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Thread: Throttle cracker activate/deactivate

  1. #1
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    Default Throttle cracker activate/deactivate

    messed with the activate/deactivate speed today...changed to 10 and 9...yet below 10mph ie 8mph and 4 mph per the TC table still seems to jump a tiny bit of rpm when it hits those and still wants to die sometimes when rolling to a stop...so it still seemed like it was adding that airflow in when it hit 8 and 4 even tho i had it activated at 10mph and deactivated at 9mph....do i need to zero out the TC table to achieve this at 8 and below or what?

  2. #2
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    another questions...when does my car use the base timing in gear and when does it use the LO or HO spark tables...ETC car 02Z06....experimenting with some stuff to chase down this dreaded bucking

  3. #3
    R.I.P Shawn, 1956-2011 WeathermanShawn's Avatar
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    Well, remember your have Throttle Follower Airflow and your Desired Airflow are also contributing to your total airflow.

    My TC table is almost zeroed out in the lower RPM's, but I followed the Idle Tutorial and added more air via the TF.

    Usually more air keeps your RPM's up. Stalling might be fueling, spark, or not enough air. I have 4g/s in my 400 RPM row on the TC table just to insure I have enough air if the RPM's drop.

    Are you sure that your stalling is TC related? I did not mess around with the activate/deactivate function speed at all. I believe if you deactivate TC, the TF is also deactivated. You might not have enough airflow if you are stalling.
    Last edited by WeathermanShawn; February 9th, 2010 at 11:39 PM. Reason: Grammer
    2002 Black Camaro Z-28 M6 Hardtop 11.0:1CR 425HP/410TQ SAE (400TQ@3500RPM)
    200cc Heads, 228/232 110+2 Cam, 1 3/4" LT's w/catts, GMMG, Koni Shocks, Hotchkis Springs, 35/21 Sways, 17" ZR1's, 3.90 Gears Roadrunner PCM LM-2 Serial Wideband
    EFILive Closed-Loop MAF/SD Hybrid Tune..


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    i guess i'll turn this into a thread of questions....initial startups on my car...commanded is per my CFOL table but actual per my WB is wayyy leaner IE 15:1....same on hot starts....can i help this with the charge temp blending table? and if so which way should i go?

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    Quote Originally Posted by WeathermanShawn View Post
    Well, remember your have Throttle Follower Airflow and your Desired Airflow are also contributing to your total airflow.

    Not sure exactly what you are encountering. My TC table is almost zeroed out in the lower RPM's, but I followed the Idle Tutorial and added more air via the TF.

    Usually more air keeps your RPM's up... stalling might be fueling, spark, or not enough air. In fact I have 4g/s in my 400 RPM row on the TC table just to insure I have enough air if the RPM's drop.

    Are you sure that your stalling is TC related? I did not mess around with the activate/deactivate function speed at all. I believe if you deactivate TC, the TF is also deactivated. You might not have enough airflow if you are stalling.

    Let us know how it works out.

    ..WeathermanShawn..
    thanks for the response...watching my afr...Ltrims turned off but closed loop enabled only using strims...my average Strim value last drive was only a couple percent and it follows stoich very close...dont think its fueling...nor do i think my bucking is coming from fueling...prob nature of my cam but i like to think not My stalling is not bad at all...its more of a finicky thing 8 of 10 stops are fairly good...2 dip down and i also have 3 grams in the 400 row to help a stall. I have my idle learning set to where it will not take away any airflow only add if needed and watching STIT's the average is pretty close as i got my desired airflow is pretty much where it needs to be.
    Also recently did a maf bypass with a 3.5" ID pipe...my kpa at idle went from 68 or 69 to 63-64....my problems i describe arent new though
    what did you do with your timing tables...ie base and HO and LO tables...matched or what? And where you were bucking in the .08-.20 grams part on the timing table...what timing values seemed to smooth out your bucking?
    Reason i think its TC is its usually clutch in rolling idle kind of a deal....from what i read this is when TC is active and TF is not....i havnt really messed with the TF...should i read up on it more?

  6. #6
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    BTW shawn...how do you like working at Denver airport? Im a Air Traffic Controller Tower guy in the USAF in NC...prob will get out after my enlistment and work FAA, DOD, or Contract work.

  7. #7
    R.I.P Shawn, 1956-2011 WeathermanShawn's Avatar
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    Denver is great. Weatherman's dream.

    Did USAF for 7 years (2 enlistments) including Fulda Germany, Offutt AFB, and Altus in OK. Got out and have been in Aviation Meteorology since. Re-started up my interest in cars with the last year of LS1 Camaro production (2002).

    I basically got Desired Airflow lined up with RAFIG..my car still wanted more air, and worked a lot on lowering the air in the TC Table . Really no more than .25-1g for most Rpms. Added air with the TF because I personally like the throttle response through the IAC with this parameter. When you push the throttle down you get more air. Release the throttle and the additional air decays.

