Jump to content
SAU Community

Which Cat-back Is Less Restrictive ?

cobrAA

By cobrAA,
in Engines & Forced Induction

 Share

  

8 members have voted

You do not have permission to vote in this poll, or see the poll results. Please sign in or register to vote in this poll.

Recommended Posts

cobrAA Mentor

cobrAA

Posted
Posted (edited)

I have a dilemma. I've been reading about cat-back for the last 2 weeks. I have to swap my RS*R Exmagt2 for either:

1. a 3' non straight pipe cat-back ( I.E: Magnaflow XL turbo) + Swap the downpipe for an Aftermarket.

http://www.magnaflow.com/02product/shopexd...ain&id=8264

xl02.jpg

Or

2. The OEM cat-back which is 2.5' but straight pipe + adding a Y pipe with a electric open-valve ( cutout) just before the cat. But I'm afraid it will be way too loud to run it on the street and won't use it enought to make it worth the hassle.

006-2.jpg

EchappementOEMGTR2.jpg

3. Varex cat-back with the butterfly valve but is there any backpressure problem with this exhaust because if you close the valve it will only have a 1 inch hole?

VarexDiagram.png

Which one should be less restrictive?? a 3 inch 3 chamber system or a 2.5' straight free-flowing..

For the moments, I'm fairly stock ( approx. 340whp) but I plan on upgrading the turbo( -5) and go to the 450ish whp marks and I don't want to loose like 50 HP because of those exhausts.

Edited by cobrAA
Link to comment
https://www.sau.com.au/forums/topic/305899-which-cat-back-is-less-restrictive/
Share on other sites
R31Nismoid Grand Master

R31Nismoid

Posted
Posted
waits for nismoid's normal exhaust answer :P

''you can have a quiet exhaust which IS fairly well flowing"

:teehee: Nah i've got a better one! :P

450rwhp - you have the wrong wrong wrong turbo choice. The choice you want is the Garrett -9s!!!!!

Not really on topic, but needs to be said as far too many people are poorly informed about turbo selection.

Varex - Crap. They sound dreadful. I've not heard one car fitted that sounds any good. Must be the materials used, they just give off a woeful exhaust note.

OEM - Crap... OEM is like the pinnacle of restriction. You can't hope to make 330rwkw with a 2.5" exhaust.

Magnaflow - NFI, but just looking at the design i cannot see how that's going to flow at all well.

Why don't you just build a proper 3" straight through system?? It will 100% be under 90dB if done right.

Hell even off th shelf jap systems are under 90dB and you can get them 2nd hand for $600-$800 worst case.

Ideally you want a 3.5" system for the power goal, but you will "get away" with a 3" if you must, without question, be legal.

3.5" is a bit harder to get to legal without some love :bunny:

cobrAA Mentor

cobrAA

Posted
  • Author
Posted
:P Nah i've got a better one! :thumbsup:

450rwhp - you have the wrong wrong wrong turbo choice. The choice you want is the Garrett -9s!!!!!

Not really on topic, but needs to be said as far too many people are poorly informed about turbo selection.

Varex - Crap. They sound dreadful. I've not heard one car fitted that sounds any good. Must be the materials used, they just give off a woeful exhaust note.

OEM - Crap... OEM is like the pinnacle of restriction. You can't hope to make 330rwkw with a 2.5" exhaust.

Magnaflow - NFI, but just looking at the design i cannot see how that's going to flow at all well.

Why don't you just build a proper 3" straight through system?? It will 100% be under 90dB if done right.

Hell even off th shelf jap systems are under 90dB and you can get them 2nd hand for $600-$800 worst case.

Ideally you want a 3.5" system for the power goal, but you will "get away" with a 3" if you must, without question, be legal.

3.5" is a bit harder to get to legal without some love :P

The problem is to be legal I have to have a non-straight through system( excepting the OEM) or else I will get a exhaust ticket and will have to go to court to fight it( something I'm freakin tired to do)

Cosa Community Regular

Cosa

Posted
Posted (edited)

I read an article in HPI where they tested an OEM catback against after market on an R32 GTR with mild mods. Had 3" from turbos to the cat back.

In the article they CLAIMED they made 2kw more with the OEM.

Edited by Cosa
PM-R33 Grand Master

PM-R33

Posted
Posted
Varex - Crap. They sound dreadful. I've not heard one car fitted that sounds any good. Must be the materials used, they just give off a woeful exhaust note.

