how much power are you guys running through your 6l90E
11-28-2008, 05:13 PM
#21
Yes I have, If your going to bump up the power 120 horses don't you think you might want to tune the transmission too?? That makes sense to me. And yes I am aware of the C3 clutch problems. I have seen pressure as low as 90 psi when C3 is commanded on. That will defently burn it up. If your not sure on the tuning of the trans, then get the ATS co-pilot.
The trucks getting a SC IV kit as soon as he's some where that can do it. (currently in western OR) Then 500+ rwhp and 1000 rwtq will be no problem. 
The Alison is a very strong tranny, just needs a little reinforcement over what the factory did. The ATS co-pilot is to much money since you still need to build the tranny to take advantage of it. Been a while since I looked into if, but iirc, $6500+ for there tranny and co-poliot, vs. $2800 for the SC IV plus install... ($7-800ish???)
11-28-2008, 05:48 PM
#22
Ya, I believe it's Powertrain Control Solutions. They've been supposedly working on it for close to 2 years and every time some one enquires to them, they are "still working on it" But don't seem to be making any progress. 
Believe me, I would like to have one of these trannies in my truck.
Believe me, I would like to have one of these trannies in my truck.
Not the 1st time this has happened to you & me both, Kyle. Or when they (Mags.) so it'll be out by the time u read this...
. Hog, Per usual on lower in a truck appl. Too bad GM didn't say, "Hey, this is going in a truck. Let's put some stronger parts in it from the get-go!! That'd be sweet!
Let's not forget torque management, gentlemen. They put the 4L60/65/70E in lots of truck applications, and the only reason it lives is because they cripple it with TM. ...
Just because the 6L80/90E is in a high-HP application, does not mean it is strong enough to handle the job. They could be governing it such that you never even get to feel the 550HP (or whatever it is) at the input.
Just because the 6L80/90E is in a high-HP application, does not mean it is strong enough to handle the job. They could be governing it such that you never even get to feel the 550HP (or whatever it is) at the input.
11-28-2008, 05:58 PM
#23
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The only reason tuning would be necessary would be if you needed to attenuate power at the shift points, to protect weak hard parts from breakage. This is exactly what the rep. from PCS is saying. Did you read what he said?
11-29-2008, 11:33 PM
#24
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Just some observations.
Any trans that is rated to handle 556 hp and 550 lb/ft of torque doesnt have "weak" hard parts.
Those ratings are almost double what a 4l60e is rated for.
Substantial tuning of these 6 speed autos is needed as shift timing MUST be exact due to the clutch to clutch design. Just because it has issues shifting without doesnt mean its weak necessarily.
The guy from PCS never said the trans was weak, he said it had shifting problems in high power apps with no TM.
Just because a vehicle has "torque management" doesnt mean that the engine NEVER produces its full rated power. The newer CERTIFIED SAE power specs guarentee that engine produce their rated power/torque
Its not such a horrible idea to close the throttle, or drop some tiiming advance for a split second during a WOT upshift.
Torque management gets so much blame for problems that it doesnt cause. Not saying that TM isnt noticeable in some instances. TM is a blanket statement for everything from lack of burnout ability, to "my trucks boggy under 3000rpm"etc etc.
1/2 of the problems blamed on TM are due to poor low rpm timng advance, smaller displacement, more agressive cam, larger 200-210 cc intake ports, not enough gearing and tall/wide tires with very good rear brakes.
My favourite TM myth is, "the older thm350 and thm 400's never had any TM".
Those transmissions never saw the power/torque that the transmissions do today. Take a 425 hp 454 with a 400 trans. Todays 4l60e is asked to handle much more power than that. Heck the LS2 is rated at 400 SAE Certified NET hp. The LS2 is an easy 500 gross hp engine and its trans is a MUCH weaker design in the 4l60e/65/70e. No wonder GM engineers decided to give it so much TM. Todays engineers are held back big time by the bean counter unfortunatley.
Allison diesel transmissions. They are designed to handle 365hp 660lb/ft of torque stock. No wonder it starts doing funky things when you add 100+hp and 300+ lb/ft of torque.
these 6 speed autos are pretty new, it will take a few years to perfect them, just like any other vehicle system.
Even the early 4l80e's were plagued with issues, lets not even talk about the 700r4 or the early 80's, which design still lives on in the 4l60e/65e/70e trans.
Lets not forget the 1999 4.8 and 5.3 engines.
The 6l80e/6l90e is just another evolution for GM. There are TCM updates coming from GM Powertrain VERY often. Just part of todays "in field testing".
If the 4l80e had a 2.75 1st gear and a .60 OD gear, it would be the perfect trans.
peace
Hog
Any trans that is rated to handle 556 hp and 550 lb/ft of torque doesnt have "weak" hard parts.
