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CST5 Ball Bearing Turbo Upgrade - 2006-2013 DISI MZR Mazdaspeed

Price: $1,499.99
Price in points: What are Points?1500 points
Mazdaspeed Turbo CST5 with Stock flange fitment, boost by 3600rpm and power to 7500...the CST5 is the turbo for your Mazdaspeed

Products in package

Stock flange fitment, boost by 3600rpm and power to 7500...the CST5 is the turbo for your Speed

Not too big, not too small and now with ball bearing! ITS JUST RIGHT for YOUR SPEED. Capable of built block power and extremely fast spool times, this turbo can make 500+whp and hit 20psi by 3400-3500rpm. The CorkSport CST5 turbo can be tuned for a more laid-back curve that is stock block safe or pushed to 30+psi for built blocks and auxiliary fueling. No matter what build you have this turbo will be sure to impress.

  • The CST5 features a MHI Ball Bearing CHRA, 0.82 Turbine A/R and 4” Anti-Surge Compressor Cover
  • The CST5 turbo will be available in two boost control setups: Internally Wastegated (IWG) & 44mm Externally Wastegated (EWG) w/included EWG elbow pipe & V-band clamp.
  • Includes a FREE CorkSport 3.5 bar MAP sensor for accurate boost pressure up to 37psi.


Mazdaspeed 3 Big Turbo Upgrade, Better than BNR S4 precision K04
A better turbo than the BNR S5 precision K04
CST5 IWG and EWG Mazdaspeed Performance BNR S4 precision K04

Balanced Performance

The CorkSport CST5 is designed with the ideal balance in response and power for the daily-driven Mazdaspeed. Now available with a ball bearing CHRA for improved response and durability at high boost levels. Just between the CST4 and CST6, the CST5 can reach ~20psi by 3400-3500rpm and carry power to 7300-7500rpm.


Mazdaspeed BNR S4 Turbo k04 precision

Stock Flange Fitment

Ease of installation and use is key to all CorkSport Performance Turbochargers. The CST5 retains the factory-style turbine flanges for a painless installation.

The turbine housing is designed with a 0.82 A/R to balance response and top-end power.


4 inch Mazdaspeed3 big turbo cover

Anti-Surge Compressor

4” anti-surge ported compressor housing is utilized for peak performance operation. The anti-surge porting increase the compressor map width paired with an industry standard 4” inlet to maximize the use of 3.5” and 4” intake system.


Mazdaspeed 6 Big Turbo Upgrade BNR S4 500 horsepower k04

High Performance CHRA

MHI Ball bearing CHRA housing is used for the CST5 turbocharger for its increased cooling capacity and proven reliability.

High-performance ceramic ball bearing cartridge is used for improved response and high boost durability vs the standard journal bearing.

Comparing the compressor and turbine wheels, we have a wheel size ratio of 1:15


k04 Mazdaspeed 3 big turbo Billet Compressor wheel

Billet Compressor

Utilizing the Gen1 GTX71 billet compressor wheel, the CST5 can efficiently support 56 lbs/min flowrate and boost pressures over 30psi.

Speed3 External Wastegate big turbo

High Flow Turbine

Paired with the compressor wheel is an MHI TF06 high-flow turbine wheel. This wheel uses a 9-blade design which reduces overall rotating mass and thus improves response and spool.

Mazdaspeed 3 Turbo Wastegate Spring Set

Tunable Wastegate Actuator

The Internal Wastegate Actuator uses a larger diaphragm and piston for improved boost control for the larger CST5.

Also included is an assortment of springs so you can specifically setup you CST5 for your Mazdaspeed.

Mazdaspeed Big Turbo Hardware Kit

All Hardware Included

The CST5 comes will all the necessary hardware for installation saving you time and money on gaskets, studs, and the specialty parts.


