Upgrading to a Powermax 64mm turbocharger on your Cummins diesel is one of the most effective bolt-on modifications you can make for significant horsepower and torque gains. Whether you drive a 5.9L 24-valve or a 6.7L Cummins, the Powermax 64mm delivers a noticeable improvement in airflow, throttle response, and towing capability. This expanded guide covers everything you need to know — from the technology behind the turbo to a detailed step-by-step installation, tuning requirements, expected performance gains, and answers to common questions. By the end, you’ll have the knowledge to make an informed decision and complete the install like a pro.

Understanding the Powermax 64mm Turbo for Cummins Engines

The Powermax 64mm turbo is a direct replacement upgrade designed specifically for Cummins engines found in Dodge Ram trucks. It features a larger 64mm compressor wheel and a redesigned turbine housing compared to the factory turbo. The result is a substantial increase in airflow capacity without requiring major modifications to your engine bay or exhaust system.

Unlike some “big turbo” upgrades that require custom piping or a high-flow exhaust manifold, the Powermax 64mm is engineered to bolt up to your existing Cummins manifold and downpipe. This makes it an attractive option for owners who want more power without the complexity and cost of a full turbo conversion. The 64mm designation refers to the inducer diameter of the compressor wheel — a key measurement that determines the turbo’s airflow potential. For comparison, the stock turbo on a 5.9L 24-valve Cummins typically uses a 56mm or 58mm compressor, so upgrading to 64mm opens up substantially more potential for increased horsepower and torque.

How the Powermax 64mm Improves Performance

The physics behind the upgrade is straightforward: more air into the engine means more fuel can be burned, producing more power. The Powermax 64mm turbo flows roughly 55-65 lb/min of air at higher boost levels, compared to 45-50 lb/min from a stock turbo. This increased airflow allows you to safely run higher boost pressures (30-40 psi or more with proper tuning) and support larger injectors or a high-pressure fuel pump if you choose to push further.

Key performance benefits include:

  • Increase of 50-100 horsepower over stock with just a mild tune and no other modifications (actual gains depend on fuel system and tuning).
  • Improved torque at lower RPM due to better spool characteristics — the Powermax 64mm spools nearly as quickly as stock but sustains higher boost levels.
  • Enhanced throttle response from reduced backpressure and faster turbine reaction.
  • Better towing and pulling power — the extra airflow gives you the torque needed to haul heavy loads without excessive exhaust gas temperatures.
  • Potential fuel economy improvements when driving conservatively, because the engine breathes more efficiently and doesn’t have to work as hard to make power.

Is the Powermax 64mm Right for Your Cummins?

Before you purchase, consider your specific Cummins variant and your performance goals. The Powermax 64mm is available for both the 5.9L 24-valve (1998.5-2007) and the 6.7L (2007.5-current) Cummins engines, though the exact model numbers and housing details differ. There are also “non-gate” and “wastegated” versions — for street driving and towing, a wastegated version is often preferred because it allows better boost control.

This turbo works optimally with at least a mild programmer or tuner. Running it on a bone-stock ECM can lead to over-boost, high EGTs, or poor drivability. It pairs well with a 4-inch or 5-inch exhaust system, an aftermarket intake, and upgraded fuel delivery if you want max power. The Powermax 64mm is a popular middle ground: bigger than stock but not so large that it kills daily driving drivability.

Installation Process: Step-by-Step Guide for the Powermax 64mm Turbo

Installing the Powermax 64mm turbo is a moderate DIY job for someone comfortable with wrenches. Plan for 4-6 hours the first time. Below is an expanded installation guide covering every detail to ensure a leak-free, reliable install.

Tools and Materials You’ll Need

  • Powermax 64mm turbo kit (includes turbo, gaskets, and sometimes oil return line hardware)
  • Socket set: 10mm, 12mm, 13mm, 14mm, 15mm, 17mm, 19mm, 21mm
  • Open-end and combination wrenches in the same sizes
  • Torque wrench (inch-pound and foot-pound)
  • Flat-blade and Phillips screwdrivers
  • Extensions and universal joints for difficult angles
  • Pry bar (may be needed to separate turbo from manifold)
  • Set of new gaskets: turbo-to-manifold, oil supply line, oil return flange, coolant banjo bolt washers
  • New oil and coolant (factory specifications)
  • Anti-seize compound for bolts
  • Penetrating oil (like PB Blaster) if bolts are rusted
  • Shop rags, drain pan, safety glasses, gloves
  • Optional: new oil return line (many reuse stock but a new silicone line prevents leaks)

Preparation and Safety

  1. Disconnect the batteries — both positive and negative terminals. This prevents accidental engine start or electrical shorts.
  2. Let the engine cool completely (preferably overnight). Working on a hot turbo can cause burns and damaged gaskets.
  3. Remove the intake piping from the air filter box to the turbo inlet. Usually a large diameter hose with clamps.
  4. Remove the exhaust downpipe from the turbo outlet. You may need to disconnect the V-band clamp or bolts securing it. On older trucks, you might also need to remove the crossover pipe if space is tight.
  5. Drain the engine oil (optional but recommended — you will disconnect oil lines, so draining at least 2-3 quarts makes it less messy). Also drain the coolant down to below the level of the coolant lines that attach to the turbo.

