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Thread: need some help

  1. #1
    Hybrid booster
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    need some help

    looking to save some gas and need help getting my cal right or just a different one entirely currently getting under or around 15mpg with premium

    i only want to run like 7psi and use standard 87 gas no racing .etc

    1990 sbec- garret turbo stock 2.2l t2 , 3bar, +20 injector, large fmic, ported 2pc, ported exhaust, 3" exhaust/downpipe, 2.5 sv, 255 pump, upgrade fuel rail. 52mm tb

    can anyone help me out? i have a cal to use as a base that runs good but its more for performance and idles very rich at times

  2. #2
    Rhymes with tortoise. Turbo Mopar Staff cordes's Avatar
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    Re: need some help

    Use a 90 VNT cal as your base. Bump up the part throttle timing in vac at about 10-20" until you stop seeing gains. Honestly, if you just take out the dip that's created in that range it'll get you really close. That's pretty much what I did in my shadow back when to eek out 42mpg with a very light foot, 87 octane, and a cruising speed of around 55-60mph on dead flat ground. It did help that I ran the car pretty hot.

  3. #3
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    Re: need some help

    i tried scaling the 89 vnt cal for the injectors and 3 bar map, but maybe i did it wrong, it was running too lean to be useable as is in boost, do you need to manually adjust everything in mptune or when you use the scaling it happens automatically ? i thinking the porting may make it flow to much

  4. #4
    Rhymes with tortoise. Turbo Mopar Staff cordes's Avatar
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    Re: need some help

    You don't need to manually scale everything, but if you have mods which increase flow, you'll need to tune the pumping efficiency table. Start out at the lowest boost possible and make WOT runs while dragging the brakes. If you use the brakes to keep the car at WOT and a specific RPM you can read your AFR, EGT, etc. and make adjustments to the pumping table based off of those readings.

  5. #5
    Supporting Member Turbo Mopar Contributor
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    Re: need some help

    if you have a wideband that you can log then you can import that log into mptune and use it to help adjust you PE table.
    89 Voyager LE, 2.5T2 - rest in peace
    87 Charger Shelby T2 (2.4 conversion in process)

  6. #6
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    Re: need some help

    i do have a wideband i can log but not sure how to sync it with the rpm or throttle position to make it useable in mp tune,

    i did just check into comparing the tables in my cal to the stock vnt 415
    pumping efficiency from rpm table is the same in both (stock)
    however the fuel part throttle and fuel full throttle tables are different, im thinking i can replicate mine in the 415 to get it closer to running my car right as a starting point. also the timing in the 415 should be less aggressive and allow regular gas ? mine ramp up early in vac from 1500-4500 witch might be a good thing for mpg ?

    i can post screenshots of my timing tables or id post the file if i knew how

  7. #7
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    Re: need some help

    im starting to think there may be some fault in the wiring somewhere or possibly the stock o2 sensor feeding it bad info because it use to run better (idle quality +mpg ) the o2 sensor was brand new but im not ruling that out along with the coolant temp sensor not reading correctly either of them would throw everything off i can check those in mp scan right ? just learning how to use this stuff

  8. #8
    We Todd D dot D Turbo Mopar Staff sdac guy's Avatar
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    Re: need some help

    Quote Originally Posted by Fox View Post
    .... also the timing in the 415 should be less aggressive and allow regular gas ?
    I don't know about that. On my VNT Daytona, the sticker on the inside of the fuel filler door, states "Unleaded Fuel Only, Premium Recommended"


    Barry
    86 Shelby Lancer Prototype
    90 Daytona Shelby VNT
    91 Spirit R/T



    For your questions about SDAC, please contact BadAssPerformance


  9. #9
    Rhymes with tortoise. Turbo Mopar Staff cordes's Avatar
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    Re: need some help

    Have you triple checked your cam timing? I'll be honest and say that I've never had gas mileage that low unless the cam was off.

  10. #10
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    Re: need some help

    well it dips into 10-11 afr at idle but is fine everywhere else, definitely not down on power but ill give it a check when i have some free time it use to get 20mpg consistently
    Last edited by Fox; 06-12-2017 at 04:00 PM.

  11. #11
    Moderator Turbo Mopar Staff Force Fed Mopar's Avatar
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    Re: need some help

    That is way too rich at idle. Should be around 15.

    I'm starting to pick up where Boost Button left off, I can build you a new cal w/ a years support. PM me for price if you're interested.
    Rob M.
    '89 Turbo GTC

    2.5 TIII stroker, 568 w/ OBX and 3.77 FD

  12. #12
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    Re: need some help

    well pulled some stuff apart to check the timing and after wiggling the harness around the idle is back to normal around 14. something over by the sbec area i think. not surprising with the condition of some of the wires so its just down to fixing that then maybe ill be ready to get another cal not sure if im going to fix this harness or just get a better one, this isnt the first time ive had issues with things just going wrong randomly

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