Compressor Wheel
44.5mm · 6-blade
Flex
Flex Pro R31-R V2 Turbo - Mini F55
Flex Pro R31-R V2 Turbo - Mini F55
Regular price
$2,322.00 NZD
Regular price
$2,581.00 NZD
Sale price
$2,322.00 NZD
Taxes excluded. Shipping calculated at checkout.
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Flex Ultimate Performance
FLEX PRO R31-R V2 · Mini F55
Signature F55 Sound • Fast Spool • 44mm Gated
44.5mmCompressor
32 PSIBoost Capable
RHF44JJ1 Flange
GatedPre-Set Actuator
The FLEX PRO R31-R V2 — the turbo enthusiasts call the Mini F55 — brings the sound and response of a proper performance build to your 4JJ1. A 44mm gated frame delivers rapid low-to-mid spool and sharp throttle, finished with the unmistakable F55 whistle and StuStuStu chatter. Purpose-built for daily driving, touring and street performance, it arrives pre-set and ready to run.
Engineering
Turbo Specifications
Turbine Wheel
46mm · 12-blade
Flange
RHF4 (4JJ1 style)
Boost Rating
Up to 32 PSI
Wastegate Actuator
Pre-set, ready to run
Signature Sound
F55 whistle + StuStuStu
Fitment
Vehicle Compatibility
- Holden Rodeo RA7 — 4JJ1 · 2007–2008
- Holden Colorado RC — 4JJ1 · 2008–2011
- Holden Colorado RG — 4JJ1 · 2012–2017
- Isuzu D-MAX — 4JJ1 · 2008–2016 (Pre-DPF; DPF models require additional mods + DPF delete)
- Isuzu MU-X — 4JJ1 · 2012–2016 (Pre-DPF; DPF models require additional mods + DPF delete)
Fitment note. Modifications may be required. Some installs call for die-grinding, drilling or tapping of the manifold or turbo housing, a 44mm dump pipe, an EGR delete, and custom oil and coolant lines.
In the Box
What's Included
- FLEX PRO R31-R V2 turbo — 44mm gated, Mini F55
- Install gaskets
- Oil feed line & oil return fittings
- Liqui Moly turbo pre-lube
A focused install kit with the essentials for a clean, correct fit.
The Difference
Why the Mini F55
- Iconic sound — the unmistakable F55 whistle and chatter
- Fast-spooling gated frame — excellent low-to-mid response
- 32 PSI capable — genuine performance headroom
- Street & touring friendly — the balance of sound and drivability
- Drop-in style — designed for a straightforward fit on most 4JJ1 setups
Installation Notes
- Manifold work — minor trimming or drilling may be required on some applications
- Dump pipe — 44mm dump pipe required (available separately)
- EGR delete — recommended for best fitment and performance
- Oil priming — always prime the turbo with the supplied Liqui Moly before first start
- ECU tuning — recommended to set safe boost, rail pressure and fueling
- Professional installation recommended
Recommended Supporting Mods
To get the most from your Mini F55:
- Quality intercooler — to support higher boost
- 3" exhaust system — maximise flow and sound
- Boost & EGT monitoring — accurate gauges are essential
- Clean oil feed & return — protect turbo longevity
- EGR delete — improves fitment and performance
- ECU remap — unlock the full potential safely
Payment & Shipping
- Buy now, pay later — Afterpay, Humm, Klarna & Zip
- Free express shipping — Australia-wide
- Fast, trackable dispatch — from our Australian warehouse
Legal Notice
For off-road / competition use only. EGR removal and turbo modifications may affect compliance. Check your local regulations before purchase.
Frequently Asked Questions
Is this a direct bolt-on for all 4JJ1 models?
Fitment suits common 4JJ1 applications but usually requires minor manifold work, a 44mm dump pipe and an EGR delete.
Do I need a tune after installing?
Yes — an ECU remap is recommended to set safe boost, rail pressure and fueling for the best results.
What boost should I run?
The turbo is capable of up to 32 PSI. Your tuner will set safe targets based on your injectors, intercooler and usage.
Will it pass a roadworthy with EGR deleted?
No — EGR removal may not be legal in your region. This kit is sold for off-road / competition use only where permitted.
What makes the StuStuStu sound?
The signature F55 whistle and chatter come from the gated wastegate actuator combined with the compressor design.
Is it suitable for daily driving?
Yes — when properly tuned, the Mini F55 offers a strong balance of performance and drivability for street and touring use.
Signature Performance
Get the Iconic F55 Sound
Fast spool. 32 PSI capable. Pre-set and ready to run — complete with Liqui Moly pre-lube.
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Disclaimer: Common Rail Cowboys is not affiliated with Holden, Isuzu Motors, or FLEX Thailand. Installation should be performed by a qualified technician. Proper tuning and supporting modifications are the buyer's responsibility.