Mazdaspeed 3 big turbo bolt in EWG Kit

Choose Your Boost Control

Do you want an easy-to-use Internal Wastegate setup or an External Wastegate setup and screamer pipe? You decide with the CST5!
Internal Wastegate setup includes the 0.82 A/R IWG turbine housing and tunable IWG Actuator.
External Wastegate setup includes the 0.82 A/R EWG turbine housing and V-Band Clamp & Elbow designed for 44mm EWGs. (EWG and Screamer Pipe Not Included) Don’t worry, if you want to change your setup later you can!


Additional Mazdaspeed Features
  • Compatible with: 2006-2013 DISI MZR found in the Mazdaspeed 3,Mazdaspeed 6, & CX-7
  • Designed in America: Designed in Vancouver, Washington, in the Pacific Northwest.
  • CorkSport Service & Support: 1-year limited warranty, full-color installation instructions, all necessary components, and knowledgeable telephone support at (360) 260-2675.

advisory header
  • Auxiliary fueling is required for the peak power operation of this turbocharger.
  • EWG variant designed for 44mm or equivalent external wastegates.
  • External wastegate is NOT included with turbo.
  • EWG dumptube/screamer pipe is NOT included with turbo.
  • Some aftermarket and all OEM downpipes will NOT clear the EWG elbow that is included with the CorkSport EWG Turbocharger. Check the "Fitment Notes" tab for details.

How To Install Your CorkSport CST5 Turbo Upgrade

It will take you five hours to install the CorkSport CST5 Turbo Upgrade with our easy-to-use instructions.

5 Hour Install Time

5 Hour Install Time

Difficulty: 4/5

4/5 Difficulty

1-Year Warranty

1-Year Warranty



CST5 installation instructions

This is a fantastic upgrade to my 06 MS6. Takes a little bit longer to spool up, but not by much. Sounds nicer through the CS 4" intake and can hold boost all the way to red line. IF YOU GET THE INTERNAL WAIST GATE OPTION, MAKE SURE YOU GET A 3 PORT BOOST CONTROLLER!!! They don't tell you you need this until half way through the instructions. Set me back about a week on my build but I guess that mechanics for you, haha!
Stock flange (super easy), ball bearing (amaze ballz) and a power curve from 3500-7500rpm? Thats the CST5 Ball Bearing. It kicks ass and doesn't give up. If you want a fun, responsive and powerful street car this is the only turbo you should be looking at. While it doesn't spool like a stock K04, its is shocking how fast this turbo wakes up and gets going for the size but then it just keeps going to a blissful 7500rpm! I use to run a BNRs4...which was ok...but the CST5 literally walks all over it. Faster spooling and holds power better. I literally have no regrets switching to the CST5, I love it.
The solid play that is the CST5 turbo just got anime angry eyes that for-shadow impending doom. Already making 20 lbs on my all out Dankai2 track build @3400 rpm, I can happily flog the piss out of this thing with the durability of the dual ball bearings CHRA. Lets face it guys, the world will let you down, CS’s hard oily balls won’t.
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On IWG, how much boost (PSI) does the CST5 can hold? I want to know more details about boost control of the CST5 on IWG. THANKS!

Asked by Dylan Rivera | 04/13/2023, 09:24 AM | 1 answer(s)
Mazda performance parts financing is available with CorkSport

Looking to finance your parts purchase and want to get 6 months NO interest on any purchase over $199? Click on the image above for more details.

Some aftermarket downpipes will NOT clear the EWG elbow that is included with the CorkSport EWG Turbocharger.
If the downpipe is not listed here then it has not been test fitted with a CorkSport EWG Turbocharger.

Mazdaspeed 6 Fitment:
CorkSport Catted Downpipe - Confirmed
CorkSport Non-Catted Downpipe - Confirmed

Mazdaspeed 3 Fitment:
CorkSport Catted Downpipe - Confirmed
CorkSport Non-Catted Downpipe - Confirmed
Cobb Catted Downpipe - Confirmed
Depo Racing Non-Catted Downpipe - Confirmed
XS Power Non-Catted Downpipe - Confirmed
Manzo/Ebay Non-Catted Downpipe - Does NOT fit. Will require custom EWG elbow and dumptube
CPe Non-Catted Downpipe - Confirmed
CPe Catted Downpipe - Confirmed