Results 1 to 7 of 7

Thread: Advice on wastegate piping

  1. #1
    Join Date
    May 2007
    Location
    Florida
    Posts
    2,077
    My Cars
    '87 325is 24v turbo buil

    Advice on wastegate piping

    Hey everyoine, i am trying to finish up my down pipe setup so that i can start working on the rest of the exhaust (center exit coming ). I have an e30 with an m52b28 swapped into it, with a rapidspool/good n' tight manifold. I have my downpipe fabbed up, and the clearance between the downpipe, head, and body of the car is all pretty good.



    My big question is, is it ok to have the wastegate dump directly into the downpipe. The way the spacing works out, the wastegate lines up perfectly with the downpipe and has maybe an inch of piping needed between.





    Is there are reason I shouldn't do this? Are there advantages to having the wastegate piping longer?
    Last edited by SS Ball3r; 02-06-2019 at 08:24 PM.

  2. #2
    Join Date
    Jul 2005
    Location
    California
    Posts
    565
    My Cars
    Bima
    this is just anecdotal hearsay but a straight up 90 merge is not the best for gate flow.
    it might* cause control issues by back pressure.

    my current setup is also very close to the exhaust as well so what i think* i perhaps improved
    to give it a better flow and just gave it longer runway to enter.
    So just cock it to the side and murge a small bend into the side of the pipe.

    i'm not a gas flow professor so my ideas could be totally shit.
    welds where flux core don't judge.

    no control issues btw 8psi spring. holds spring pressure or 16psi on controller.

    Tie in by jet jones, on Flickr
    Inside of tie in by jet jones, on Flickr
    Last edited by Robocop; 02-06-2019 at 09:14 PM.

  3. #3
    Join Date
    Aug 2017
    Location
    San Luis Obispo, Ca
    Posts
    64
    My Cars
    1997 BMW 328i
    Yeah main issue would be boost creep if the wastegate can't flow exhaust into the downpipe well enough.

    I also did similar to robocop though i tried to make my outlet curve and funnel air a bit more directional into the downpipe, but it looks like you dont really have much room to work with. I agree that if you try and cock it to the side and use a portion of a U bend to try and route it back into the downpipe flowing slightly downward that should be fine.

  4. #4
    Join Date
    May 2007
    Location
    Florida
    Posts
    2,077
    My Cars
    '87 325is 24v turbo buil
    Thanks for the feedback. I was thinking that kinda like a paint gun, having the high velocity gas pass by the 90 degree T, it would create "suction", but i have never had a turbo car let alone build one.

  5. #5
    Join Date
    Aug 2007
    Location
    Vancouver, B.C., Canada
    Posts
    7,915
    My Cars
    '97 M3
    The farther down stream the wastegate dumps into the exhaust the better and try to have it join at a shallow angle. Open dump would be best but the noise will drive you (and anyone near you) insane eventually. Here is how I did mine...


  6. #6
    Join Date
    May 2007
    Location
    Florida
    Posts
    2,077
    My Cars
    '87 325is 24v turbo buil
    I was under the impression from some of my reading that an open dump pipe/screamer pipe would cause boost creep. I'm definitely in the learning stage being my first turbo car, lol. I don't mind running an open pipe for the wastegate being that this car is fully gutted, solid mounted, caged, etc. I do have a feeling tracks won't like me for that either. I will have to see how much space I will have if I rotate the wastegate opening towards the block and see if I can fit a 90 degree fitting in there.

  7. #7
    Join Date
    Aug 2007
    Location
    Vancouver, B.C., Canada
    Posts
    7,915
    My Cars
    '97 M3
    People that have poorly designed exhaust manifolds with less than ideal waste gate exit angle, ie 90į, or the waste gate is not dumping from all six runners. People with an open waste gate dump sometimes benefit from recirculating the wastegate back into the down pipe because the volume of wastegate gasses entering the exhaust reduces the overall capacity of the exhaust which causes back pressure which helps reduce boost creep. It works if your exhaust size is already marginal. Itís a bandaid for a crap manifold.

    Keeping the wastegate dump separate from the exhaust will net you the most power on a properly designed system. The noise is not tolerable IMHO. Iím willing to take a reduction in power to not attract attention and be able to pass the sound level checks at my local track.

Similar Threads

  1. (4) 1.5" SS 304 wastegate pipes: (2) 90's; (2) 45's
    By rt turbo in forum Race Cars & Track Parts
    Replies: 2
    Last Post: 08-19-2010, 07:20 PM
  2. Wastegate pipe clearance
    By M3ZT in forum Forced Induction
    Replies: 2
    Last Post: 04-17-2010, 02:18 PM
  3. question about wastegate pipe
    By gnarfy in forum Forced Induction
    Replies: 23
    Last Post: 05-16-2009, 12:48 AM
  4. FS: spa manifold w/ wastegate piping, turbo studs and exhaust gaskets
    By ltw97m3 in forum Race Cars & Track Parts
    Replies: 5
    Last Post: 04-10-2008, 04:48 AM
  5. WTB: SPA Wastegate piping
    By djcontra in forum BMW Parts Wanted sponsored by Bavarian Auto Recycling
    Replies: 0
    Last Post: 06-02-2006, 02:42 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •