General exhaust discussion & questions
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By 92dxeg
#339282 ok so i have a all motor stock intake manny and tb b18c in my hatch with some shitty eBay exhaust . i am getting a 4-1 header and getting a custom exhust made with a vibrent street power muffler what do u cuz think that the best piping size would be for me i think i want to go with 2.5 all the way threw also i will be making a test pipe
By rustyrex
#339287 I used 2.5" on my exhaust with a test pipe. I would highly suggest using a actual cat. The sound and smell is not worth using a test pipe. Plus the performance gains are very minimal.
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By 92dxeg
#339311 well i have a cat now with some eBay exhaust and my car already runs rich cuz of the tune so i could only imagine how it would smell with out that. but does a actually cat restrict the motor a lot to notice a difference and will i notice a difference from switching from 2.25 to 2.5 ?
By rustyrex
#339312 The smell will get a lot worse without a cat. As far as the pipe diameter only a dyno will tell you if you gain or lose.
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By 92dxeg
#339334 ok so do u suggest 2.5 threw with a cat
By rustyrex
#339339 Yes sir.
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By Apexracing
#339347 You will gain a bunch of power removing the cat. But you should get a retune if you do so.
By rustyrex
#339348 You do not gain as much power as you think man. I gain 3ho removing mine and now it smells and is stupid loud
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By Apexracing
#339349
rustyrex wrote:You do not gain as much power as you think man. I gain 3ho removing mine and now it smells and is stupid loud



Any restriction in the exhaust when your trying to make power is a bad one. The netted 5-10 hp gain might be worth it to some one. I know for k series engines it makes quite the difference. The smell is because you need a retune. If your car is too loud then get a different exhaust.
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By Uknterror
#339438 Gains would be minimal even with tune but will help (slightly) up top. Get a good resonator and it will help with the noise.
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By Apexracing
#339440
Uknterror wrote:Gains would be minimal even with tune but will help (slightly) up top. Get a good resonator and it will help with the noise.



Would be a good setup for turbo. And yea the bigger the resonator the better the tone.
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By 92dxeg
#339464 well i plain on getting a retune in the future not right now tho i was just looking to gain some hp buy simple bolt ons and i need a new exhust anyway