If you're serious about waking up your VQ, picking up a set of g37 isr long tube headers is hands down one of the most effective ways to do it. Let's be honest, the G37 is a fantastic car out of the box, but the stock exhaust manifolds are arguably the biggest bottleneck in the entire system. They are heavy, cramped, and designed more for heat retention and emissions than they are for actual airflow. When you swap those stock units out for long tubes, you're basically letting the engine finally breathe the way it was supposed to from the factory.
Why Long Tubes Over Shorties?
A lot of people ask if they should just go with shorty headers and pair them with test pipes. While that's an option, it's rarely the best option if your goal is maximum power. The beauty of the g37 isr long tube headers is that they replace both the manifold and the catalytic converter in one continuous piece of piping.
Because the piping is longer and the bends are more gradual, you get what's called the scavenging effect. This is where the exhaust pulses actually help pull the next pulse out of the cylinder. With shorty headers, you still have that awkward flange where the header meets the test pipe, which creates turbulence. Long tubes eliminate that turbulence entirely. You get a smoother, faster exit for exhaust gases, which translates directly to more horsepower and a much broader torque curve.
The Sound Profile
Let's talk about the elephant in the room: the sound. The VQ37VHR engine has a very distinct "trumpet" sound that people either love or hate. When you install these headers, that sound is going to get a lot more aggressive.
What's cool about the ISR design is that it tends to produce a deeper, more refined tone compared to some of the cheaper, thin-walled alternatives. Because they are made from high-quality stainless steel, you don't get as much of that "tinny" or "raspy" vibration. However, don't get it twisted—it's going to be loud. If you have a straight-through cat-back exhaust with no resonators, installing these will probably make your car loud enough to wake the neighbors three blocks over.
Most guys find that pairing these headers with a resonated cat-back is the "sweet spot." It keeps the volume manageable while still giving you that exotic, high-pitched scream when you're pushing past 5,000 RPM.
Build Quality and Materials
ISR has really carved out a niche for themselves by offering parts that feel a lot more expensive than they actually are. Their g37 isr long tube headers are constructed from 304 stainless steel, which is pretty much the gold standard for exhaust components. It's resistant to rust and can handle the immense heat cycles that come with spirited driving.
The flanges are thick and heavy-duty, which is important because thin flanges tend to warp over time, leading to exhaust leaks. There's nothing worse than finishing a ten-hour install only to realize you have a tiny tick-tick-tick sound because the flange isn't sealing properly. With the ISRs, the welds are usually very clean and the fitment is surprisingly spot-on for a mass-produced part.
The Install Process (The Reality Check)
I'm not going to sugarcoat it: installing headers on a G37 is a total pain in the neck. The VQ engine bay is incredibly tight. If you're doing this on jack stands in your driveway, give yourself a full weekend and maybe buy a 12-pack for the friend who's helping you.
The Infamous Demon Bolts
Every G37 owner who has touched their exhaust knows about the "demon bolts." These are the bolts connecting the stock manifolds to the cats, and they are notorious for being seized, rusted, and positioned in the most unreachable spots imaginable. Since the g37 isr long tube headers replace the whole unit, you'll be dealing with these directly.
Clearance and Steering Rack
One of the trickier parts of the install is working around the steering shaft. Since the long tubes take up significantly more space than the stock manifolds, you have to be very precise with how you wiggle them into place. Sometimes you even have to slightly loosen the motor mounts and tilt the engine a fraction of an inch just to get the clearance you need. It's a tedious process, but once they're bolted up, the reward is worth the struggle.
Do You Need a Tune?
The short answer is: Yes.
When you install g37 isr long tube headers, you are drastically changing the air-fuel ratio of the engine. Because the exhaust is leaving the cylinders so much faster, the car's ECU won't quite know how to handle the new flow characteristics.
Without a tune (like Ecutek or UpRev), you'll almost certainly get a Check Engine Light (CEL) because you've removed the primary catalytic converters. More importantly, you won't actually see the full power gains without a tune. A good tuner can adjust the timing and fueling to take advantage of that extra airflow. Most people see gains in the neighborhood of 15 to 25 wheel horsepower when combining these headers with a solid intake and a professional tune.
Driving Impressions
Once everything is buttoned up and tuned, the car feels completely different. The first thing you'll notice is the throttle response. It feels much "snappier." The G37 can sometimes feel a bit heavy and sluggish in the lower RPM range, but the long tubes help eliminate that "soggy" feeling.
As you climb through the gears, the power delivery feels much more linear. Instead of the power tapering off as you approach the redline, it feels like the car just keeps pulling harder and harder. And the sound—man, the sound is addictive. There's something about the way a VQ sounds with long tubes at full tilt that just makes you want to drive through every tunnel you can find.
Maintenance and Longevity
Since these are stainless steel, they should last the life of the car. However, it's always a good idea to re-torque the header bolts after a few hundred miles of driving. The heat cycles can cause things to expand and contract, which might loosen a bolt or two.
Also, keep in mind that since these are "off-road use only" (because they delete the cats), you'll need to figure out your local emissions situation. Some people use O2 spacers to try and trick the sensors, but your mileage may vary depending on how strict your local testing is.
Final Thoughts on the Upgrade
If you're at the point where you've already got a cat-back exhaust and an intake, but you're still craving more power, the g37 isr long tube headers are the logical next step. They aren't the easiest thing to install, and they definitely aren't quiet, but the performance per dollar is hard to beat.
You're getting a high-quality, stainless steel part that solves the biggest flow restriction in the VQ37 platform. It changes the personality of the car, making it feel more like a raw sports car and less like a heavy luxury coupe. Just be prepared for the install, make sure you have a tuner lined up, and get ready to hear your G37 like you've never heard it before. It's a transformation that most owners wish they had done a lot sooner.