Back in 2013, a good customer of ours came to us looking to build the ultimate canyon racer. The stock BRZ/FRS is a great platform, but in stock form it simply lacks power and grip. Starting in the power department, we decided to build our own custom turbo kit. The basis of the kit would be the new Borg Warner EFR 6758 turbo which features ball bearings, billet compressor, and a lightweight Titanium Aluminide turbine wheel for immediate response and fast spool. Our goal was no more that 400hp, but the car had to have instant response with no turbo lag above 4000rpm. We set about fabricating the turbo manifold out of schedule 10 stainless steel.
Once the manifold and downpipe were complete, we completed the intercooler installation. We chose a relatively small intercooler because we did not want to cut all the airflow to the radiator. The FA20 engine runs very hot, and closing off the airdam with a large intercooler significantly reduces the cooling efficiency of the radiator. Additionally, because we are running water/methanol injection, intercooler efficiency is less critical. One of the most important aspects of installing an intercooler or any other type of cooler is getting a sufficient pressure differential across the core. By ducting the intercooler, we are able to significantly improve the efficiency of a relatively small intercooler. By using a top mount inlet and outlet, we were able to significantly reduce the volume of piping and thereby improve the transient response of the turbo.
And there you have it… the completed turbo setup. We were very impressed with this engine’s response to forced induction. The FA20 just wants to make tons of power, and with the new combustion chamber design combined with direct injection, is extremely resistant to detonation, especially compared to other Subaru engines such as the EJ20 and EJ25. That’s the good part about the FA20. The bad part is that the connecting rods are extremely weak (they are cast, not forged), and we highly recommend that anyone thinking of installing a turbo or SC on this car FIRST invest in an engine build. This is not something you want to put off, as a connecting rod failure will mean throwing the entire engine out, and will be much more costly than building it right the first time. For added reliability, we ran the Element Tuning Hydra EMS stand-alone engine management coupled with Aquamist water/methanol injection.
Of course, we did not leave the rest of the car unattended. The addition of 17×9 Enkei RPF1’s wrapped with Hankook 255/35R17 RS3’s gave this GT86 enormous levels of grip. We would also like to thank Cusco Japan for their assistance and sponsorship of this car. Cusco provided their Zero A suspension package coupled with electronic remote adjusters, strut brace with integral brake master cylinder brace, catch can, steering bushings, transmission bushings, rear differential support and bushings, as well as front and rear roll bars. The capabilities of this car, when well modded, are truly remarkable!
And last, but certainly not least we upgraded the brakes to provide endless fade free performance. Since this was not built to be a pure track car, we went with our “Stage II” 13″ solid rotor upgrade kit featuring 6 piston forged Wilwood race calipers and Goodridge USA stainless steel brake lines all around. Our Stage II kit is designed specifically to retain the proper brake bias, reduce unsprung weight, and provide massive stopping power.