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Thread: Turbonator Pump Shot tuning

  1. #1
    Moderator Turbo Mopar Staff Force Fed Mopar's Avatar
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    Turbonator Pump Shot tuning

    I've been changing this a lot lately but it never seems to make much difference. The problem I'm trying to correct is lean stalling on cold start running when letting the clutch out and my foot on the gas. When I rev it up and try to back up out of the driveway, as the vacuum drops it goes super lean and tries to stall. It does it hot also but nowhere near as bad. It's there while driving also but it doesn't try to stall since the car is moving. If I'm cruising at 2k rpm and stab the gas, it spikes lean for a sec and jolts the car a little. It seems to be a MAP pump shot issue but not sure. I'm running a 3-bar and +40's, set injector scaling for 58# injectors which has always worked good before.

    Is there a trigger level that needs adjusting? I don't quite understand delta and hysteresis yet...
    Rob M.
    '89 Turbo GTC

    2.5 TIII stroker, 568 w/ OBX and 3.77 FD

  2. #2
    turbo addict Turbo Mopar Contributor
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    Re: Turbonator Pump Shot tuning

    What does pump shot mean?
    Brent GREAT DEPRESSION RACING 1992 Duster 3.0T The Junkyard - MS II, OEM 10:1 -[I] Old - 11.5@125 22psi $90 [U]Stock[/U] 3.0 Junk Motor - 1 bar MAP [/I] 1994 Spirit 3.0T - 11.5@120 20 psi - Daily :eyebrows: Holset He351 -FT600 - 393whp 457ft/lb @18psi 1994 Spirit 3.0T a670 - He341, stock fuel, BEGI. Wife's into kid's project. 1990 Lebaron Coupe 2.2 TI/II non IC, a413 1990 Spirit 3.0 E.S. 41TE -- 1993 Spirit 3.0 E.S. 41TE -- 1994 Duster 3.0 A543 1981 Starlet KP61 Potential driver -- 1981 Starlet KP61 Parts -- 1983 Starlet KP61 Drag 2005 Durango Hemi Limited -- 1998 Dodge 12v 47re. AFC mods, No plate, Mack plug, Boost elbow -- 2011 Dodge 6.7 G56

  3. #3
    turbo addict Pat's Avatar
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    Re: Turbonator Pump Shot tuning

    He's referring to the equivalent of an accelerator pump on a carb.

  4. #4
    Visit www.boostbutton.com... Turbo Mopar Contributor ShelGame's Avatar
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    Re: Turbonator Pump Shot tuning

    Quote Originally Posted by Force Fed Mopar View Post
    I've been changing this a lot lately but it never seems to make much difference. The problem I'm trying to correct is lean stalling on cold start running when letting the clutch out and my foot on the gas. When I rev it up and try to back up out of the driveway, as the vacuum drops it goes super lean and tries to stall. It does it hot also but nowhere near as bad. It's there while driving also but it doesn't try to stall since the car is moving. If I'm cruising at 2k rpm and stab the gas, it spikes lean for a sec and jolts the car a little. It seems to be a MAP pump shot issue but not sure. I'm running a 3-bar and +40's, set injector scaling for 58# injectors which has always worked good before.

    Is there a trigger level that needs adjusting? I don't quite understand delta and hysteresis yet...
    http://www.turbo-mopar.com/forums/kn...BEC-Tuning-FAQ

    Most of the way down, there's an explanation of the PumpShot values...
    https://db.tt/SV7ONZpQ
    Rob Lloyd
    '89 Daytona C/S

    2.5 T1 Auto
    13.24 @ 100.5mph
    NHRA #3728 AF/S

    boostbutton.com
    tuning wiki

  5. #5
    boostaholic
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    Re: Turbonator Pump Shot tuning

    Quote Originally Posted by ShelGame View Post
    http://www.turbo-mopar.com/forums/kn...BEC-Tuning-FAQ

    Most of the way down, there's an explanation of the PumpShot values...
    Rob,

    I believe your documentation on the pump shot, and its associated scaling for larger injectors has an error. On my GLHS (Turbonator GLHS) I've had trouble with an extremely rich transient enrichment and have been doing some experimentation. I noticed reducing the values in the THRTCN table actually increases transient fueling, setting them to zero eliminates transient fueling, and scaling the table to larger values reduces transient enrichment fueling. This table is scaled down by default with larger injectors and really creates a mess of the transient fueling when using large injectors (in my case, 72 lb/hr). The injector scaling increases fueling by reducing THRTCN, so you end up with huge amounts of transient fuel due to the increased pulsewidth from THRTCN on top of the larger injectors.

    I fought this issue for a few months and finally have it resolved. Please try to update this in the scaling routine so other people don't run into the same issue. I set the values in THRTCN to their minimum non-zero value and the car was nearly undriveable.

  6. #6
    Visit www.boostbutton.com... Turbo Mopar Contributor ShelGame's Avatar
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    Re: Turbonator Pump Shot tuning

    THRTCN isn't scaled for injectors, nor should it be. It's an averaging factor (filter) for the TPS. So, a higher value equates to a 'heavy' filter; and a lower delta TPS, meaning a smaller pumpshot. A value of zero would mean no averaging.

    The specific size of the injectors should have no bearing at all on this table. The size of the throttle body, yes.

    But, you're right; my description of how THRTCN (and AESLOP) affect transient fueling is backwards.

    Also, there doesn't seem to be a table that directly affects transient fuel by TPS in the GLHS cal (maybe the '87 T2 LM cal too, since they're basically the same). I'll have to look at it some more to understand how the TPS transient affects fueling.
    https://db.tt/SV7ONZpQ
    Rob Lloyd
    '89 Daytona C/S

    2.5 T1 Auto
    13.24 @ 100.5mph
    NHRA #3728 AF/S

    boostbutton.com
    tuning wiki

  7. #7
    Visit www.boostbutton.com... Turbo Mopar Contributor ShelGame's Avatar
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    Re: Turbonator Pump Shot tuning

    Fixed the GLHS code. See the T/GLHS thread. No impact to the other codebases. It was only a dis-assembly error for the GLHS code...
    https://db.tt/SV7ONZpQ
    Rob Lloyd
    '89 Daytona C/S

    2.5 T1 Auto
    13.24 @ 100.5mph
    NHRA #3728 AF/S

    boostbutton.com
    tuning wiki

  8. #8
    boostaholic
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    Re: Turbonator Pump Shot tuning

    Rob,

    You are right, MP Tune didn't scale this with the injectors. However, the car did not run correctly until I increased the values in this table. If there is a better way to correct the transient enrichment fueling, let me know, as the default injector scaling didn't seem to scale the transient enrichment. It caused the A/F ratio to drop to less than 10:1 and cause misfires in my case without adjustment. As of right now, I have the THRTCN table scaled up and the map based transient enrichment tables zeroed out. Right now the car runs better than it ever has with these injectors (and the A/F only drops to about 12:1 on quick throttle inputs).

    Quote Originally Posted by ShelGame View Post
    THRTCN isn't scaled for injectors, nor should it be. It's an averaging factor (filter) for the TPS. So, a higher value equates to a 'heavy' filter; and a lower delta TPS, meaning a smaller pumpshot. A value of zero would mean no averaging.

    The specific size of the injectors should have no bearing at all on this table. The size of the throttle body, yes.

    But, you're right; my description of how THRTCN (and AESLOP) affect transient fueling is backwards.

    Also, there doesn't seem to be a table that directly affects transient fuel by TPS in the GLHS cal (maybe the '87 T2 LM cal too, since they're basically the same). I'll have to look at it some more to understand how the TPS transient affects fueling.

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