Jump to content
SAU Community

Custom exhausts / oval exhausts

nik.

By nik.,
in Engines & Forced Induction

 Share

Recommended Posts

nik. Enthusiast

nik.

Posted
Posted

Not sure if this belongs here or in fabrication but I'm more concerned about the technical side of this , so here we go

 

I run a 1j 180sx drift car with a borgwarner s360 with plenty of custom shit 

I'm trying to make a 4" dump that merges to a 6"x2.5" oval section just under the front of the car and when it crosses under the tunnel (as a jz exhaust crosses under the car on any nissan) at the rear of the gbox it merges to 3.5" tube and points straight to the rear of the car 

 

I'm just wondering if anyone has any feedback in terms of performance or flow or any characteristics worth noting/ any discussion by making an exhaust like this 

20190109_181938.thumb.jpg.f452d241a5dda927c62b022e65542e93.jpg20190109_203239.thumb.jpg.ad05828bc611e87c4387e1f18467f997.jpg

I'm struggling to beat the metal to make it perfectly smooth. There is clearly some edges around the added in piece to make them merge but again, I dont think I'll encounter any issues, I'm just looking for any feedback/ discussion/ personal experience with changing exhaust dimensions/ shapes

 

 

 

 

And 1 bay pic because nothing is anything without pics ?

20190106_192549.thumb.jpg.6295f7bbc4da5db3445356017eee0a21.jpg

 

 

Cheers!

Link to comment
https://www.sau.com.au/forums/topic/475810-custom-exhausts-oval-exhausts/
Share on other sites
nik. Enthusiast

nik.

Posted
  • Author
Posted

I actually wrapped it up today 

20190112_170536.thumb.jpg.c638afb71d75a41c795b0371a82dc7c0.jpg20190112_172644.thumb.jpg.a613bba5367c8de8365d8e3af4a27880.jpg20190112_172629.thumb.jpg.e7fc9abe4f4387796ffb2d1e7d29da54.jpg

Was more interested in if it would disturb exhaust flow going flat or lose velocity, or if running a twin 2.5" would be beneficial because round etc

I always read about "properly designed exhausts" but my take on a turbo car was just let it flow as much as it can 

 

Anyway, I guess there is nothing to gain. I've made it now lol

 

  • Like 1
GTSBoy Grand Master

GTSBoy

Posted
Posted

The very best shape is round, because this has the highest ratio of cross sectional area to wall area.  If you make it oval shaped, you get more wall for the same number of square units of flow area, so get more friction.  But provided you don't go too extreme (ie, keep the L/D ratio to about 2 or less, it shouldn't make a difference that anyone would notice.

  • Like 1

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

    • Murray_Calavera
      Quieter performance exhausts (or muffler add-on options)

      By Murray_Calavera · Posted

      Nope.    Grab a varex and turn it down as you get close to home, win win? 
    • f00stx
      Quieter performance exhausts (or muffler add-on options)

      By f00stx · Posted

      So, I've had my V36 for about a month now and have already copped an "excessive exhaust noise" notification from QLD TMR, reported by someone in my local area. It's a twin as per the original, and can have a bit of a throaty note to it when idling cold 😄 and if I do get up it a bit, it can be noisy, but it did pass a roadworthy inspection before sale, so.... ... but in the interest of being a good neighbour, I do want to quieten it down a bit. Is anyone here running a quiet aftermarket cat-back on their V36 or 370Z? And the big, bold question: does an aftermarket cat-back really make much of a performance difference on these cars?
    • GTSBoy
      New kid on the block

      By GTSBoy · Posted

      The wiring diagram for the R33 RB25 is freely available, and is essentially the same same as most other RBs (just with differences as to which pin # does which job). To get the ECU to power up, you just need to provide power to the ECCS relay, and have the other power feeds that come in from the top left of the wiring diagram (wrt the ECU) that give perma power to the fuel pump relay, the ECU itself, etc etc, all connected. When you put power on all these it will just come to life. It's pretty clear from the diagram what needs to happen. Just follow the lines from the 12V + supply stuff in the top left over towards the ECU. I've even posted snips of such diagrams (not for vanilla 25, I think for Neo and 26) to various threads here in the last few months, talking about what it takes to get the fuel pump and FPCM up and going. Search these up and they will help get you started on doing the same with the vanilla 25 diagram. Hell, for all I know, I've done the same with that one in years past and have forgotten.
    • Duncan
      New kid on the block

      By Duncan · Posted

      Yep...so unless someone posts up the answer you will need to probe from the ECU connector to the dash plug with a multi meter in continuity mode to trace the wires.  Note the ECU has multiple - and + (and across different key settings - Battery, IGN and Start) and most likely the power is fed from the connector(s) that is normally near the left hand headlight.
    • Songo
      New kid on the block

      By Songo · Posted

      Thanks Duncan, I am actually just trying to get the Rb turning and running with the RB25DET S2 original loom itself  I am just trying to get it going outside the body and not thinking about the S15 or trying to match anything to the S15 loom at all I am only trying to see if anyone has done this and what pin they found to be the ignition trigger and ECU+/- on the dash connector, that's about it. Thanks  
×
×
  • Create New...