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| RX-7 2nd Gen Specific (1986-92) RX-7 1986-92 Discussion including performance modifications and technical support sections. | 
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		#1 | 
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			 FC3S 
			
			
			
			Join Date: Jun 2010 
				Location: Townsville, QLD, AUS 
				
				
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				Exhaust question
			 
			
			
			So when I got my FC it came with a full 3" exhaust on it, when I fitted the new turbo I made all my dump and wastegate piping out of stainless, and it goes as far as the stainless cat.  From there back though it's mild steel and I'm looking at remaking the rest of it.  Now tt's not overly loud or anything as it is but what I want to do is put in a Y peice and buy a second muffler because I've always prefered the look of the 2 pipes coming out the back.  Basically is it going to be any louder or quieter?  I'm assuming quieter as it's the same amount of exhaust gas getting split into 2 mufflers instead of going through one.  Am I missing anything here?
		 
		
		
		
		
		
		
		
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		#2 | 
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			 RCC Addict 
			
			
			
			Join Date: Mar 2008 
				Location: Honolulu, Hawaii USA 
				
				
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			You are correct. 
		
		
		
		
		
		
			
		
		
		
		
	In general, more mufflers = more quiet. -Ted  | 
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		#3 | 
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			 Don Mega 
			
			
			
				
			
			Join Date: Dec 2008 
				Location: Utopia 
				
				
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			If you "Y" pipe it at 3" it will get louder not quieter, despite the one extra muffler. 
		
		
		
		
		
		
			This is due to lower pressure in the system, which is a great silencer. To stop it getting to loud you will need to step down the pipe at the "Y" to say twin 2.5" maximum. 
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		#4 | |
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			 rotors excite me 
			
			
			
				
			
			Join Date: Mar 2008 
				Location: Iowa 
				
				
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			^^^  Uhhhh... what?  If reducing exhaust pressure silences then full open with big pipes should be somewhat quiet, and it's not.  You DO want to Y it down to two smaller pipes.  I'd just figure the cross sectional area of the 3" and then split it down to two that add to about the same cross sectional area, but you could also look at system like Racing Beat makes and compare to see what ratio they used.
		 
		
		
		
		
		
		
			
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	He isn't a killer. He just wins -- thoroughly. ![]() ![]() '87 TII 240+ rwhp on my DIY streetport, ~13psi on stock turbo, Racing Beat REVTII exhaust ![]() rTek 2.1 awaits a tune Quote: 
	
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