Getting Graphic Mar 18, 2010
We've started to prepare our 2010 Mazda MX-5 for the SCCA's new Street Touring R class. The first step: Flying our colors in the form of some vinyl decals.
Knife to a Gun Fight Mar 22, 2010
With just over 600 miles on its odometer, it was time to stretch our Mazda MX-5’s legs. The Tire Rack’s Chris Harvey and John Rogers flew down from Indiana and ran the car in the Tire Rack SCCA Solo Dixie National Tour in southern Georgia.
The GRM/Tire Rack MX-5 was the proverbial knife at this gun fight. While the competition included fully prepped S2000s and MR-2 Spyders, our car had nothing but an autocross-friendly alignment to maximize negative camber. That’s right, our suspension, tires and wheels were bone stock. Even the owner’s manual was still in the glove box.
After a cone-fest on day one—ahem, for one of the drivers—day two was an improvement. Chris and John finished eighth and 11th, respectively, out of 13 drivers. They were just over 8 seconds behind the winner.
This was the first National Tour of the year, and S2000s claimed the top three spots; MR-2 Spyders took the next three. While the S2000s looked dominant on this high-speed course, the jury is still out on which car will dominate the class. We expect proper tires and wheels plus other vehicle prep over the summer to help close the gap between the leaders.
New Wheels and Rubber for Our MX-5 Mar 30, 2010
The factory tires and wheels on our Mazda MX-5 looked fine for the average driver, but this project isn’t about being average. It’s about being competitive in the STR class, and that means upgrades.
We test fitted the tire and wheel upgrade using the widest tires allowed by the rules: 255/40R17 Dunlop Direzza Sport Z1 Star Spec tires mounted on 17x9.0 ET48 TRMotorsports C3 wheels. The mild-mannered MX-5 now looks more like a steam roller with this package on board. We can’t wait to see how much this bolt-on upgrade helps lap times.
Apparently Size Matters Apr 2, 2010
It's a question racers often ask: How much faster are proper competition tires than regular street tires? One second? Two? Three or more?
Thinking back to our first competitive outing with the bone-stock car at the Dixie Tour, we were easily 4-plus seconds off the pace of the prepped cars on proper tires and wheels. We had a lot of ground to make up.
Recently we ran some baseline laps with the OE 205/45R17 Bridgestone Potenza RE050A wheel-and-tire package. Then, after doing nothing else to the car but bolting on the 255/40R17 Dunlop Direzza Sport Z1 Star Spec tires wrapped around 17x9 TRMotorsports C3 wheels, we were well over 2 seconds faster on a 55-second course. As you would expect, steady-state lateral g-loads were higher, too.
Next up, we'll install the coil-overs to see what sort of difference upgrading the suspension can make.
Project STR Gets Coil-Overs Apr 22, 2010
Now that we'd fitted the MX-5 with proper race tires and wheels, it was time for the next step in the project: coil-overs.
We opted to use KW Variant 3 coil-overs for several reasons. This package provides independently adjustable compression and rebound settings, with a large effect on low-speed travel. KW coil-overs have a proven track record: They've been winning races in Europe for years, and they're included on the OE suspensions of the Viper ACR as well as select AMG Mercedes vehicles. And man, do they look cool, too.
These units offer several adjustment points, including ride height, so we now have plenty of options to dial in the package.
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