Project Evo X GSR- Testing the Greddy RS Catback Exhaust System
By Mike Kojima
In our last edition of Project Evo X GSR, we tested the K&N Typhoon Cold Air Intake with excellent results. Since the next logical choice in the path to modding our car is to free up the exhaust, we went to our friends at Greddy to get one of their RS exhaust systems to evaluate. The Greddy RS is a new line of exhausts that are constructed much like their race only systems. The main differences in the RS exhausts are that they allow the use of the stock catalytic converter and do not feature exotic titanium in their construction.
|Chris Marion removes the stock Evo X exhaust main muffler. We were able to switch the exhaust in a few minutes at home.|
The Evo X has a pretty decent stock exhaust. With twin outlets and a straight design with minimal bends, the stock exhaust is pretty free flowing. However, it is very heavy. The stock muffler is huge and constructed of very thick gauge metal. We were curious if the Greddy exhaust could out power it without a downpipe and a less restrictive turbo outlet.
|Chris removes the cat to muffler pipe.|
One thing for sure was that the Greddy exhaust was much lighter, we estimate that the Greddy system saved about 30 lbs over stock. The Greddy RS exhaust is made of fairly thin wall 304 stainless steel, a high quality rust resistant grade of stainless. The tubing diameter is a generous 80mm which should be enough to support some pretty aggressive horsepower goals.
The Greddy RS exhaust is an aggressive exhaust much like the race only Greddy titanium exhaust system. It is designed to be lightweight with a minimum of power robbing bends. Unlike the race system, the RS can be used with the stock cat.
The RS has two mufflers. The main muffler has an oval polished 304 stainless case and a perforated core inner main tube with a 130mm diameter tip. Perforated cores provide the lowest possible backpressure as the perforations contribute minimally to turbulence. The core tube is wrapped with a stainless steel wool which provides mechanical strength against exhaust pulses and acts like a buffer to prevent the exhaust from blowing the packing out like common fiberglass packing will.
|The stock dual outlet muffler is pretty low backpressure but is heavy, really heavy. The RS exhaust saves a lot of weight at the rear of the car. In this picture you can compare the stock muffler vs the RS muffler.|