MY TRANSMISSION REPAIR 8hp90

[coolblue]

Couple misconceptions here I need to mention. Track does NOT shift harder than Sport. The opposite is true actually in most cases from what I can tell. Mike taught me that a while back as well when I used to use Track myself. It's complicated, but I found a thread discussing it on the HPTuner forum for anyone that wants to read. it has to do with driving patters, G Forces, and algorithms used to determine which table, or a blend of tables, to use for shift pressures.

https://forum.hptuners.com/showthread.php?69843-A8-hellcat-labeling

The real meat is in post #9

I've looked through all the shift pressure settings in a 2019 factory Redeye and 2016 factory Hellcat tune. There actually is no pressure setting labeled "TRACK" but there is Normal, Perf, Sport, and Max. Max from best I can tell is a base table of some kind and not actually a maximum since Perf and Sport actually have settings higher than what's in Max.

Surprisingly settings in Normal are HIGHER in the 2016 Hellcat tune than they are in the 2019 Redeye tune. Maybe due to the difference in the torque converter or maybe the extra grunt had them soften the shifts a bit?? This led me to check a 2018 Hellcat factory tune and everything matches the 2016 Hellcat tune EXCEPT Normal. The differences are all over the place so seems even the factory isn't sure what they want. Comparing the Hellcat tune to the Redeye tune Perf and Sport settings they're again kinda all over the place. The big difference is nearly all the settings for "on coming ramp" which the software defines as "oncoming clutch pressure ramp rate". The Redeye oncoming clutch pressure ramp rate settings are MUCH higher values in most cases. I'm not sure if higher = more pressure or if it's a time based value where higher = longer time?? @hellno any idea what that is doing? It's in the "Shift Pressures" "Upshift" table so I ass|u|me it's pressure.

There's not a ton of difference between Sport and Perf but in "most" areas Sport has a higher shift pressure defined. I "ass|u|me" Perf or a derivative is used in Track. Sport is obviously Sport. Here's a screen shot of a few gears showing Normal, Perf, Sport for the 2-3 (top) and 3-4 (bottom) shift so you guys can see. The pressures are different in each gear, but this is a good example. This is from a 2019 Redeye factory tune:

Note it's odd that Sport stops at 516 ft/lb turbine torque where Normal and Perf have a higher setting. Not a big deal, just weird. Sport will use the last row settings for anything over 516.

View attachment 7663

Ok, I'll show my ignorance for the sake of education. I follow the charts (2-3 shifts upper and 3-4 shifts lower and the X/Y axis's of rpm and torque) but what are the actual number values representing?

 

[FFBOS]

@zhc and @FFBOS. So your saying at the end of a run at 140+ to 155+ The cars have enough braking on just the Brembo's to safely haul it down on most tracks unless there's something unusual with a really short shut off area on some tracks. Because if that's the case I would def have to say that would be easier on the tranny, motor and bearings esp. IMO. Meaning, I dk why that wouldn't be more of a known 'normal use' deal for guys drag racing with the auto.

I use z26 pads and have no issue getting it down. You will smell brakes sometimes, but I feel it is much nicer on the motor and trans.

 

[coolblue]

I use z26 pads and have no issue getting it down. You will smell brakes sometimes, but I feel it is much nicer on the motor and trans.

Must be onto something if you have 21,000 hard WOT street miles and some track time as well at that weight, power level,+ speed and tranny is still fine.

 

[FFBOS]

Must be onto something if you have 21,000 hard WOT street miles and some track time as well at that weight, power level,+ speed and tranny is still fine.

I never go WOT unless I’m in trans track

 

[72 440 Barracuda]

Wow - this is a great discussion, my Hellcat is an M6, but I am learning a lot on how everything operates. I know the newer cars have come a long way in transmission designs, but this takes it to whole new level. Auto transmissions are complicated beasts these days - this helps bring a better understanding on what's actually going on inside. Thanks

 

[Mean Cat]

Couple misconceptions here I need to mention. Track does NOT shift harder than Sport. The opposite is true actually in most cases from what I can tell. Mike taught me that a while back as well when I used to use Track myself. It's complicated, but I found a thread discussing it on the HPTuner forum for anyone that wants to read. it has to do with driving patters, G Forces, and algorithms used to determine which table, or a blend of tables, to use for shift pressures.

https://forum.hptuners.com/showthread.php?69843-A8-hellcat-labeling

The real meat is in post #9

I've looked through all the shift pressure settings in a 2019 factory Redeye and 2016 factory Hellcat tune. There actually is no pressure setting labeled "TRACK" but there is Normal, Perf, Sport, and Max. Max from best I can tell is a base table of some kind and not actually a maximum since Perf and Sport actually have settings higher than what's in Max.

