How much power does the GT4845 Sports Turbine Kit add?

On the HKS test car peak power rose by 54PS and peak torque by 14Nm. That car was a Japan-market FL5 running the HKS Mastery ECU PHASE3, LEGAMAX Sports exhaust, R Type intercooler and piping kit, so the figure belongs to the whole package. On track HKS recorded three seconds a lap and 12 km/h more top speed.

Do I need an ECU tune with it?

Yes, and this is the most important thing to understand before buying. HKS measured its figures with the Mastery ECU PHASE3, which is sold only in Japan. The factory ECU manages output on a torque model, so without calibration the turbine cannot deliver what it is capable of. Budget for tuning alongside the kit.

Does it fit the FK8 Civic Type R as well?

HKS records this part against the FL5 only, in both its Japanese product database and its US fitment data. Some distributor listings describe it as FK8 and FL5, which appears to come from an abbreviated product name rather than fitment data. Treat it as an FL5 part unless HKS confirms otherwise.

What comes in the box besides the turbine?

Every gasket the job needs, covering the turbine, exhaust, intake, water lines and oil lines, plus the studs and bolts for the turbine change. HKS supplies these because a turbine swap that arrives without them stalls halfway through, and sourcing correct gaskets separately is slow and error prone.

Will it hurt reliability compared to the factory turbo?

HKS designed the GT4845 Sports Turbine Kit to hold primary exhaust pressure at the factory level, which is what keeps heat and back pressure in check. A larger turbine that raises exhaust pressure is the one that shortens engine life. That said, any turbine upgrade with more boost asks more of the engine.

What else should be fitted first?

Cooling and exhaust. HKS ran the R Type intercooler, the intercooler piping kit and the LEGAMAX Sports exhaust on the car it used to develop the GT4845 Sports Turbine Kit, and all three are the sensible groundwork. Charge cooling in particular matters, because a larger turbine makes hotter air and the factory core is already the limit.

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Description

HKS GT4845 Sports Turbine Kit for FL5 Honda Civic Type R

HKS’s GT4845 Sports Turbine Kit is the answer to the one complaint owners have about the FL5 Honda Civic Type R at the top of the rev range, which is that the factory turbocharger runs out of breath before the engine does. The GT4845 replaces it with a larger compressor and turbine while holding primary exhaust pressure at the factory figure, and that last detail is the engineering point: boost arrives efficiently rather than being forced, so the power comes on smoothly without loading the engine in ways it was never designed for. HKS took a car so equipped to Fuji Speedway and recorded 12 km/h more top speed, 232 rising to 244, and three seconds off the lap.

Development and Testing

HKS validated the GT4845 Sports Turbine Kit on a Japan-market FL5 running its own Mastery ECU PHASE3, LEGAMAX Sports exhaust, R Type intercooler and intercooler piping kit. On that car HKS recorded peak power rising by 54PS and peak torque by 14Nm, with the torque peak moving up the range from 3320rpm to 4680rpm, which is exactly what a larger turbine does. The Fuji Speedway result, 12 km/h more top speed and three seconds a lap, is the figure worth weighing, because it was measured on track rather than on a roller.

Design and Performance

The kit runs an electric actuator and is calibrated against the factory ECU data, so it works with the car electronics rather than around them. Primary exhaust pressure stays at the factory level, which keeps the turbine efficient and avoids the heat and back pressure that a badly matched upgrade brings. High-rpm output is where the gain sits: the factory turbocharger is sized for response and emissions compliance, and the GT4845 Sports Turbine Kit trades a little of that for genuine top-end.

Features

GT4845 turbine and compressor sized for high-rpm output the factory turbocharger cannot reach
Primary exhaust pressure held at the factory figure, so boost is made efficiently
Electric actuator calibrated against factory ECU data
All gaskets supplied: turbine, exhaust, intake, water lines and oil lines
Studs and bolts for the turbine change included
The GT4845 Sports Turbine Kit is a complete replacement assembly rather than a rebuilt factory unit

What’s Included

GT4845 Sports Turbine Kit assembly with electric actuator
Gaskets for the turbine, exhaust, intake, water lines and oil lines
Studs and bolts for turbine replacement

Applications

Honda Civic Type R: FL5 | 2023-present | K20C

Notes

The published power figures were recorded with the HKS Mastery ECU PHASE3, which HKS sells only in Japan. Without ECU calibration the factory torque model will cap what the turbine can deliver, so budget for tuning as part of this purchase rather than after it.
HKS measured on a Japan-market FL5 fitted with its LEGAMAX Sports exhaust, R Type intercooler and intercooler piping kit. The figures describe that whole package, not the turbine alone.
The supporting parts from the HKS test car are all available here: the HKS LEGAMAX Sports Exhaust for FL5 Honda Civic Type R 31021-AH005, the HKS R Type Intercooler Kit for FL5 Honda Civic Type R 13001-AH007 and the HKS Intercooler Piping Kit for FL5 Honda Civic Type R 13002-AH002
HKS quotes this part against the FL5 in its own product database and in its US fitment records. Some distributor listings show it as FK8 and FL5; the manufacturer records FL5 only.
Ships as a single box measuring 432 x 320 x 275mm at 9.74kg
Browse the full HKS range on Bulletproof Automotive

