Page 1 of 4 1 2 3 ... LastLast
Results 1 to 10 of 33
  1. #1
    abie_lah's Avatar
    Join Date
    Jul 2009
    Location
    Kuala Terengganu, Malaysia
    Posts
    264

    post ur 4tec engine AFR

    hope all frend have a air fuel ratio meter at their jetski post their afr reading,, we all compare with engine setup,,


  2. #2
    Site Admin Green Hulk's Avatar
    Join Date
    Apr 2005
    Location
    Morgan City, LA
    Posts
    36,398
    +1
    2,524
    Quote Originally Posted by abie_lah View Post
    hope all frend have a air fuel ratio meter at their jetski post their afr reading,, we all compare with engine setup,,
    Regardless of modifications, everyone should have close to these AFR numbers on a forced induction engine

    idle should be around 12
    Midrange cruising around 13+
    wide open throttle 11.7 to 11.9

    If your air to fuel ratio is not close to the above then tuning adjustments need to be made.

  3. #3
    home of the dislexic fingers breon's Avatar
    Join Date
    Aug 2007
    Location
    port st lucie fl
    Posts
    3,471
    +1

    i run my idle a little leaner 13ish.....and run my cruze at 12.5 to 12.7 then anything abouve 6 8 psi it starts dropping...to the 11.7 ish..

  4. #4
    R88ory RXP's Avatar
    Join Date
    Feb 2008
    Location
    Kent, England
    Posts
    2,737
    +1
    46
    Quote Originally Posted by breon View Post
    +1

    i run my idle a little leaner 13ish.....and run my cruze at 12.5 to 12.7 then anything abouve 6 8 psi it starts dropping...to the 11.7 ish..
    When I was running my rude controller I got a little cleaver with it and ran the idle in high 13s as it was soo crisp and smooth, but you get a lean stumble when hitting the throttle so you have to find the cells around idle that it jumps to and add fuel in them to stop this happening, took some work but got it reacting very well after some time.

    Remember that up until you see boost the engine is effectively NA so can be run a lot leaner. As soon as you get some boost you need the extra fuel.

    I will eventually be doing this in the Haltec but it's a lot more complicated as there are 5-6settings that you have to use for the transient throttle settings.

    R88

  5. #5
    masta2000's Avatar
    Join Date
    Aug 2009
    Location
    montreal-quebec
    Posts
    576
    +1
    1
    running 11.3 at 14psi, too rich?

  6. #6
    sniper300's Avatar
    Join Date
    Apr 2009
    Location
    Perth Western Australia
    Posts
    165
    +1
    6

    Red face

    Idle 12.5
    cruise 13.0
    wot 11.7-11.9
    LES ecu, 48"s and R3
    This was before i rebuilt my engine. I am now all over the place because i stuffed my timing up.....

  7. #7
    home of the dislexic fingers breon's Avatar
    Join Date
    Aug 2007
    Location
    port st lucie fl
    Posts
    3,471
    you will pick up 2 to 300 rpm if you get your at to 11.8 wot over 11.3

  8. #8
    ROTAX RACING performance
    Join Date
    Apr 2005
    Location
    sweden
    Posts
    1,462
    +1
    17
    for a turbo or high boost SC setup, close to 12:1 is absolute save, just as 12.6-12.8 is save and makes lots of power on a lowboost high compression setup.

    I open more then 40 engines every year, and the pistons on a 12.8 AFR setup that have been racing in offshore for long time WOT are absolute perfekt, no melting no deto.

    But you also need the perfekt EGT value.

    @abi lah, why you want to compare AFR settings if your stock hull RXP-X is running 96 mph, with a GT28

    As Jerry posted, AFR is not a option , there is only 1 AFR that is save an makes power.

  9. #9
    home of the dislexic fingers breon's Avatar
    Join Date
    Aug 2007
    Location
    port st lucie fl
    Posts
    3,471
    Quote Originally Posted by mrracing View Post
    for a turbo or high boost SC setup, close to 12:1 is absolute save, just as 12.6-12.8 is save and makes lots of power on a lowboost high compression setup.

    I open more then 40 engines every year, and the pistons on a 12.8 AFR setup that have been racing in offshore for long time WOT are absolute perfekt, no melting no deto.

    But you also need the perfekt EGT value.

    @abi lah, why you want to compare AFR settings if your stock hull RXP-X is running 96 mph, with a GT28

    As Jerry posted, AFR is not a option , there is only 1 AFR that is save an makes power.
    mr is that with a riva ecu or a stand alone watching the timing..and egt"S

  10. #10
    Eric Ocman's Avatar
    Join Date
    Aug 2008
    Location
    Cataula, Georgia, United States
    Posts
    4,700
    +1
    77
    Sounds like he is saying 12.1 is safe for high boost regardless of the ECU system providing EGT's are acceptable. Ive been told that 12.2 is "Max Power" but it is best to stay in the 11.9 Range.

Page 1 of 4 1 2 3 ... LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. What have you lost under the 4tec engine?
    By MikeTrin in forum Sea Doo Open Discussion
    Replies: 30
    Last Post: 11-13-2007, 03:36 AM
  2. 4Tec Engine for other use ?
    By tibrin04 in forum 4-Tec Performance
    Replies: 6
    Last Post: 10-31-2007, 05:19 PM
  3. SS rings for 155hp 4tec engines
    By spd5535 in forum Sea Doo Sport Boats
    Replies: 5
    Last Post: 06-27-2007, 11:49 AM
  4. 03 sc 4tec engine trouble?
    By AintStuck4x4 in forum 4-Tec Performance
    Replies: 3
    Last Post: 06-19-2007, 11:28 PM
  5. Tiny Tach use on RXP/T/4TEC engine
    By RXP'in in MI in forum 4-Tec Performance
    Replies: 2
    Last Post: 10-12-2006, 11:13 AM

Posting Permissions

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