2015 6.4L (rods, pistons, blower) e85 power delivery issues...log attached

[r2r]

Hi hoping someone with plenty of Dodge tuning experience can take a look at the attached log. Traction control was shut off in the ROM for the dyno. The pull was taken in 5th gear.

Problem - power delivery at WOT feels like surging, apply/release feeling, like it's coming from the transmission. I don't have any dyno graphs on my laptop at the moment but you can see the log. The car is using a Hellcat blower with an under drive pulley along with an electronic bypass for boost control. The issue is happening at any boost level from 0-15 psi. Fuel trims and WOT AFR close enough. I don't see any torque flags. Throttle angle stays constant. Ignition timing isn't being pulled to cause this and after getting the injectors dialed in, I also re-scaled knock sensors.

Originally the ECU was sent for an unlock to HPT by the owner and he was told that it wasn't factory stock (he's the second owner of the car) but he wasn't aware as to what had been done to the car previously. Since there isn't a segment swap function available, I built a new map set for it to reflect the mod list; 1200cc injectors, adjustable FPR with dual pump return fuel system set to 43 psi static, forged rods and pistons, new 6.4 block, stage 2 cam with VVT delete, and of course the Hellcat blower and TB with boost controller.

I don't have a stock read on the TCM programming so not sure what was changed in it previously. I made sure to raise limiters there as well to prevent the trans from causing issues while trying to figure out the problem. I ran out of time to further troubleshoot but need to go back through TCM tune to check still.

Ideas? I went ahead and pulled it off the dyno for now. Not finished with it due to the issues that it was experiencing. The 'expected torque' is far off from actual and demand torque but not sure if that plays a role here as to what's happening. Other things to note is that I tried a bunch of different strategies with torque demand and nothing changed. The boost is low in the log but again it's having power delivery issues at any boost level. Thanks in advance for any helpful input.

2015 6.4.hpl

[N2speed]

First few issues is no fuel trim info in log,
Second issue Knock Sensors are going crazy You may have them desensitized to much
Log is also only showing 5lbs of boost
No IAT Info

What Map sensor are you using?

Post tune file as well

[r2r]

First few issues is no fuel trim info in log,
Second issue Knock Sensors are going crazy You may have them desensitized to much
Log is also only showing 5lbs of boost
No IAT Info

What Map sensor are you using?

Post tune file as well

HI and thx for the feedback. I was never given a clear answer on compression ratio but it's not running much timing relative to the boost pressure. It's running e85. I did find a spot to add an external knock sensor kit and I am able to listen in and no knock. Seems like a noisy motor. In the log as you can see it's open loop, so no fuel trims. I've rescaled the injectors several times and during vacuum / light load is all good and during tip-in fueling not bad at all. The MAP sensor is supposedly a factory Hellcat sensor but it was showing 123 kpa KOEO so I rescaled it a bit to get it to read properly. I deleted IATs (from the log) because they were all good and trying to save logging speed. No air caught in the blower cooling system and temps were very stable.

Anyway, any other ideas? I've tuned a handful of these NA to FI cars now and they can be challenging, but this one is different. Back to the knock sensors, since this was a new build (old transmission but new motor) is it even possible that bank 1 and bank 2 can get flip flopped? That could cause erratic voltage readings. But like I mentioned, the primary issue is the apply/release issue @ WOT on the dyno. After pulling it off the dyno, drove it around the business park and it drives very well.

[N2speed]

You should not be tuning a modern hemi in open loop. Also add the Knock sensors back in. Logging speed is not really an issue on these unless you have a slow laptop.

Use this channel list for next log

[r2r]

You should not be tuning a modern hemi in open loop. Also add the Knock sensors back in. Logging speed is not really an issue on these unless you have a slow laptop.

Use this channel list for next log

Hi thanks for your input again. Yep you're right logging speed never seems to be an issue on these cars. I don't know why I just have a habit of limiting channels to eliminate crashes on other tuning platforms and vehicle brands and carries over into HPT/Dodge etc.

As far as open loop and closed loop fueling, I agree with you on that, but it's also common practice to get the WOT VE tables dialed-in in open loop as well, especially working through a unique setup. Once I have the injectors dialed-in in low load/vacuum and the fuel trims are close, I'll work through the rest of the VE calibration in OL. This tune isn't near finished, that's why I pulled it off the dyno and asked for assistance on this forum. Thanks again. I'll probably put it back on the dyno Monday and grab some more logs.

[FstdodgeKY]

N2speed how do you take car of the lean spot these cars get when going into boost, I've only ran in open loop because of this issue. Huge lean spot not matter what I try, anytime I start to see boost the car leans out before going into wot or pe kicking in.

[Tommerrr]

First of all, check if you are running VE or ANN

Also check:

Enrichment Rate - FA Increase

You may also need to play with Power Enrichment Delay Conditions.

[LilSick]

You should not be tuning a modern hemi in open loop.

on a dyno?

you adjust the tune to stay in closed loop when the throttle is wide open before you do a pull?

[TaylorJ]

You should not be tuning a modern hemi in open loop.

Why?

[N2speed]

His tune was in open loop even at part throttle is what I was getting at, obviously you would tune for open loop when PE is activated at wide open throttle.