Not entirely true. The rear mufflers/cannons might not sound the best, but i use one of their universal ones underneath the car to keep the car quite when needed (99% of the time its opened) and you would never pick something wasn't right on the car when it is opened. When it is shut its just quite as all hell. Im getting a 3" straight pipe to bolt on and off to replace the varex when needed due to the Varex weighing half a million kg's and sitting quite low.

cobrAA Mentor

cobrAA

Posted
  • Author
Posted
Not entirely true. The rear mufflers/cannons might not sound the best, but i use one of their universal ones underneath the car to keep the car quite when needed (99% of the time its opened) and you would never pick something wasn't right on the car when it is opened. When it is shut its just quite as all hell. Im getting a 3" straight pipe to bolt on and off to replace the varex when needed due to the Varex weighing half a million kg's and sitting quite low.

Yeah, my valve would be open 99% of the time. the 1% will be when I see a police. It is that heavy?

Do you have a sound clip of that varex :worship: ?

Parag0n Mentor

Parag0n

Posted
Posted (edited)

All those catbacks look shit to be honest.

Get something fabricated, will probably end up coming out on top in both price and performance.

If you're paranoid about the loudness of your car get some mid mufflers / resonator or just baffle the shit out of a box and call it your exhaust.

Edited by Parag0n

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

    • MBS206
      Tein Circuit Master- rebuild worth it?

      By MBS206 · Posted

      If they can dyno them, get them dyno'd, make sure they're not leaking, and if they look okay on the dyno and are performing relatively well, put them in the car.   If they're leaking oil etc, and you feel so inclined, open them up yourself and see what you can do to fix it. The main thing you're trying to do is replace the parts that perish, like seals. You're not attempting to change the valving. You might even be able to find somewhere that has the Tein parts/rebuild kit if you dig hard.
    • MBS206
      Best place to order Authetic R32 Parts in Japan

      By MBS206 · Posted

      Can you also make sure the invoices on the box (And none exist in the boxes) are below our import duty limits... I jest, there's nothing I need to actually purchase and order in. (Unless you can find me a rear diff carrier, brand new, for stupidly cheap, that is for a Toyota Landcruiser, HZJ105R GXL, 2000 year model...)  
    • MBS206
      NC MX5

      By MBS206 · Posted

      Murphy strikes again! Nothing at all would have gone wrong if you had the tool kit in the car! You'd have just found the clamp loose the next time you went to touch it...
    • MBS206
      Blue slip

      By MBS206 · Posted

      I have been being VERY quiet about what you're alluding to, as it is something that ticks me off... The number of cars from factory that run coil overs is HUGE! Most of them these days do... The other part that annoys me, is people saying "Well all the incabin adjustable suspension is illegal by blah blah blah"... If that's the case, then why can I buy a car brand new that can do it if, FULL STOP in cabin adjustable suspension is illegal...   Also, I could just chuck some aftermarket shocks in my car, throw the stock springs on, after my blue slip, dump my super low springs back in. Same shock and spring style setup... Hell, they could also be the same colour springs etc.     I'm voting, BlueSlipper didn't want to touch the above car for some reason. Whether it be some sort of bias against the car, the owner, them maybe having previously done dodgy shit and now they're being super careful in case they get slapped in the face by the Gumbyment again... Find a new blueslip place.   And can confirm as you had said, yes there are holy bibles of vehicle heights, and all sorts of other suspension stuff. Heck your run of the mill mechanic, and tyre shop has access to all of that stuff. It's how they do wheel alignments...
    • The Bogan
      NC MX5

      By The Bogan · Posted

      Funny story Heading to Sydney this morning on the HWY there was some slow traffic, so I gave it the beans and midway through my overtaking "power run" I lost all power It seems that I missed a hose clamp,  and the MAF and filter went WiFi To make this more problematic, the little tool kit that lives in the boot, is sitting in the sun room at Goulburn......LOL Luckily for me I found a bit of steel on the side of the road that could be used like a rusty and bent flat head screw driver to tighten it up enough that it got me into Sydney, it is now all tight like a tiger with the aid of a 8mm socket Note to self: Use my brain and double check stuff, and always keep that little tool kit in the car for when I have a brain fart
×
×
  • Create New...