Jump to content
SAU Community

Question About Cat

WESTWD

By WESTWD,
in Engines & Forced Induction

 Share

Recommended Posts

WESTWD Community Regular

WESTWD

Posted
Posted

Hey all,

firstly, i have done a search and could NOT find what i was after.

i got stock r34 exhaust system and am looking to upgrade to a catback and high flow cat.

i plan to go 2.5" but...

what size cat do i get?

2.25 (as stock system is 2.25) or 2.5??

thankyou

Link to comment
https://www.sau.com.au/forums/topic/294961-question-about-cat/
Share on other sites
(OO)SKYLINE(OO) Grand Master

(OO)SKYLINE(OO)

Posted
Posted

2.5" should do you just fine.

Cat, same size 2.5", high flow, the exhaust place will sort you out.

Some say you could go 3" but you would lose a bit of low down response, unless you tune your car.

You planning on getting a canon or an oval shape muffler?

(OO)SKYLINE(OO) Grand Master

(OO)SKYLINE(OO)

Posted
Posted

Depending on how loud the Canon muffler is...

All the Canon mufflers I have owned are loud, but they all had 4.5" out pipes LOL!

In most cases you probably will to dull the noise / drone down a bit, but I think a resonator will effect the exhaust flow.

Or you can go for a Canon but with a silencer bolted into it.

If you get a Oval shape, you won't need a resonator, as Oval shape ones are mostly fairly quiet.

Juliet (llama au) has a Fujitsubo turbo back exhaust and you can hardly hear it.

Fujitsubo seem to do a great job.

(OO)SKYLINE(OO) Grand Master

(OO)SKYLINE(OO)

Posted
Posted

Yeah they still are high flow.

I think it is how the muffler is made / fabricated, the metal on the inside of the Oval shape muffler dulls out the noise better then the Canon mufflers, but can still retain a good flow.

If anyone on SAU can explain how this is done the post a way... :(

AYW550 Collaborator

AYW550

Posted
Posted
ok, cheers,

are oval tips high flow though?

i put an oval stainless dual tip power pro muffler on mine and its very high flow (you can see straight thru it via two, 2.5 tubes inside the muffler)

but it was just as loud as any cannon even with a resonator and i later had to put a muffler+resonator 2in1 muffler in the system right after my extractors and before the other resonator!

AYW550 Collaborator

AYW550

Posted
Posted
Yeah they still are high flow.

I think it is how the muffler is made / fabricated, the metal on the inside of the Oval shape muffler dulls out the noise better then the Canon mufflers, but can still retain a good flow.

If anyone on SAU can explain how this is done the post a way... :(

i think its a combination of a few factors,...the type of metals used, the type of sound deadening material used to pack the muffler and the fact that inside a high flow oval muffler there is simply more surface area to obsorbe the sound waves

(OO)SKYLINE(OO) Grand Master

(OO)SKYLINE(OO)

Posted
Posted
i think its a combination of a few factors,...the type of metals used, the type of sound deadening material used to pack the muffler and the fact that inside a high flow oval muffler there is simply more surface area to obsorbe the sound waves

Thanks for that! :(

Where as a Canon muffler has less surface area to obsorbe the soundwaves... Hence it being louder...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • joshuaho96
      R33 GTR running -9 with no tune

      By joshuaho96 · Posted

      Yeah I suspect even if you hold airmass per cycle/cylinder constant if you get too far away from stock you're still going to have problems running the factory tune within the bounds of the factory load scale. Cams, different displacement/rod ratio, etc. I'm just lucky that the GTIII-SS with wastegate boost + CA compliance cats is pretty much equivalent to stock turbos. When I have actual space I can finally get it tuned and modify the fuel system for flex fuel to 100% handle any detonation concerns when cranking the boost to whatever those dinky turbos can put out.
    • The Bogan
      NC MX5

      By The Bogan · Posted

      I would say no, why, because my daughter, who also lives in Goulburn, hasn't recommended us going there Pity, as we miss all the German joints around in Sydney, actually, the restaurants are the only thing I really miss about Sydney, and a special mention to Ishibanboshi at Bondi Junction, their Kara-age Don is heart cloggingly deliciousness (always added a special boiled egg...or 2) 😋 
    • GTSBoy
      NC MX5

      By GTSBoy · Posted

      Does that German restaurant still exist in the old place out the NW end of Goulburn? When I say "out the NW end of"...I am really being vague. It was 1997 when I was last there, and the only point of reference I can recall is that it was on the opposite side of the main drag from the big merino. And when I say "opposite side of the main drag", I don't mean "on the main drag". It was either a couple of streets back from there, or might have even been out in the sticks a bit further. Was an old farm building or mill or somesuch. And when I say "the big merino" I might actually be thinking of a completely different part of town, because I just looked on maps and the big bugger is not where I remembered him to be! The food was good, consisting largely of various German mystery-meat sausage/loaf things and kartofflen.
    • GTSBoy
      R33 GTR running -9 with no tune

      By GTSBoy · Posted

      So while the second sentence is completely correct and the whole point of the conversation, the first sentence bears consideration. If this bloke is just hoping to throw big turbos on and drive it around, because there are no helpful facilities at all in his tropical paradise** then he likely has zero chance of even knowing what the TP is on the last column in the stock maps, let alone know whether the ECU is operating anywhere near it or past it. So the point is very very moot. And, per what I said before, at stock boost on those turbos, you may well be off the end of the map. **I'm just back from Vanuatu, so I know exactly what small Pacific nations can be like wrt paradise without requisite facilities. But it's not even that simple. I put a high flow on my car and had to drive it around without a proper tune because of the lack of opportunity*** to put the bigger AFM and injectors into it to allow it to be tuned. I had to turn the boost down to less than I had before, and back off the boost controller's ramp, because it was exploring parts of the map that it didn't drive in before, and really couldn't access for tuning on the dyno either, and so was pinging. It was still well within the last column, because when I first**** set up the Nistune on the Neo I rescaled all axes of the maps to give some more space to explore. ***Family dyno was broken ****This was 13 years ago, and the TIM thing wasn't a thing then and so TP would definitely grow when pushing past the stock tune's limits.
    • joshuaho96
      Squeaking clutch/throw out bearing

      By joshuaho96 · Posted

      Yep, this bit another local owner. I caught it before putting the transmission back into the car, what I noticed was the pressure plate fingers weren't flat and even. It's more obvious with the pull style clutch because the throwout bearing ring was visibly not flat once everything is put together. Nismo should really update their instructions to call out this specific detail. I'm not even sure the clutch as-shipped orients everything properly.
×
×
  • Create New...