles

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