After more than a year of development, we are pleased to release our new hybrid turbocharger upgrade for the Mk8 Fiesta ST.
The S285 is a beautifully well-rounded upgrade for the latest Fiesta ST, delivering strong performance gains, but maintaining OE levels of refinement thanks to a highly sophisticated design.
Full specification list for the S285:
- Larger TT spec billet compressor wheel upgrade, with extended tip technology
- Larger TT spec high-flowing turbine wheel upgrade
- Significant modifications to compressor housing, including advanced machining for ‘anti-surge ports’, CNC re-profile to match upgraded compressor wheel, and bell-mouth intake tract
- Turbine housing CNC re-profiled for larger turbine wheel upgrade
- All new bearing and shaft system, designed specifically for this application
- Journal and stub shaft diameters increased for greater durability
- TT designed journal bearing (bespoke to this application)
- TT designed 360° thrust bearing assembly (bespoke to this application
- Bearing housing modified for TT turbine and new heatshield design
- TT designed seal plate to match compressor wheel upgrade, machined from billet
- Modified compressor clamp disc to match TT seal plate
- TT designed upgraded heatshield and clamp arrangement to suit turbine wheel upgrade
- Bearing housing modified for TT turbine and new heatshield design
- Core assembly balanced to high speed on Turbo Technics VSR ® balancing machine
Design & Development
As always, Turbo Technics development engineers began with a careful examination and analysis of the standard turbocharger. This highlighted some weaknesses within the stock unit, which could then be addressed in parallel with the performance improvements.
TT engineers were concerned that the standard shaft diameters were not robust enough to support upgraded compressor and turbine wheels with sufficient safety margin. Consequently, the upgraded turbine wheel and shaft assembly in the S285 features much larger journal and stub shaft diameters, paired with an all-new bespoke journal bearing design which further improves shaft stability. The 360° thrust bearing assembly is also a new design, with a particularly complex oil feed arrangement for superior lubrication and durability.
The compressor and turbine wheel upgrades have been carefully specified to provide maximum performance improvements, whilst maintaining a suitable match to their respective housings to avoid compromising compressor and turbine stage efficiency. Naturally, the compressor wheel is machined from billet for improved strength, and to allow for a slimmer hub, increasing flow capacity. The turbine wheel is made with a much larger, more open blade form to reduce back-pressure without needing to compromise efficiency by cutting back the blades.
Both end-housings are re-profiled using CNC machining, but the compressor housing also has additional machining features to form ‘anti surge’ ports. These ports increase compressor map width to combat surge/flutter on spool-up; a phenomenon sometimes found on highly tuned Mk8 STs (with both standard and hybrid turbochargers). The ports eliminate any surge, providing a smoother and faster spool up (as well as some subtle but entertaining lift-off noises!).
Typical performance figures are 290-305lbft torque, and 260-270whp. But the peak figures really are only half the story for this unit – it has to be driven to appreciate the true strength of its performance.
Thousands of miles of testing have been carried out over many months to refine the design, and to confirm that the driveability and durability is up to our high standards. We believe you will struggle to find a hybrid turbo for your Mk8 Fiesta that will perform as reliably and consistently as the S285, thanks to the thorough engineering development that has gone into it.
For more information on how to purchase this unit, please contact us, or speak to Collins Performance Engineering.
