Jump to content
SAU Community

Is It Possible To Have A 3" Exhaust And Still Make Power?

Mid_Nite_R33
 Share

Recommended Posts

TiTAN Grand Master

TiTAN

Posted
Posted

R31 nismoid is making around 300kw and has a legal exhaust, my car is 92db and makes over 300kw.

ask an exhaust place to make you up an exhaust with the biggest straight through mufflers they can fit.

Mid_Nite_R33 Mentor

Mid_Nite_R33

Posted
  • Author
Posted
R31 nismoid is making around 300kw and has a legal exhaust, my car is 92db and makes over 300kw.

ask an exhaust place to make you up an exhaust with the biggest straight through mufflers they can fit.

Awesome, I heard magnaflow muffler are the quietest, any others?

cheers

NYTSKY Grand Master

NYTSKY

Posted
Posted

The Kakimoto Regu and Trust PE2 are the quieter exhausts out of the Jap ones, im sure there are others.

Or like has been mentioned get an exhaust shop to make you one. My friends 700hp 25/30 sounds stock. 4inch dump with 3 1/2 exhaust with big mufflers.

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

Yes it's possible...

I'm just over legal, ~91dB with a 3.5" exhaust (it'll be good for 350rwkw). 3" can be made legal, plenty of people have done that on the forum.

My mufflers are fully custom (hand made) etc. So it wasn't cheap, but then to keep the fuzz outta your hair these are the measures we have get to today :woot:

There are some off shelf Jap ones that are under, I'm not sure what their names are though.

Basically just get a custom 3" made and have 2x the biggest possible mufflers installed + 4" cat. Should sort you out.

Mid_Nite_R33 Mentor

Mid_Nite_R33

Posted
  • Author
Posted

to put things into perspective, im making 250rwkw now and might be increasing to about 280 soon,

I have a 3" turbo back exhaust atm, I was thinking of leavin the first section of the exhaust as is and maybe having a 3.5" catback made up implementing the largest 2 mufflers, that way the extra 0.5" diaemeter will make up for the restriction of the mufflers......

Anyone know any exhaust shops in inner melbourne that could look after me?

cheers

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

280rwkw = 3" is fine.

Straight through mufflers really should not post much restriction at all mate, so i'm not sure what you mean about the extra half inch alleviating restriction...

Mid_Nite_R33 Mentor

Mid_Nite_R33

Posted
  • Author
Posted
280rwkw = 3" is fine.

Straight through mufflers really should not post much restriction at all mate, so i'm not sure what you mean about the extra half inch alleviating restriction...

I thought that the mufflers may restrict so gotta increase diaemeter...

Who should i head to for this in melb inner suburbs ??

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

Well they do restrict, but you ain't talking massive amounts mate.

280rwkw you need -

1x 3" piping, mandrel bent. A little bends through the system as possible

2x 3" straight through mufflers, largest possible you can get under the car

1x 4-4.5" Hi-Flow cat

Just get it done in mild steel and it'll be nice and cheap. Turbos make enough heat to keep rust @ bay.

As for where to get it done - NFI mate, i don't use anyone inner city.

discopotato03 Grand Master

discopotato03

Posted
Posted

Personally I think the greatest gains are from being larger in the first 1/3 to 1/2 of the exhaust system .

The gasses are pretty hot out of the turbo on full load so giving them some volume to expand into seems to work .

The gasses cool and contract (increase in density) quite quickly and you can afford to go a bit smaller in tube size toward the rear half of the exhaust system . Usually the cat and mufflers are back there anyway so 3.25 or 3" mufflers should be reasonably easy to fit .

Cheers A .

Mid_Nite_R33 Mentor

Mid_Nite_R33

Posted
  • Author
Posted
Well they do restrict, but you ain't talking massive amounts mate.

280rwkw you need -

1x 3" piping, mandrel bent. A little bends through the system as possible

2x 3" straight through mufflers, largest possible you can get under the car

1x 4-4.5" Hi-Flow cat

Just get it done in mild steel and it'll be nice and cheap. Turbos make enough heat to keep rust @ bay.

As for where to get it done - NFI mate, i don't use anyone inner city.

Ok, why the 4.5" cat? cant i just retain my 3" high flow cat?

