How do I control DFCO entry spark? (burble tune)

[M3T1]

So, I'll start with the goal. I'm trying to make a drivable burble tune. I have gone the route of disabling DFCO and pulling a ton of timing in the main (and min) spark tables. The car drives like crap when I do this. Rolling back onto the gas is super jerky. The way I actually want it to work is I want a bunch of pops, bangs, and cracks when I let off the gas and I transition into DFCO. I'm aware I will most likely get flamed for this. I know it's not for everyone.

Now before someone says "just lower the values in the min spark tables in the cells corresponding to deceleration", I have done this. My car basically will pull timing until it hits around 0 degrees, and then it stops pulling timing. This creates some gurgling and small pops, which is nice, but I want more. That said, it doesn't matter how much lower I put the minimum spark tables, it stops pulling timing around 0 degrees. I could set the minimum spark cells to -30....no change.

I also noticed that it doesn't matter what I run in the main tables. I could have them set to 5 degrees or I can set them to 35 degrees, on decel my car just pulls timing until it's around 0 and then stops.

Now, I know the Gen IV cars have DFCO entry and exit spark control, as well as DFCO entry delay. I don't see anything like that in the Gen V tables. I'm assuming that torque management is handling this somewhere (please correct me if I'm wrong). The question is, where is this happening and how can I change it? Basically I want the car to continue pulling timing on decel down to whatever I have the minimum values set to (let's say -20 degrees for full blown gunshots). But when I roll back onto the gas, I want it to use my main spark table. I noticed in my logs that my car will sit around 0.16-0.18g cylinder airmass on decel. However, the airmass doesn't change until I'm at least 10% back on the throttle. So, if I run negative timing in those cells in the main spark tables, the car hesitates and jerks as I roll back onto the throttle until I'm on the throttle enough to increase the cylinder airmass (basically need to be at least 10-15% back on the throttle). So, as I mentioned before, I just want to figure out how/where the car knows to only pull timing on decel/DFCO entry, and I want to tell it to pull more.

I hope I have explained this well. Any help would be greatly appreciated. I've read a bunch of other threads on here, and I've learned a lot. I just still can't get the car to do what I want it to do, and my existing burble tune is pretty awful from a drivability standpoint.

Thanks!

[Jonblarc7]

it's not in the main spark table that you make the changes. Its the min spark base table and long spark. Read this thread it will help alot. I left my DFCO turned on so it burble for just a second right when I let off after hard acceleration. If I turn off DFCO it pops and bangs for to long and drives me crazy.

https://forum.hptuners.com/showthrea...e-pops-on-dece

[M3T1]

it's not in the main spark table that you make the changes. Its the min spark base table and long spark. Read this thread it will help alot. I left my DFCO turned on so it burble for just a second right when I let off after hard acceleration. If I turn off DFCO it pops and bangs for to long and drives me crazy.

https://forum.hptuners.com/showthrea...e-pops-on-dece

I am the last person to comment on that thread. @TriPinTaZ mentioned in comment #45 that he "made tunes where I changed the Hi/Lo tables as well but usually only when I disable DFCO so that it starts popping sooner than waiting on Torque Management when you lift the throttle" and that he "also had a car recently where I had to make Virtual Torque changes because they had a large aftermarket throttle body and Torque Management Advance behavior was limited on decel preventing all pops." These statements are what made me curious about how Torque Management works.

As I mentioned in my post, I'm trying to figure out how to modify the Torque Management behavior so that it pulls more timing on DFCO entry. Lowering my minimum spark tables lower than 0 degrees basically has no effect. It will stop pulling timing around 0 degrees.

[TriPinTaZ]

I make burbles tunes for a ton of people. I don't judge but it is the popular thing to do. Post your file and your mods. It takes more finesse the more mods you have. Specifically, larger throttle bodies can make it more challenging and you have to change more things than just Minimum Spark. You don't usually need to adjust the main spark tables for burbles, but I have had to on one car before. It really just depends on the setup.

On most Gen V cars I can make three levels of burbles:

#1) Moderate with great drive-ability, only snaps and pops on decel above 2500 RPM and during DFCO transition.
#2) Aggressive with still good drive-ability, crackles harder with steeper decel, DFCO is disabled so it can get aggressive and annoying.
#3) Moron mode. Terrible drive-ability. Not for daily use. But allows for you to make gunshots in the parking lot at a car meet by regulating the throttle and RPMs. It's literally really stupid but if someone pays me to tune their car and asks for it, I'll give them the Moron Mode as a second file that they can destroy their cats with. Oh yeah, def not for catted cars. It will destroy them.

[M3T1]

I make burbles tunes for a ton of people. I don't judge but it is the popular thing to do. Post your file and your mods. It takes more finesse the more mods you have. Specifically, larger throttle bodies can make it more challenging and you have to change more things than just Minimum Spark. You don't usually need to adjust the main spark tables for burbles, but I have had to on one car before. It really just depends on the setup.

On most Gen V cars I can make three levels of burbles:

#1) Moderate with great drive-ability, only snaps and pops on decel above 2500 RPM and during DFCO transition.
#2) Aggressive with still good drive-ability, crackles harder with steeper decel, DFCO is disabled so it can get aggressive and annoying.
#3) Moron mode. Terrible drive-ability. Not for daily use. But allows for you to make gunshots in the parking lot at a car meet by regulating the throttle and RPMs. It's literally really stupid but if someone pays me to tune their car and asks for it, I'll give them the Moron Mode as a second file that they can destroy their cats with. Oh yeah, def not for catted cars. It will destroy them.

