BNR Supercars has several bolt on turbo upgrade options for the Mazdaspeed 3, Mazdaspeed 6, and the Mazda CX7. These turbo upgrades are designed to be a bolt on replacement for the K04 factory turbocharger. The stock K04 is a throw away unit that shouldn't be rebuilt. The weak points of the K04 is the long shaft length, small shaft width, and thrust bearing design. BNR's newly designed replacement/upgrade far overshadows the K04 turbocharger that comes equipped on the Mazdaspeeds.
The benefit of the BNR turbo upgrade for the Mazdaspeed 3, Mazdaspeed 6, and Mazda CX7 is the increased shaft size, shorter shaft length, bigger bearings, better thrust bearing assembly, better turbine wheel, more efficient compressor wheel, and last but not least, more reliability. No question this turbo upgrade is far more superior to the original equipment turbocharger on the Mazdaspeed MZR DISI.
Bolt on! You read that right, it says bolt on. The BNR is a bigger that stock turbo though it still fits withen the factory K04 frame and is therefore one of the easiest turbo upgrades to install. This Mazdaspeed turbo upgrade is for the customer wanting to reach the limitations of the stock engine without killing turbo response!
Don't judge the BNR S4's book by its cover. Just because it is roughly the same size as stock doesn't mean stock like performance. The BNR S4 has proven itself worth of hanging with its bigger counter parts while maintaing lightning quick spool and transient response. If you want more power but don't want to sacrific the quick spool of the stock K04 on your Mazdaspeed 3, Mazdaspeed 6, or CX7, the BNR S4 turbo upgrade is the turbo upgrade for you!
*Current version features a 3.5" inlet with revised anti-surge compressor housing.
- Mazdaspeed 3/Mazdaspeed 6
Absolutely pleased with the turbo, pulls hard and sounds amazing. Very please with how it all turned out. Thank you Edge!
I'm getting 23.2 psi with 0 wastegate duty cycle. 20.1 with the actuator arm disconnected and the wastegate wide open. I'm stock block on E30 trying not to go lean. Avoid this turbo, find something with an external wastegate. Yes, this A new version 3.
If your considering a turbo upgrade , this is the turbo to go with. It's a great deal and price complete bolt on. I was debating between a bnrs3 or bnrs4 and am glad I got the bnrs4. Don't waste your time looking at other options , if you looking to stay within stock block or beyond stock block limitations this is the perfect turbo. I'm on a base map at 17-18 psi and this turbo pulls.
Followed the installation video that Edge made, including removing the exhaust manifold and it was relatively pain free. Love that it retains the turbo mounting bracket and OEM heat shields. Spool is slower than a K04 but that is expected with a larger turbo.
Turbo is a total sleeper! Sounds amazing when spooling, and even changes exhaust not at idle. Still haven't finished tuning,, though I'm faster than what I was with the k04 on 20psi and full tune, and that's only on 17psi!