02' 2500HD w/ 6.2 LS3, Poor Drivability

[AaronAutoCS]

Before I jump in, I'm not a professional tuner and I just love old gmt800's. I don't plan to tune for the public, don't wanna tune for the public and don't want the headaches of that business or clientele. All that said, truck is a 2002 2500HD (factory 4.10/6.0/4L80E 4x4) with 6,500lbs of CHONK to push around.

Engine is new, finished a couple weeks ago. LS3, Hooper Heads, 220/230's cam and 10.8:1 compression on pump gas (very tight quench) with 1 3/4 ARH headers, factory muffler, factory airbox from a 2013 (better maf) and a gen 4 square port factory intake with 50lb injectors.

The engine does well and feels like it's mapped out correctly, but my problem is the drivability. With the added cubic inches, high compression and small cam this shouldn't be so absolutely lazy. 406rwhp/388rqtq down in Victoria, Tx on a Mustang dyno. Looks great on paper, drives like butt. Transmission does strange things.


Absolutely abysmal acceleration unless you're just flooring it (light switch acceleration) and the transmission feels odd sometimes between 2-3, has random bumps and flares and has other odd quirks.
Transmission has dual feed mod and 3000 stall triple disc Circle D converter. Edit: I have two identical built transmissions, both dual feed mod, rollerized, etc. I have one Circle D triple disc 3K stall and a Precision triple disc 3K stall that are rotated out between transmissions being killed. So far, I've killed 3 transmissions. 2-3 clutches roasted, TCC applying converter at idle when hot (stalls out engine) and I blew the snap ring off the drum in the 3rd. Whatever I'm doing on the tuning side to the trans is murdering transmissions.

ReveilleLS3.hpt
File above correct, file below incorrect.

[Alvin]

The timing is pretty lazy.. are you trying to run this on 87?

[5FDP]

Who the hell put the stoich for the fuel at 12.92 if you are running 87 octane fuel that is maybe E10 at most.

That is totally wrong.

[TransGo Robert]

I can't help with any tuning issues, but if you post a log with the transmission parameters recorded and let me know what your line pressure is I should be able to tell you why the transmission keeps on failing.

[AaronAutoCS]

Thanks Robert! I just picked up a 90 degree fitting to allow access to a pressure gauge with everything in position (it's behind the neutral safety switch, but you know that) and I'll get some readings as close to 150 degree fluid temp as I can.

From what I've read, I need to manipulate the voltage to the EPC via the tune corresponding to the mechanical pressure readouts.

I can always pick up a 5v pressure sensor and log it through the same prolink pigtail as the wideband uses if need be, but as long as the pressures correspond it doesn't have to be to the tenth degree.

Thanks for taking a look everyone else- the AF change (12.9?) isn't proper, I changed it this morning and saved the different file as seen so I can easily differentiate between (wasn't sure if people would modify and repost, idk (new guy). Everything else is proper.
Also, yes it does run on 87 and was put on the dyno on 87 with the same tables you see- I did have to pull 2 degrees out on the low end between 1500-3000rpm once it got off the dyno and had to actually shove around all the weight, just ignore that and put "pump gas" in your heads instead. I'm sure it could use more timing with 93, but that's not what I built it for and it runs excellent at WOT from a standstill to 3rd, I just want to stop killing transmissions.

[AaronAutoCS]

ReveilleLS3.hpt

Here's the file as driven.

[Alvin]

Thanks Robert! I just picked up a 90 degree fitting to allow access to a pressure gauge with everything in position (it's behind the neutral safety switch, but you know that) and I'll get some readings as close to 150 degree fluid temp as I can.

From what I've read, I need to manipulate the voltage to the EPC via the tune corresponding to the mechanical pressure readouts.

I can always pick up a 5v pressure sensor and log it through the same prolink pigtail as the wideband uses if need be, but as long as the pressures correspond it doesn't have to be to the tenth degree.

Thanks for taking a look everyone else- the AF change (12.9?) isn't proper, I changed it this morning and saved the different file as seen so I can easily differentiate between (wasn't sure if people would modify and repost, idk (new guy). Everything else is proper.
Also, yes it does run on 87 and was put on the dyno on 87 with the same tables you see- I did have to pull 2 degrees out on the low end between 1500-3000rpm once it got off the dyno and had to actually shove around all the weight, just ignore that and put "pump gas" in your heads instead. I'm sure it could use more timing with 93, but that's not what I built it for and it runs excellent at WOT from a standstill to 3rd, I just want to stop killing transmissions.

I've had LS2 and LS3's pick up 40 + rwhp from 87 to 93.

The cam and compression are not ideal for what you are trying to do. The easiest fix right now would be to run premium.

[TransGo Robert]

ReveilleLS3.hpt

Here's the file as driven.

If that was for me, it is a log I need to be able to help, not the tune.

[TransGo Robert]

Thanks Robert! I just picked up a 90 degree fitting to allow access to a pressure gauge with everything in position (it's behind the neutral safety switch, but you know that) and I'll get some readings as close to 150 degree fluid temp as I can.

From what I've read, I need to manipulate the voltage to the EPC via the tune corresponding to the mechanical pressure readouts.

I can always pick up a 5v pressure sensor and log it through the same prolink pigtail as the wideband uses if need be, but as long as the pressures correspond it doesn't have to be to the tenth degree.

A transducer would be awesome of course since we could look at the log and see if the pressure matches the pressure control solenoid command, but it is not a must. All I really need to know is that the transmission is capable of doing what it is asked to do pressure wise. The rest I can all infer it from the regular PIDs in the log. So you would just have to let me know what the gauge reads under the conditions I would ask you to check.

