Exhaust... 2.5 or 3"

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Old Jul 24, 2009 | 02:21 PM
  #1  
bezerker's Avatar
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Default Exhaust... 2.5 or 3"

Well, I'm going to have to redo my exhaust as the current persons job was.... terrible. Tons of holes in the pipes etc.

He threw on a 3" pipe and a flowmaster (Thinking its a 30... cant really tell) with a single 3" outlet. Then he painted the muffler blue to match the car. Needless to say it looks terrible.

Anyways I want to redo it but I am torn between going back to 2.5" inlet and dual 2.5" outlet, or should i stay 3" inlet? Im still debating between dual 2.5 or single 3" out. I want volume more than performance right now. Don't get me wrong, it performs well now, but it's stock 305 TPI (89 iroc). I WILL eventually drop a 350 in it, but not any time soon.

I guess my biggest question is... is 3" hurting me ? Or should I just stick with it.
 
Old Jul 24, 2009 | 03:37 PM
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what size is the pipe from the exhaust manifold? from the y to the cat? from the cat to the muffler. u want the same size from the y pipe to the muffler and larger than the y pipe. if its 3 then stay with 3.
 
Old Jul 24, 2009 | 08:55 PM
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the stock 305 responds well to a 3 inch exhaust upgrade. it responds more if there are other upgrade done like headers or intake. if its all stock, you can see about 15 more hp, which will come down to about 10 more at the wheels. you will feel the difference. and since you plan on going with a 350 later, then thats another reason to go with a full 3" now
 
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