| Cat Back Exhaust - Tunerology
The evolution of a muffler system is and always will be an ongoing restructuring process. While manufactures are always figuring out new ways to make more power out of exhaust systems they're also trying to meet the latest trends involved with muffler tips, shapes and most importantly, sound. We've also seen trends in muffler systems that come and go and come back in again. It works like most everything in this world. Personally, I never would have though corduroy pants would be back in style but at one point they were and I'm sure it will probably be trendy somewhere down the road again. For some states muffler systems are about the decibels they produce in conjunction with State law. When it comes down to sound being your primary reason for purchasing an exhaust system GReddy has mastered the art of legal decibel ratings. Some enthusiasts out there enjoy the sound of 100-plus decibel exhaust and for them; manufactures have designed the muffler with a removable baffle. These work great for the guys that enjoy taking their car to the track and want to uncork a few extra ponies by removing the baffle but do not want heat from cops about decibel laws. So let's see our choices when we want to be loud to scare off the guy you are ready to race, First, we can either go with a muffler system that is beyond loud but need a quick foot to step on the clutch and coast when a cop is in sight. Second, go with a silencer system but risk the chance of getting blown away at a stoplight because the silencer installed is robbing a few ponies. Last, but not least, sticking with the system that meets the decibel laws while still making good power. Being a law-abiding citizen, your instincts point you towards the dB route but the animal inside wants the 100-plus decibels to front on racers and wake up your neighbors. As we stated earlier, new trends come and go so get ready for the next latest and greatest from Japan. It turns out Japan also has laws that aren't in a racers favor when it comes to decibels. This is why both HKS and A'PEXi have taken the initiative to design a muffler that can cater to both meeting dB laws and give the driver the ability to increase the dB as well as horsepower without even exiting the vehicle. Both designs are very sophisticated in design but the costs of production on each are very different.
The HKS design is known as the High Power EV System muffler system. According to Ryan Nufable of HKS, "right now the system is designed for Skyline R32, 33 and 34 models and is only available in Japan." This system is extremely high tech when it comes to muffler design. Using an electronic gear-actuated motor, the muffler has the ability to change its exhaust orifice outlet size. Watching it in action, it reminds me of a science fiction spaceship door opening and closing. It work a lot like a removable silencer but able to be controlled from the drivers seat. The driver has the ability to control the decibels by either RPM, throttle position or in auto mode. Since there is electronics involved, expect the muffler system to be expensive, but worth it. Since it is able to be controlled from the cockpit this give the driver the ability to activate the silencer at anytime unlike how the A'PEXi unit works.
The A'PEXi muffler system is the more cost effective of the two since it doesn't use any electronic components to actuate its valve system. However, the sacrifice is a minimal power loss in the top end. Regardless, the muffler is much cheaper and dB level is less then stock at idle. The valve is actuated by an increase in exhaust pressure. At wide-open throttle, the valve is opened to evacuate exhaust gas while still maintaining some decibel control. When the throttle is released, the valve shuts the muffler's larger exit to route gas out to an alternative smaller exit. The valve is spring-loaded and acts on high exhaust pressure to open. The key reason A'PEXi incorporated the valve system was to lower the cost of the muffler to the retail. You have to admit when electronics become involved. cost goes up.
Both these mufflers are the lastest in high-tech mufflers but both originate from the good old exhaust cut out. Remember these? By the quick pull of a cable the exhaust was routed out before it got to the muffler. Evolution of routing exhaust gas has worked its way back around but in muffled form, After all this is said and done, the big question is will HKS and APEXi release this muffler stateside. I'm pretty sure they understand that Japan's new 103 dB law is much higher then the U.S. which makes these mufflers perfect candidate for U.S. laws.