2015 Reaper surging on acceleration

[vettemakesemwet]

New to gen 5 tuning as a whole. My personal stuff is all gen 3.

Customer has a 2015 reaper, 6.2l with the Magnuson 1900 supercharger tuned by Lingenfelter. He brought it in saying it was hunting gears, turns out there is something "surging" the TB on acceleration. Does not always happen, but also somewhat regularly. Throttle control source always says torque, and the TB is being commanded to do what it does, thus eliminating a weak TB motor and such. I'll attach a log and tune, but basically around 3000ish RPM and up, and at 50-60% throttle the TB starts opening and closing some on its own. Unsure of the cause, and need some direction here. Looked through the VE tables and the torque management/model tables and do not see anything jumping out at me. Can someone give me some pointers as to what is going on? Does in in 2nd, 3rd, and 4th.

surge log 1 03:35:55.492 after the shift into 4th.

surge log 3 right after shift to 3rd time 03:00:17.767, also again at 03:03:23.128, major one time dip at 03:03:42.554

surge 4 log 03:22:31.115 major dip but did not surge

reaperfullread1.hptsurgelog1.hplsurgelog3.hplsurgelog4.hpl

Thanks for looking and hope you can give some advice!

[vettemakesemwet]

Noticed over 100 views, but no replies. Just want to clarify, I work in an auto repair shop, not a tuning shop. Customer wants me to fix this, not take it to a tuning shop. And my personality of never give up won't let me give up.

For those of you interested, here is what I have found on this vehicle:
It is a 2015 silverado 6.2L with a supercharger added, no other supporting mods, and a body kit that I will keep my opinions to myself on.
Tune in it is a PE raped clusterf**k of a disaster that disables dynamic airflow above 1500rpm, hence no drive-ability and a ton of other issues. Went through the whole tune comparing it to a stock file to figure this out. I am by no meas an expert, but if any of you that know what you are doing looked at the tune I posted, you would probably think the same, if not worse. In short, this is a pig with a bow on it, and I want to get it to where it is fun to wrestle with this pig, rather than wanting to take it out back and slaughter it for the bacon.

I am starting from scratch on this tune, and could use some advice, and I will make a new thread asking the questions I need answered. I have been pouring over the tune, a stock file, reading everything I can get my hands on, watching youtube videos on tuning gen3-5,

I'm proceeding with the understanding that MAF and VVE need to be dialed in first just like the gen3 stuff I have experience with. Main questions I have are about what order to tune what in as there are torque tables, tq management settings, and all kinds of new stuff compared to gen 3.

So, I am thinking I need to set up the virtual torque first with the expected torque to be made with the mod(s), plus a little but not too much extra. Un-rape the PE table, and start with MAF tuning, then move into VVE, then timing, then some minor tweaks to tq mgmt and the DD table as needed.

Any thoughts on this "order of tuning"?

[wdiegogarcia]

Noticed over 100 views, but no replies. Just want to clarify, I work in an auto repair shop, not a tuning shop. Customer wants me to fix this, not take it to a tuning shop. And my personality of never give up won't let me give up.

For those of you interested, here is what I have found on this vehicle:
It is a 2015 silverado 6.2L with a supercharger added, no other supporting mods, and a body kit that I will keep my opinions to myself on.
Tune in it is a PE raped clusterf**k of a disaster that disables dynamic airflow above 1500rpm, hence no drive-ability and a ton of other issues. Went through the whole tune comparing it to a stock file to figure this out. I am by no meas an expert, but if any of you that know what you are doing looked at the tune I posted, you would probably think the same, if not worse. In short, this is a pig with a bow on it, and I want to get it to where it is fun to wrestle with this pig, rather than wanting to take it out back and slaughter it for the bacon.

I am starting from scratch on this tune, and could use some advice, and I will make a new thread asking the questions I need answered. I have been pouring over the tune, a stock file, reading everything I can get my hands on, watching youtube videos on tuning gen3-5,

I'm proceeding with the understanding that MAF and VVE need to be dialed in first just like the gen3 stuff I have experience with. Main questions I have are about what order to tune what in as there are torque tables, tq management settings, and all kinds of new stuff compared to gen 3.

So, I am thinking I need to set up the virtual torque first with the expected torque to be made with the mod(s), plus a little but not too much extra. Un-rape the PE table, and start with MAF tuning, then move into VVE, then timing, then some minor tweaks to tq mgmt and the DD table as needed.

Any thoughts on this "order of tuning"?

Hi, I'm a newbie in tuning GEN V engines and I've some experience in GEN IV, but maybe could help you to understand why Dynamic Airflow was disabled above 1.500 RPM in your tune. There're two strategies to improve performance trough tuning fuel: Speed Density and MAF Only Mode. To tune the engine using MAF Only Mode strategy you need to disable Dynamic Airflow, doing that you can make adjustements to the Airflow vs Frequency table to reach your desired AFR (comparing Command AFR versus Actual AFR).

[azsteve01]

I have had something similar. When I did a mild acceleration from a stop light my engine would surge after each gear shift and would accelerate (surge) until i backed off the pedal or sped up. My tuner could not resolve this issue and magnuson knows there is an issue but never got back to me (3 years ago) with a solution.

I put a camera on the bypass valve arm and the actuator. What I discovered was that the actuator was floating right after the gear change resulting in the bypass valve allowing more air (boost) into the engine. This was just a slight amount of additional air but enough to tell the engine to accelerate. It only did this on mild accelerations, anything strong like 50%+ pedal from the stop light it did not behave like this.

My solution was to put a spring on the bypass valve arm and connect it to the actuator mounting bracket. This forced the actuator to not allow more air into the engine after the gear shift with the results being that the engine would not surge. Every once in a while it would surge but not like it was. My overall performance was not affected that I can tell.

I really think that this actuator should either be electronic or a hybrid, unless there is a way to keep the actuator from floating. Because the vacuum at shift is unstable we will continue to have this problem unless magnuson either puts a spring internal to the actuator or puts a spiral spring on the actuator arm. Think about it this way, how well would your carburetor work if it only had the linkage to the pedal and had no spring for resistance.

PM me if you need more details on this solution.

[4wheelinls1]

Can you add the axle torque PIDs to the logger, it appears it may be making more torque than the request and the throttle is reducing to clip the torque to the request.

[azsteve01]

@4wheelinls1 Sure...if you were replying to my post.....I will need some time. I am going to exchange my device for the upgraded version. I have been sitting on this for 3 years now so a couple more weeks won't matter. I also realize my tune was done while on a dyno so it was made quick without smoothing stuff out (as I have seen some tuners discussing on youtube) so my next step is to study, read and get into this so I can smooth things out so it performs and runs better, not that I am complaining on how it runs now. Just think it could do better.

Since I am new if there are a list of PIDS you would like to be in the log, let me know and I will make sure they are there....thx