Step-by-Step Removal of the Old Turbo

  1. Disconnect the oil supply line from the top of the turbo. Use a 12mm or 14mm line wrench. Expect some oil spillage — have a drain pan ready.
  2. Disconnect the oil return line at the bottom of the turbo. It’s usually a banjo fitting with two washers. Take care not to lose the washers.
  3. Disconnect the coolant lines — typically two lines (supply and return) with banjo bolts. Have new copper or aluminum crush washers ready for reassembly.
  4. Remove the turbo support bracket if equipped (found on most 6.7L trucks). Use a 15mm socket.
  5. Unbolt the turbo from the exhaust manifold. There are usually three or four bolts (most are 14mm). Use penetrating oil if they resist.
  6. Carefully lift the turbo off the manifold studs. It may be stuck due to carbon buildup; a gentle pry from the manifold flange helps. Avoid damaging the studs.
  7. Remove the old gasket from the manifold flange and clean the surface thoroughly with a scraper and brake cleaner.

Installing the Powermax 64mm Turbo

  1. Install new oil return and oil supply gaskets onto the new turbo. Use anti-seize on the threads of the oil return bolts.
  2. Attach the coolant banjo bolts with new crush washers. Torque to manufacturer spec (typically 15-20 ft-lbs for M10 banjo, but check kit instructions).
  3. Place the new turbo-to-manifold gasket onto the manifold studs. Ensure it’s oriented correctly (some have a tab or notch).
  4. Lower the Powermax 64mm onto the manifold studs. You may need to rotate the housing slightly to align the oil return port downward.
  5. Tighten the manifold flange nuts or bolts gradually in a cross pattern to 30 ft-lbs on a 5.9L or 35 ft-lbs on a 6.7L (check specific torque from Powermax instructions). Use anti-seize.
  6. Reconnect the oil supply line — use new copper washers on banjo fittings; do not overtighten (25-30 ft-lbs max).
  7. Reconnect the oil return line — ensure the rubber hose is in good condition; if in doubt, replace it. Tighten clamps securely.
  8. Reconnect the coolant supply and return lines with new crush washers. Torque banjo bolts to 18 ft-lbs. Do not overtighten as the aluminum turbo housing can strip.
  9. Install the turbo support bracket (if applicable). Torque to spec (usually 30 ft-lbs to the block and 20 ft-lbs to the turbo).
  10. Reattach the intake piping and tighten clamps.
  11. Reconnect the exhaust downpipe. Use a new gasket if your kit included one.
  12. Refill engine oil and coolant to correct levels. Factory spec: use 15W-40 diesel oil and Cummins-compatible coolant (OAT or HOAT).
  13. Reconnect batteries.

First Start and Boost Leak Check

  1. Before starting, prime the oil system: remove the fuel pump relay or disconnect the injection pump harness, then crank the engine in 10-second bursts (letting starter cool) until oil pressure registers on the gauge (you’ll hear the engine note change). This prevents dry start damage to the turbo bearings.
  2. Start the engine and let it idle. Check for oil and coolant leaks immediately. Rev gently to 2000-2500 RPM and watch for smoke or unusual noises.
  3. Inspect all connections while the engine runs. Tighten any weeping fittings after the system has pressurized.
  4. Take a short test drive, staying below 15 psi boost and 2500 RPM for the first 50 miles. This “break-in” period seats the bearings and seals.

Performance Gains: What to Expect After the Upgrade

With the Powermax 64mm properly installed and a corresponding tune, you can expect dramatic improvements. The table below summarizes gains for typical setups:

ConfigurationHorsepower Gain (over stock)Torque GainBoost Pressure (peak)
Stock fuel system, mild tune+50-60 hp+100-120 lb-ft30-32 psi
Stock injectors + water/methanol injection+80-100 hp+150-180 lb-ft35-38 psi
75hp or 90hp injectors + hot tune+120-150 hp+200-250 lb-ft38-42 psi

These numbers assume a properly tuned ECM. Without tuning, the engine may not see full benefits and could risk high EGTs or over-boost. Always pair an upgraded turbo with a custom tune from a reputable diesel tuner.

