Nissan Skyline GT-R R34 HKS GT3037S Turbo Upgrade - Complete Installation Guide

The HKS GT3037S turbo kit represents one of the most popular and proven turbo upgrades for the RB26DETT engine, offering substantial power gains while maintaining excellent drivability and reliability.

Performance Overview

Expected Power Gains

• Stock Power: 280 hp (official) / 320 hp (actual)
• Post-Upgrade: 450-480 hp at the wheels
• Power Gain: +130-160 wheel horsepower
• Torque Gain: +110-130 lb-ft

Upgrade Specifications

• Turbo Model: HKS GT3037S (twin configuration)
• Compressor: GT3037 (0.82 A/R housing)
• Turbine: Stainless steel with anti-surge coating
• Peak Boost: 18-22 psi (safe on stock internals)
• Spool: 3,200-3,800 rpm (improved over stock ceramics)

Required Components

HKS GT3037S Turbo Kit

Part Number: 14002-AN013
Price Range: $3,800-$4,200
Kit Includes:

• 2x GT3037S turbochargers with internal wastegates
• Twin stainless steel oil feed lines
• Twin stainless steel oil drain lines
• All mounting hardware and gaskets
• Installation manual (Japanese/English)

Supporting Modifications (REQUIRED)

1. Upgraded Fuel System

Components:

• Walbro 255 LPH high-flow fuel pump ($120-180)
• Nismo or Tomei 740cc fuel injectors ($800-1,200)
• Aeromotive adjustable fuel pressure regulator ($220-280)

Why Required: Stock fuel system maxes at ~400 wheel hp. Running lean at high boost WILL destroy the RB26DETT.

2. Upgraded Intercooler

Options:

• Budget: GReddy V-Spec kit ($1,200-1,500)
• Mid-Range: Blitz NUR-Spec R ($1,800-2,200)
• Premium: HKS R-Type ($2,500-3,200)

Why Required: Stock intercooler heat-soaks above 380 hp, causing timing retard and detonation risk.

3. Downpipes and Exhaust

Components:

• HKS 3" high-flow downpipes ($800-1,000)
• Tomei Expreme Ti catback exhaust ($1,400-1,800)

Why Required: Stock exhaust is restrictive above 400 hp. Expect EGT spikes and slower spool without upgrade.

4. ECU Tune (CRITICAL)

Options:

• OEM+ Tune: Nistune piggyback ($800-1,200 tuned)
• Standalone: Link G4X Storm ($2,200-3,000 tuned)
• Premium: AEM Infinity ($3,500-4,500 tuned)

Why CRITICAL: Do NOT drive on stock ECU map. Even with boost controller limiting pressure, AFR will be dangerously lean. Professional dyno tune MANDATORY.

Optional But Recommended

5. Upgraded Clutch

Options:

• OEM+: Exedy Twin Plate ($1,200-1,500)
• Race: OS Giken Triple Plate ($2,500-3,200)

Why Recommended: Stock clutch rated to 350 lb-ft. New torque output will exceed this significantly.

6. Cooling System Upgrades

Components:

• Koyo aluminum radiator ($400-600)
• Twin SPAL electric fans ($200-300)
• Mishimoto oil cooler kit ($500-700)

Benefit: Maintains safe temps during spirited driving and track use.

Tools Required

Specialty Tools

• Engine hoist (2,000 lb minimum) - Rental: $50/day
• Transmission jack - Rental: $30/day
• Torque wrenches (10-150 lb-ft range) - Purchase: $80-200
• Breaker bar (24" minimum) - Purchase: $30-50

Standard Tools

• Full socket set (metric 8mm-24mm)
• Full wrench set (metric 10mm-22mm)
• Ball-end Allen key set (4mm-10mm)
• Screwdriver set (Phillips and flathead)
• Oil drain pan (6 quart minimum)
• Shop rags and degreaser

Consumables

• Engine oil (Mobil 1 5W-30, 6 quarts)
• Oil filter (Nissan OEM or equivalent)
• Coolant (Nissan Long Life or equivalent, 2 gallons)
• RTV silicone sealant (high-temp, gray)
• Anti-seize compound
• Brake cleaner

Installation Process (12 Steps)

Step 1: Preparation and Safety

Time Estimate: 30 minutes

1. Park vehicle on level surface, engage parking brake
2. Disconnect negative battery terminal
3. Allow engine to cool completely (minimum 4 hours)
4. Drain engine oil and coolant into appropriate containers
5. Remove engine cover and intake manifold cover

Safety Warnings:

