Results 1 to 9 of 9

Thread: AFM reversion

  1. #1
    Guest
    Join Date
    Jun 2009
    Location
    walsall/tamworth
    Posts
    6,744
    Rides
    0

    AFM reversion

    I was drifting the other week doing backwards entries etc.. and found that when I would do an entry which envolved going from flatout to completely off the throttle the car would sometime cut out and I would have to then 'bump start' it with the clutch.
    I used to suffer with this occasionally on my old lower power setup when doing some crazy entries but now ive got me more power its more often.

    im thinking that it maybe due to the turbo backfeeding airflow back up the intake and confusing the AFM which is shutting down the engine.
    I do have a one piece metal turbo intake pipe, but it has two 45 degree and a 90 degree bend in it.
    I seem to remember ages ago welding a 'cross' into a mates intake pipework but cant remember what this was to solve.

    has anyone on here suffered with an issue like this? what is my best cure?
    ive a pretty basic setup really, 2871R on a generic stainless manifold and metal pipework.

  2. #2
    Guest Hugh Janus's Avatar
    Join Date
    Jun 2004
    Location
    Essex
    Posts
    7,394
    Rides
    0
    air straightener (welded in cross you mentioned, or a honey comb) plus a 30º bend in pipe between AFM and turbo

  3. #3
    Guest
    Join Date
    Jun 2009
    Location
    walsall/tamworth
    Posts
    6,744
    Rides
    0
    I was thinking that the 'Accordion' section of the OEM rubber pipe probably helps prevent this.
    not having a BOV probably doesn't do me any favours.

    which end would you put the 'Cross' AFM side or turbo side? I guess I could just put one at either end. I also guess that the AFM mesh helps to straighten the air flow by a small amount.

  4. #4
    Guest mattvaughan180's Avatar
    Join Date
    Nov 2008
    Location
    Tewkesbury
    Posts
    219
    Rides
    0
    I asked Horsham developments this question as I currently have the oem rubber elephant trunk intake but want to replace it with a apexi hard pipe that I’ve got they said to weld a cross in it as the air needs to spin up or roughen up hence why the oem one is ribbed(like the johnnys lol) plus I would have to get it remapped


    Sent from my iPhone using Tapatalk

  5. #5
    Guest
    Join Date
    Jun 2009
    Location
    walsall/tamworth
    Posts
    6,744
    Rides
    0
    See I thought the cross was usually for people who had big top mount turbos and very short almost straight intake pipes, so its purpose was to straighten the incoming airflow.

    i will put one into the AFM side of the pipework and see how i get on.

  6. #6
    Guest Hugh Janus's Avatar
    Join Date
    Jun 2004
    Location
    Essex
    Posts
    7,394
    Rides
    0
    mine is directly after the AFM

  7. #7
    Guest jj205mi16's Avatar
    Join Date
    Sep 2009
    Location
    Ayrshire, Auchinleck
    Posts
    1,445
    Rides
    0
    Ditch the old afm and go with a slot one either before or after the turbo. It’s the way forward

  8. #8
    Member alanjuggler's Avatar
    Join Date
    Feb 2004
    Location
    manchester
    Posts
    9,970
    Rides
    0
    I had this. (well, not with reverse entry drifting )

    RB25 with Z32 AFMs for the RB26 twin turbos didn't work out so well initially.

    Did this:

    https://www.ebay.co.uk/itm/HKS-EIDS-...lAjU:rk:1:pf:0

    not exactly a great solution, but worked and didn't involve buying a pair of R35 AFMs. basically ignores the AFM signal when the throttle is completely closed.

    the crosses, the mesh, the honeycombs, tried all of them and didn't work in my more extreme case.

    I think a type H1 is the right one for the Nissan AFMs but check the manual before you buy.
    white '94 s13 200sx scrapped - mapped to 1.45bar. OS giken box, garrett GT2876R, 950cc injectors, ORC twin plate, nistune. 349bhp/325lbft @ 1.3bar CA18DET
    white '96 s13 180sx - type g with more kouki bits - RB25DET, GTR steel twin turbo conversion, RB26 crank & rods. 2.6L VVT twin turbo, SR20 OSG box, OSG STR twin plate clutch, Z32 ECU w/ nistune.

    current status: 180 a bit broken but to be repaired.

  9. #9
    Guest
    Join Date
    Jun 2009
    Location
    walsall/tamworth
    Posts
    6,744
    Rides
    0
    its just mad that it now does it when all ive really done is put a slightly bigger turbo on and run a bit more boost.

    ironically I was going to convert to R35 MAF before i got it remapped but couldn't be bothered.

Posting Permissions

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