A BNR S3 turbo walkthrough

A few things have changed about the BNR as it has matured as one of the most common medium turbo upgrades for the MazdaSpeed looking for 320-400whp.New compressor housing surrounding the 71mm compress wheel and two port wastegate actuator. This along with our Boost Dial and the factory 2 port solenoid gives you excellent boost control.

2871 journal bearing CHRA remains. No more smokey K04. Journal bearing means it can be rebuilt and although it spools a little slower than a ball bearing centre section, it keeps the costs down.

The exhaust housing is still a machined K04 unit making it easy to bolt on. The bolts holding the exhaust housing to the CHRA now have special washers so they don’t back out; a common issues with older BNRs.

2871 turbo wheel in machined K04 exhaust housing. The exhaust housing allows you to brace the turbo from underneath meaning tubular exhaust manifolds are less likely to crack.

Happy turbo-ing!