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Thread: Bigger Throttle Body

  1. #81
    Quote Originally Posted by B00STJUNKY View Post
    To help clarify the question, are you expecting that Throttle Position Sensor voltage should be higher than 3.8 to be considered at WOT, and following pedal? Or is it that you are seeing Throttle Position Sensor voltage hit WOT conditions (3.8 volts) before your pedal position is actually at WOT command? I ask because I see that your Trans Pedal is showing 100% pretty much exactly when your TPS voltage reaches WOT conditions (3.8 volts - which is possibly/probably the intent of the control method for tcm to follow TB WOT conditions, rather than pedal itself), but then I also see that your TPS voltage is reaching WOT state before Throttle % ever reaches WOT conditions.

    I can say given the experimentation I've done with my '06 JGC SRT-8 that the smaller you make your airflow values in the throttle tables, the more the TB opens given a pedal position. So, say you went to multiply the stock TB flow values by .5 (effectively halving the flow values per pedal position), and say that before altering airflow values, 20% pedal would result in 15% TB opening at a given NV Ratio. Now, after halving the airflow values, the same 20% pedal would result in 30% TB opening at the same NV Ratio.

    It's a case of the PCM using a strategy something like this. The driver demand table (pedal percent power request) says that at 20% pedal, we expect to see 23% of max power delivery. Power is calculated from a combination of constants (engine size vs V.E. - I'm sure that's a simplified statement) and variables (atmospheric and other conditions) and a derived airflow is reached for that power request. PCM looks at the TB airflow table, and using the target airflow calculated from the power percent request along with all the other aforementioned constants/variables, it picks the Throttle Position Percentage that matches that calculated required airflow to reach driver demand.

    So, looking at it in that fashion, you can see why driving down the TB Airflow model will result in an overly sensitive pedal. And vice versa, drive the TB Airflow model up, and you'll end up with a laggy pedal. And I think within the wording "TB airflow model" lies the key to understanding the strategy. If you look at those TB airflow tables as "airflow models" rather than "request tables" (which we've established they aren't), it becomes clear as to why things respond the way they do when you mess with them.
    What I am trying to accomplish is having the throttle body % (making the assumption this is the actual throttle body opening) be fully open when the trans pedal, accelerator pedal power & throttle voltage are at 100%(throttle voltage @ 3.80V) just as if it were a cable operated throttle body.
    2006 Chrysler 300C SRT-8
    Stock headers and cats
    Mopar CAI
    Innovate dual WBO2 sensor kit
    Custom tuning by me via HPT

  2. #82
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    Quote Originally Posted by Moparmatty View Post
    What I am trying to accomplish is having the throttle body % (making the assumption this is the actual throttle body opening) be fully open when the trans pedal, accelerator pedal power & throttle voltage are at 100%(throttle voltage @ 3.80V) just as if it were a cable operated throttle body.
    You might want to check your polling rate for the Throttle % PID to see if it's set too slow for it to capture the change accurately. It appears, based off of your trans pedal and throttle volts that you're getting about as quick a response as one can expect from ETC. 3.8 volts is considered WOT. I see in your screenshot a slight delay between the TPS Volts to WOT vs the Trans Pedal showing 100%.

    That too could possibly be a polling rate difference between those PIDs. I think you are probably already aware of how to check/change polling rates, but if not, it's just a matter of right clicking on the PID in question in the parameter list.

  3. #83
    Quote Originally Posted by B00STJUNKY View Post
    You might want to check your polling rate for the Throttle % PID to see if it's set too slow for it to capture the change accurately. It appears, based off of your trans pedal and throttle volts that you're getting about as quick a response as one can expect from ETC. 3.8 volts is considered WOT. I see in your screenshot a slight delay between the TPS Volts to WOT vs the Trans Pedal showing 100%.

    That too could possibly be a polling rate difference between those PIDs. I think you are probably already aware of how to check/change polling rates, but if not, it's just a matter of right clicking on the PID in question in the parameter list.
    The last tune and log are posted above with my screen shots if you want to have a look.

    Polling rates are all listed as 0ms (Fastest).

    It just feels like the throttle body isn't open fully until it shows the Throttle % PID @ 86% well after the Throttle voltage hits 3.80V.

