Martin Sifredi is a passionate car enthusiast who is gradually building on his Alfa Romeo car collection. He eventually wanted to build his own Alfa Romeo race car and chose one of his favourite models: the 1991 Alfa 33 Boxer 16V. He deemed this particular model a perfect choice, because they are such great cars to drive in factory trim. He already owns a show winning 1991 33 16V, so it was a natural progression for him to find another 16V to use as a base for his project.

Martins industrial design background and mechanical knowledge gave him the perfect tools to style and engineer the 33 to a standard that will be very competitive in its respective racing class (R, under 2000cc). The plan was to research as much information as possible regarding the Italian racing series CSAI (Commissione Sportiva Automobilistica Italiana), similar to CAMS in Australia that the 33 16V used to be raced in. It was quite hard to find detailed information regarding certain aspects of the suspension and engine, but finally a small workshop in Italy that still races the 33 was kind enough to help out with some much needed details.

The overall condition of the base vehicle was very good, it just needed a little repair to the nose panel and some re-painting of body parts was required to give the 33 a presentable appearance. The nose panel repair and spraying was a joint effort between Martin and Lee Parra, owner of Extreme Body Repairs in Dandenong.

There are a number of changes made to the body including the complete removal of the boot floor and spare wheel well, which is now a flat 3mm aluminium floor with a sunken rearward mounted alloy battery box to bring some of the weight to the rear of the car. The 6-point rollcage keeps the weight down to a minimum, but also adds plenty of chassis rigidity and safety. It ended up weighing in at 40 kg in total.

The boxer 1.7 l Quad Cam 16V engine internals are standard, the modifications made to increase engine reliability was to incorporate an enlarged baffled sump and 13 row fan-assisted remote mounted oil cooler, which increased oil capacity to 6.8 l. Engine power has been upgraded via a custom designed lightweight stainless steel exhaust and custom “Ram Plenum” cold air intake, which feeds through the guard and picks up fresh air from behind the front bumper. The ECU has been remapped, allowing all the modifications to work at their full potential. The fuel system has undergone modification too, consisting of standard under car fuel cell, a low pressure pum, an aluminium swirl/surge pot and a sport rated high pressure pump. Power has gone up from stock 137 Hp to 160 Hp and 170 Nm of torque .

The Interior was completely removed and re-designed, to achieve the DTM look with such details as the forward mounted digital dash pod and custom fabricated centre console, relaying all the necessary information to the driver. Other components added in where the OMP race pedal set, OMP suede steering wheel mounted on a quick release hub, hydraulic hand brake and also for added safety an extra remote operated “fire bomb” extinguisher for the engine bay, which can be activated from the dash. The Sparco EVO2 seat and OMP 6 point 3” harness add comfort and safety for the driver.

Once underway with the weight reduction, Martin was keen to explore what could be achieved with the overall look of the final product. He is passionate about the DTM in the 90’s that he decided to style the 33 16V based on the Alfa Romeo 155 DTM cars, hence the design of the rear wing and other aero elements found on the 33 now. The process of recreating certain aero components just by looking at photos and using reference points was complicated.

The rear hatch has been extensively modified, including structural weight reduction and also the use of a 4 pin quick release system. The glass has been swapped for polycarbonate. The main feature of is the DTM style double aerofoil wing, which has been carefully positioned to provide the original look from the 155 DTM and also maximising the aero effect. It can be adjusted to a high angle of attack for slow tracks and low angle of attack for fast tracks, depending on the amount of down force needed.

Martin fabricated a one-off carbon fiber and kevlar quick release bonnet, weighing in at a featherweight 3 kg compared to the factory steel version of 16 kg. It incorporates functional heat vents and NACA ducts. The front bumper received a few aerodynamic modifications consisting of a grafted bolt-on Alfa 75 EVO front spoiler and incorporates side air exit vents to vent hot air away from the oil cooler and depressurise the front.

The performance side of the equation is simple: the key to going fast is “power to weight” plus mechanical grip, so the goal was to shed 200 kg off the standard 1000 kg. The 33 now weighs in at just 820 kg.

The chassis and suspension have been completely rebuilt and the car is now running similar spring rates the 33 16V used to run in competition back in Italy under the CSAI. The inclusion of re-valved Koni sport dampers are working very well with this set up. A custom designed chromoly tube front control arm assembly will be part of the next package going on the car before the next race meeting. The installation of a rear sway bar will provide fine tuning adjustments to really get the most out of the suspension package .

The front brake package now consists of 155 Q4 282mm vented and slotted rotors, with the brilliant Alfa Romeo 147 GTA Brembo 4-piston calipers. There was a fair amount of modification to be made to make the big 4 pots fit so Martin designed a brake caliper adapter to suit this application. The rear brake set up has been upgraded from the conventional drum brake setup. The brakes that used to be on the front are now in the rear with slotted and ventilated rotors. Martin plans to install a pair of twin piston Brembos and remove the heavy, low efficiency, factory calipers. The whole braking system is also fine tuned via a brake bias valve.

The side skirts have also been exchanged with items he fabricated to suit the original look and adding more functionality. The quick release rear bar also has extensive modification to cater for the DTM styled rear Diffuser, which aids to the cars down force at speed and also finishes off the overall look nicely.

The link between the tarmac and the 33 is a set of perfectly balanced Sparco Cromodora 7×15″ wheels, which are wrapped in a set of very sticky 205/50 R 15 Yokohama Advan A048 and are perfectly suited for this package.

Race cars are always an ongoing affair, trying to learn the behaviour of the car and refining and adjusting and re-building components until you have reached a point of satisfaction and squeezed that last bit of performance possible to gain those extra few seconds per lap. Having seen and experienced many different cars at Club and National level, Alfa Romeos’ inherit performance capabilities did not stop with the GTV or the 75, but bled into a lot of the other models as well! The 33 can be transformed into a very serious track/race car with a fairly moderate budget.

Finally after 11 months from starting to the finished product, the Sifredi Corse 33 16V has had its debut track “shake down” at Winton Raceway in December 2012, and Martin is pleased to say that “straight out of the box” the 33 didn’t miss a beat and was very well behaved out on track. There will be a few minor adjustments carried out to fine tune the suspension and also engine. Martin says that it has been a great pleasure to undertake this race car project and it has only made his passion for Alfa even stronger – “Viva Alfa Romeo”.