Surprisingly settings in Normal are HIGHER in the 2016 Hellcat tune than they are in the 2019 Redeye tune. Maybe due to the difference in the torque converter or maybe the extra grunt had them soften the shifts a bit?? This led me to check a 2018 Hellcat factory tune and everything matches the 2016 Hellcat tune EXCEPT Normal. The differences are all over the place so seems even the factory isn't sure what they want. Comparing the Hellcat tune to the Redeye tune Perf and Sport settings they're again kinda all over the place. The big difference is nearly all the settings for "on coming ramp" which the software defines as "oncoming clutch pressure ramp rate". The Redeye oncoming clutch pressure ramp rate settings are MUCH higher values in most cases. I'm not sure if higher = more pressure or if it's a time based value where higher = longer time?? @hellno any idea what that is doing? It's in the "Shift Pressures" "Upshift" table so I ass|u|me it's pressure.

There's not a ton of difference between Sport and Perf but in "most" areas Sport has a higher shift pressure defined. I "ass|u|me" Perf or a derivative is used in Track. Sport is obviously Sport. Here's a screen shot of a few gears showing Normal, Perf, Sport for the 2-3 (top) and 3-4 (bottom) shift so you guys can see. The pressures are different in each gear, but this is a good example. This is from a 2019 Redeye factory tune:

Note it's odd that Sport stops at 516 ft/lb turbine torque where Normal and Perf have a higher setting. Not a big deal, just weird. Sport will use the last row settings for anything over 516.

View attachment 7663

Stock tunes is 1 thing but once you have a tcm tune , then I guess then it would be up to how the tuner sets things up either in Track or Sport modes , if that matters ?...& I guess the tcm tune would be at WOT mostly anyway ?

 

[motorhead]

Food for thought, you can always attempt to up the max values to avoid banging into a threshold.



Factory settings in this TrackHawk tune were 6750 if I remember right:



I am not going to commit much brain power to this simply because I don't have anything, or any reason, to test on/against. But, there are usually work-arounds in the software before a new OS gets written.

 

[Blkout]

I never go WOT unless I’m in trans track

Same here. I might play around in street or sport mode for short bursts, but its rarely ever full throttle, just 1/2 or 3/4 throttle. I don't think I've ever run the car to the redline in street mode except when it was completely stock which wasn't long.

 

[WhipCat]

I go Wot in street all the time.

 

[hellno]

I go Wot in street all the time.

I did it a little too much on mine I think 456 to redline I think the biggest problem was the initial wot kick down from anywhere from 7th or 8th in street with my 2.65 set up logging so I could check all the data the forced downshifting was too much I believe in street mode , I’ll not do it again lol

 

[FFBOS]

I go Wot in street all the time.

No bueno

 

[FFBOS]

I did it a little too much on mine I think 456 to redline I think the biggest problem was the initial wot kick down from anywhere from 7th or 8th in street with my 2.65 set up logging so I could check all the data the forced downshifting was too much I believe in street mode , I’ll not do it again lol

My tuner always advised to never let the car downshift. If I do pulls on the street I’m always in paddles. I select the gear I want and then hammer it.

 

[fubar569]

I would say based on what I'm reading here the amount of Bueno depends on how the tuner set up the Trans tune.

 

[fubar569]

My tuner always advised to never let the car downshift. If I do pulls on the street I’m always in paddles. I select the gear I want and then hammer it.

This is predominantly how I operate as well.

If I hold the left paddle to select "lowest possible gear" I will let the Trans complete the shift before applying full throttle.

Never let it downshift under anything more than part load...ever...

 

[FFBOS]

I would say based on what I'm reading here the amount of Bueno depends on how the tuner set up the Trans tune.

Yes, but the customer also has to have a clear understanding about what that means.

 

[motorhead]

I would say based on what I'm reading here the amount of Bueno depends on how the tuner set up the Trans tune.

Which is the root cause of the problem.

 

[FFBOS]

Root cause most of the time is the customer.

 

[hellno]

Root cause most of the time is the customer.

I agree it was my fault lol

 

[FFBOS]

I agree it was my fault lol

I do believe the tuners could benefit from actually having printed instructions for a guy when he picks up his car. Dos and donts etc.

 

[hellno]

When curt had me log he always had me put it in manual mode and do 4 th and 5th gear pulls , the logs I did in street mode was of my own doing just to make sure everyone knows I always raced at the track in track mode