Frequently Asked Questions

How much power does the GT4845 Sports Turbine Kit add? On the HKS test car peak power rose by 54PS and peak torque by 14Nm. That car was a Japan-market FL5 running the HKS Mastery ECU PHASE3, LEGAMAX Sports exhaust, R Type intercooler and piping kit, so the figure belongs to the whole package. On track HKS recorded three seconds a lap and 12 km/h more top speed.
Do I need an ECU tune with it? Yes, and this is the most important thing to understand before buying. HKS measured its figures with the Mastery ECU PHASE3, which is sold only in Japan. The factory ECU manages output on a torque model, so without calibration the turbine cannot deliver what it is capable of. Budget for tuning alongside the kit.
Does it fit the FK8 Civic Type R as well? HKS records this part against the FL5 only, in both its Japanese product database and its US fitment data. Some distributor listings describe it as FK8 and FL5, which appears to come from an abbreviated product name rather than fitment data. Treat it as an FL5 part unless HKS confirms otherwise.
What comes in the box besides the turbine? Every gasket the job needs, covering the turbine, exhaust, intake, water lines and oil lines, plus the studs and bolts for the turbine change. HKS supplies these because a turbine swap that arrives without them stalls halfway through, and sourcing correct gaskets separately is slow and error prone.
Will it hurt reliability compared to the factory turbo? HKS designed the GT4845 Sports Turbine Kit to hold primary exhaust pressure at the factory level, which is what keeps heat and back pressure in check. A larger turbine that raises exhaust pressure is the one that shortens engine life. That said, any turbine upgrade with more boost asks more of the engine.
What else should be fitted first? Cooling and exhaust. HKS ran the R Type intercooler, the intercooler piping kit and the LEGAMAX Sports exhaust on the car it used to develop the GT4845 Sports Turbine Kit, and all three are the sensible groundwork. Charge cooling in particular matters, because a larger turbine makes hotter air and the factory core is already the limit.

About HKS

HKS is a Japanese performance engineering brand founded in 1973 and headquartered in Fujinomiya, Shizuoka, with a long-standing reputation for developing high-quality aftermarket parts and motorsport-proven technology for enthusiast and professional applications. Known for innovations in turbocharging and engine performance, HKS produces a broad range of components including exhaust systems, turbo kits, electronics / engine management, and suspension solutions, with product development heavily influenced by decades of involvement in racing disciplines such as circuit time attack, drag, and drifting.

Additional Information

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Shipping Policy

Items that are in stock in the US, either at Bulletproof’s warehouse or at a supplier’s warehouse, are generally delivered within 7-10 days. Special order items from overseas take considerably longer. As a courtesy Bulletproof offers delivery estimates to our customers which take into consideration manufacturer availability and shipping schedule. These estimates represent our best guess based on previous orders from the manufacturer and do not in any way imply a guaranteed delivery window. Many manufacturers work in a “just in time” inventory system and often take 2-20+ weeks to produce an item once an order is submitted. All deliverable items are then sent to our Japanese warehouse. Bulletproof ships a minimum of one full ocean freight container every month from Japan, oftentimes more than one a month. Ocean freight takes an average of 4 weeks. Typically it breaks down to one week in Japan for paperwork and customs, two weeks by boat and one week in US customs/clearance. Due to the wide number of variables between manufacturer and shipping schedules, delivery estimates are simply just that – estimates. We attempt to estimate conservatively and we usually deliver faster than our estimates suggest. It is not Bulletproof’s policy to guarantee delivery time of any special order item, this is impossible for us to do. By ordering you acknowledge that there is no required delivery ETA and an order may not be canceled or altered due to manufacturing or shipping delays, all ETA’s are provided as a best guess only. Please review the full Terms & Conditions here.

BP Pricing Difference

We do pricing a little differently on our JDM brands and we believe in making things simple and clear. No hidden fees or surcharges. Every price you see includes the shipping cost to our office in Los Angeles, California and all the associated taxes/duties/fees for bringing the products into the US. The only shipping you ever pay is from our facility in the US to your location. Be wary of resellers that don’t include the cost of international shipping in their pricing on JDM parts. While we believe we’ll always have the lowest all-in price on JDM products, we offer a price match guarantee for all authentic parts purchased from authorized dealers as well. For many international customers, it’s much more affordable to ship from the USA than from Japan directly, as the air freight and ocean freight costs are typically much less. However, for customers looking to ship directly from Japan outside of North America, or domestically in Japan, we can provide pricing specifically for that scenario. Please do not hesitate to contact us with any pricing questions or concerns. Please email us at sales@bulletproofautomotive.com with any inquiries.

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HKS GT4845 Sports Turbine Kit for FL5 Honda Civic Type R [11004-AH006]

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HKS GT4845 Sports Turbine Kit for FL5 Honda Civic Type R

Development and Testing

Design and Performance

Features

What’s Included

Applications

Notes

Frequently Asked Questions

About HKS

Reviews