Grassroots Motorsports

Big brakes Jul 2, 2001

Our Miata has been the center of attention lately, as its Flyin' Miata Big Brake install is detailed in the August issue of the magazine. We don't want to give away the punch line, but the experience was interesting. (Basically, it's hard to argue against physics.)

In addition to the brake work, the car recently received a full suspension makeover: PowerFlex polyurethane bushings, Koni's new coil-over shocks/spring setup, Racing Beat anti-roll bars, a new Carbing Okuyama front subframe brace and fresh Mazda bumpstop from Performance Buyers Club. A BSI Racing "sporty" alignment finished it up.

We were a little nervous about installing the PowerFlex suspension bushings (check with http://www.opmd.com for details), afraid that they would bind and make the car ride like an ox cart. Well, we're happy to report that nothing bad happened. In fact, our Miata now has a new-car feel. Installation could be tough for the do-it-yourselfer, although air tools do help. The complete suspension redo is scheduled to appear in the October issue.

In addition to spending time in the shop, the car has been making appearances at local autocrosses. We have been running with both the Buccaneer Region and Central Florida Region of the SCCA, while we're planning to attend the Sunriders Miata Club's July 21 night autocross. For more info on that event (Miata not required), check out http://www.sunriders.com. 

Work continues Oct 12, 2001

Even though the series is official done, work and mods to our Miata still continue, as the car is just too much fun. We recently did a track test day with the car, where we found it still a little too loose, even for our tastes. Ground Control's Jay Morris suggested some changes to our anti-roll bar setup, so we'll be trying them soon. We'll let you know how it works out. 

Long-Term Testing Dec 24, 2001

Three years ago today, we bought our '92 Miata, so here's a little real-world "long-term testing" feedback on the car.

The car had about 68,000 miles when we bought it, and it just recently turned 94,000. Aside from stuff upgraded for increased performance or editorial, problems and breakage have been pretty minimal (knock on wood). However, it's fair to say that our car has received above-average care, as it sleeps in a garage and receives lots of preventative maintenance. For example, when we did the head, we also replaced all of the belts, hoses and seals. When we did the clutch, we spent the extra 20 bucks to replace the rear main seal. We also take the time to wash, wax and vacuum the car on a regular basis. It may be approaching the 100,000-mile mark, but the only way to tell is by looking at the odometer.

Here's the list of problems encountered during our three years of ownership:

• Had the clutch pilot bearing go about 2 years ago--and it went loudly (eeeeeeeeeeeeeeeeeeeeee!!!!!!!!!). We found a locked pilot bearing when we pulled everything apart, but we used this as an excuse to upgrade to a Moss Motors aluminum flywheel and Jackson Racing clutch. During the repair, we installed brand-new Mazda seals.
  
• Also about 2 years ago, the clutch slave cylinder went. Pumping the pedal at stop lights gave us enough clutch action to limp the car back home, but the piece itself wasn't too expense ($39.95 through Moss Motors).
  
• Dead battery. The Miata uses a small, vented battery, so it's not something in stock at every parts store. We paid $100 for one at the dealership. You can save a few dollars by buying a battery via mail order, but the dealership had one in stock. Ours went after a particularly cool winter night. (Well, cool by Florida standards.)
  
• The airbag light came on during some recent track testing. The car did a little soil sampling, however, so something may have been jarred loose. The leather on the wheel is getting a little dingy, so a race-style wheel is probably in the car's future.
  
• Okay, really stretching here, but almost all of the little teeth on the back of the driver's floor mat have fallen out, so it doesn't always sit straight. Yeah, that's piddly, but that's really the only other problem encountered. The top, paint and rest of the interior have aged quite nicely.
  

Future plans: We're still having way too much fun with this car, so we're kicking around ideas for future projects. Turbo? Supercharger? Supercharger with high-boost pulley? Individual throttle bodies? New camshafts? Deck the block? Or, should we just run the car as-is and enjoy it? If there's something that you'd like to see, let us know. 

