Best Turbo Size for Duramax: 64mm vs 66mm vs 68mm

What Turbo Size is Best for My Duramax? (64mm vs 66mm vs 68mm) Upgrading the turbocharger is one of the most impactful modifications you can make to your Duramax diesel. Whether you’re chasing more horsepower, lower EGTs, or improved towing performance, choosing the right turbo size can make or break your build. But with popular options like 64mm, 66mm, and 68mm turbos, which one is the best fit for your truck? In this guide, we’ll break down the pros and cons of each size so you can pick the right turbo for your Duramax performance goals. Why Turbo Size Matters on a Duramax The size of your turbo’s compressor wheel directly impacts airflow, spool time, and power potential. Smaller turbos spool quicker (great for towing and daily driving), while larger turbos flow more air (better for high-RPM horsepower). The goal is finding the right balance between response and top-end power. 64mm Turbo: The Perfect All-Around Upgrade A 64mm turbo is often the sweet spot for Duramax owners who want better performance without sacrificing drivability. Best For: Daily driving, towing, light performance builds (500–650 HP range). Pros: Fast spool-up, minimal lag Excellent towing characteristics Keeps exhaust gas temperatures (EGTs) under control Reliable power gains without heavy supporting mods Cons: Limited for high-horsepower builds (tops out in the mid-600s HP) ???? Looking for the perfect towing and daily driver upgrade? Check out our 64mm Duramax turbo options here. 66mm Turbo: A Step Toward Serious Power The 66mm turbo sits right in the middle—ideal for truck owners who want more top-end power without going to extremes. Best For: Street performance builds, weekend warriors, trucks shooting for 650–750 HP. Pros: Strong balance between spool and airflow Capable of big mid-range and top-end power Handles larger injectors and CP3 upgrades well Cons: Noticeably more lag than a 64mm when towing heavy Supporting mods are required to make full use the turbocharger ???? Ready to push your Duramax into the 700+ HP range? Shop our 66mm turbo upgrades here. 68mm Turbo: For High-Horsepower Builds If your goal is maximum power, the 68mm turbo is the ticket. These units are built to move serious air and are a popular choice for competition setups. Best For: Race trucks, sled pullers, and big builds (700–850+ HP). Pros: Massive airflow for high-horsepower applications Lower EGTs at wide open throttle Perfect for drag racing or sled pulling Cons: Slower spool time = not ideal for towing or daily driving Requires strong supporting mods (injectors, dual fuelers, built trans) ???? Building a competition-ready Duramax? Browse our 68mm high-performance turbochargers. Which Turbo Should You Choose? 64mm: Best for towing, daily driving, and mild builds. 66mm: Best for street performance with serious top-end pull. 68mm: Best for race/competition trucks pushing big horsepower. At the end of the day, the best turbo for your Duramax depends on how you use your truck. Daily driver? Stick with a 64mm. Weekend performance? Go 66mm. Competition build? Step up to a 68mm. Final Thoughts A turbo upgrade can completely transform your Duramax—but choosing the right size is critical. If you’re unsure, give us a call or message us at Dan’s Diesel Performance. Our team has built and tuned hundreds of Duramax trucks, and we’ll help you choose the perfect turbo for your setup. ???? Ready to upgrade? Contact us today or shop our full line of Duramax turbo upgrades and take your truck to the next level.