BEWARE - Michael's 1969 Mazda R100

Story: Ben Winstone  Photos: Michael English

Regular visitors to the Jamboree event held at Willowbank Raceway in Queensland who have taken a walk through the show and shine area will have seen that when Queenslanders modify their cars, they do it differently to other states. Whilst there isn't one main thing that these guys do, the overall result is certainly unique to their southern neighbours. If you had visited the Jamboree event in 2004 you will have noticed one standout car amongst all the four, six and rotary machines on display, the 'BEWARE' R100 Coupe. This brings us to Michael English's 1969 example of the classic R100 model. Nestled amongst plenty of other old school rotaries and current shape imports, the R100 had that certain something that made it stick out from the crowd, with bright paint that seemed to change shade depending on the time of day and angle, polished billet wheels and the custom baby blue interior. It seemed that the more you looked at the car, the more you noticed something different that stood out.

It didn't always look like this however and when Michael purchased the car three years ago it was in an average state. It wasn't long however before the paint was rubbed back to be prepared for the BMW Atlantis Blue pearl paint scheme. The paint seems to change colour depending on the angle and the time of the day that you look at the car and really sets the lines of the car off.

Under the bonnet the original 10A is long gone and in its place resides a completely rebuilt Series 5 RX-7 13B motor. Rotary Motorsport in Brisbane were responsible for the rebuild with the inlet ports being ground out to a large extend port shape, while 24 additional dowels were placed through the block to provide additional strength in preparation for the boosted life this motor was about to embark on. The standard inlet manifold remains, while hanging off the engine on a custom made manifold is a GT35R Garrett turbocharger (rated to 700hp), the ball-bearing unit blows 14psi into the motor with the street tune and is wound up to 24psi at the track. Cooling the boosted air is a custom BH Performance front mounted intercooler and intake air is then mixed with premium unleaded provided by two 12A Turbo 880cc injectors and two Indy Blue 1700cc injectors setup as secondaries. Contrary to popular belief, Michael comments that "it is actually very streetable with the Indy's and cruises fine at any speed". The injectors are fed from two Bosch 044 750hp pumps and a 2 litre surge tank. Controlling the boost is a Turbosmart 45mm Pro-Gate external wastegate which vents to a screamer pipe, and assists in keeping residents in Brisbane's western suburbs awake at night as Michael comes home from one of the many cruises he frequents in the R1. The rest of the exhaust gases exit via a 3-inch system from the turbo to the diff, where it then splits into two separate 3-inch pipes leading into two cannon mufflers which Michael assures me are very loud. Make no mistake, the exhaust system on this car has one priority - maximum flow, everything else comes second and that includes quietness.

A Toyota Supra gearbox is used for its strength, and Michael reports that so far there has been no problems with it, a real testament to the way that Toyota engineers its products to cope with double or triple the power that they were intended to be used with.

Assisting with the cooling duties are a PWR aluminium radiator and oil cooler combo which ensure this R100's vital fluids very rarely reach boiling point. The engine bay has also received its fair share of detailing with polished touches like the oil catch can, compressor cover, inlet manifold, intercooler pipes and alternator.

When the car was strapped onto the dyno it initially reeled off a power figure of 263kw (352hp) at the wheels on 14psi using premium unleaded, just a slight increase on the 100hp or 74kw that the car made at the flywheel in stock form. Michael then ventured out to Willowbank Raceway to a test and tune meeting where the car ran 10.71 at 126mph. The car was driven to the track and back, the only change being made was to swap the street tyres for a pair of Mickey Thompson 24.5x8x15-inch slicks, the interior and exhaust remained untouched.

Not content with a high-10 second street car, Michael returned to the workshop and had the car tuned on C16 with an extra 10psi being force fed into the engine, this time round the dyno responded with a power figure of 321kw (430hp) at the wheels, more than enough power for a low 10-second pass. The next time out at Willowbank, the car ran 10.16 at 133mph with Michael commenting that "down the track is where it really surprised me, for a very basic setup it launches extremely well, with no real wheel lift or wheelspin and it drove off the line nicely", he continues by saying that "the car also pulled consistent low 1.5/high 1.4-second 60ft times". In fact, Michael even went to the extent of saying that the 10.1 pass was "just a nice, easy, comfy run with no skating or sliding, it did the pass quite easy and I am very confident that it would run a high 9 with the current setup with a little more boost".

So while the car has no problems accelerating, what about the other factors of a cars performance, its handling and braking?

Holden VX Commodore SS calipers clamp 280mm ventilated discs on the front end, which help Michael pull up after reaching speeds in excess of 215km/h after a run at the drag strip, whilst R31 Skyline discs and calipers are supported by the 4.56:1 full-spooled Ford 9-inch diff in the rear end. Michael says that "the brakes are good but could be better, perhaps if a booster was added, but once you are used to them, they actually work very well for the power it has".