I just PM'ed you haha. Thanks for jumping in!

Here is my current tune: Rob Z06 Performance Tune + C6 Burble.hpt

I am using the minimum tables from a C6 corvette in the decel region. I basically want something between option #1 and #2. I want harder crackles but only during DFCO entry.

Mods are pretty basic. I have an aftermarket intake, but the throttle body is stock. I do have a full exhaust with 2" headers. Car is totally catless. I have achieved moron mode already with the advice you gave me in the thread referenced above. The drivability does blow, so I never use it. I basically want to retain my current tune (good drivability) but have a way more aggressive DFCO entry phase.

[TriPinTaZ]

PM'd back. I can help. Yes your Minimum Spark tables are no bueno. That's why it drives terrible.

[M3T1]

PM'd back. I can help. Yes your Minimum Spark tables are no bueno. That's why it drives terrible.

I actually figured it out today. Min tables weren't the problem. As I mentioned, no matter what I set those values to, the car would only go down to 0 degrees of timing. It wouldn't pull timing beyond that. The car drives fine with the tune I sent you. It just doesn't pop enough for my liking. As you mentioned, lowering the mins AND messing with the main tables (for moron mode) makes the car drive like shit, and I think I now know why.

Basically, when you force the car to pull that much timing, the torque management freaks out because you're making way less torque that it expects under certain circumstances (decel airmass and MAP). So, it adds timing to compensate. Then, the main table continues to tell it to run something stupid like -10 degrees, and it corrects again. Rinse repeat and you get the car jerking all over the place. It also hesitates when you roll back onto the gas because under very light throttle for a brief second or two, your airmass conditions are the same, so the car still tries to run moron timing (-10) and the car continues to jerk around.

Instead of messing with the main spark tables, I was able to achieve the desired result by dialing in some new torque management settings. I watched some videos and saw that when people are tuning for more power, they update the virtual torque tables to expect more torque under higher airmass and MAP values, and then they interpolate down. That way, the torque management allows the additional timing (doesn't pull timing because it expects additional power). I did the opposite because I want the car to pull timing on deceleration. So, I had to tell the car to pull more timing in order to command less power under deceleration conditions. In order to do this, I logged some data using my base tune. I found that under deceleration, my intake cam angle and exhaust cam angle were both at 0 degrees (intake cam angle changes the more throttle i apply). So, I only messed with the torque tables corresponding to 0 degrees of intake cam. Since my car would continue to pull timing until it hit around 0 degrees. I moved the low airmass and MAP values (decel columns only) in each table up such that the expected torque for what was previously the 0 degree spark table were now the values for the -10 table, the 10 degree spark were now the values for the 0 degree spark table, etc. This basically tells the car 'in order to achieve this amount of torque reduction, you have to run -10 degrees now, not 0 degrees'. Since driver demand was already commanding that delta, I didn't need to change anything else besides making sure the minimum spark tables were low enough to allow it.

All said and done, moron mode achieved on decel, and the car is very drivable. No jerkiness or anything. It drives exactly the same, but it pops like crazy on decel. Obviously you could make more minor changes in the torque table if you don't want moron mode. I didn't mess with any of the other intake cam angles because that would correspond to acceleration conditions, and I don't want to be pulling any timing there

[TriPinTaZ]

Sounds like you got it. Increasing the virtual torque in the decel area basically tells the car that it is making more torque in that area so it will pull more timing on decel. The Minimum Spark tables are just a "floor" that Torque Management Advance is allowed to hit to reach the torque target. It doesn't mean the ECU will hit that value and the ECU doesn't switch between main spark tables and minimum spark tables.

[M3T1]

Yeah exactly. I wanted to lower that floor so that I could actually hit the minimum values I put in there (which came from an LS3 minimum spark table btw haha). I missed the old decel pops I would get out of my C6 with an LS2. They're back now! I appreciate the help man. Your mention of Torque Management Advance in the other thread is what got me on the right path. This is going to be good future knowledge as well, since I am dropping a nice lumpy cam in there this winter

[rango crackhead]

I make burbles tunes for a ton of people. I don't judge but it is the popular thing to do. Post your file and your mods. It takes more finesse the more mods you have. Specifically, larger throttle bodies can make it more challenging and you have to change more things than just Minimum Spark. You don't usually need to adjust the main spark tables for burbles, but I have had to on one car before. It really just depends on the setup.

On most Gen V cars I can make three levels of burbles:

#1) Moderate with great drive-ability, only snaps and pops on decel above 2500 RPM and during DFCO transition.
#2) Aggressive with still good drive-ability, crackles harder with steeper decel, DFCO is disabled so it can get aggressive and annoying.
#3) Moron mode. Terrible drive-ability. Not for daily use. But allows for you to make gunshots in the parking lot at a car meet by regulating the throttle and RPMs. It's literally really stupid but if someone pays me to tune their car and asks for it, I'll give them the Moron Mode as a second file that they can destroy their cats with. Oh yeah, def not for catted cars. It will destroy them.

im in a 2013 dodge durango and ive been trying for 3 days to get a loud pop and bang when i decel. everytime i change my pt spark and min spark to -20 and i rev itll keep revving up without my foot on the throttle. even at like 5-10 timing it still wants to surge (if thats the right name for it). anything you can help with?