• ⚠️ Hot coolant can cause severe burns - wait minimum 4 hours
• ⚠️ Wear safety glasses throughout installation
• ⚠️ Use jack stands rated for vehicle weight (NEVER work under car supported only by jack)

Step 2: Remove Stock Intake System

Time Estimate: 45 minutes

1. Disconnect MAF sensor electrical connector
2. Loosen intake pipe clamps (4 total)
3. Remove airbox mounting bolts (3x 10mm)
4. Disconnect vacuum lines from intake manifold (mark positions with tape)
5. Remove intercooler piping (both hot and cold sides)
6. Remove stock intercooler (4x 12mm bolts)

Critical Notes:

• Mark ALL vacuum line positions with masking tape and Sharpie
• Photograph connections before removal
• Inspect old clamps for cracks - replace if damaged

Step 3: Remove Stock Turbos

Time Estimate: 2-3 hours

1. Remove turbo heat shields (6x 10mm bolts per side)
2. Disconnect wastegate actuator rods (12mm wrench)
3. Unbolt oil feed lines from cylinder head (2x 14mm banjo bolts)
4. Remove oil drain lines from block (2x 12mm bolts)
5. Unbolt exhaust manifold studs (6x 14mm nuts per side)
6. Support turbo weight and remove mounting bolts (4x 14mm per turbo)
7. Carefully extract stock turbos (ceramic wheels are FRAGILE)

Pro Tips:

• Soak exhaust studs with penetrating oil 24 hours before removal
• Use 6-point sockets (12-point will round off rusty nuts)
• If studs break, use easy-out extractors - DO NOT drill yet

Step 4: Inspect and Clean Mounting Surfaces

Time Estimate: 45 minutes

1. Inspect exhaust manifold flanges for cracks (common failure point)
2. Clean all gasket surfaces with brass brush
3. Check for warped flanges using straight edge
4. Inspect turbo oil drain holes for carbon buildup
5. Clean cylinder head oil feed ports

Warning: If manifold cracks detected, replacement REQUIRED before turbo install. Running cracked manifolds = exhaust leaks = boost loss.

Step 5: Install HKS GT3037S Turbos

Time Estimate: 2-3 hours

1. Install new turbo gaskets on exhaust manifold flanges
2. Apply anti-seize to turbo mounting studs
3. Carefully position HKS GT3037S turbos (note orientation - compressor housing clocking)
4. Install mounting nuts and torque in star pattern:
   • First pass: 15 lb-ft
   • Second pass: 25 lb-ft
   • Final pass: 35 lb-ft
5. Connect wastegate actuator rods (adjust length if needed)

Critical: Do NOT overtorque studs. Cast iron manifolds can crack. Use torque wrench, not impact gun.

Step 6: Install Oil Feed and Drain Lines

Time Estimate: 1 hour

1. Install new oil feed line banjo bolts with crush washers
2. Torque oil feed connections: 18-22 lb-ft
3. Route oil drain lines with clearance from hot exhaust
4. Install drain line bolts: 12-15 lb-ft
5. Apply RTV sealant to drain flange interfaces

Pro Tip: Pre-fill oil feed lines with fresh engine oil before connecting. This ensures immediate lubrication on first startup.

Step 7: Install Upgraded Intercooler

Time Estimate: 1.5 hours

1. Test-fit upgraded intercooler in stock location
2. Mark mounting hole positions
3. Install mounting brackets (if not pre-welded)
4. Secure intercooler with provided hardware: 15-18 lb-ft
5. Install intercooler piping (hot side first, then cold side)
6. Tighten all clamps: 65-75 in-lb (do NOT overtighten)

Note: Silicone couplers should compress slightly but not bulge. Overtightening causes premature failure.

Step 8: Install Fuel System Upgrades

Time Estimate: 2 hours

1. Remove rear seat bottom (4 clips)
2. Access fuel pump assembly (8x 10mm bolts)
3. Disconnect fuel lines and electrical connector
4. Replace stock pump with Walbro 255 LPH
5. Reassemble pump assembly with new O-ring seal
6. Install 740cc injectors (mark cylinder positions)
7. Install adjustable fuel pressure regulator in fuel rail

Critical: Fuel system must be 100% sealed. ANY leaks = fire hazard. Pressure test before first startup.

Step 9: Install Downpipes and Exhaust

Time Estimate: 1.5 hours

1. Install HKS 3" downpipes to turbo outlets
2. Use new gaskets and stainless hardware
3. Connect mid-pipe section
4. Install Tomei catback exhaust
5. Ensure all hangers engaged and aligned
6. Torque exhaust bolts: 35-40 lb-ft

Tip: Leave all bolts finger-tight until entire system is aligned, then torque from front to back.

