If you're thinking about swapping your g35 coupe headers, you probably already know that the stock setup is one of the biggest bottlenecks in the entire VQ35DE engine. Nissan built a fantastic car with the G35, but like most mass-produced vehicles, they had to make some compromises when it came to the exhaust manifold. The factory units are basically heavy, cast-iron "log" style manifolds designed more for quiet operation and cheap manufacturing than actual performance. If you want to let that V6 breathe and finally get that iconic growl to sound crisp rather than muffled, headers are the way to go.
It isn't just about the sound, though. Replacing those restrictive factory pieces allows the exhaust gases to exit the cylinder heads much more efficiently. In the world of naturally aspirated tuning, it's all about airflow. The faster you can get the old air out, the faster you can get fresh air in. But before you go out and buy the first set you see on a forum or a budget site, there are a few things you really need to wrap your head around, because a header install on a G35 is not exactly a "Sunday afternoon with a beer" kind of job.
The Big Debate: Long Tube vs. Shorty Headers
When you start shopping for g35 coupe headers, you're going to run into two main categories: long tubes and shorties. This is where most people get stuck, and the right choice really depends on what you plan to do with the car and how much you hate dealing with emissions testing.
Shorty Headers
Shorty headers are designed to be a direct replacement for the factory manifolds. They bolt right up to the engine and then connect to your existing catalytic converters (or test pipes/high-flow cats). The main advantage here is versatility. If you live in an area with strict smog laws, you can run shorty headers with your stock cats and usually stay under the radar.
From a performance standpoint, shorties provide a decent bump in the mid-range. They aren't going to give you massive peak horsepower gains, but they definitely help the engine feel "peppier" when you're merging onto the highway. They're also slightly—and I mean slightly—easier to install than long tubes because they take up less physical space in an already cramped engine bay.
Long Tube Headers
Now, if you're looking for maximum power, long tubes are the king. These delete the catalytic converters entirely, combining the header and the downpipe into one long, flowing piece of stainless steel. By removing the restriction of the cats and providing long, tuned primary tubes, you get much better scavenging. This means the exhaust pulses actually help pull more air out of the engine.
The downside? They are loud. Like, wake-your-neighbors-three-blocks-away loud. They also usually require a tune to get rid of the Check Engine Light (CEL) since you're removing the primary cats. But if you're building a track car or a serious street machine, the power gains from long tubes are hard to beat.
The Installation Reality Check
I'm going to be completely honest with you: installing g35 coupe headers is a genuine pain in the neck. If you've never worked on a VQ engine before, you should know that there is almost zero room to move between the engine block and the steering rack/frame rails.
Most people recommend pulling the engine or at least dropping the subframe a bit to get enough clearance. You'll be dealing with rusted studs, incredibly tight angles, and at least one or two "how does a human hand even fit in there?" moments. If you're doing this on jack stands in your driveway, give yourself a full weekend. And please, for the love of everything holy, buy a set of high-quality swivel sockets and some extra-long extensions before you start. You're going to need them.
One common horror story with the G35 is snapping a manifold stud. Since these cars are getting older, those heat-cycled studs get brittle. If you snap one off in the head, your "fun" weekend project just turned into a nightmare. Soak everything in PB Blaster or some kind of penetrating oil for at least two days before you even think about putting a wrench on those bolts.
Why Material Choice Actually Matters
You'll see a lot of cheap g35 coupe headers online made from mystery metals. It's tempting to save a few hundred bucks, but this is one area where you get what you pay for. Cheap headers are prone to cracking at the welds because of the intense heat and vibrations of the VQ engine.
Look for headers made from T304 stainless steel. It's much more resistant to corrosion and can handle the heat cycles without becoming brittle. Also, pay attention to the thickness of the flanges. Thinner flanges tend to warp, which leads to exhaust leaks. An exhaust leak right at the cylinder head sounds terrible—kind of like a rhythmic ticking—and it can actually mess with your air-fuel ratios because the O2 sensors get confused by the extra air sucking in.
If you have the budget, getting your headers ceramic coated is a pro move. It keeps the heat inside the tubes and out of the engine bay. This helps keep your intake temps down and protects your wiring harnesses from getting baked over time.
Sound Profile and the "VQ Rasp"
We can't talk about g35 coupe headers without talking about the sound. The G35 has one of the most distinct exhaust notes in the car world. Some people love it, some people think it sounds like a trumpet. When you change the headers, you're going to change that tone significantly.
Long tube headers tend to make the car sound much more aggressive and "raw." However, they can also introduce a lot of rasp—that metallic, tinny sound that happens around 3,000 to 4,000 RPM. If you want to keep it sounding deep and smooth, you'll want to pair your headers with a high-quality resonated Y-pipe and a decent cat-back exhaust. If you just go straight pipes from the headers back, it's going to sound like a swarm of very angry bees, and not in a good way.
Don't Forget the Tune
Here's the deal: if you go through the trouble of installing g35 coupe headers, especially long tubes, you need a tune. The factory ECU is programmed to work within the narrow parameters of those restrictive stock manifolds. Once you open up the airflow, the engine might run lean, or you might find that you're not actually making any more power because the computer is trying to compensate for the change in backpressure.
Getting a custom tune using something like UpRev or EcuTek will allow you to actually take advantage of the hardware. A tuner can adjust the timing and fuel maps to match the new airflow, which usually results in a much smoother power band and better throttle response. Plus, they can turn off those annoying rear O2 sensor codes if you went the long tube route.
Is It Worth It?
At the end of the day, upgrading your g35 coupe headers is one of those "milestone" mods. It's a lot of work (or a decent chunk of change in shop labor), but the transformation is real. The car feels more alive, the throttle response is crisper, and the sound is finally worthy of a sports coupe.
Just make sure you go into it with a plan. Decide whether you can live with the volume of long tubes or if you need the compliance of shorties. Buy the best gaskets you can find—usually, the multi-layer steel (MLS) ones are the way to go—to avoid having to do the job twice. It's a tough install, but once you're out on a backroad and you hear that VQ singing through a set of high-flow headers, you'll forget all about the bruised knuckles and the hours spent under the car.