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apexi vafc

Discussion in 'General Tech and Maintenance' started by hondaman16lx, Feb 1, 2004.

  1. hondaman16lx

    hondaman16lx Member

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    just got gsr and plan to build it as a daily driven little street beast build up the motor a little and run nitrous, anyways i was looking into buying an apexi vafc any suggestions warnings about these... if i understand correctly i can buy this thing and set my vtec to kick in at whatever rpm i desire
     
  2. E_SolSi

    E_SolSi Member of the 20 nut club Moderator VIP

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    you dont want to just guess where to set shit like VTEC crossover .... bring it to a dyno and get it tuned properly.... otherwise youll most likely lose HP
     
  3. hondaman16lx

    hondaman16lx Member

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    im extremely new , but i always assumed the earlier vtec engaged the more power engine produced .? now im confused lol
     
  4. E_SolSi

    E_SolSi Member of the 20 nut club Moderator VIP

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    no

    VTEC is not a magical power producer

    its just a more agressive cam profile

    more agreeive cams allow for more power to be produced at high RPMs.... agressive cams make shit for power at low RPMs though

    so switching lobes too early will just make you bog out in your mid range

    switching too late makes the car "feel" faster, because again the mid range bogs out then you switch lobes closer to the "sweet spot" for the VTEC profile... so there is a large jump

    you want to set it on a dyno and pretty much never touch it again (untill you do more mods)
     
  5. xj0hnx

    xj0hnx I wanna be sedated VIP

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    Another thing about the VAFC, or any A/F controller is, Honda engineers did a damn good job of choosing fuel maps, and crossover points, so unless you have modified your motor more than just the usual I/H/E, more than likely your gains will be very small. Of course a nice set of cams, intake manifold, maybe some headwork can see greater benefits from them.
     
  6. hondaman16lx

    hondaman16lx Member

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    ahh i see now....perhaps my stock motor until i build it slightly would benefit more from a more general ecu chip upgrade and of course some basic bolt ons before i move on to this eventually
     
  7. dohch22a4

    dohch22a4 Senior Member

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    The stock Honda ECU will correct itself enough in the presence of bolt-ons that a chip is not necessary. Besides, most "Mugen" "JUN "Skunk2" "whatever other random japanese tuner you can think of" chips run rich and don't have an optimum VTEC switchover. Also, they usually have the rev limiter removed so if you accidentally over-rev with your stock valvetrain, you'll be proper fucked. :ph34r:
     
  8. pissedoffsol

    pissedoffsol RETIRED

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    most off-the shelf chips are horrible. they make you run stupid rich.

    rich = less gas mileage
    rich = less power

    why anyone runs those chips as a solution is beyond me.

    Chet's "skunk2 program" p28 put him at almoat 10:1 air/fuel ratios. ideal, is around 13:1

    here- see for yourself.

    [​IMG]

    the ship lost him over 6 horsepower PEAK, and almost 20 in the vtec cross over... see the dip? its because vtec engaged at the wrong time.

    notice the ari/fuel curves on the bottom too.

    and that was compared to an h22 (p61)ecu.

    and how well did the h22 compare to the stock ecu (p30)???

    # green - skunk2 P28
    # blue - p30
    # red - p61

    [​IMG]

    chips suck.


    complete story:
    http://www.hondaswap.com/~pills/chet_ecu.html
     
  9. dohch22a4

    dohch22a4 Senior Member

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  10. hondaman16lx

    hondaman16lx Member

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    if vafc and switching chips both arent very smart to do what can i do with the elcectronics of the car , perhaps run hondata, or maybe that plug and play aem system i have a laptop so that is a possibility for me to do ..i hope i dont sound too green here but i really do know nothing about electronics
     
  11. pissedoffsol

    pissedoffsol RETIRED

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    with what you plan to do, going to a full standalone is a little pricey.

    however, both units you mention offer nitrous control - which will adjust fuel and compensate on the fly CORRECTLY and ACCURATELY by taking o2 sensor readings for the more "air" you are effectively pushing in to combust.

    if you have the cash, by all means, you can't go wrong.

    but depending on the nitrous setup you go with- it very well may come with a control module- such as zex or venom. effectively, it does the same thing, to a lesser extent.
    it really depends how big of a shot you plan to run.

    its like crack.... the more you use it- the more it costs you. the more you use it- the more you want. but, if you take too much, your engine overdoses and goes boom. :)
     
  12. pills_PMD

    pills_PMD Super Moderator

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    a vafc is definately a possibility for mild tuning.. i had one for a while before i got the hondata system.

    it really limits you as far as tuning timing goes, but to protect the engine so its not running to lean and to make sure you aren't running hella rich...

    go for it.. if you have a G or more to drop on hondata or AEM do that up too... its all in your budget.
     
  13. hondaman16lx

    hondaman16lx Member

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    ahh i see , well i suppose all considering i'll just save up and prepare to drop in a standalone or perhaps a more friendly plug and play system, my pockets arent deep but my brand new teg just got rear ended and my back hurts so ...haha well anyone have anyexpereinces with the aem plug-and-play or should i just go hondata or ...srry i know im extending this post way to much
     
  14. xj0hnx

    xj0hnx I wanna be sedated VIP

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    Just a question for you man. Why would you want to drop money on a more useless for your application than not computer? You really have no need to run any kind of fuel system till it is modded, lightly a VAFC is good, and heavily, either built high C/R, or force fed the AEM, Hondata, etc...really, till you have more of a plan or are a littel further along you should invest your money else where in the car. Maybe think about suspension and brakes, to handle the power you want to make eventually. Just a suggestion.
     
  15. E_SolSi

    E_SolSi Member of the 20 nut club Moderator VIP

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  16. pissedoffsol

    pissedoffsol RETIRED

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    plug and play means it plugs in. thats about it.

    its a MUCH harder system to tune than hondata.

    don't think you plug it in and drive off.

    i know a few people it took a month to get their car just to idel with it.
     
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