6.6 Duramax vs 6.7 Cummins: Which One Should I Choose?

General Automotive Discussion
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Introduction

Comparing the 6.6L Duramax and 6.7L Cummins diesel engines has become a popular discussion among diesel enthusiasts and potential truck buyers. Both engines are well-respected in the heavy-duty truck community, but each offers unique advantages and potential drawbacks. This post aims to dive into the key specifications, performance metrics, and owner experiences to help you decide which engine best suits your needs.

Performance Comparison

Power and Torque

  • 6.6L Duramax: Known for its smooth power delivery and high torque, especially in the Duramax LML variant, which peaks at around 765 lb-ft of torque.
  • 6.7L Cummins: Famous for its raw power, particularly in towing situations, often peaking at around 850 lb-ft of torque in newer models.

Fuel Efficiency

  • Many owners report better fuel efficiency in the Duramax, especially when towing lighter loads.
  • The Cummins might not be as fuel-efficient but offers significant torque for heavy towing, which often balances out when loaded.

Specifications Breakdown

Feature 6.6L Duramax 6.7L Cummins
Horsepower Up to 445 HP Up to 420 HP
Torque 765 lb-ft 850 lb-ft
Diesel Type Ultra-low sulfur Ultra-low sulfur
Transmission 6-speed automatic 6-speed automatic

Owner Experiences

Duramax Owners

  • Many users appreciate the quieter operation and smoother driving experience of the Duramax.
  • A common sentiment is that the maintenance costs are somewhat lower, and parts are readily available.

Cummins Owners

  • Cummins enthusiasts often highlight the engine’s durability and the ease of working on the engine due to its design.
  • There’s a strong community around the Cummins engine, with plenty of aftermarket support for modifications.

Recommendations for Buyers

  • If you prioritize a smooth ride and slightly better fuel economy, the Duramax might be the way to go.
  • On the other hand, if towing heavy loads is your main priority, you may find the Cummins provides the edge.

Conclusion

Ultimately, the choice between the 6.6L Duramax and 6.7L Cummins will depend on your specific needs and what you value most in a diesel engine. Both have loyal followings and unique characteristics that make them great choices in their own right. Let’s hear your thoughts or experiences with either engine. What do you think?

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I’ve been driving the 6.6 Duramax for a few years now, and I can say it has great torque, especially for towing. The fuel efficiency is decent too!

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I’ve heard the 6.7 Cummins has a bit of an edge when it comes to horsepower. Can anyone confirm its towing capacity?

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In my experience, the 6.7 Cummins excels in torque numbers, especially under heavy loads. It makes a noticeable difference on steep hills.

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Exactly! I’ve had both engines, and while the Cummins pulls harder, Duramax feels more refined on the highway.

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Fuel efficiency? I’ve heard the Duramax models tend to last longer in terms of mileage. Anyone else found that to be true?

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I think fuel efficiency also depends on driving style. My 6.7 Cummins is surprisingly efficient on the highway.

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I love the sound of a 6.7 Cummins! It’s like music to my ears, especially when towing something heavy.

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Haha, I get that! But sometimes the Duramax has a smoother sound that’s also nice. Depends on personal preference!

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No doubt both engines have their merits. But if I had to choose, I’d go with the 6.6 Duramax for its longevity and ease of maintenance.

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It’s interesting how preferences vary. Some swear by Cummins, while others are die-hard Duramax fans. What do you think the main deciding factors are?

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For me, it’s all about reliability and performance under load. Definitely a tough choice overall.

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Honestly, I have friends who can’t stop arguing about this. There’s definitely a rivalry between the two brands!

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Right? I’ve seen it get pretty heated! But at the end of the day, both engines are fantastic choices.

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Always a good debate! My 6.7 Cummins has been great for towing and hauling, but Duramax fans make a solid case for their engine.

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I don’t know how to choose! They’re both so good in different ways. I just hope I can make the right decision!

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You’ll be fine! Just consider your specific needs, and you can’t go wrong!

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As long as you go for a diesel, you will enjoy! Just don’t overthink it too much. Life’s too short for that!

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I’ve had a 6.6 Duramax for over a decade now, and the longevity has been impressive. Regular maintenance is key, though. I change the oil every 5,000 miles and check the fuel filters more often than recommended.

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That’s great to hear, James! I’ve been thinking about getting a Duramax too. How about the common issues you’ve faced?

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