Those ratings are almost double what a 4l60e is rated for.
Substantial tuning of these 6 speed autos is needed as shift timing MUST be exact due to the clutch to clutch design. Just because it has issues shifting without doesnt mean its weak necessarily.
The guy from PCS never said the trans was weak, he said it had shifting problems in high power apps with no TM.
Just because a vehicle has "torque management" doesnt mean that the engine NEVER produces its full rated power. The newer CERTIFIED SAE power specs guarentee that engine produce their rated power/torque
Its not such a horrible idea to close the throttle, or drop some tiiming advance for a split second during a WOT upshift.
Torque management gets so much blame for problems that it doesnt cause. Not saying that TM isnt noticeable in some instances. TM is a blanket statement for everything from lack of burnout ability, to "my trucks boggy under 3000rpm"etc etc.
1/2 of the problems blamed on TM are due to poor low rpm timng advance, smaller displacement, more agressive cam, larger 200-210 cc intake ports, not enough gearing and tall/wide tires with very good rear brakes.
My favourite TM myth is, "the older thm350 and thm 400's never had any TM".
Those transmissions never saw the power/torque that the transmissions do today. Take a 425 hp 454 with a 400 trans. Todays 4l60e is asked to handle much more power than that. Heck the LS2 is rated at 400 SAE Certified NET hp. The LS2 is an easy 500 gross hp engine and its trans is a MUCH weaker design in the 4l60e/65/70e. No wonder GM engineers decided to give it so much TM. Todays engineers are held back big time by the bean counter unfortunatley.
Allison diesel transmissions. They are designed to handle 365hp 660lb/ft of torque stock. No wonder it starts doing funky things when you add 100+hp and 300+ lb/ft of torque.
these 6 speed autos are pretty new, it will take a few years to perfect them, just like any other vehicle system.
Even the early 4l80e's were plagued with issues, lets not even talk about the 700r4 or the early 80's, which design still lives on in the 4l60e/65e/70e trans.
Lets not forget the 1999 4.8 and 5.3 engines.
The 6l80e/6l90e is just another evolution for GM. There are TCM updates coming from GM Powertrain VERY often. Just part of todays "in field testing".
If the 4l80e had a 2.75 1st gear and a .60 OD gear, it would be the perfect trans.
peace
Hog
11-30-2008, 12:58 AM
#25
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None of you guys bashing them even have one! There are a few out there with 500-600hp in front of them. Longevity can only be speculated as they are too new.
So far mines holding up but I've only put a few thousand miles on it. Does anyone really think the 6L80 is weak?
So far mines holding up but I've only put a few thousand miles on it. Does anyone really think the 6L80 is weak?
11-30-2008, 01:08 AM
#26
I've always felt strongly that it's the programming and bi-directional communication between the PCM and TCM that allow these to not only exist, but also survive. I also still hold firm to the opinion that the 6L80/90-E are not as overbuilt as the 4L80-E is.
We had a productive discussion on this subject almost a half-year ago, here's what I said then:
https://www.performancetrucks.net/fo...=395010&page=3
We had a productive discussion on this subject almost a half-year ago, here's what I said then:
https://www.performancetrucks.net/fo...=395010&page=3
11-30-2008, 01:20 AM
#27
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I've always felt strongly that it's the programming and bi-directional communication between the PCM and TCM that allow these to not only exist, but also survive. I also still hold firm to the opinion that the 6L80/90-E are not as overbuilt as the 4L80-E is.
We had a productive discussion on this subject almost a half-year ago, here's what I said then:
https://www.performancetrucks.net/fo...=395010&page=3
We had a productive discussion on this subject almost a half-year ago, here's what I said then:
https://www.performancetrucks.net/fo...=395010&page=3
12-05-2008, 08:57 PM
#28
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I knew that it wasn't a good idea to argue with James B. j/k. It seems the Lock Up Feature of my Precision Industries (PI) TQ Converter has taken a crap. Frik, figures the trans is fine and the damn converter has issues. The transmission shifts fine but the lock up took a dump earlier this week.
Has anyone had to deal with PI's customer service for a simular issue?
Has anyone had to deal with PI's customer service for a simular issue?
12-05-2008, 09:26 PM
#29
Sorry to hear that. If you have the means to do your own tuning, disable Torque Converter clutch lockup entirely until you can pull the converter. The easiest way to do that is probably to raise the lockup speed to 255mph or whatever is maximum.
If you do that now it could prevent the converter clutch from overheating and coming apart fouling the rest of the trans. Keep and eye on trans temperature if you do that though, no towing and be careful on long hills - use third.
If you do that now it could prevent the converter clutch from overheating and coming apart fouling the rest of the trans. Keep and eye on trans temperature if you do that though, no towing and be careful on long hills - use third.
