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Suitable Exhaust Size For An N/a R32?

arthur32

By arthur32,
in Engines & Forced Induction

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arthur32 Contributor

arthur32

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Posted

Hey all,

I need to know a suitable size cat back exhaust for an N/A r32 rb20. I've been told that 3" is way to big so i'm looking for something between 2" and 3".

The main reason im changing my exhaust is that really annoying rattle between 2-3 grand, and where the rattle goes crazy after 5 grand rpm, also wondering if a high flow cat and a different tip/cannon/muffler will get rid of this awesome sounding rattle?

Thanks, Arthur

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arthur32 Contributor

arthur32

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have you checked your exhaust , sounds like your cat may have broken up?? 2 1/2" should be enough for a NA

Not entirely sure on how to check it :\. All i know that it sounds like absolute shit. How would i be able to check it? Would that include me having to take it out and weld it back together?

mick2nv Contributor

mick2nv

Posted
Posted

That raspy noise you hear is a very common noise heard on all NA skylines, it isnt a problem, its just gotta be replaced with a good exhaust system to get rid of it. Cheap generic cannons make it heaps worse so dont think about one of them!! And for size for an rb20de i would think 2.25 inch should be good.

arthur32 Contributor

arthur32

Posted
  • Author
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That raspy noise you hear is a very common noise heard on all NA skylines, it isnt a problem, its just gotta be replaced with a good exhaust system to get rid of it. Cheap generic cannons make it heaps worse so dont think about one of them!! And for size for an rb20de i would think 2.25 inch should be good.

Yeah i found that out after a fait bit of the search button lol. Would replacing the cat to a new high flow cat and changing the piping all the way from the cat back to the muffler fix this? Just want to get this fixed already!

mick2nv Contributor

mick2nv

Posted
Posted
Yeah i found that out after a fait bit of the search button lol. Would replacing the cat to a new high flow cat and changing the piping all the way from the cat back to the muffler fix this? Just want to get this fixed already!

Yeah mate im sure it will fix it as long as its good quality, your better off going to a custom exhaust place and telling them you dont want the noise there and they will do it for you, thats exactly what i did and it was the best decision i made.

arthur32 Contributor

arthur32

Posted
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Yeah mate im sure it will fix it as long as its good quality, your better off going to a custom exhaust place and telling them you dont want the noise there and they will do it for you, thats exactly what i did and it was the best decision i made.

How much did it set you back? I went to 'Fast Fit' today and he quoted me that a high flow 2.25 cat, piping and a muffler would cost me 800 something..... I'm not too knowledgable about cars but im pretty sure hes ripping me off hardcore. But if i supplied the high flow cat myself and the muffler, he'd supply the piping and weld it on for $30.

TwoCents Proficient

TwoCents

Posted
Posted
How much did it set you back? I went to 'Fast Fit' today and he quoted me that a high flow 2.25 cat, piping and a muffler would cost me 800 something..... I'm not too knowledgable about cars but im pretty sure hes ripping me off hardcore. But if i supplied the high flow cat myself and the muffler, he'd supply the piping and weld it on for $30.

Depends on what brand/quality of parts hes using, 800 is a pretty reasonable price

arthur32 Contributor

arthur32

Posted
  • Author
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Depends on what brand/quality of parts hes using, 800 is a pretty reasonable price

Yeah i guess thats true, just seems abit much for a cat and piping. If you dont mind me asking, whats the stock piping size of my n/a r32? Haven't measured it myself, but searching online is getting me nowhere :)

  • 4 weeks later...
blk94r33 Mentor

blk94r33

Posted
Posted

My exhaust is in my signature, personally I love it, has that nice deep I6 rumble at idle, drones a little at low revs, but anything above 4k is perfect, good racey note and loud enough. Depends on what you want your car to sound like,each to their own. Listen to other peoples cars and ask what they have, and work from there, but 2-1/4" to 2-1/2" is enough for a NA 2.0l. Also, the horrible rattle around 2.5-4k is normal for NA skylines, something to do with the twin-cam head? Search, it's been covered before. You say it gets worse above 5k? Not so normal, does it do it all the time? Only at certain loads?

-Jimmy- Mentor

-Jimmy-

Posted
Posted
my mechanic told me 2 1/4 inch is perfect, any bigger your starting to lose power, own a na r34.

This is wrong technically I think. You won't be 'losing' power, you'll just be sacrificing a bit down low, but gain a little bit more up high.

mad082 Grand Master

mad082

Posted
Posted
This is wrong technically I think. You won't be 'losing' power, you'll just be sacrificing a bit down low, but gain a little bit more up high.

well actually technically it is right because you do start to lose power. the peak power it puts out may be the same or a bit higher than the smaller exhaust but the low down power will start to drop, which means you have lost power.

it really comes down to what sort of driving you do. if you do a lot of track days and want it to be a bit of a dyno warrior (well as much of a dyno warrior as a NA skyline can be.....) and don't mind a bit of police attention then go a nice big 2.75 or 3" system. just remember that it will start to become a bit of a slug in the lower rpm so you may want to use 2nd gear in the 50kmh zones if there are any hills, lol.

mad082 Grand Master

mad082

Posted
Posted
n/a needs backpressure

nuff sed

no it doesn't. the reason why NA cars need smaller diameter exhausts isn't because of a need for backpressure. this is a myth. the reason they need smaller tubing is all about exhaust gas velocity and the scavenging/syphoning effect that happens. backpressure is a byproduct of smaller tubing and is bad for both turbo and NA engines.

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