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If you are diving into the world of Nissan and Infiniti performance, you are eventually going to face the ultimate crossroads: VQ35 or VQ37? Whether you’re staring at a 350Z, a G35, or the later 370Z and G37 models, the engine under the hood defines your entire build path.
At DTX Performance, we don't care about "good enough." We care about what wins on the street and the track. Both the VQ35 (specifically the HR variant) and the VQ37VHR are engineering marvels, but they handle power very differently. If you want to build a high-horsepower monster, you need to know which block will hold together and which heads will breathe deep enough to support your goals.
Let’s break down the technical differences between these two legendary V6 platforms.
CHOOSE YOUR WEAPON: VQ35DE VS. HR VS. VHR
Before we compare the 3.5L to the 3.7L, we have to clear the air. Not all 3.5L engines are created equal.
- VQ35DE: Found in the early 350Z (2003-2006) and G35. It’s a single-throttle body design. While it’s the most affordable to buy, it has the weakest internal architecture for high-boost applications.
- VQ35HR: The "High Response" version found in the 2007-2008 350Z and G35 Sedan. This was a total redesign, featuring dual intakes and a significantly stronger block.
- VQ37VHR: The 3.7L beast found in the 370Z and G37. It takes the HR’s dual-intake design and adds more displacement and Variable Valve Event and Lift (VVEL) technology.
If you are serious about high horsepower, the DE is usually the "budget" choice, while the HR and VHR are the heavy hitters.
REINFORCE THE FOUNDATION: BLOCK STRENGTH
When you start pushing 500, 600, or 700+ horsepower, the first thing that fails isn't the tune: it’s the physical metal of the engine.
The VQ35HR and VQ37VHR share a major structural advantage over the older DE: the bedplate design. Unlike the DE, which uses traditional main caps, the HR and VHR utilize a massive, one-piece aluminum bedplate to secure the crankshaft. This provides incredible rigidity to the bottom end, preventing the "main cap walk" that kills high-boost engines.
Furthermore, the VQ37VHR features a taller deck height (by about 8mm) compared to the 3.5L. This was done to accommodate the longer stroke of the 3.7L engine, but it also allows for a better rod-to-stroke ratio in certain build configurations.
The Verdict on Strength: The VQ37VHR is the strongest factory block Nissan ever put in the Z/G chassis. If you’re looking to push 550whp on stock internals, the VHR is your best bet.
MAXIMIZE THE FLOW: HEAD DESIGN AND VVEL
Airflow equals horsepower. It’s that simple. If your heads can’t breathe, your turbocharger is just heating up air for no reason.
The VQ35HR heads were already a massive upgrade over the DE, featuring larger valves and improved port shapes. However, the VQ37VHR took it a step further with VVEL.
VVEL is Nissan’s answer to BMW’s Valvetronic. Instead of relying solely on a traditional throttle body to regulate air, the engine can vary the duration and lift of the intake valves on the fly. This allows the VQ37 to have an extremely broad powerband. In a naturally aspirated (NA) build, the VQ37VHR is the undisputed king. The head flow on a stock VHR is better than almost any ported DE head on the market.
However, VVEL adds complexity. When you’re building a dedicated race car with massive cams, some tuners prefer the simpler valvetrain of the VQ35HR. But for 95% of builds, the VQ37's superior flow is the way to go.
THE BOOST FACTOR: COMPRESSION RATIOS
This is where the debate gets heated. Power is easy when you have a low compression ratio because you have a larger "window" for error in your tuning.
- VQ35DE: 10.3:1 Compression
- VQ35HR: 10.6:1 Compression
- VQ37VHR: 11.0:1 Compression
High compression (11.0:1) is fantastic for throttle response and NA power. But when you add a large turbocharger, that high compression makes the engine very sensitive to fuel quality. If you are stuck on 91 or 93 octane pump gas, the VQ37VHR is much harder to boost safely than an older VQ35.
The Pro Tip: If you are building a VQ37 for high boost, you must use E85 or water-meth injection. The cooling properties of ethanol allow you to take advantage of that 11.0:1 compression to make massive power without knocking. If you can’t get E85, the VQ35HR or a built-bottom-end VQ35DE might actually be "safer" for a daily driver boost setup.
BOLT-ON POTENTIAL: REAL WORLD GAINS
If you aren't ready to tear the engine apart, bolt-ons are your bread and butter.
Because the VQ37VHR has dual throttle bodies and superior head flow, it reacts to simple mods much better than the 3.5L engines. A set of high-quality long tube headers and a 3-inch exhaust system can unlock significant power on a G37 that a G35 simply won't see.
At DTX Performance, we always recommend starting with the "Big Three":
- Cold Air Intakes: The VQ37 needs air. Get a long-tube 3-inch intake setup.
- Exhaust: You need a true dual exhaust to let that V6 scream.
- Test Pipes/Headers: The factory catalytic converters are the biggest bottleneck on the VQ platform.
THE COST OF POWER: BUDGET VS. PERFORMANCE
Let’s talk numbers. The VQ35DE is dirt cheap. You can find these engines in every junkyard in America. If you blow one up, you swap it for $800 and keep moving.
The VQ37VHR is more expensive. The parts are more expensive. Because it has two of everything (two intakes, two throttle bodies, two VVEL actuators), your "buy-in" cost for modifications is roughly 1.5x higher than a single-intake VQ35DE build.
However, you get what you pay for. The VQ37VHR offers:
- A higher redline (7,500 RPM stock).
- Better oiling (though 2008-2011 models need the gallery paper gaskets replaced: oops, we don't sell gaskets, so we recommend upgrading to metal ones from a specialist).
- Much higher NA ceiling (330-350whp with basic bolt-ons and a tune).
RELIABILITY AT THE LIMIT
Pushing a VQ to high horsepower requires more than just a turbo. You need to address the cooling. Both engines are known to run hot, especially the VQ37. If you are tracking your car, an oil cooler is not optional: it is a requirement.
The VQ35HR and VQ37VHR fixed the "oil consumption" issues that plagued the early 350Z engines, but they replaced them with "oil temperature" issues. Keep your temps in check, and these blocks will live at 500whp for years.
THE FINAL VERDICT: WHICH ONE SHOULD YOU BUILD?
So, which platform is actually better for a high-horsepower build?
THE VQ35 IS FOR YOU IF:
- You are on a strict budget.
- You want a "disposable" drift missile that is cheap to repair.
- You are doing a budget turbo build on pump gas and want lower compression.
THE VQ37 IS FOR YOU IF:
- You want the highest ceiling for power (NA or Boosted).
- You have access to E85.
- You want the most modern, technologically advanced V6 Nissan produced before the VR30DDTT.
- You value a high redline and a broad powerband.
At the end of the day, the VQ37VHR is the superior engine. It has the better block, the better heads, and the most displacement. It is the pinnacle of the VQ line. While the entry cost is higher, the results speak for themselves when you're looking at the timeslip.
Build for Excellence. Shop with Confidence.
Ready to start your build? Whether you’re looking for the perfect cold air intake or a high-flow exhaust system to make that VQ sing, we’ve got you covered. We promise to only send you the good things: no filler, just performance.
Push your build further. Select your parts at DTX Performance today.
