Viper Drive-by-wire Throttle Response Tuning Issues

[MeentSS02]

It's still recommended, but I know of quite a few Gen 5 owners that were able to get around it. I had the relearn done on my Gen 4.

[MeentSS02]

Pulling in from another thread that I completely derailed:

Question: on the Gen 4 Viper, we have a drive-by-wire table labeled Pedal Percent Torque Request - it is very similar to Ram's Pedal Percent Power Request table, only instead of being set up in terms of pedal voltage and NVRatio, it is set up by pedal % and RPM, with the values in the table being the % of torque being requested.

Here's the actual question: for the percentage of torque being requested, what is it a percentage of? Max torque at the given RPM?

Should be the percent of the max torque value overall, not max torque by rpm. I would think of it the same way our tables are setup in the NGC3 and NGC4 PCMs. think of it as a relative table, if you want more power delivered with less pedal, raise up the values by a certain percentage in the left columns of the table.

Allow me to expand - I have to work within the confines of this:



In this case, REP mode causes the most ridiculous stumbling, spitting and general nastiness you've ever seen, enough so that you can't even drive the car until you shut it off and do a reflash. Heaven help you if you are on a road without a shoulder to pull off on to.

I can log something referred to as "potential torque" from the list of PIDs I have available, which varies by RPM. There's another table in the editor, seen here:



Where the peak torque also varies by RPM. Unfortunately, this table does not match up to the logged potential torque PID (the logged values are substantially higher than the values in this table).

Bottom line: if I can figure out what is being referenced by the Pedal % Torque Request table, I can work around the 120 N-m bounds to alter the throttle response without triggering limp mode. I can log the actual calculated torque values, so I just need this other part of the puzzle. At least that's what I'm trying to do.

what do you see under your Engine Diagnostic tab, in the General tab?

This:



The problem with the Gen 4/5 Venom PCM is that it is unique to this platform, and uses a different base code than the rest of the Mopar lineup.

Alright so now I see what is missing and what the engineers is saying is encrypted, we have access to the allowable torque difference, you do not.

I would setup a log and setup a graph identical to that peak torque table, with rpms same as the table across the top and log the torque coming out. If you have a log already you can set it up and itll fill it in. We need to see what values that thing is spitting out.

I already have that data and the histogram set up, although I've got it set up currently to only spit out values logged at WOT (since that would be as "peak" as you could get). Unfortunately, it is on my computer at home at the moment. I'll make another thread later since I've already done a fantastic job of derailing this one. My apologies.

Ok, I am curious to see the values that it is recording. Can you post up your screen shot of the Engine>Airflow>Electronic Throttle tab?

I've logged both the calculated actual torque and something called "potential torque" - at WOT, the actual torque values usually stay in the low 500 range, with potential torque values ranging from the mid to upper 500s to mid to upper 600s. I'll get you some screen captures when I get home this afternoon/evening.

also post up a screen shot of that tab mentioned in my previous post, might be some places to adjust the actual torque calc, or just post up your tune too and I can open on my end.

[MeentSS02]

As requested, attached are stock calibrations for a 2008-2010 Viper, and one for a 2013 Viper.

[MeentSS02]

Screen caps of the calculated actual and potential engine torque logged (these are WOT only):

Average Potential Torque vs. RPM:



Maximum Potential Torque vs. RPM:



Average Calculated Engine Torque vs. RPM:



Maximum Calculated Engine Torque vs. RPM:



Config and log file also attached for reference.

[MeentSS02]

So changing the Peak Torque table to match the logged maximum potential engine torque didn't do what I wanted...on a hard 2-3 shift or just during a hard 3rd gear pull, it wouldn't open the throttle bodies all the way, which I found very odd. It didn't do the same thing on a 2nd gear pull though...now I'm really not sure what the peak torque table does.

[FrgMstr]

As requested, attached are stock calibrations for a 2008-2010 Viper, and one for a 2013 Viper.

So general consensus here is to just leave the settings alone that pertain to throttle response on the Gen IV?

Also, I can load these stock calibrations posted to set those table specific to throttle response back to stock?

I am a newbie at this and just trying to learn a little more as I move along with a couple of tuners.

[MeentSS02]

So general consensus here is to just leave the settings alone that pertain to throttle response on the Gen IV?

Also, I can load these stock calibrations posted to set those table specific to throttle response back to stock?

I am a newbie at this and just trying to learn a little more as I move along with a couple of tuners.

You just need to leave the pedal % torque request table stock...you can modify the throttle % vs. area table to an extent without issue, and the jury is still out on the desired airflow (I haven't personally had the time to mess with it).

I have a running Gen 4 Viper issues/request thread here, and throttle response tuning is #1 on my list:

http://www.hptuners.com/forum/showth...ssues-Requests

I can also send you my current file if you'd like to take a look at my timing tables, my work-around for the torque management settings, and some mods I've made to the exhaust cam table.

[FrgMstr]

You just need to leave the pedal % torque request table stock...you can modify the throttle % vs. area table to an extent without issue, and the jury is still out on the desired airflow (I haven't personally had the time to mess with it).

I have a running Gen 4 Viper issues/request thread here, and throttle response tuning is #1 on my list:

http://www.hptuners.com/forum/showth...ssues-Requests

I can also send you my current file if you'd like to take a look at my timing tables, my work-around for the torque management settings, and some mods I've made to the exhaust cam table.

PM'd you my email address to send the file to. Many thanks.