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Discussion Starter #1
i know i want a 4-2-1 as i want benefits at mid range rather than a peaky top end.

i know that reducing restrictions here see the restrictions further down the pipe affecting power.

i also know that at the end of the header (collector) end the bracket is to be fitted onto a 2 1/2" to 3" catalyst/decat pipe.

i want a quiet exhaust that gives me more power mid rev range.

if i

get a new manifold, get a larger/freer flowing catalyst, reducing slightly to a smaller b pipe into a standard/quieter backbox

will i reap the rewards at mid range? as the amount of restriction is only there when the flow is very high. so in the mid range where the flow is lower there will be less restriction. therefore getting the rewards of powerful mid range, quiet peformance, with only slight restriction in the higher reaches of the rev range.

also ive heard that for best silence per hp increase that the main restriction wants to be nearer to the end of the exhaust system.

so i need to find

4-2-1 manifold
freer flowing catalyst-expensive or modify the old/9 year old catalyst i have
find a larger b pipe
slightly modify the tail box for a bit more flow (its 2 1/4 pipe in and out anyway)
find brackets/connectors to fit the lot together.

i dont mind if its stainless but i know that that increases noise but only when being revved.

i just want something i can still go places. i know it will be really loud on vtec anyway!!!
 

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if you want a quiter one, get a new manifold, decat, then a 2 1/4 inch powerflow b-pipe with one silencer and a large silencer for the back box, they will custom make one and there quite quiet even at 5k

i've got a blitz system and its v quite untill you get to 5k :) perfect
 

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Discussion Starter #4
could i get them to just use the original backbox i have? its quite big even compared to some of the powerflow stuff ive seen. plus i want to pass the mot!
 

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You will pass the MOT as long as you have a cat. Why do you want to keep the stock back box? That's one of the best bits!
 

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Discussion Starter #7
i need the cat for mot. i want it quiet enough for motorway use. did 200 miles today at 70 in basic silence. i know it will be a little louder changing some of the exhaust but keeping some restriction (at the end where the air has slowed a bit) i should keep noise as low as possible. I had to get new b pipe and centre section in feb and dont want to waste the money i spent making it a nice car!
 

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I know, keep the cat. But getting a new improved back box doesn't necessarily mean it louder.

I have a huge back box and I love it lol.
 

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Discussion Starter #9
its really loud in vtec as it is.....need to video it from the outside...

i reckon i need to get some sort of cat that will fit onto a new header.

straight through exhaust vs standard would be so loud! i know how loud cos i had one on a 1.3 fiesta!
 
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