    Obviously it could just be the fact that a looser converter would help, and that I am chasing trying to fix something that isn't broken.

    I need to put it on the dyno and run it without the CAI on it so I can watch the TB when I mash the throttle I guess.

    It also doesn't help that the TCC starts to lock once WOT is reached. Something that I think can only be rectified with the addition of some WOT TCC apply and release tables.
    Last edited by Moparmatty; 08-26-2018 at 11:35 PM.
    2006 Chrysler 300C SRT-8
    Stock headers and cats
    Mopar CAI
    Innovate dual WBO2 sensor kit
    Custom tuning by me via HPT

  4. #84
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    Resurrecting this thread.....

    Found this linked to another "throttle lag" thread and there's some good information here. I don't have a hemi vehicle but the current vehicle I'm trying to tune is a 2013 Dart with the 2.0 and M6 trans. I've looked over a few cals for the hemis and they are very similar to my GPEC2 cal. Unfortunately my calibration doesn't seem to have nearly as many defined parameters but it does have the throttle flow and the inverse large/small tables. The scanner def doesn't seem to have nearly as much as well, and no torque req items to log. Not sure if HPT didn't care enough to define everything and I fear there is enough missing to prevent me from finding a solution to reducing the terrible throttle lag.

    Yesterday I thought I had a breakthrough after adjusting the TB airflow Large table. Raised up the demanded airflow across most of the voltage range and it immediately made a night/day difference. The throttle response was immediate and without any delay. Too bad that was short lived after a very short test drive that sent the engine to redline after a shift. Tried reducing the airflow per voltage cells down until the throttle didn't hang and send the engine RPM to the limiter, and it ended up near the original values, even .2-3 added would cause the engine speed to hang and push the car like cruise control was set. Even tried to match the TB airflow model to the large range table and that didn't do anything.

    After reading multiple threads again today with suggestions to lower the TB airflow model table, I tried that. Didn't make one bit of difference at all. I even tried dropping all the values to 1 across the table and not one bit of difference. I'm beginning to think this table isn't actually changing anything within the calibration or this table is just there for reference.

    Last year i spent alot of time tweaking the pedal power request tables and while it seems like it made a difference, it did nothing but demand more power at less pedal, and the horrible lag was still there.

    Help?


    Thanks!

  5. #85
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    Quote Originally Posted by Hemituna View Post
    I have a 700whp Whippled 6.4 with a hellcat 95mm TB that has the max TB airflow number as 400.
    Just to check - is that 400 max number on the Sonic table, or one of the others?

  6. #86
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    Quote Originally Posted by Hemituna View Post
    Take the factory flow numbers with a grain of salt.
    Don't be afraid to play with them.
    I have a 700whp Whippled 6.4 with a hellcat 95mm TB that has the max TB airflow number as 400.
    Why?? because P/T responsiveness/drivability is soooooo much better with smaller numbers.
    The factory numbers above 1v are too big. Above 1.5- 2v, they are waaaay tooo big.
    Fit a larger TB and drive it and it will feel better...Add 10-15% to TB tables as you 'should' do and it goes back to feeling like it did prior to the mod.
    So try a bigger TB and smaller numbers and hey it now feels even better... go figure!!
    The idle areas 0 -.5v will sometimes need adjusting to a slightly larger number to get that area correct.
    Quote Originally Posted by Hemituna View Post
    Let me explain the above a little more.........
    A stock 6.4L tune has the WOT airflow limit as 353 g/s.
    But the TB table goes to 1100 g/s ??
    So how does that work??
    Now, if you log max airflow on a stock 6.4, the biggest number will be 350-360 g/s.
    So 350 g/s makes 475hp it seems....So why is everyone using 1000 - 1500 g/s to make 100-300hp more???
    The factory it seems has imbedded an airflow model in the PCM, hence why you must designate an engine capacity.
    Now this model only affects P/T operation. Between the TB airflow and what they deem the engine requires at P/T,
    the TB will track an airflow target. Now WOT is WOT and the TB will open 100% no matter what the numbers are in the tables.
    But P/T between 25 - 75% throttle, you are limited to the numbers in the model. So if the 6.4 is in P/T mode it will never open the TB past 353 g/s whether at 30% pedal or 70%. Most never notice this. If you move WOT threshold lower, you notice it less. BUT, if you make the airflow tables bigger, the gap between P/T and WOT gets even greater.
    If you make the numbers bigger, the TB will be opened less until it goes WOT.
    If you try and increase the ETC tables, what often happens is the ETC opens the TB, the airflow exceeds what's allowed and the ETC is forced to close the TB. So you get this strange surging effect.
    Why the factory has done this is to give the engine the amount of TB that they feel it needs at certain rpm to maintain velocity/airflow/smooth the torque curve or whatever!
    However, when modding or adding a blower, this is now not ideal.
    So following their lead with TB flow tables often wont get the result you are after.
    On a blower engine, 50% pedal, wont give enough TB opening to make much boost so you don't get 50% power. so you keep leaning on the pedal till finally it goes WOT and BAM - full boost and look out! The often talked about light-switch effect! This same response is felt when NA also.
    The trick I have found is to lower (a lot!) the 3 TB airflow tables in the .75 -1v and above areas.
    This will give a much more linear pedal to the point where the transition to WOT is seamless.
    The added benefit is that you no longer hit lots of Airflow/Tq mgmt limits!
    Keep in mind the stock airflow max numbers and give it a try.
    We can talk more about NOV and Wheel Power tables later.......
    Does this apply with the Pentastar engine as well? I have a hemi TB on it. I copied over airflow tables from a stock 5.7 Challenger, but it feels better with the stocke 3.6 tables. Just curious as to what I should do if anything?

