4" Dp

Discussion in 'Modifications & DIY how-to' started by Greg, Jul 4, 2007.

  1. Greg

    Greg Active Member

    Joined:
    Apr 16, 2006
    Messages:
    1,714
    Likes Received:
    0
    What are the advantaged that a 4" DP has over a 3" bellmouth? Is it just something for the 'bigger turbo guys' or what?
     
  2. Jake

    Jake Active Member

    Joined:
    Jul 8, 2006
    Messages:
    3,845
    Likes Received:
    0
    I would assume the less restriction would equal faster spool. But u can only spool a vf39/43 so fast. So it would probly be most advantageous for the bigger turbo guys, yes. Jason is running one on his 18g.
     
  3. Greg

    Greg Active Member

    Joined:
    Apr 16, 2006
    Messages:
    1,714
    Likes Received:
    0
    Yeah, thats what brought up my question
     
  4. Deke

    Deke Active Member

    Joined:
    Jan 28, 2006
    Messages:
    2,694
    Likes Received:
    0
    Is there any other 4 inch besides the turbo xs?
     
  5. keeganxt

    keeganxt Active Member

    Joined:
    Nov 13, 2006
    Messages:
    1,071
    Likes Received:
    0
    Yeah its the only one. We call it the fat nasty.
     
  6. Maniacurabus06

    Joined:
    Mar 19, 2006
    Messages:
    397
    Likes Received:
    0
    Even if you do have a small turbo(td04/vf39/34/16g). Would you see any diffrence in numbers if you go with a 4" dp instead of a 3" one?
     
  7. pEd

    pEd This ain't no Piccadilly!

    Joined:
    Mar 5, 2004
    Messages:
    2,460
    Likes Received:
    3
    No. I don't think you'd have any different numbers or spoolup time.
     
  8. Maniacurabus06

    Joined:
    Mar 19, 2006
    Messages:
    397
    Likes Received:
    0
    really? For a turbo car isn't bigger supposed to be better?
     
  9. Greg

    Greg Active Member

    Joined:
    Apr 16, 2006
    Messages:
    1,714
    Likes Received:
    0
    It is, to a point...
     
  10. Maniacurabus06

    Joined:
    Mar 19, 2006
    Messages:
    397
    Likes Received:
    0
    that makes sense. thanks
     
  11. GTscoob

    GTscoob Black is Beautiful

    Joined:
    Jul 30, 2004
    Messages:
    4,813
    Likes Received:
    1
    I doubt it would make a noticeable difference on stock-ish turbos but probably would make a bigger difference at higher boost levels.

    Bigger is normally better but its always got diminishing returns; going from 2.5" to 3" creates gains across the entire power band. Some people swear that by keeping the 2.5" exhaust piping their car feels torquier but dynos dont seem to back that up. 3.5" exhausts are for the faster end of cars and sacrifice some low end. 4" pipes are reserved for the fastest Supras, etc.
     
  12. FACE

    FACE Active Member

    Joined:
    Oct 5, 2006
    Messages:
    3,286
    Likes Received:
    6
    hummmm...I have the turbo xs 4'' dp to the 3" race and mid to a 2.5''stromung...I think the low end torque is less but the eventual pull is worth it.
     
  13. Deke

    Deke Active Member

    Joined:
    Jan 28, 2006
    Messages:
    2,694
    Likes Received:
    0
    Hmm...interesting. I've been planning on going with the standard turboxs exhaust (whenever I finally get around to buying one) for a while now. This doesn't change my plans or anything, but interesting none-the-less :)
     
  14. jason

    jason Member

    Joined:
    Mar 30, 2005
    Messages:
    250
    Likes Received:
    0
    This is Turboxs' philosophy.

    Quote
    "Why is that important? Because, despite what your girlfriend might tell you, size does matter. Turbochargers work best when there is large pressure and temperature differential across the turbine wheel. Having a large, free flowing downpipe is what give you that large pressure and temperature differential."
     
  15. WJM

    WJM Banned

    Joined:
    Dec 12, 2004
    Messages:
    5,401
    Likes Received:
    0
    Really, anything larger than 3" on a SUBARU with anything smaller than a GT35 is a waste.

    Unless you are making over 600hp...its just more noise.
     
  16. Greg

    Greg Active Member

    Joined:
    Apr 16, 2006
    Messages:
    1,714
    Likes Received:
    0
    I doubt theres going to be a noticeable difference though... Maybe 2-3hp
     
  17. BrianGT

    BrianGT Banned

    Joined:
    Jun 4, 2005
    Messages:
    2,264
    Likes Received:
    0
    i bet a 4" dp would work better with a 4" cat
     
  18. WJM

    WJM Banned

    Joined:
    Dec 12, 2004
    Messages:
    5,401
    Likes Received:
    0
    and a 4 inch mid pipe...and 4 inch 'muffler'....
     
  19. BrianGT

    BrianGT Banned

    Joined:
    Jun 4, 2005
    Messages:
    2,264
    Likes Received:
    0
    yeah.. I was actually thinking about getting a random technology 4" cat, as they say that they flow better than the 3" ones...
     
  20. WJM

    WJM Banned

    Joined:
    Dec 12, 2004
    Messages:
    5,401
    Likes Received:
    0
    i bet I could make 50 more HP with a 4" TBE....
     
  21. BrianGT

    BrianGT Banned

    Joined:
    Jun 4, 2005
    Messages:
    2,264
    Likes Received:
    0
    I bet that I could make 50 more hp having SS ride in my trunk, datalogging.

    --
    Brian
     
  22. WJM

    WJM Banned

    Joined:
    Dec 12, 2004
    Messages:
    5,401
    Likes Received:
    0
    No, thats 100hp, and 300tq.
     
  23. BrianGT

    BrianGT Banned

    Joined:
    Jun 4, 2005
    Messages:
    2,264
    Likes Received:
    0
    damn! did he learn new tricks?
     
  24. WJM

    WJM Banned

    Joined:
    Dec 12, 2004
    Messages:
    5,401
    Likes Received:
    0
    I think so. he tunes with Cobb, enginuity, ecutek, AEM, hydra and JDM all at the same time, while using all 3 fuel types at the pump.

    Oh, and a big ass meth nozzle.
     
  25. BrianGT

    BrianGT Banned

    Joined:
    Jun 4, 2005
    Messages:
    2,264
    Likes Received:
    0
    nice! he is a true pimp tuner, and i admire him like a taxi driver
     
  26. Greg

    Greg Active Member

    Joined:
    Apr 16, 2006
    Messages:
    1,714
    Likes Received:
    0
  27. keeganxt

    keeganxt Active Member

    Joined:
    Nov 13, 2006
    Messages:
    1,071
    Likes Received:
    0
    Not sure if this is tension or friendly banter!?

    Turboxs' 4 in dp is the nasty, I'd get one, and the philosophy makes sense so...
     
  28. Greg

    Greg Active Member

    Joined:
    Apr 16, 2006
    Messages:
    1,714
    Likes Received:
    0
    :rofl: my thoughts exacly
     
  29. BrianGT

    BrianGT Banned

    Joined:
    Jun 4, 2005
    Messages:
    2,264
    Likes Received:
    0
    nah, just joking around. I can't wait to get our car tuned, and will definately get it done by SS.

    --
    Brian
     
  30. WJM

    WJM Banned

    Joined:
    Dec 12, 2004
    Messages:
    5,401
    Likes Received:
    0
    indeed, a good joking time. I'm bored.
     

Share This Page