Why Upgrade to the Holset HE351VE on Your Evo X?

The Mitsubishi Lancer Evolution X is already a formidable machine, but the stock TD05H turbocharger can leave you wanting more—especially when chasing higher horsepower numbers or faster spool times. Enter the Holset HE351VE, a turbo originally found on 5.9L Cummins diesel engines, but now a legendary upgrade for the 4B11T. Its variable geometry (VGT) system allows the turbine to behave like a smaller unit at low RPM for snappy throttle response, then open up to flow like a much larger turbo at high boost. The result: 500+ wheel horsepower with spool similar to a stock Evo X.

But installing a diesel turbo on a gasoline engine isn’t a simple bolt‑on affair. This guide walks you through every step, from tool selection to tuning considerations, so you can avoid common pitfalls and enjoy a reliable, high‑performance setup.

Tools and Materials You’ll Need

Before diving in, gather all necessary components and tools. The HE351VE requires a few custom parts beyond a typical turbo swap.

  • Holset HE351VE turbocharger (used or new; inspect the VGT actuator for smooth movement)
  • Turbo installation gasket kit – manifold inlet gasket, turbine outlet gasket, oil drain gasket
  • Mickey Mouse Evo X specific components:
    • Oil feed line: -4AN stainless steel, with proper restrictor (0.060″ orifice recommended)
    • Oil drain line: -10AN (or -12AN) with a 45° or 90° fitting to clear the engine block
    • Custom intercooler piping: 2.5″ or 3″ aluminum, plus couplings and T‑bolt clamps
    • Boost control solenoid (e.g., MAC solenoid 3‑port) and vacuum hose
  • Socket set and wrenches (10mm, 12mm, 14mm, 17mm, 19mm, plus 5mm Allen for VGT actuator bolts)
  • Torque wrench that reads in lb‑ft (25 to 100 lb‑ft range)
  • V‑band clamp tool (if you’re removing the compressor housing)
  • Penetrating oil (e.g., PB Blaster) for stubborn exhaust bolts
  • Jack and jack stands (the Evo is low; raising the front helps access)
  • Scan tool or OBD2 logger to monitor post‑installation

Preparing Your Workspace and Vehicle

Park the car on a level surface, disconnect the negative battery terminal, and let the engine cool completely. Remove the hood for better access (three 10mm bolts and one clip per side). Lay out all tools and new parts in order of use. Safety first: wear gloves and eye protection when handling exhaust components and oil lines.

Removing the Stock Turbocharger

The Evo X factory turbo removal is straightforward if you follow a systematic approach.

  1. Drain engine oil and coolant. Open the oil drain plug (17mm) and drain into a pan. Drain coolant from the radiator petcock or lower hose. This step prevents massive spills when you disconnect oil and coolant lines from the turbo.
  2. Remove the intake piping. Unbolt the intake tube at the compressor inlet (4x 10mm) and the MAF sensor. Remove the entire pipe.
  3. Disconnect intercooler piping. Loosen the clamp at the compressor outlet and at the intercooler. Pull the hot‑side pipe aside.
  4. Unbolt the exhaust manifold heat shield. Three 10mm bolts at the top; two 12mm nuts at the bottom. You may need to remove the dipstick tube support bracket to slide the shield out.
  5. Disconnect the oil feed line. Use a 12mm crow’s foot wrench on the turbo’s banjo bolt. Have rags ready for residual oil.
  6. Disconnect the oil return line. Two 10mm bolts securing the drain tube to the turbo. Slide the tube out; you may need to wiggle the turbo to free it.
  7. Remove the turbo‑to‑manifold bolts. There are four 14mm nuts holding the turbo to the exhaust manifold. Apply penetrating oil, then break them loose. The top two are easiest with a swivel socket. Note: The Evo X manifold is a T3 flange; the HE351VE also has a T3 inlet, so your new turbo will bolt directly to the stock manifold.
  8. Lift the turbo free. Carefully slide it out from the engine bay. The wastegate actuator arm will need to be unfastened (one spring clip). Set the old turbo aside.

Clean the manifold mounting surface with a wire brush and a flat file to ensure a perfect seal for the new gasket.

Preparing the Holset HE351VE for Installation

Out of the box, the HE351VE needs some pre‑fit adjustments to work on an Evo X.

Clock the Compressor Housing

The stock Holset compressor outlet points straight down; for the Evo X it should point toward the driver side about 45° to align with your custom intercooler pipe. Loosen the six 5mm Allen bolts on the compressor backplate, rotate the housing to your desired orientation, and retorque to 8 lb‑ft in a cross pattern. Use a small amount of threadlocker.

Install the Oil Drain Flange

The HE351VE uses a rectangular oil drain flange with two M8 holes. You’ll need a custom drain tube (or a modified stock piece). Position the drain flange so the hose exits toward the passenger side of the engine block. Secure it with the supplied bolts and a new gasket.

Set Up the VGT Actuator

The variable geometry nozzle ring is controlled by a pneumatic actuator on the turbine housing. For gasoline applications, you must use a 3‑port boost control solenoid to modulate pressure to the actuator. Do not plug the actuator port directly to intake pressure – that would lead to over‑boost and serious damage. We’ll cover wiring in a later section.

Prepare the Oil Feed

The HE351VE uses a 1/8″ NPT port for oil feed. Install a restrictor fitting (0.060″ orifice) into the port to prevent over‑oiling, then attach a -4AN male to the restrictor. Connect your braided line from the oil filter housing feed location (stock banjo bolt location) to this fitting. DO NOT use the factory banjo line – the Holset journal bearings require a different flow rate.

Installing the Holset HE351VE Turbo

  1. Bolt the turbo to the manifold. Place a new manifold gasket on the studs, then slide the HE351VE onto the studs. Use the stock 14mm nuts and torque to 35 lb‑ft in a criss‑cross pattern.
  2. Connect the oil return line. Attach your custom -10AN drain hose from the turbo drain flange to the stock drain pipe (or directly to the block if you’ve removed the stock pipe). Ensure the hose has a smooth, vertical drop with no kinks.
  3. Install the oil feed line. Carefully route the -4AN line away from hot exhaust surfaces. Secure it with a heat sleeve if possible. Tighten the banjo at the filter housing to 20 lb‑ft; tighten the -4AN connection at the turbo by hand then a 1/4 turn with a wrench.
  4. Attach the intercooler piping. The compressor outlet is 4″ round; you’ll need a reducing coupler (4″ to 2.5″ or 3″) to match your existing piping. Clamp securely.
  5. Intake pipe. You may need a silicone reducer from the MAF housing (3″) to the compressor inlet (4″).
  6. Reinstall the exhaust manifold heat shield or leave it off if it doesn’t clear the larger turbo – many tuners remove it for better heat dissipation.

Wiring the Boost Control Solenoid

Proper control of the HE351VE’s VGT is critical for driveability and engine safety. The actuator should see a mix of pressure and vacuum to move the nozzle vanes. A typical 3‑port MAC solenoid works well.

  1. Mount the solenoid in a vibration‑free location (e.g., the stock boost solenoid bracket).
  2. Connect vacuum lines:
    • Port “COM” to the turbo actuator.
    • Port “NO” to a boost source (e.g., a nipple on the compressor cover or intercooler pipe).
    • Port “NC” to a filtered atmospheric vent (or to intake vacuum if you want faster spool).
  3. Electrical: Power the solenoid with 12V from a switched source (e.g., the stock boost solenoid harness). Ground the other wire. Use a relay if desired.
  4. Tuning … You will need a reflash of the ECU (via Cobb Accessport or EcuFlash) to control the solenoid duty cycle. A typical table ramps from 20% duty at low RPM to 70% at high RPM / high load. Discuss with a tuner or consult EvolutionM.net for base maps.

Final Checks Before Firing the Engine

  • Torque all fasteners – manifold nuts (35 lb‑ft), oil drain bolts (8 lb‑ft), oil feed fitting (hand tight + 1/4 turn).
  • Check for clearance between the turbo and the engine block, frame rail, and brake booster. The HE351VE is large; you may need to dimple the firewall slightly.
  • Reconnect battery and fill with fresh engine oil (5W‑40 recommended for modified Evo X). Refill coolant.
  • Prime the turbo: Disable the fuel pump (pull the relay) and crank the engine for 10 seconds five times to get oil throughout the turbo before it sees combustion.
  • Start and inspect – let the engine idle, check for oil leaks at the feed and drain, listen for unusual noises. Watch the oil pressure gauge – should be >10 psi at idle hot.

Test Drive and Fine‑Tuning

Take the car out cautiously. Keep an eye on boost pressure – an HE351VE can build 30+ psi if the VGT is closed too much. Use your boost controller (or tuning software) to adjust the solenoid map. Target 20‑25 psi initially and log knock correction. If you see knock retard >3°, reduce boost or enrich the mixture.

Do several full‑throttle pulls in 3rd gear to dial in the VGT curve. The goal is spool similar to stock by 3500 RPM, but holding boost to redline with no taper. Recommended reading: Extreme Turbo Systems’ HE351VE Upgrade Guide for more tuning tips.

Also check your air/fuel ratio – with proper tuning, the 4B11T loves this turbo and can make 500-550 whp on E85. Evans Tuning offers remote tuning services for Holset setups.

Conclusion

Installing a Holset HE351VE on your Evo X is one of the most rewarding upgrades you can perform – the combination of diesel‑tough bearings and variable geometry gives you ferocious acceleration without sacrificing daily driveability. This DIY project requires patience, attention to detail, and a willingness to learn about VGT control, but the results are worth it. With the right boost solenoid setup and a custom tune, your Evo will spool like a built 2.3L stroker while exceeding the power of turbo kits costing three times as much.

For sourcing Hoiset turbos and installation kits, check out Goleby’s Parts, a trusted supplier of Cummins and Holset components.

Now go make your 4B11T sing. The HE351VE is waiting.