  7. #87
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    Quote Originally Posted by gokart2 View Post
    Does this apply with the Pentastar engine as well? I have a hemi TB on it. I copied over airflow tables from a stock 5.7 Challenger, but it feels better with the stocke 3.6 tables. Just curious as to what I should do if anything?
    Absolutely applies to pentastar.
    I use 150-160g/s as the max flow number for TB and small/large tables on blower pentastars with 80mm Hemi TB's
    Try similar on your NA.

  8. #88
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    FYI...the throttle body model is simply a characterization of mass flow at different throttle positions with a fixed pressure drop resulting in air moving at the speed of sound through the throttle. Even the 6.4 at 6500rpm isn't going to draw an 80mm throttle down to low enough pressure to create sonic flow. So while your throttle is technically characterized to flow 1000+ g/s, you can't create that draw on it. Even with a roots blower it would be difficult.

  9. #89
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    Quote Originally Posted by Hemituna View Post
    I have a 700whp Whippled 6.4 with a hellcat 95mm TB that has the max TB airflow number as 400.


    Spectacular Noob question...

    I've found the Large Range and Small Range tables (under Engine > Airflow > Electronic Throttle)

    What I can't find is the Throttle Body Airflow table - can someone give me a clue where I should be looking please as it's driving me slightly nuts


    Car is a 2015 Challenger SRT392 A8, with a whipple 426 fitted.

  10. #90
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    Go to the top under EDIT>NAVIGATOR. You can search for tables there where it says [Text Filter]

    In the file I'm looking at it's called Throttle Body Model and the button is Airflow
    If in doubt, multiply everything by 1.1.

  11. #91
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    Quote Originally Posted by spoolboy View Post
    Go to the top under EDIT>NAVIGATOR. You can search for tables there where it says [Text Filter]

    In the file I'm looking at it's called Throttle Body Model and the button is Airflow
    What a very useful feature - thank you for point it out to me


    Now, I've searched on "throttle" "airflow" "ETC" and a few other similar terms - and the only two tables I can find are large and small range, not the third... So that's confusing - do you have the table number for yours for me to see if I can search on that please?





    ***EDIT / UPDATE***

    Edit Menu > View > Advanced

    Table has appeared now
    Last edited by Dex_UK; 08-20-2020 at 05:43 PM.