    Working of the TC Table did more to alleviate my bucking than anything else. This was bucking that occurs at low cylinder air and with the foot off the throttle. I think with too much air (especially TC), the engine speed doesn't want to fall, but the cylinder air drops as you let off the throttle. By taking air out of the TC, engine speed falls more in sync with the rapid drop in cylinder air as you let off the throttle.

    As far as spark advance..I did many many trial and error runs. Some with very little spark, others matching HI-Low & Base Spark and others with a lot of timing. For me it worked out to be the opposite of what others have found. My car was more smooth in deceleration, throttle response, and had less bucking with more spark advance in the .08-.20 g/cy range.

    Spark advance changes did not effect my bucking issues at all. Lowering the TC air cured 95% of the problem for me. My car does not require much timing at WOT, so the slope of my timing curve is quite steep. But, I like the throttle response with higher spark advance in low cylinder air areas, and then it drops off rapidly as I got WOT. I match my Hi-LO, and Base Spark tables.
    Last edited by WeathermanShawn; February 9th, 2010 at 11:43 PM. Reason: Grammer, Length..
    2002 Black Camaro Z-28 M6 Hardtop 11.0:1CR 425HP/410TQ SAE (400TQ@3500RPM)
    200cc Heads, 228/232 110+2 Cam, 1 3/4" LT's w/catts, GMMG, Koni Shocks, Hotchkis Springs, 35/21 Sways, 17" ZR1's, 3.90 Gears Roadrunner PCM LM-2 Serial Wideband
    EFILive Closed-Loop MAF/SD Hybrid Tune..


  8. #8
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    Cool, I got a few buddies at the weather shop i play golf with and had lots of weather buddies when i was in Keesler for tech school a couple years ago.

    care to show your tune off? I'd like to check out the TC and TF...i made some changes last night to my TC lowering it and upped the desired air just a hair as idling stopped my idle trims would be positive. Do remember I have a ETC car.
    Anything on why my startups are lean even though commanding rich? Looking at that charge temp blending table...it references the MAF...I no longer run a maf...i took it out and installed a IAT sensor and wired it in.
    Also made some additional changes to my timing tables upping the timing values in the 1200-2000rpm section .08-.20 grams...I'll try matching my timing tables again and see what happens...I had it this way before...
    also let me state 95% of my bucking is light throttle...off throttle it rarely bucks....which TF airflow table do you change? the multipier? decay rates? airflow? All of them?
    Im gonna be doine a few WOT pulls on the highway to get my WOT AFR a little tighter and may hit the dyno this weekend...shootin for 480rwhp
    made 469rwhp 417rwtq before my most recent round of changes

    Quote Originally Posted by WeathermanShawn View Post
    Oh yea, Denver is great. Weatherman's dream.

    Did USAF for 7 years (2 enlistments) including Fulda Germany, Offutt AFB, and Altus in OK.

    Got out and have been in Aviation Meteorology since. Re-started up my interest in cars with the last year of LS1 Camaro production (2002).

    Yea, figuring out all the air parameters almost drove me nuts. I basically got Desired Airflow lined up with RAFIG..my car still wanted more air, and worked a lot on lowering the air in the TC Table . Really no more than .25-1g for most Rpms.

    Added air with the TF because I personally like the throttle response through the IAC with this parameter. When you push the throttle down..more air..release the throttle..air goes away (TC+Desired,etc).

    In all honesty, the working of the TC Table did more to alleviate my bucking than anything else. Now this was bucking that occurs at low cylinder air and with the foot off the throttle. I think with too much air (especially TC), the engine speed doesn't want to fall, but the cylinder air drops as you let off the throttle. By taking air out of the TC, engine speed falls more in sync with the rapid drop in cylinder air as you let off the throttle.

    As far as spark advance..I did many many trial and error runs. Some with very little spark, others matching HI-Low & Base Spark and others with a lot of timing.

    For me it worked out to be the opposite of what others have found. My car was more smooth in deceleration, throttle response, and had less bucking with more spark advance in the .08-.20 g/cy range.

    Perhaps stating it differently, spark advance changes did not effect my bucking issues at all. Lowering the TC air cured 95% of the problem for me. My car does not require much timing at WOT, so the slope of my timing curve is quite steep. But, I like the throttle response with higher spark advance in low cylinder air areas, and then it drops off rapidly as I got WOT.

    I match my Hi-LO, and Base Spark tables. Just makes it easier for my mind to sort it out when testing.

    Sorry, for the book response here. Hey, I got a lot of open roads out here and the job does not eat up as much time as previous ones.

    Need any more help, let us know. Every car is different, just letting you know what worked for me.

    ..WeathermanShawn..

  9. #9
    Joe (Moderator) joecar's Avatar
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    You can edit your modification history.

  10. #10
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    Quote Originally Posted by joecar View Post
    You can edit your modification history.
    How is that accomplished Joe? I've often wanted to do that just in an effort to clean it up after working through a tuning issue but could never figure out how.

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