SxExCx Custom Intake Mod

_DSC1944I’m going to start off with the bold statement that virtually every intake system for the G35 generally has at least one major design fault. If the intake is too low, you pick up excessive heat from the road, if it’s too high you get heat from the engine, metal intake tubes transfer too much heat into the air, and other systems are too restrictive. Is it even possible to design a really good intake system for the G35? Well, I believe I have found one that solves as many of these problems as possible.

The Design

There are a few design aspects that we want to consider and try to address with this design:

  • Start with the coolest air possible
  • Avoid adding heat from the engine
  • Remove all choke points and air restrictions
  • Keep the design as simple as possible
  • If we can save weight, that’s a bonus

If we look at the design of the G35, the best possible place to pull air from would be directly behind the grill. This location is isolate away from the engine so no heat from the engine gets there and is high enough off the ground to prevent water and debris from the ground, and avoid the hottest air right at the pavement level. The trick is, how to route incoming air from the grill to engine. The air box from the G35 has a hole on the wide where the “power funnel” attaches. There is really no way to route air from there that will work. A perfect replacement for the air box is the air box from an early model 350Z. It will bolt right in and has a front facing opening. To this, we will need to add another opening about 3″ around (more on this later). First, we need to remove the air box, and a┬áseverely┬ástupid extra catch basin beneath it that seems to serve no purpose (mine was full of dead bees).

Next, its time to drill a hole.


Sean currently does not offer this as a kit because it require more than simply bolting something on. Since you are drilling into a major panel, you do risk screwing something up if you don’t do this right. We started with a small pilot hole before moving to the big guns.


With the hole finished. We now run some ducting from the Z-Box out through the hole and into a funnel attached to the top of the bumper.


Once everything is in place and the grill is reinstalled, this becomes a pretty stealth modification.


The Results

This mod checks every one of our boxes from our wish list. The Z-Box protects the air from the engine heat, we start with the coolest air possible, we improve airflow, and we even saved some weight. Another plus is that you now don’t have to remove the entire airbox to replace the air filter, it just pulls right out the top.

If the car isn’t moving, this mod isn’t helping any. However, get the car rolling and air is forced into the system. Now because we still have another hole that put in the airbox (needed to ensure low speed performance) the incoming air isn’t acting like a real ram induction system that forces air into the system, but it does create some positive pressure ensuring that the air that the engine needs is always there.

On the road, there is a distinctly new feel to the car. The power seems to come on smoother as well as faster. I am not going to make any claims about increased horsepower because to really test that we would need to put the car on a dyno and simulate the air being pushed into the funnel at highway speeds.

If you are in southern California and would like Sean to do this for you, contact him via SxExCx at

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2 Responses to SxExCx Custom Intake Mod

  1. Nick says:

    So when you install the Z box, you drill a 3″ hole in the z box beside the factory front opening and you connect the duct pipe to the 3″ hole that you drilled in the airbox? If that’s correct what did you do with the factory opening in the box, just leave it open? It sounds like a great setup, I’m actually doing mine the same way so I just wanted to make sure I do it the right/best way

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