Cage
The car was gutted and a full cage installed.  Dry ice was used to remove the sound deadener on the floor.  Lay the pellets in all over the floor, wait for 1 beer and listen for the crackling to stop, then tap the floor all over with a rubber mallet.  The material shatters from the floor and can be vacuumed out after the dry ice sublimes. 

The basic cage uses 1.5” diameter drawn over mandrel (DOM) steel tubing and is mounted at 8 points.  We decided to run the front tubes through the firewall up into the shock towers, and the rears attached inside the cockpit  - but  still tied into the shock towers behind the rear bulkhead. 

A NASCAR style doorbar was installed on the driver side to provide a little extra elbow room and help keep stray Miata's out of the cockpit. The cage was stitch welded to the A and B pillars (allowed in production class), as well as over the windshield frame.  The interior and cage tubing were sprayed with SEM Rust-shield.

The GTV6 chassis is pretty stiff to start with, but when the cage was installed one entire side of the car could be lifted easily at either the front or rear jack points.

An 8 gallon Fuel Safe Cell was installed using a cage made of square tubing.  It was set as low and far back as practical.  The cell has a trap door pick up system and the stock fuel pump in the location shown below has been running with no issues for 5 years now.  The filter is a generic Chevy 350 filter with large inlet/outlet ports.  Braided line was used on the high pressure feed to the fuel pressure regulator as well as on the return line (they both pass through the cockpit).

Dashboard and Wiring
The stock dash and wiring harness were removed and purpose built replacements were installed.  The fuseblock is a marine unit from West Marine.  A Tyco power relay was used to power up the main bussbar on the fuseblock, and individual relays were used for fuel pump and cooling fan.

CSC headers were used.  These long primary headers run down to a pair of bullet muflers tucked up as close to the body as possible.  Two 2" pipes exit the right side of the car.  When this was first installed, the crossover section was not there but it had been in an earlier version of the exhaust.  When the car was subsequently dyno'd, it had lost power (noticeable on the track as well vs other known cars).  It also sounded like a pair of 3 cylinder engines (horrible if you can imagine it).  The crossover was added - the sound is much better and testing this year will tell on performance.

A limited slip transaxle was rebuilt with stock gear ratios.  Pictures below show a set of lightened gears which were installed in the car when it was doing HPDE's, but unmodified gears are in the rebuilt unit.  Upon diassembly, I found that 7 of the 8 bolts that hold the pumpkin together where snapped off at the heads.  The bolt heads had been floating around in the rear housing but never made it to the teeth side of the ring gear.  Amazingly there was no damage to any components so new high strength bolts were used, the friction disks were replaced, and the unit was reassembled and installed.  New syncro rings were used throughout, and the 2nd gear dog was replaced with a used piece that was in much better condition.

The GTV6 starts out somewhere around 2800 lbs.  We are now down to about 2320 lbs (without driver).  Below are some examples of the weight savings.....

Stock front and rear calipers were retained, but pads, pistons, and fluid were upgraded.  Pistons are SS versions from John Farrell.  Pads are Carbotech XP8 in the rear, XP10 in the front.  The carbotechs have great pedal feel/modulation, and are very easy on rotors.  Boiling the fluid in the rear brakes has been problematic at  some tracks (NHMS) but using pads with at least 1/2 material remaining  along with Motul RBF 600 has solved the problem.  The car still has the stock brake proportioning valve in it (the one underneath the car in the rear brake line circuit).  The master cylinder has been upgraded to a 23.6mm version (vs 22 stock) for a higher pedal and better feel.

Brake cooling project in progress....
The XP10 pads in front have, at times, transferred compound to the rotors in spite of proper bedding.  During hard braking, the car shakes violently.  Rotor runout was checked to rule out warping.  Cooling is being installed to try to prevent this, and moving to the XP12 compound will be the next step if cooling doesn't help.  2" high temp hose was available from a previous project so that hose size was used (it looks like 2.5" would be the largest hose that could fit without significant interference and rubbing).  The headlight ducts were fabricated from a stock headlight buckets, 3.5" to 3" exhaust reducers, and 3" to 2" hose reducers.

The splash shield at the rotor had a 2" hole placed so incoming air will aim at the center of the rotor and and make its way to the vents.  A separate duct plate was made to attach to the stock splash shield.  A curved section of 2" mandrel bent tubing was cut and welded to the duct plate - the curve allows the hose to compress and extend when the wheels are turned without kinking/binding.

The car has been lowered and now has 33 mm torsion bars (www.performatek.com) with 275 lb/in rear springs.  Adjustable Koni shocks are at all 4 corners.  The front anti-sway bar is built from Speedway Engineering components (gundrilled torsion bar with steel arms).  The frame has been reinforced at the mounting points.  The rear sway bar is a bigger piece, again from Performatek.  We started with Hoosier radials but have since switched to the race slicks.  These tires seem to work well with -1 deg camber and 1/16" toe out.  All bushings (except lower control arm) have been replaced with polyurethane.  The dedion is otherwise still stock and with the car's weight on it, has -.2 to -.4 degrees of camber.  Based on tire wear and temperatures, adding small amount of additional negative camber there may help.

Wheel spacers are used on all 4 hubs.  Aluminum hubcentric pieces add 12.7 mm of track at each wheel (wheels are 15x7 with a 35 mm offset).  Longer studs were required:
FRONT- ARP 100-7713
REAR - ARP 100-7720
The hub holes had to be opened up to maintain a .004"-.006" press fit between stud and hub.

The stock watts links were replaced with aluminum tubes and rod ends.  The center fitting was left stock with a urethane bushing.  Standard size 1/2"  rod ends (vs metric) were chosen or cost and availability, and the holes in the center fitting and outer mounting ears on he chassis were opened up accordingly.  The rods were set to exactly the same length as the stock units.  Safety washers and seals-it seals were used on each end.