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

CAT's are restrictive. Just have a look @ em :woot:

Such tight honeycomb blocks are the enemy of good flow... so hence get a larger CAT and help the process along.

Car is still legal and emissions will be good so there is no real downside.

I would hedge a bet that if you had a 3" hi-flow cat on there and then dropped it for the next dyno run - you'd see a power increase :D

Hell even with my 4.5" CAT i can feel a difference in or out... It's not a massive difference but it's noticeable.

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

    • drifter17a
      R34 gtt rb25det neo timing belt kit

      By drifter17a · Posted

      So now doing the change and first time dealing with rb so little nervous giving engine power and potential for screwing it up When you align all marks and then remove crank bolt, timing move little I assume you can put the bolt back in once you have removed the pully to get timing to where you want?   here is pic of my both intake and exchust cam aligned, depending on angle you look they seem to be either aligned or a half tooth or so out. Any thoughts? Should you angle your face and look at each mark that way as if looking straight rather than from above as it can be misleading   <a href="https://ibb.co/ZpnhcvbF"><img src="https://i.ibb.co/HfWrGR9b/IMG-4447.jpg" alt="IMG-4447" border="0"></a> <a href="https://ibb.co/4wm2wn4q"><img src="https://i.ibb.co/JWBqWwr1/IMG-4445.jpg" alt="IMG-4445" border="0"></a>   https://ibb.co/ZpnhcvbF https://ibb.co/4wm2wn4q
    • sunsetR33
      braided lines for the turbos

      By sunsetR33 · Posted

      Thanks for the reply @GTSBoy Haven't really thought of that yet, but you are right. If the hose was damaged it should be absolutely pissing by now. I'll put some heat sleeve around it for good measure since I'm already removing the line anyway.  Maybe I'll put on some of the stock hardlines if I ever fully remove the turbos again. Maybe when T51R modding the compressor housings? Might be a fun mod on GT28s for that "fake single turbo" effect.
    • sunsetR33
      Unpeeling the Orange

      By sunsetR33 · Posted

      Update 1: I did some work on the car already before finalizing this post and my "issues" list. I dropped the Tomei exhaust in favor of the HKS Hi Power Silent. Sounds nice and I can actually hear myself think now. Also gives me a realistic chance to legally drive without silencer inserts. A bit of cheating was necessary to still be able to mount the Top Secret style diffuser. Some malusage of washers and a bit of "convincing" toward the brackets and exhaust hanger seemed to do the trick. The shaky steering wheel has been resolved as various suspension components were worn, like sway bar bushings and link bars. Most notably the two steering tie rod ends. Had some trouble finding bushings because my sway bars are not OEM thickness, 23.x up front and 27 rear. But non adjustable, so no aftermarket I suppose. Maybe they are nismo units? Turbo oil drain hoses were definitely still the originals and are new now. Wasn't the cause of the turbo oil leak sadly. Currently removing the rear turbo because of it, I suspect the braided oil feed line is the culprit. This issue needs to be dealt with so I can work towards actually getting the turbo setup legal and inspected. Two new issues to add to the list as well. Rear Main seal is probably leaking. Time will show how bad it is, I don't really want to drop the gearbox right now just for the stupid seal. Could fix a few other things in one go once I do that. Front right driveshaft grease is going past the cv boot, so at some point I'll fix that too.
    • Kapr
      RB20DE NEO smallbox clutch.

      By Kapr · Posted

      Ok so no 4cyl clutch... Yeah it is a factory manual. So if iam correct i need clutch and flywheel too? I can use something that suits something like R32 GTST?   EDIT: https://www.ebay.com/itm/224291042776 Is this ok?   EDIT2: i maybe forget to mention this(dk how important it is) but the trans will be behind RB25DET NEO(iam doing swap) It will be there for a little while. Iam planing to do bigbox or BMW tranny..
    • sunsetR33
      Unpeeling the Orange

      By sunsetR33 · Posted

      You're probably right about that one. Thanks for your suggestions, I hope I don't need a new 3rd brake light. Although wiring issues might arguably be worse. Right now I'm in the midst of a turbo removal because of my oil leak, other problems are going to have to wait for now.
×
×
  • Create New...