If there is one car that has been denied a lot of aftermarket it would definitely be the 2002 Nissan Sentra Spec V. Since its debut, there has only been a handful of companies making parts for the 2.5-liter beast. Of course the Nissan gurus like Nizmo, Jim Wolf and Stillen offer plenty of modifications for the car but there are currently only a few header systems out there that give real power. It's not until recently that more products for the Spec V have been popping up in the scene. I spoke to Ben Ma from AEBS a while back and he informed me that they have a header that will post some big horsepower numbers. My first thought was to bet him money but then, after remembering some of the products they have made in the past, I though better of it. Based on teh quality products of the past, I knew I might as well pay him the money right now. A year in the making, the AEBS Spec V header is now in production and on the shelves. Before you go out and give them your money, first listen to what you get...then give them your money. To start with, the header is a bolt-on unit that doesn't require any cutting or welding. To create the most power they relocated the catalytic converter. This allowed AEBS to make the header much more flow efficient by extending the primaries. The tri-y design uses a unique cylinder-merge technique not normally used for the conventional type. In a normal 4-2-1 header design the two top dead-center cylinders are merged in order to keep exhaust pulses in sync from one cylinder to the next without disrupting cylinder intervals. On a typical inline four cylinder which has a firing order of one, three, four and two, the one and four cylinders are merged together while the two and three are paired up.
Always being on the cutting edge of performance, AEBS went against the grain and tried merging opposing cylinders in search for more power. In turn what this created was a zipper theory, which merges the two cylinders that open their exhaust valves one right after the other, in hope of lining the two pulses in sequence at the collector. This pulses the two exhaust sequences from the each cylinder to make the two in the end. Their tri-y header merges the number one and two cylinders while the three and four cylinders are together. What they found was remarkable: It produces is a higher top-end horsepower for big displacement four cylinders. In the QR25DE engine that boasts 2.5 liters and 175 lb-ft of torque is necessary to have plenty of top end but also ample amount of bottom to midrange. Then again if you own a SPEC V, then you know bottom end horsepower and torque already exist.
The header is constructed of mild steel but helping out in the heat dissipation area is a thermal ceramic coating. Thermal coating not only drops engine bay exhaust temperature, it's also another reason that the AEBS unit makes so much power. Primary tubes come sized as 1.625 in and all flanges are 3/8-in thick to prevent unwanted warping. Since the header replaces the factory cat with a high-flow unit, it was necessary to make the header two piece. Another plus for the AEBS header is the check-engine light never threw an O2-sensor trouble code.
On the dyno the Nissan put out a total of 146.8 horsepower equipped with a Place Racing air intake and Stromung cat back exhaust system. With the header bolted in the car, it produced 162.9 horsepower, with power made throughout the power band and the highest gains in the high rpm area. Torque also went from 160.3 to 167.1 lb-ft. There was a 12.7 degrees temperature difference and the horsepower is SAE corrected, but you can tell there is an obvious difference in power. The car still produced 16.1 horsepower over baseline at peak as well as 15.8 lb-ft of torque at 5900 rpm.
Only those that own the QR25DE engine know of the hidden potential in the car and it's only a matter of time before more people realize this engine will be a competitive race engine. Everything from the cylinder head design to the blocks strength is superior to most engines in its class. As more parts become available for the Spec V, you can bet that we'll be there to show the true potential for the car and its powerplant.