exhaust question

  • #1

    exhaust question

    Just wondering if there would be any gains on an NA motor from widening the downpipes .25" and merging to single 2.5" cat back. Current port size on the manifold is 2". Like I said just a theoretical thought for the fun of a discussion, thanks in advance
    96 300zx twin turbo - jwt ecu 13psi, dual intake, 2.5" dp's & tp's, 3" catback
    86 300zx Na - intake, exhaust
  • #2
    You'll see a gain going to a 2.5" cat-back, but messing with the downpipe short of a set of headers doesn't give any noticable gain from my experience.
    - VG30DET (HE341) 86 300ZX - 1982 280ZX Turbo - Headered NA 1986 300ZX 2+2 - 2000 Xterra -
  • #3
    Ok thanks. Sadly headers are out of my current budget. Eventually I'd like to swap to turbo but I want to enjoy enjoy the NA for what it is till then.
    96 300zx twin turbo - jwt ecu 13psi, dual intake, 2.5" dp's & tp's, 3" catback
    86 300zx Na - intake, exhaust