  12. #92
    Tuner in Training Hammersrt's Avatar
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    I changed my throttle body from a 90mm to 105mm. Started up runs ok but not right. So i pull up my scanner and do a relearn on the throttle body thinking this would help. Now I'm running super lean and can't drive worried about damage. I'm new to this and my car is a 2012 Dodge Challenger 6.4 thats stroked to 430 cubes. I had it tuned but after the tune I would get a throttle light and would cut power, I would pull over restart and everything is ok. Tuner says its a bad throttle body so I bought a bigger and better one and this is where I'm at. Why did the relearn make it go lean? How can I get the AFR right to get this to where I can drive it? NEED HELP PLEASE

  13. #93
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    iwould like to pick your brain im not just a neb im a master b6tech just wrapping ,my head ariund this

  14. #94
    Quote Originally Posted by Hemituna View Post
    Absolutely applies to pentastar.
    I use 150-160g/s as the max flow number for TB and small/large tables on blower pentastars with 80mm Hemi TB's
    Try similar on your NA.
    Hello Hemituna,

    when you do that you also change in engine diagnostic AIRFLOW MAX RPM or something else ?

    Thanks in advance

  15. #95
    Quote Originally Posted by RedShark_JK View Post
    Hello Hemituna,

    when you do that you also change in engine diagnostic AIRFLOW MAX RPM or something else ?

    Thanks in advance
    Getting P2173 also,

    I increases engine diagnostic AIRFLOW MAX RPM already, not sure if that is required ?? (please advise)

    saw in another thread to enable sensed MAP, currently i have it disabled will enable it and tr again

  16. #96
    Quote Originally Posted by RedShark_JK View Post
    Getting P2173 also,

    I increases engine diagnostic AIRFLOW MAX RPM already, not sure if that is required ?? (please advise)

    saw in another thread to enable sensed MAP, currently i have it disabled will enable it and tr again
    Ok so I have enabled the Sensed Map and also did Throttle Relearn,
    Should have done one by one to see each effect ��

    So far no more P2173, but can't stop thinking about it what fixed it
    Senses Map or Throttle Relearn ����

  17. #97
    Tuner in Training Hammersrt's Avatar
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    I'm new to tuning and I installed a bigger TB. I went from 90mm to 105mm. Installed running lean in spots and on WOT super rich. I did a relearn on the TB and then my problems really begun. Went way lean and started surging at Idle. Why would a relearn cause this? I started working on the TB base settings and have it idling much better...still learning

  18. #98
    Tuner in Training Hammersrt's Avatar
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    Large Throttle Body

    Quote Originally Posted by mxatunerjg View Post
    Here is the part I don't seem to be getting with everything. Like Hemituna I have found matching the 3 TB tables does not net the results that it seems they should. The bigger thing that I've found though, when running a bigger cam, or anything that generally requires more airflow at idle or higher idle, seems to react best to increasing the airflow values in the Throttle Body Airflow table and only that table. The part I struggle with is in theory this should cause the throttle body to run less throttle position. It does just the opposite in practice, at least in every situation I've encountered. Can anyone explain this?
    I have installed a 105mm TB. playing with the TB table....went way lean and I increased making the numbers larger to get the AFR's much better but still not right.....looking at the STFT and the LTFT they show way rich but the WB shows just in the safe zone. So I'm going to try your above .5 volt and cut 20% and see what happens

  19. #99
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    greetings peeps. what is the max airflow for a 08 throttle body?
    By the prickle of my thumb something wicked this way comes!2008 Chrysler 300c! 2013 heads/220/230 comp cam/LTheaders/FTI 2600 stall converter.

  20. #100
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    Need more debate on this.

    I installed a 108 N Williams on my Gen5 Whipple. Waiting on trans to fire it up.

    What am I looking at for changes going from the 84 +4 TB?
    2018 Trackhawk PCM/TCM tune by Dusterhoff.
    Flex Fuel, MMX faux 95mm TB, GripTec 2.85, 10% ATI lower, FIC1200, ARH 1 7/8 w/cats, 180 T-stat

    13 Chrysler 300S, RAM BGE 412 stroker, cam motion 232/246 619/619 118 +4, ATI 18% OD pulley
    Whipple Gen5 3.0, 2.50 upper pulley, Smooth Boost controller, FIC 1200 inj. Nick W 108mm TB, FORE dual return fuel system, E85, FTI 2800 stall(SRT83380), SHR WAR Viking trans and valve body, Getrag 3.73, 1 7/8 kooks w/hi-flow cats, 3" Magnaflow Cat-back 943rwhp