Real World Improvements Jan 3, 2002

Two of the products on our Miata--the Falken Azenis tires and the Powerflex urethane suspension bushings--have been hot topics on the Miata Internet message boards, so we figured it's time for a little real-world update.

Last year, the street tire wars welcomed a new player in the Falken Azenis, an aggressive-looking offering from Japan's Ohtsu Tire and Rubber Company. Designed for high-performance street use, the Azenis features a treadwear rating of 200, making them eligible for the SCCA's Street Touring autocross class. While appearance doesn't mean much with performance tires, the Azenis does look cool: bold side lettering, square shoulders and big, meaty tread blocks. Underneath the skin, the tire features stiff, reinforced sidewalls.

Sizes available include 195/60R14, 195/55R15, 205/50R15, 205/55R16, 215/45ZR16, 225/50R16, 225/45ZR17, 235/45ZR17, 245/45ZR17, 255/40ZR17 and 245/40ZR18. Falken does not set their retail prices, but we have found the Azenis to be very reasonably priced, making the tire one of the better values out there. Check with your favorite Falken dealer for exact prices.

We are running a set of 205/50VR15 tires on the Miata, which weigh in at 22 pounds apiece, about the same as a similarly-sized Michelin Pilot SX MXX3. Not the lightest tire out there, but stiff sidewalls sometimes come with a price. The Azenis is also a little on the wide side, with a section width of 8.3 inches in the 205/50VR15 size. By comparison, a similarly-sized Kumho ECSTA Supra 712 has a section width of 7.9 inches. (However, Falken doesn't have the widest 205/50R15 tire out there, as the Bridgestone Potenza S-03 Pole Position features a section width of 8.4 inches.)

Some high-performance tires are a bear on the street, but we have found the Azenis to be quite social with no annoying buzz or hum. They also don't dart from side to side, and they have been well behaved in the rain. They may not be as fast as a dedicated R-compound tire, but the Azenis has been predictable and pretty grippy on both the autocross and race track. We started at 28 psi all the way around, but in an attempt to reduce oversteer, we bled the rears down to 26 psi. This move didn't help, and according to Ground Control's Jay Morris, the Miata isn't super-responsive to changes in tire pressure.

After about 3000 miles--including a few autocrosses and a track test day--we still have a good amount of tread left. Our tires started with 8/32-inch of tread, and the fronts now show 7/32-inch while the rears are at 5/32-inch. For more info on the Azenis, check out Falken's Web site: http://www.falkentire.com.

Like our Falkens, our Powerflex bushings have been aging well. Before installing them, we were more than a little concerned that the urethane bushings would bind and turn our car into an ox cart. Fortunately, that hasn't been the case, as the bushings' stainless-steel inserts allows them to rotate freely. Our urethane rear anti-roll bar bushing--which came with the bar and not from Powerflex--has been a little cranky, however, so we'll be checking it out soon. Our Powerflex bushings came from An Open Mind Associates: http://www.opmd.com 

Pre-autocross attention Mar 26, 2002

Our Miata recently participated in a little autocross test day, so it first received some attention. First, in an effort to stabilize handling, we swapped the Racing Beat rear anti-roll bar for the stock piece. We normally don't mind a little extra rear bar, but our car had become a little too tail-happy when fitted with Racing Beat piece. Fortunately, swapping Miata rear anti-roll bars is about a 10-minute job.

We also had BSI Racing (http://www.bsiracing.com) install our Kaaz limited-slip differential. This is a clutch-style diff, and since BSI has recently jumped into the Spec Miata market with both feet, the job wasn't too hard for them. During the install, they also rebuilt the differential, replacing all wear items.

The Kaaz paperwork says the differential will be a little noisy at first, and they're 100-percent correct. However, we have been following the break-in instructions, and the noise level has been dropping. Under power and during autocross-type moves, however, the locked diff produces no noise. When making slow, tight turns, there is some chatter as the clutch plates get friendly.

With the new diff and smaller rear bar, our testing revealed a new car--we can easily power off the turns, the energy once used to produce tire smoke now propelling the car, while a little trail-braking will get the rear end to rotate just right on corner entry. Can't wait for our first competition event this season. 

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