[AaronAutoCS]

Here's what the old analog gauge had to say about things.

Park: 40-45psi idle
Reverse: 70psi idle speed, 235-260 under power
Neutral: 45psi idle
Drive: 45psi idle, 150-160psi under power.

Cruising 60mph under light throttle: 70-90psi
Light throttle (50%): 115psi
More throttle (70%): 75psi, then clumsily pops up to 115psi (sounded like it was figuring out what gear to go for)
Wide Open Throttle (100%): 140psi

slapping the throttle down will occasionally get you spikes of 170-180psi for just a split second before it settles on 140psi at wot.

Thanks for any advice/insight.

[AaronAutoCS]

I've had LS2 and LS3's pick up 40 + rwhp from 87 to 93.

The cam and compression are not ideal for what you are trying to do. The easiest fix right now would be to run premium.

Thank you for your insight, my problems aren't related to the engine, just the transmission. Not having any problems with the engine and can always swap to 93 in the future. All of my issues are transmission/tune related.

[AaronAutoCS]

Disconnected the harness and put it in drive, maximum pressure achieved is 175-180. Should I drop the pan and turn in the epc screw 1/8th of a turn?

is 180psi good enough for 400rwhp/6500lbs or should I shoot for 200?

99% of my problems are in the Force Motor Current tables and line pressures based on "gauge science" and observed behavior. The next question is what to data log to "tune" such tables and to snag a 5v pressure transducer. Yeehaw!

I did mod the force motor current tables with some data I found from kingtal0n and it has significantly improved drive pressures and feel. Truck is far better and fluid temps are getting back to "normal" instead of hitting 200 degrees in a 5 mile test drive.

Still very interested to learn the scientific way of tuning the 80 vs playing with voltages and looking at a gauge, but it's working.
All of you who have a modified 4L80e with dual feed, rollerized and other heavy modifications will need to modify the force motor current tables and shift pressures/upshift/general and performance to properly hit your targets. Unplugging the harness and checking in drive will show you the maximum pressure achievable with your setup/mods and epc.

[RDF1]

Those pressures seem to be pretty low.
On a built 80E i shoot for 210-215psi when under load. 30-35% throttle on a a turbo truck so the clutches have full clamp before it starts making torque.
And ususally 75-80 at hot idle. Ramp up to 200ish by 35% throttle and make sure it stays in the low 200s all the way to the limiter.
Havent hurt a clutch pack or case yet.

[TransGo Robert]

Here's what the old analog gauge had to say about things.

Park: 40-45psi idle
Reverse: 70psi idle speed, 235-260 under power
Neutral: 45psi idle
Drive: 45psi idle, 150-160psi under power.

Cruising 60mph under light throttle: 70-90psi
Light throttle (50%): 115psi
More throttle (70%): 75psi, then clumsily pops up to 115psi (sounded like it was figuring out what gear to go for)
Wide Open Throttle (100%): 140psi

slapping the throttle down will occasionally get you spikes of 170-180psi for just a split second before it settles on 140psi at wot.

Disconnected the harness and put it in drive, maximum pressure achieved is 175-180.

OK so aside from having only stock pressure your transmsision, it is capable of doing what it needs to do. Don't mess with the solenoid calibration screw, that's a big mistake many people make, not knowing any better. To raise line you have to do it with the PR valve spring.

So, this is all tune related like you suspected, but I can't show you what it is doing wrong since you never posted the log I asked for. With the log I could show you what is wrong and what needs to happen. Then you can tweak things in the tune to get it to command the pressure proper by comparing the changes you try with what yo see in your subsequent logs.

[AaronAutoCS]

OK so aside from having only stock pressure your transmsision, it is capable of doing what it needs to do. Don't mess with the solenoid calibration screw, that's a big mistake many people make, not knowing any better. To raise line you have to do it with the PR valve spring.

So, this is all tune related like you suspected, but I can't show you what it is doing wrong since you never posted the log I asked for. With the log I could show you what is wrong and what needs to happen. Then you can tweak things in the tune to get it to command the pressure proper by comparing the changes you try with what yo see in your subsequent logs.

Can you send a list of pid's to monitor or a quick file to upload to data log? I'm not 100% sure what all you'd like logged but will gladly accommodate. I just need to know what to record

edit: didn't touch the forbidden screw.

[TransGo Robert]

Can you send a list of pid's to monitor or a quick file to upload to data log? I'm not 100% sure what all you'd like logged but will gladly accommodate. I just need to know what to record

edit: didn't touch the forbidden screw.

Here's a channel config file that will select the transmission PIDs I need: 4L80E.Channels.xml

[AaronAutoCS]

Here's a couple of drive logs, I hope i have what you need within!

Cruise12024.hplcruise22024.hpl

[AaronAutoCS]

Working on loading it, got it

[TransGo Robert]

Tried to open your file, computer thought it had herpes and wouldn't work with it, and this is all i could see. Sorry.

LOL It is not a file you open like that, it is meant to be loaded on your computer in the channel config folder of HP tuners so that you can select it and then it will log all the pids listed in there. Do a quick Google search to learn how to use it with HP Tuners.

[TransGo Robert]

Here's a couple of drive logs, I hope i have what you need within!

Cruise12024.hplcruise22024.hpl

Those two have the PIDs i need but the sampling rate is horrible. It makes it look as if the computer is commanding 1-4 instead of 1-2-3-4. I am good at looking at log, unfortunately I have very little experience at taking them since all I do is tech support. So I don't know how to change things in there so that it record with a faster sampling rate, hopefully others can help with that.