Step 10: Reconnect Intake System

Time Estimate: 45 minutes

1. Install intake piping to turbo inlets
2. Reconnect vacuum lines (refer to photos/tape labels)
3. Install MAF sensor in cold-side piping
4. Secure airbox and filter
5. Double-check all clamps tightened

Step 11: Refill Fluids and Prep for Startup

Time Estimate: 30 minutes

1. Refill engine oil: 5.5 quarts Mobil 1 5W-30
2. Install new oil filter
3. Refill coolant system (bleed air pockets)
4. Check all fluid levels
5. Reconnect battery negative terminal

Step 12: First Startup and Break-In

Time Estimate: 20 minutes initial, 500 miles total

Initial Startup Procedure:

1. Turn ignition to ON (do not crank) - listen for fuel pump priming
2. Disconnect ignition coil packs
3. Crank engine for 5 seconds to build oil pressure (no combustion)
4. Reconnect coil packs
5. Start engine and idle for 5 minutes (monitor for leaks)

Break-In Period (500 miles):

• Keep RPM below 4,000
• No full-throttle pulls
• Vary load and RPM (do NOT cruise at constant speed)
• Change oil at 100 miles, 500 miles, and 1,000 miles
• Monitor oil level daily (turbos consume slightly more oil)

Tuning Requirements

DO NOT DRIVE WITHOUT TUNE

Critical Warnings:

• Stock ECU map designed for ceramic turbos (different flow characteristics)
• AFR will run dangerously lean under boost (risk of detonation)
• Timing advance will be incorrect for higher boost levels
• One full-throttle pull on stock tune can destroy engine

Professional Dyno Tune - MANDATORY

What to Expect:

• Baseline pulls: 320-340 wheel hp (stock turbos)
• Tuned pulls: 450-480 wheel hp (HKS GT3037S)
• Peak boost: 18-22 psi (safe for stock internals)
• AFR target: 11.8-12.2:1 under boost
• Timing: 12-15° advance at peak torque

Dyno Session Cost: $800-1,200 (3-4 hours)

Tuner Selection:

• MUST have RB26DETT experience
• Request to see previous R34 dyno charts
• Ask about safety margins (knock detection, boost cut)

Total Cost Breakdown

Parts (Required)

Labor (If Shop Install)

Optional Upgrades

Total Investment

• DIY Install: $9,120-13,060 (parts only)
• Shop Install: $11,340-16,410 (parts + labor)
• With Optional: $12,440-21,210 (all upgrades)

Expected Reliability and Maintenance

Reliability Outlook

With Proper Installation and Tuning:

• HKS GT3037S proven reliable to 100,000+ miles
• Stock RB26DETT internals safe to 500 hp
• Regular maintenance critical (oil changes every 3,000 miles)

Common Issues to Monitor:

• Turbo seal wear (blue smoke on startup) - typical at 60-80K miles
• Wastegate creep (boost rising past setpoint) - adjust actuators annually
• Intercooler piping leaks (inspect clamps every 10K miles)

Maintenance Schedule

Performance Comparison

Before vs After

Dyno Chart Analysis

• Power comes on HARD at 3,500 rpm (vs 4,500 on stock)
• Broader, flatter torque curve (less peaky)
• Maintains boost to redline (stock falls off at 7,000 rpm)

Frequently Asked Questions

Q: Can I run HKS GT3037S on stock internals?
A: Yes, safe up to 500 wheel hp with proper tune. Above this, upgrade pistons, rods, and head studs.

Q: Will this pass emissions testing?
A: Depends on region. Catless downpipes will fail most emissions tests. High-flow cats available but reduce power by 15-20 hp.

Q: What octane fuel required?
A: Minimum 93 octane (US). 100+ octane recommended for track use above 20 psi.

Q: Can I install this myself?
A: Advanced DIY project. Requires engine hoist, torque wrenches, and mechanical experience. Budget 15-20 hours for first-time install.

Q: How long do HKS turbos last?
A: 60,000-100,000 miles with proper maintenance (oil changes every 3,000 miles, cool-down period after spirited driving).

Q: Will this void my warranty?
A: Yes. Any aftermarket turbo upgrade voids powertrain warranty. Consider this if vehicle under warranty.

Conclusion

The HKS GT3037S turbo upgrade delivers substantial, usable power gains for the R34 GT-R while maintaining excellent drivability and reliability. Proper installation, supporting modifications, and professional tuning are CRITICAL for success. Budget $10,000-15,000 total investment for complete upgrade including labor and tuning. Results: 450-480 wheel hp, improved spool, and broader power band - transforming the R34 into a legitimate supercar killer.