NSX owners all have one thing in common: they’re either closet or outright elitists. That’s why the fastest way to get NSX groupies in an uproar is to tell them the holy C30A or C32B engine that resides inside the NSX is nothing more than an overgrown version of the B-Series found in a lowly Integra or Civic. They’ll conveniently ignore the fact that single-cam versions of the C-Series engine all ended up in Acura Legend Sedans. But NSX elitists will have none of this and will forum-jump you with the help of thousands of their elitist friends until you are posted into submission.
Once you get over the usual NSX owner’s mentality, tuning the C-Series engine revolves around much of the same concepts and technologies as tuning a B-Series engine, it’s just a lot more expensive. This boils down to four basic categories in the order of how much power you’ll make and how far you want to go into debt: NA bolt ons, bolt-on supercharging, all-motor power and displacement, and turbos on rebuilt bottom ends. Only two of these solutions will not blow up the very expensive NSX transmission in the long run. Guess which one we went with.
The Fujitsubo Ti exhaust weighs...
The Fujitsubo Ti exhaust weighs in at only 19.8 lbs for such a large muffler. Using such a larger muffler helps keep this NSX very discrete in sound as we putt around, but it still sounds beautiful when fully opened up. Upstream we also replaced the two heavy stock catalytic converters with lightweight, high-flow Random Technology units that further reduce weight as well as increase exhaust flow since the A/F ratio has now leaned out with just the cats.
Even though we’re perusing a pretty mundane power solution using mostly bolt-on parts, it doesn’t mean it’s all yawns. In fact, being smart about the type of bolt-ons and how they’re used to get a slight winning edge is exactly what spec racers spend a great deal of time on. Being realistic with what you want to achieve also helps. Like most Honda engines, the C30A was designed to be a high-rpm and high-horsepower engine most at home on the track. Unfortunately, 90 percent of NSXs will never see the track or be driven with the talent that it was intended for. So instead of tuning our car for big top-end power numbers that we will never see on the street, we’re going to fatten up the torque available at lower rpm and maybe see some mild horsepower gains past 6000 rpm, where VTEC kicks in. Remember, the goal of tuning a car is to make it faster, and not necessarily more powerful.
On the intake side, we started with a simple K&N Engineering 57 Series Fuel Injection Performance Kit (FIPK). The kit is designed to eliminate the stock airbox and panel filter assembly and replace it with an open element air filter to diminish high-rpm flow restrictions that come from the airbox. It’s basically a large cone filter fitted onto a venturi-shaped adaptor that hose-clamps onto your stock intake tubing. It might seem like a very simple solution, but according to K&N, it’s proven to make power.
We made our own little improvements by welding the intake kit onto a section of 3-inch mandrel-bent aluminum tubing, which replaces the stock baffled intake flex tube. The idea here is to eliminate the corrugated baffles or sudden changes in pipe diameter that can cause turbulence inside the tubing, which restricts flow. To ensure that the intake gets fresh cold air from outside of the engine bay, we left the stock intake air plumbing and lower intake box in place.
Since our NSX already came with a DC Sports header installed, much of the power gains were already made. As was, the car made 249 whp on the dyno, and because one of the simplest power gains is through a tubular header, we didn’t expect to see huge subsequent gains. Instead, we’d try to gain speed through lighter parts.