Real-World Driving Impressions

Owners frequently report that the Powermax 64mm transforms the truck from a capable hauler into a truly fast daily driver. The spool is almost instantaneous — by 2000 RPM you’re well into positive boost. Passing on the highway requires no downshift; the turbo delivers a strong surge of power from 1500-3000 RPM. EGTs stay manageable under load because the turbo moves so much air, especially if you’re still running a stock exhaust (but a 4-inch exhaust helps further).

Tuning and Supporting Modifications

To get the most from your Powermax 64mm turbo, tuning is essential. Stock ECM programming cannot deliver enough fuel to match the turbo’s air volume, and boost levels quickly exceed factory boost sensor limits (usually maxing at ~28-30 psi). A tuner or programmer allows you to:

  • Increase fuel delivery to match airflow.
  • Adjust wastegate control for optimal boost response (if wastegated version).
  • Raise boost limits (if your sensors and head gasket can handle it).
  • Optimize timing for lower EGTs and better torque.

Popular tuning options for Cummins include quadzilla modules, EfiLive custom tunes, or Edge products. For the Powermax 64mm, a mild tune that adds 40-60hp is safe on stock internals. Rugged diesel engines can handle up to 450-500hp on stock head bolts with this turbo, but beyond that, head studs become necessary.

Supporting modifications that maximize the Powermax upgrade:

  • High-flow intake — a 4-inch cold air intake reduces restriction before the turbo.
  • Exhaust system — 4-inch turbo-back exhaust with a free-flowing muffler or straight pipe reduces backpressure and EGTs.
  • Upgraded injectors — from 50hp to 100hp over stock, depending on power goals.
  • Fuel system upgrades — lift pump, CP3 kit (on 6.7L) for higher HP levels.
  • Boost and pyrometer gauges — essential to monitor EGTs and boost when tuned aggressively.

Maintenance and Longevity of the Powermax 64mm

The Powermax 64mm uses journal bearings like most stock turbos, so oil quality and changes are critical. Use a quality 15W-40 diesel oil (Cummins CES 20078 or better) and change every 5,000-7,500 miles. Check the oil return line for kinks or blockages, as a restriction can cause seal failure. Many owners report 100,000+ miles of trouble-free service with proper maintenance.

If you ever have a turbo failure, inspect for oil contamination in the intercooler and intake. Clean or replace the intercooler if oil has filled the core. The Powermax is rebuildable, and bearing kits are available.

Common Questions About the Powermax 64mm Turbo

Will the Powermax 64mm turbo work with my 5.9L 24-valve (common rail)?

Yes, there are specific versions for 1998.5-2002 24-valve (non-common rail) and 2003-2007 5.9L Common Rail as well as 6.7L. Ensure you order the correct flange pattern (Holset HX35/HE351 style or T3/T4 depending on year). The Powermax is designed to fit the factory manifold.

Do I need a new wastegate?

Some Powermax units are non-wastegated; others include a built-in wastegate. For street use, a wastegated version is recommended to maintain driveability and prevent over-boost. If you buy a non-wastegated version, you can use an external wastegate, but installation is more complex.

Will I notice a loss of low-end spool?

Surprisingly, the Powermax 64mm spools very similarly to stock. The 64mm compressor is efficient at low pressure ratios, so you won’t feel a lag. In fact, many owners report improved off-idle response due to reduced restriction in the turbine housing.

Can I run 40 psi of boost safely?

On a stock head gasket, sustained 40 psi is risky — most recommend staying at 35 psi max for safety. With head studs and a proper tune, 40-45 psi is achievable. Monitor EGTs (pyrometer) and keep pre-turbine EGTs below 1250°F for long-term durability.

What about warranty?

The Powermax 64mm is an aftermarket part. Installation will void any factory turbo warranty and may affect engine warranty if the truck is new. For older trucks (10+ years), this is rarely a concern, but check with your dealer if under warranty.

Where to Buy and Additional Resources

The Powermax 64mm turbo is available from many diesel performance retailers. When purchasing, look for complete kits that include gaskets,  oil line hardware, and installation instructions. Avoid no-name eBay knockoffs — the genuine Powermax uses higher-quality bearings and precision-machined wheels. Trusted sources:

Final Thoughts

Upgrading to a Powermax 64mm turbo on your Cummins is one of the most satisfying performance modifications you can make. It delivers a noticeable boost in power, improves drivability, and remains reliable when installed correctly and paired with a proper tune. Follow the installation steps carefully, use new gaskets, and don’t skip the oil priming process. Whether you use your truck for towing, daily driving, or weekend pulls, the Powermax 64mm will transform your driving experience without overwhelming your engine or your budget.