HPI Reinforced 6-Speed Transmission for L-Series Engines (S30 / S31)

Part Number: HPKM-N02
 
The HPI Reinforced Transmission continues to be the choice for many competitive vehicles, boasting the capability to handle up to 50kg/m (approx. 360 lb-ft) of torque and 430ps.
 
Optimized Gear Ratios
To maximize enjoyment in circuit racing and drifting, we have engineered the ideal gear ratios.
The 1st and 2nd gears are positioned closer to 3rd, while 6th gear is brought closer to 5th.
Unlike pure competition gears that often prioritize strength and ease of manufacturing—resulting in loud "whining" noises and poor mesh ratios—our design ensures a smooth, natural feel for daily driving without sacrificing performance.
HPI has successfully enhanced the potential of the NISMO-based transmission through proprietary internal processing, earning the trust of top drivers.
 
Superior Strength & Reliability
Increased Gear Diameter: High strength is ensured by increasing the gear diameter through ratio optimization.
Large-Module Design: By reducing the tooth count and increasing the size of each individual tooth (module adjustment), we have significantly boosted the strength of the counter and main gears.
Thrust Impact Reduction: By reducing the helix angle of the teeth, we minimized the forward thrust impact on the counter shaft caused by torque spikes, preventing damage to the counter-reverse gear end face.
Modern Operability: While maintaining the strengths of the standard "FS6R92A", we offer operability and silence that old-school synchro or race-only dog-clutch transmissions simply cannot match.
 
Artisan Precision & COA Technology
Every unit is hand-assembled in a climate-controlled, dust-free clean room.
We utilize HPI-exclusive One-Off SST (Special Service Tools) to perform meticulous checks on every component.
During assembly, we apply our popular COA next-generation lubricant to reduce metal fatigue and ensure a buttery-smooth shift feel.
 
Full Compatibility (Speedometer Solution)
Standard S15 transmissions take their signal from the ABS sensor, meaning the transmission lacks a drive gear.
This made speedometer operation impossible for older models.
To solve this, we have integrated a speedometer drive gearand include the necessary Nissan OEM/NISMO components for the swap.
 
Technical Specifications & Precautions
S15-Based Design
COMPETITION USE ONLY: This product is for competition use and is not covered by warranty.
Input Limits: Exceeding designed power/torque limits may result in gear failure.
Required Maintenance: * Must be used in conjunction with a NISMO clutch.
Must use NISMO gear oil.
Non-specified additives may cause damage.
Driving Technique: To ensure longevity, please rev-match on downshifts to reduce the torque load from the road surface.
 
Important Notice regarding Competition Parts
These parts are developed for extreme motorsport conditions, prioritizing performance.
You may experience increased "noise" or "vibration."
Proper installation, fine-tuning, and frequent maintenance are required.
Please consult a specialist to ensure this product suits your vehicle's condition and purpose.
Modifying your vehicle with competition parts may require structural inspection or official re-registration depending on local regulations.
 
Please follow the included instruction manual and ensure installation is performed by a certified mechanic in accordance with Nissan’s service manual.