2016 Cobra Jet GT Help (logs attached)

[Dev1360]

Hey guys, long time lurker, first time poster feeling my way through this coyote platform and having a few issues. I am a tuning noob, but figuring all of this out as I go. Car is a 2016 GT with a CJ, longtubes, Twin 67, PMAS CJ intake with Flex Fuel turned on.

Car is dropping load as I climb above 7,000RPMs, but it doesn't seem to be losing power. I figured load being low was cam timing not being optimized, but after spending many hours bracketing the cams, I feel that I'm just running in circles.

Also noting that TPS shows as only 78%, but power doesn't seem to be for the worse. Predicted angle and effective area are from known-good tunes I found on here. Car drives perfectly and I have no issues with drivability. I think there is room to grow, and I am learning as I go. I have worked with a friend, and good tuner, who built this tune, but I have since started playing with it and trying to dial it in that last 20% while using it as a platform to learn on.

Car will be on the dyno soon with him so we can finish up that last bit of VCT, but I just don't feel that the car is where it should be. I don't know if it is in torque calculations, or somewhere else. I have ran out of my abilities, and just need SOME direction to go for to learn and adjust.

The logs I am posting are from me playing with different driver demand settings from files posted here. I ran into an insufficient fuel flow and had the throttle closing a bit due to torque calculations being off. I got those sorted with some DD values a little above stock. I noted that the load falls off as the vehicle transfers 100% to Mapped Point 22. That led me to change the torque and inverse table for that mapped point, but no improvement.

Am I chasing my tail on the load numbers? Do I have something wrong that it causing it to calculate load incorrectly? Is my TB even all the way open? Logs are posted, let me know what you think.

Look forward to learning. Thank you.

111111123.hpl
ddToq1.hpl
driver Demand 4.hpl

[murfie]

Load numbers are a good thing to look at and if they are dropping your torque/ HP is as well. Its not calculating load incorrectly. Load is calculated using MAF and RPM so if your load is dropping it usually means your RPMs are raising faster than your air flow. Your TB is staying open.

I would say while you do have good spark advance your borderline is higher than your MBT values. This is preventing the knock advance from adding timing in and essentially "capping" the timing or even telling the ecu to work towards less timing. With E60-E85 make sure your MBT values are 3-6* higher than borderline values. you should have your borderline values 0-3* below where the knock sensors see knock. This would be a knock advance value between 0 and -3 through out the pull. This way the ECU is keeping the timing as close to the true borderline. Running a fixed timing advance always seems to cause a flat line or drop in the higher RPMs as the fuel is not being utilized properly.

[Dev1360]

I've been watching the load numbers while initially playing with VCT, but the frustration of watching them drop at 7,000RPM has lead me down this wonderful rabbit hole of learning to tune on a torque based ECU lol.

You think I am chasing my tail, or do they look pretty normal to you? The vehicle should have plenty of air available to it. This is a very large PMAS and filter with a twin 67TB on an NA CJ car. Based on the load numbers I am hitting peak VE around 5,600 or so. Which seems right, but this manifold should make plenty of power up to about 7700 before falling off of a cliff. I was initially thinking that it has to be VCT not optimized, but I have began questioning everything the more I learn.

[murfie]

No your MAF numbers are low for your setup and ethanol.

Work on the timing and see if it improves.

[Dev1360]

Thank you for the help. I was specifically hoping you would see this! I will start there and report back.

[Dev1360]

So would you lower the borderline table or raise the OP MBT table? I noted the spark is almost always sitting in "Base". I have recently adjusted the borderline and MBT to try and get more timing. I was getting phantom spark dropping while the spark source said "base". It would hang out about 28-29 sometimes, and be at 32* other times. Having steady spark is a recent thing for me.

[murfie]

Your MBT and borderline should be swapped in the log so swap them in the tune. 31-32 for borderline and 34-35 for MBT.

[Dev1360]

Thank you very much for the help. PM sent.

[Dev1360]

tenten.hpl



Updating, played with some torque tables and changed the timing around today. In much worse DA than the previous logs, I actually saw an improvement. But I ran into some issues. "Torque Reduced..Driver demand" and "insufficient fuel flow". Any direction on those?

[murfie]

Insufficent fuel shows up when your ETC torque is much higher than your engine brake torque. ETC torque is calculated from the MAF so it thinks its going to get way more air that it can provide fuel for. You have been lowering the torque values and increasing your load values.

This usually happens when torque and load values get a little too far away from each other in their inverse relationship. You need to raise the torque values in the Y axis of the inverse tables to bring your engine brake torque up closer to your ETC torque.

Also watch your torque maximum IPC values and any other torque limit values as your indicated seems to be leveling off just above 500.

[Dev1360]

Any idea why my TPS is only showing 75%? It won't go any higher than 78% ever. Other logs lead me to believe it should be 90% at least. I've double checked max throttle angles and everything seems to be in line.

[murfie]

sensor slopes, Just remember the mono is more area per degree as well so I could make the throttle touchy and you may need to reduce the steepness of the driver demand table.

[Dev1360]

Sorry if I wasn't clear, it is a VMP Twin 67 TB.

[murfie]

Your tune had mono blade data as far as I could tell. I searched and found this tune that should have twin 67 TB data.

Bama 91P Cobra Jet GT500 TB Tune.hpt

But I also found this data and several others that say thats what the twin 67 data is so I am not really sure.

TB.png

[Dev1360]

I'll double check it when I get to my computer in the morning. I have a few tunes with the FRPP 65/67 data I can compare against. I also have a few with the GT500 twin 60 data. I previously had the twin 60 on the car. It actually ran better than the new CAI and TB.

[15PSI]

Those are the correct values for a VMP Twin 67mm TB. I have one on my car and it is exactly the same.

[Dev1360]

The picture posted is correct? Because my values on the row axis are different. Along with many others. Comparing to a few different "twin 67" files, mine is way different.

[murfie]

The area of two 67mm circles is about 11square inches. Minus the throttle blades about 2 square inches. I would guess a maximum of 8.75 effective area is correct data.

[Dev1360]

Good Log 2.hpl


Added the FRPP 65 data and tinkered with the injector data a bit. Main flow tables were correct, but the flow per second values were a tad different than the roush tune. I was impatient, and made too many changes at once to say which one did it exactly, but it worked!

Need to clean up a wheel torque error when blending to WOT and still getting the fuel flags/torque reduced message, but they aren't hurting power yet. Thank you for all of the help so far. Very happy with how today went. Also a little bit of false knock sprinkled in. Sometimes it'll pull 10* and none at all on the next pull. Exhaust hanger in the rear broke and 350 muffler is hitting the fake tip in the valance.

Car drives better with the new data, but having an issue with it idle searching and randomly dying when pushing in the clutch at highway speed. I added a little throttle angle at the bottom of the ETC vs airmass table and got it to clean up in the driveway and at low speed, but I can't get the issue solved at speed.