Bigger Throttle Body

[bluegoat06]

Thanks Jaime, i maxed out the 1200rpm cell, and it's doing the same thing. in fact, throttle from idle is laggy as hell, i didn't know how laggy it was because in 2 months i've had ther car, i've never gave it throttle from a rolling idle until yesterday when i was testing, and my god, it takes a good second or more, by the time i push the throttle, and the time it takes for the car to move, say i'm rolling without touching the gas, just barely moving with the clutch out, but i'm not on the gas, then i give it some, and it lags badly, then it takes off, i'm not feeling this when i take her to 10-15mph and give her gas, but i figure if the throttle is not opening quick enough, that will be the reason why i'm not braking the tires loose.

Also, the amount of KR during this condition is a little too much considering the thottle input i was giving to her, the crazy stuff was i could also hear the engine rattling a bit , which i was also correlating in my logs KR with the 20-25% TPS ?
To fix it, i tried removing 5* from the WOT spark table for the .45-.75g aircharge from 900rpm-2000rpm, though as expected did nothing, then i did the same with the PT spark table where i was expecting to find the cure, to my surprise, i was still seeing KR upon a quick tip throttle, finally found a stupid launch spark table, that was adding a buch of timing when the coolant was 203-205F, i did set it 0, and that seemed to have fixed the crazy KR during idle launches, i made that table -3*, and i'll leave like that for the time being, no more rattles, i'm commanding 2* still in the tip-in throttle spark, as i don't want to take it off completely,as i figure i need a little bit for the wamer months.

Here are some screen shots with this idle roll KR
idle_KR1 by Wrangler RSM, on Flickr

idle_KR2 by Wrangler RSM, on Flickr


After making tht launch table negative
IDle_afterlunchSpark by Wrangler RSM, on Flickr

In any case i'm also attaching the new tune file

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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.

Will a stock TB benefit from the skewed numbers in the three ares? airflow Desired TB large & small?

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wasn't able to see any gains using the stock tb and adjusting the 3 tables for my srt4. If anything, it seemed 'sluggish'. Is that to be expected in my case (stock tb, 3 values decreased) ?

[B00STJUNKY]

wasn't able to see any gains using the stock tb and adjusting the 3 tables for my srt4. If anything, it seemed 'sluggish'. Is that to be expected in my case (stock tb, 3 values decreased) ?

In the event you're referring to a Neon SRT-4, of course adjusting TB Airflow won't have any effect on throttle response. You have a cable operated TB. These tricks/adjustments for improving throttle response are for drive-by-wire systems.

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Sorry, this is for the Caliber SRT.

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Does the changes to those aforementioned tables gain any benefits to a stock sized eTB?

[Hemituna]

Sorry, this is for the Caliber SRT.

Not sure about Caliber SRT but this defo applies to hemis and pentastars.

It can be used to get the ETC better as there are often airflow/tq limits at smaller (PT) pedal % commands.

So basically you get to a situation where you add and add to driver demand tables but the PCM wont allow any more TB.

These airflow changes enable you to get more TB opening before being limited (only at PT, WOT is always WOT).

Works on any size TB and is a major key to getting the pedal-feel correct in these things (most common complaint even stock!)

Driver demand tables will now respond correctly and if used with the flywheel power table you can get it super nice.

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Ok. Thanks for explaining it.

Now that i know those 3 tables function like that, i just now need to figure out which tables to change that will control and increase boost pressures.

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Not sure if the warmer temps are playing a role, but I've noticed the boost psi dances. It'll go above the preset psi by about 2 psi, then waiver down/up and fault to 5/5.5 psi. Happens in all gears depending the conditions outside and throttle given, but it is rather consistent in 5th and 6th gear. No DTC's were popping up until today. Low Boost Detected, I forget the code it displayed.

Wonder if the stock TB and the three flow numbers being changed has something to do with it?

[Hpindy]

I have a quick question on this topic. I have a 2018 challenger hellcat and a installed a fastman 99 mm throttle body and about every 80 miles or so on the highway I trip a P2173 code.. How do I stop this? What tables need to be adjusted to compensate for the 8-10% more air flow?

Thanks

[Chainyanker]

hpindy,

No guru here, in fact less then a newbie ...

I would guess, Airflow under
Engine
..Airflow
...Electronic Throttle
....Throttle Body Model

Like I said, I know NADDA, just trying to learn.

[Jay@HAP]

I have a quick question on this topic. I have a 2018 challenger hellcat and a installed a fastman 99 mm throttle body and about every 80 miles or so on the highway I trip a P2173 code.. How do I stop this? What tables need to be adjusted to compensate for the 8-10% more air flow?

Thanks

You may be able to take of the issue on the ENGINE DIAG>AIRFLOW sections. There are a few things there for the P2173 DTC. I know with the Whipple TB they needed to be changed, not for sure with the one you have.

[Hpindy]

I tried changing the values in there but all it did was make the car jerky and hang the idle ..
Thanks for the suggestion

[Hpindy]

You may be able to take of the issue on the ENGINE DIAG>AIRFLOW sections. There are a few things there for the P2173 DTC. I know with the Whipple TB they needed to be changed, not for sure with the one you have.

It's a factory throttle body bored and a bigger throttle blade installed .

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I tried changing the values in there but all it did was make the car jerky and hang the idle ..
Thanks for the suggestion

Did u lower or increase the #'s?

[coanan]

https://forum.hptuners.com/showthrea...-Throttle-Body

[Hpindy]

Did u lower or increase the #'s?

Increase the numbers 8%

[Hpindy]

What I found that works so far is to do a "throttle relearn". With the vcm scanner. I did that and no codes in 500 miles ..

[Moparmatty]

I am trying to get the throttle body to follow the pedal on my 2006 SRT 300C.

Am I correct that I need to just keep lowering these table values until the throttle body opens fully when WOT is reached? Or am I just missing adjusting something else?

Untitled (1).png

Here is a screen shot of a log where you can see the throttle opening does not match the pedal.

Untitled (2).png

2006 SRT8 300C_CL_V30.hpt
V30 Thrash.hpl

[B00STJUNKY]

I am trying to get the throttle body to follow the pedal on my 2006 SRT 300C.

Am I correct that I need to just keep lowering these table values until the throttle body opens fully when WOT is reached? Or am I just missing adjusting something else?

Untitled (1).png

Here is a screen shot of a log where you can see the throttle opening does not match the pedal.

Untitled (2).png

2006 SRT8 300C_CL_V30.hpt
V30 Thrash.hpl

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.