Great Lakes Divisional Championship Video

Here are the video highlights from last weekend's Great Lakes Divisional Championship event in Peru, Indiana. Our team used the event to get ready for the upcoming Tire Rack SCCA Solo Nationals held in Lincoln, NE in early September.   Read More

Project STR Captures THREE Divisional Championships

It’s been a busy two weeks for Project STR.Our first outing took us to Miller Park in Milwaukee, WI for the CENDIV Divisional Championship. This area has been a hotbed for street tire competition with plenty of fast drivers to help us gauge our performance. GRM/Tire Rack drivers Chris Harvey and John Rogers traded fast times both days. Chris pulled out the...  Read More

Another Victory for Project STR at the Toledo ProSolo

As our 2010 Mazda MX-5 autocross project continues to evolve, we’ve been hard at work on Project STR, installing and testing suspension components and adding some go-fast graphics.We’ve also tried to answer the question about what tire and wheel size produces the quickest lap times. One thing we did confirm is that what feels good isn’t always fast, and...  Read More

Project STR scores at the Peru National Tour

The blog has been a little quiet while we were hard at work installing and testing “go-fast parts” on the Project STR MX-5. In addition to the KW Variant 3 Coil-Overs and Hotchkis Sport Anti-Roll Bars, we’ve been experimenting with different sizes of Dunlop Direzza Sport Z1 Star Spec tires to find out what makes our MX-5 faster. A full tire test report will...  Read More

Hotchkis Anti-Roll Bar Upgrade

Since the beginning we have noticed significant lateral body roll in the Project STR MX-5. Installing the KW Variant 3 Coil-Overs with the stiffer spring rates improved it marginally, but we feel it still needs to be reduced further. Past test experience has shown us that tuning the anti-roll bars can have a significant positive impact on responsiveness...  Read More

Project STR gets its first Tire Rack SCCA Pro Solo win!

After a few local autocross events to gain valuable seat time, Chris Harvey made the 10 hour drive to Lincoln, NE for the 2nd Tire Rack SCCA Pro Solo event of 2010 driving the Grassroots Motorsports/Tire Rack Project STR Mazda MX-5. The site is the same used for the year-end Pro Solo Finale and National Championship events, making this a great advanced look...  Read More

KW Variant 3 Coil-Overs Tested

Now that the KW Variant 3 Coil-Oversuspension has been installed and the car re-aligned, it was time to see what sort of improvement in lap times the suspension upgrade brings. KW’s installation and tuning information included with the kit provide initial recommendations for ride height, as well as rebound and compression settings. Figuring this was the best...  Read More

Project STR Gets a Suspension Upgrade

The next step for project STR is a suspension upgrade to replace the Mazda shocks and springs. We’ve settled on the KW Variant 3 Coil-Over system. It offers flexibility in adjustments, with separate controls for compression and rebound settings. Ride height is adjustable, too. All together, this system should do a good job helping to control the increased...  Read More

Wider Proves to be Faster

So, now that we have tires and wheels installed, it’s time to find out how much quicker around our test track this combination is versus the O.E. tires and wheels. To simulate the total lap time of a typical national level autocross event, we combined 2 flying laps of our standard test course. First setting a baseline reference with the factory 205/45R17 Brid...  Read More

First Outing for Project STR

Project STR Mazda MX-5 saw its first competitive action over the weekend at the Tire Rack SCCA Solo National Tour in Georgia. To capture a baseline before the upgrades begin, Chris and John drove the car in stock trim – with nothing more than an optimized alignment. They competed against fully prepared S2000s and a few MR-2 Spyders using the MX-5’s...  Read More

Project STR Comes To Life

Tire Rack has teamed up with Grassroots Motorsports magazine to prepare a car for competition in the Sports Car Club of America’s new STR autocross class. This class allows common bolt-on performance improvements to an otherwise stock street car, such as wider performance tires and wheels, suspension upgrades and an engine ECU retune. Sticky R-compound...  Read More

Tire and wheel installation

The first upgrade has to be tires and wheels. So it’s off with the old and on with some more serious rubber. Using the widest size allowed by the class rules, we’ve installed 255/40R17 Dunlop Direzza Sport Z1 Star Spec tires mounted on 17x9.0 ET48 TRMotorsports C3 wheels. This is a very aggressive custom fitment, which required some work to get to fit. The...  Read More