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mikeyisfresh

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thinking of installing a high-flow cat or test pipe to bolt up to my Yonaka catback. will the exhaust be noticeably louder with a high-flow cat? obviously a test pipe will make it louder, and I'm assuming a high-flow cat will, as well. but I'm always seeing "for offroad use only" on a lot of these cats, is the sound difference that much?
 

mymmeryloss

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Yes, it can be...
 


00siboy

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Any kind of a less restrictive exhaust is louder, so yes it will be a little different. An OEM cat does more to muffle sound than you realize.
 

2slo4u

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I think it's sort of useless to add a test pipe or high flow unless your trying to make some power from boost or something. It's been proven that replacing a stock cat only gives at most 2 hp. Which isn't worth poluting the air IMO.

The " for off-road use only" thing is basically on every aftermarket part. Even a sale for an air filter will say that.
 


00siboy

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Magnaflow has a comparison on their website of stock, test pipe, and high-flow on an em1, and like 2slo4u said its only a couple HP, not worth it imo.
 

emerican

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I have the yonaka cat back and have a megan high flow cat on it which is just a test pipe it has no guts what so ever it does change the sound quite a bit, but it didnt make it horrible i acutally like the way it sounds.
 

young_

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I have the yonaka cat back and have a megan high flow cat on it which is just a test pipe it has no guts what so ever it does change the sound quite a bit, but it didnt make it horrible i acutally like the way it sounds.
It does have an aggressive tone. I like it :D
 

civexspeedy

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A test pipe is just a pipe, no restriction. It'll be stupid loud and probably very buzy. Not a good idea...
 

anfrey

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I think it's sort of useless to add a test pipe or high flow unless your trying to make some power from boost or something. It's been proven that replacing a stock cat only gives at most 2 hp. Which isn't worth poluting the air IMO.
this right here. unless you're running a FI setup, the gains are minimal and not worth the environmental damage.
 

MistahJuice

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Agreed^ Plus you haven't said anything about your header. If it's stock or like a DC or ebay one the same size as stock then a test pipe will definitely be pointless for you since the header will still be restricting you right out of the gate. If you had a header with a 2.5 in collector then yes you definitely want a bigger cat but it would be going into ur 2.36in catback anyway so still no very helpful
 

mikeyisfresh

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I have a DC 4-1 header on the car.... I ended up getting a high-flow cat from eBay... Some brand called OBX-R or something. the real only important thing is that the cat required no welding, which is why I originally started looking for a replacement cat to begin with.
 

mikeyisfresh

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I have a DC 4-1 header on the car.... I ended up getting a high-flow cat from eBay... Some brand called OBX-R or something. the real only important thing is that the cat required no welding, which is why I originally started looking for a replacement cat to begin with.

this is what I got: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=190641057293

I shouldnt have any problems bolting this onto my Yonaka (60mm) catback, should I?
 

MistahJuice

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You probably should have showed us before u just went out and bought that. Is your DC header the JDM 4-1 Type R replica or just a regular 4-1? If it's a regular 4-1 then it has a 2in outlet and this cat has a 2.5in inlet and outlet so no you're header won't bolt up to it unless its the jdm one. As for your catback I'm not sure. This is definitely bigger than your catback and it's made to bolt up to a stock cat so I'm not sure. You'll need to weld a new flange onto your header (assuming its not the jdm one) and maybe onto the inlet of the catback or outlet of the cat.
 

MistahJuice

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Also if you really have a B20Vtec you should have just went with a 2.5in exhaust from the start for max power gains
 

anfrey

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i don't mean to be pedantic, but you only have one header, not multiple headers....

[SGH-T989/Tapatalk]
 

mikeyisfresh

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You probably should have showed us before u just went out and bought that. Is your DC header the JDM 4-1 Type R replica or just a regular 4-1? If it's a regular 4-1 then it has a 2in outlet and this cat has a 2.5in inlet and outlet so no you're header won't bolt up to it unless its the jdm one. As for your catback I'm not sure. This is definitely bigger than your catback and it's made to bolt up to a stock cat so I'm not sure. You'll need to weld a new flange onto your header (assuming its not the jdm one) and maybe onto the inlet of the catback or outlet of the cat.
I realize that now. I ordered it about 4am, and I was sleepy and not thinking clearly. I just remember thinking "I need to order one of these ASAP"
 

MistahJuice

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Well it may not be that bad but u never said wheter ur header is the jdm dc or just the regular one yet. Does it have a carb eo number on it? If so it's most likely a regular dc and ur screwed untill you get a header with a 2.5 in outlet or unless you decide to return this cat and get a smaller one.
 

mikeyisfresh

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i don't mean to be pedantic, but you only have one header, not multiple headers....

[SGH-T989/Tapatalk]
right. thanks.

Well it may not be that bad but u never said wheter ur header is the jdm dc or just the regular one yet. Does it have a carb eo number on it? If so it's most likely a regular dc and ur screwed untill you get a header with a 2.5 in outlet or unless you decide to return this cat and get a smaller one.
yes. it does have one, I just checked. pretty sure it's the ceramic coated one.
 

mikeyisfresh

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if anyone could recommend a decent header with a 2.5 inch outlet, it'd be much appreciated. I'm seriously trying to avoid having anything welded.
 


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