The suspension has also received an overhaul with RX-2 struts and King springs being fitted to the front of the car, whilst stiffened and lowered rear leaf springs and Koni Red shock absorbers help keep the rear of the car in line, assisted with a set of tramp rods to prevent the dreaded axle tramping. Michael comments that the car "actually handles well in my opinion, I'm not sure why, laws of gravity suggest it shouldn't with its tiny wheelbase, short track and high centre of gravity for example, but I find it goes around corners fine, unless you sink the boot in, then she slides... easy!" Not that Michael would ever drive like that on public roads however.

The final aspect of the cars exterior is the wheel choice, in this instance, the smooth 17-inch Intro Vista 5 billet wheels. Rather than go for the traditional Simmons route, Michael thought outside the square and tried something different, with the results paying off as aside from generating lots of comments at the shows he attends with the car, the wheels suit the rest of the package so well.

Step inside the car and the attention to detail and high quality does not end at the exterior. The interior has received a complete retrim in a baby blue colour officially known as Iceberg. Even the Titanic wouldn't miss this Iceberg as the roof to the floor and everything in between has been covered in it, even the four point rollcage has also received a similar colour in its padding. The standard instruments have been replaced with a full array of Autometer gauges which allow Michael to monitor speed, revs, water temp, oil pressure, boost, fuel pressure, oil temp, fuel level, air/fuel ratio and voltage, and in his quest to make the interior stand out a Microtech handset has even been recessed into the drivers side of the dash which also provides more engine data and allows the car to be tuned easily.

Whilst all the gauges may be a distraction, at least it keeps the passenger entertained as the majority of them are placed on the left hand side of the original R100 dash. Michael's hands are kept occupied with the SAAS steering wheel, Isotta chrome ball gear knob and a Clarion CD player which is connected to Pioneer 4-way speakers, whilst fixed back race seats and OMP harnesses ensure that neither occupant move around much whilst the car is in motion, and incase you hadn't guessed, a four point cage, harnesses and fixed back seats mean that this R100 is strictly a two seater, but then again, extra passengers will only slow you down anyway.

So where to now? Michael comments that the build up is complete and that he has no regrets although he did run into a bit of trouble during the build with a few workshops and he has since discovered who he would use for the next build up. The car has taken seven trophies at various car shows, made more than 400hp, ran an extremely low 10-second pass and is an awesome and comfortable cruiser, it has achieved his goals and it is time to move on.

The car is currently for sale for $29500 and Michael can be contacted on 0402 842 548 (mention that you saw it on mazdarotary.net)

In the meantime if you are cruising the streets of Brisbane and pull up alongside a schmick little Mazda with nice wheels, just beware...
 

Model: 1969 Mazda R100

Engine: 13B Twin Rotor Turbocharged

Engine Modifications: Rebuilt Series 5 13BT motor (large turbo/extend port), 24 additional dowels, standard Series 5 inlet manifold, Garrett GT35R (700HP) Ball-Bearing turbocharger, Turbosmart Pro-Gate 45mm external wastegate, two 12A Turbo 880cc injectors (primary) two Indy Blue 1700cc injectors (secondaries), custom 2-litre surge tank with Holley Blue pump, 2 Bosch Motorsport 044 750HP fuel pumps, custom BH Performance front-mounted intercooler, PWR Aluminium Radiator and Oil Cooler, Turbosmart Type 2 blow-off valve, 3-inch Stainless-Steel exhaust from the turbo back, two Cannon mufflers, Microtech MTX-8 engine management system.

Driveline: Lightweight steel flywheel, Daiken super heavy-duty single-plate clutch, Toyota Supra Turbo 5-speed gearbox, heavy-duty 3-inch custom tailshaft, Ford 9-inch diff 4.56:1 with full-spool.

Suspension & Brakes: Front: RX-2 struts, king springs, 280mm ventilated discs with VX Commodore SS calipers, heavy duty master cylinder.

Rear: Leaf springs stiffened and lowered, Koni Red shock absorbers, R31 Skyline discs, tramp rods.

Performance: 263kw (352hp) @ wheels (14psi, PULP) and 321kw (430hp) @ wheels (24psi, C16). 10.16 @ 133mph on 24psi/C16, and 10.71 @ 126mph on 14psi/PULP.

Wheels & Tyres: Intro Vista 5 Billets 17x7 inch (f and r), 205/40/17 Nankang N1 tyres (f and r). Mickey Thompson 24.5x8x15-inch slicks for the strip.